John and I needed to ensure that we could have hardwoods that were free of PPB. We have not had a problem with them but we have been reluctant to sell any hardwoods that may cause an issue for customers down the road. We spray with DOT off of the mill but we want to take every precaution.
A little while ago we decided to build a box and insulate and heat it to do this job. We will install the rest of the insulation tomorrow. We spent longer than I anticipated to get the doors hung and trimmed today. The heat source will be halogen lights. We still need to do the corners and stain the wood.
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Looks very nice.
What are the dimensions?
When you don't have any lumber to sterilize, you can smoke a hog in there.
You'll have to talk to them that know but I think halogens might make hot spots, like a magnifying glass on dry leaves?
We are going to put a fan inside to stir the air. The dimensions inside of the insulation are 45" deep, 49" tall, and 11' 4" wide. My tractor's forks are 42" and that is the width we try to make our lumber stacks. The front insulation panel will have to be removed each time we load or unload it but it is made so that if we have a small load we can push it towards the back making the heated area smaller.
WDH, I have plenty of smokers that I can smoke a hog or several hogs on. We have discussed installing a window shaker AC, a PVC pipe pee hole, TV and a recliner and it would be the perfect place to take mini imaginary vacations to destinations like Colorado or Alaska (just stay in there bundled up until we run out of food or it cools down around here).
If the halogens do not work right for a heat source we will go to plan B.
The doors and the homemade hinges hang and swing very well. I think I will make some similar but much heavier duty ones for the kiln when we redo the doors. Removing and installing the kiln access panel is such an exercise that we seldom use the kiln.
If you heat the chamber up to 150 F, you will actually have the bulbs hotter than this in order to heat the air. You want to make sure that the electrical fixtures can withstand the heat. As wood dust can ignite at fairly low temperatures, you do want to keep the interior very clean.
Thanks, Doc. We will certainly have to watch it closely when we first start using it to sterilize to determine how much heat for how long it will take to get the box up to 150° for a day.
Would you guys please post your results here? Looking at doing the same thing.
We will certainly post results. John went home with a list of items to look for. I called a neighbor last night and may have a fan coming today. After we cut the foam insulation to fit, I got inside and had John shut it up to locate any leaks. There were not too many and we should be able to seal them up without too much trouble. We are going to have to come up with a convenient way to remove and install the insulation panels behind the doors to ensure they fit tight but we have a plan.
We still have to wire it, buy and install a thermometer, nail down the floor spacers over the joists to make room for the tractor's forks.
I am just asking why not use a couple of electric heaters? And maybe add a dehumidifier and you would have a great would dryer too.
We have discussed that too. We have a good sized solar kiln that does a good job of drying but I am not sure it stays hot enough, long enough to ensure the wood is sterilized. We even entertained the idea of adding a heat source to the solar kiln to sterilize wood. The main issue with the solar kiln is making the process of loading and unloading less of a process and more of a mundane task. I do like the trailer latch to use on the doors like WDH posted. I was going to build something like that but for the price advertised on the link he posted, ordering them seems like the way to go.
We will see how this hot box does and we may eventually use it to finish off air dried wood with a dehumidifier and possibly another heat source.
I've been using halogens worklamps for many years for aux heat, still do, and by far the best and safest heat source I've found. They are sealed, won't corrode, put out a lot of heat and don't have thermal shutdowns. The bulbs will last for a year or so and can be replaced for $5 at Lowe's. The halogen light cycle operates at a much higher temp than incandescent and the main thing is to use the same precautions you would use for them anywhere, don't back them against a wall, keep some clearance to the ceiling, and it's best to have fans moving air over them to help with the circulation.
In my L53, I've found that 4 of the 500 watt halogens, 2,000 watts is good, with reasoable heating times. For a baseline, the Nyle 200 has 4,000 watt heat strips and the Nyle L53 has 1kW. So I routinely use the halogens in the L53 but aren't needed in the L200.
Make sure your circuit can handle the load, I'd recommend no more than 2 lamps per 20 amp circuit, and don't put the breakers or switches inside the box, they will corrode in short order. Wire up some outlets outside and simply plug the lights in to the outlet. No switches to go bad and it lets you control the temps. For example, use 4 lamps to heat up, then typically 2 to maintain temps.
I also recommend the little "Sensor Push" device we talked about at the Project. It has Bluetooth connectivity, and displays the temps and RH on a graph anytime you get within wireless range without having to open the doors or otherwise disturb the environment.
It's also a very good idea to put a well insulated vent or two on the hot box, as if the wood isn't completely dry, it will give off moisture which will significantly extend heating times. So it's best to do a vent dump and get rid of the moisture laden air and the box will repeat quickly. Also, vent dumping is a good way to finish the load after heating, turn the lights off and let it come slowly down for a day, the moist air slowly exiting the vents, and will drop the load another moisture percent or two.
A Wal Mart dehumidifier 6 qt/day will work also, except when the temps go up, and will last a year to two before they die.
Thanks for the guidance. I was looking at the thermometers trying to decide which to get and I stumbled across a previous post where you (YellowHammer) mentioned the weather stations with the remote sensor.
I have been taking down a fence made of cypress boards. Some of the boards have carpenter bees in them. I am saving them for the maiden voyage of the hot box.
Carpenter bees are a good test, when "well done" they look like little black pistachios and you will see piles laying on the floor. I hate bugs in my wood.
The toughest thing to kill I've seen are those big black carpenter ants, readily found in cedar. They take some substantial heat. If you kill them, you are killing everything.
i use a homeowner W-mart one to maintain my dry wood in a container, and looks new after several years. just got ant bait Advance 375a bait and killer. kills carpenter ants and even the tiny black ones in the house. any one with plans for a carpenter bee trap, or pics. i assume they are like most bee traps. @YellowHammer (http://forestryforum.com/board/index.php?action=profile;u=11488) @customsawyer (http://forestryforum.com/board/index.php?action=profile;u=1861) . the remote weather station i.e. temp and humidity are 14 dollars on line or at W-mart. i have one working for 5 years now, just change the batteries. I think they are accurite
@doc henderson (http://forestryforum.com/board/index.php?action=profile;u=41041)
I don't have any pictures but I recently made some new traps. I used pieces of 2x6 or 2x4. As I recall I ripped it to 2.25 and cross cut at about 6 to 8 inches. I then butted one length wise to anther so the 1.5" thickness of one lay length ways against the 2.25 length of a second piece and glued/ air nailed. This formed an L shape when viewing from the end. I repeated this so I had two L shaped pieces. Then I put them together forming a box with a 3/4" square hole in the very center end to end. I bored 1/2" holes at an angle with a forstner bit in each of the 4 long sides. The angle was steep but such I could drill to the center and join the 3/4" opening in the center.
On one end I put a piece of cedar as my top, glued and nailed with a screw eye in it to hang. I had some pint and half pint canning jars. I used the center disc of the canning jar top and cut about a 1/2 " hole in it. seems I used a spade bit, some have used a sharpened conduit as a circular hole punch. Either way be careful of spinning sharp can lids and bits so you don't end up in the dumb things I've done thread. Placed the canning disc in the ring and nailed it to the bottom of the trap center on the 3/4" hole. Then screwed the canning jar onto the canning ring.
Down side it is a glass jar but I have not broken one ..... yet. I placed them around my pole barn and have only been back once since I hung them and they were working.
We have a customer build some carpenter bee traps for us, and we resell them. His design works about twice as good as any other configuration we have tried, including the ones I built. We have 8 of them hung on our barn alone and they will literally fill up in a couple weeks time.
The carpenter bees attack our drying pallets, so we cycle them through the kiln regularly, and whatever bees have tried to make a home in them get cooked, along with the mice and snakes. We don't have bees in our lumber, but they love our barn and pallets.
sam thanks for the great instructions. @samandothers (http://forestryforum.com/board/index.php?action=profile;u=18664) . @YellowHammer (http://forestryforum.com/board/index.php?action=profile;u=11488) i would love to see a pic, unless you feel it is an original design and do not want to infringe. i know there were a ton at @customsawyer (http://forestryforum.com/board/index.php?action=profile;u=1861) about 1 every 5 feet on his eves. might try to make a design of my own, but want to understands what is what. i know you leave the bee's in for a while, what do you bait it with first? sugar water? Thanks guys. guess my brother is having some eat on his house.
I'll take a pic tomorrow, it's probably time to empty them anyway. A couple tips and observations.
The hole design is critical, I believe he uses a 5/8" hole at a slight upward angle. The upward angle is very important. They need to crawl upward and they make their nest that way so, I assume, it won't fill with rain water.
The traps work best on corners, the bees like to fly around them. We have some on eaves, and they catch maybe half or less than a trap on a outside corner a couple feet away. The more traps, the more bees you'll catch. It's weird, as one trap just a few feet away from another will catch all the bees, and the next day, the other trap is doing all the catching.
The traps, although hung with short pieces of coat hanger, should not swing in the wind. The bees know that a good nest doesnt swing in the breeze to spin around, and will not use them, (until the wind dies down) so I like to mount the wire where the trap roof will rest or brace against the eave or something to steady it.
No bait is necessary, the hardest bee capture is the first. They put out a phermone or something and they make the best bait. So the worst capture results are when a trap is new, or it's just been emptied.
The little buggers are mean, they love to fight, so if a trap gets one, others fly by, see the one in the trap, want to fight, and will go head to head across the clear plastic and then they they will find a way in. So having live buzzing bees in the traps works better than having dead ones.
The key to emptying the traps, when there are literally dozens if not hundreds of bees, some still alive and really mad, is to mix up a bucket of soapy water, loosen the bottom cap (don't take it off yet) and dunk it in the soapy water and let the water come into the bottom of the trap, soaking the first few layers of bees. They can't fly with soap on them, which keeps them from chasing you down. Then pull the end of the trap out of the bucket, let the water drain out, take the cap off and again dunk the open end in the water and start swishing it around until all the bees are swimming in the soapy water. Reset the trap and get the next one.
Most of our traps are made of Poplar or cedar, and the more weathered they get, the better they work.
In the fall we throw a hunk of meat in them and they catch yellow jackets and wasps.
I have several hanging on the pole barn but as stated I have not been back to the land in a while. I'll try to catch a picture next time up there. Yellowhammer gave great detail that I can't add to.
I have made them with a 4x4 and bored a center hole length wise with a large spade bit. I had to bore from both directions to get through the length of the piece. I then bored 1/2" holes at an up angle from the bottom toward the top through the sides of the 4x4 to the center for the channel they crawl up through. I added a top and used a plastic Gatorade bottle (16 Oz I believe) and a water bottle (16 Oz I believe) to catch the bees. The top of the water bottle was used as a funnel on the bottom of the trap. I cut the top off about a half or 3/4 of an inch down from the neck. I split the short sides to make tabs to staple through. I then stapled this over the bottom of the bore neck/cap pointing down. The smaller neck allowed the bees to see the light once they were in the center of bored 4x4 and crawl through the hole but the small size would make it difficult to get back through if they tried a reverse trip to exit, though I don't know they would do this and exit the 'light'.
I cut the bottom off The Gatorade bottle. Again sliced to make some short tabs. I turned it upside down and stapled it so it covered the water bottle top on the bottom of the trap with the neck/cap pointing down. The two bottles were lined up so the center of the bottle cylinders where on the same line, concentric. The Gatorade bottle was what the bees would fall into as they climbed down through the water bottle neck and be captured. You could then unscrew the cap of the Gatorade bottle and empty. It is good to have some bees in the bottle and I did not clean often, it helps to draw others in as YH stated.
There are quite a few YouTube videos with peoples ideas for bee traps. I watched some of those and then 'winged' it!
I guess I don't have them as bad as Yellowhammer. Mine will get full and the bees will be dead. I just dump the freshest one in my hand and pour out the rest then put the fresh one back in the jar and let it go back to work.
@doc henderson (http://forestryforum.com/board/index.php?action=profile;u=41041)
Here are some pics. Although the "season" is generally over, I had them all buzzing in my traps yesterday. I didn't realize this one was already filled up to the bottom of the inner funnel.
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Ours are made the same as @samandothers (http://forestryforum.com/board/index.php?action=profile;u=18664) describes, a water bottle as the inner funnel, then either a Gatorade or 2 liter bottle as the bottom of the trap. The first picture shows two traps yesterday, about 4 feet apart, and illustrates how the one trap at the corner eave is slam full to the bottom of the funnel, can't take another bee, and how the other trap is only maybe 1/4 full. Considering I have 8 or 9 of these traps on this one building alone, it shows how bad these bees are getting.
You can also see how the corner trap kind of leans out at an angle, thats where I have it braced against the side of the building.
The second photo shows a close up of the entry hole, and its upward angle.
If there are any doubts about how bee resistant poplar is, here is the proof. Although the barn's pine framing lumber is shot through with these bees, they will not hit the barn siding, which is poplar. They just won't touch it.
Those do look familiar! I had one of the burgers drill into one of the pressure treated pickets on my deck here at the house this year. First I'd noticed here in a while.
They do cause me concern when contemplating some exterior timber frame for our home!
Mine do great too. Made a big difference. But when one of them bored into my catcher. . . . .I broke out the Hatchett. It is a restricted chemical here in GA, but it made a big dent in the local Carpenter BEE population!
Which remote weather station will stand the temperature of a kiln during the sterilization cycle? The low price one I found will only reach 122 degrees.
I use the "Sensor Push Wireless" from Amazon. It reads to over 140F but that is its rating. It Bluetooths to your phone whenever you get in range. Works great.
@YellowHammer (http://forestryforum.com/board/index.php?action=profile;u=11488)
Are you their dealer or just the cheerleader? :D ;D
I appreciate the guidance. I spent several hours reading about various weather stations and grill thermometers trying to decide which to buy. If something does the job that is good but if it is inexpensive and does the job, that is icing on the cake.
Neither,
But I did stay at a Holiday Inn once. :D
It must depend either on location, cussidness or something, I have replaced poplar with long bee tunnels in it and they hit my treated fascia boards as well as my folks. I have a white pine TF entry porch on the house and am getting ready to replace shingles on the house. I need to take the roof off the porch and pull the outer purlins that they have thoroughly riddled. They'll be locust this go round, bite this ;D.
To stray from the bee thread a bit, John and I made a little more progress on the hot box today. He came up with some 12v fans and a 12v power supply that runs off of AC 120v. The fans are only 3 amps each and about 4" in diameter but they move the air. I hope they can take a little heat. We nailed down 2" slats on 16" centers on the floor and we still need to wire up receptacles and the brown truck needs to deliver the thermometer.
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Nice looking fans. I am watching with interest your results. I feel I need something to treat lumber with.
Update: We installed two lights, each on its own metal box and one of the 12v fans inside the box. On the outside, we installed weatherproof box with duplex outlets and the 12v converter. To test it, we ran an extension cord to it and turned on two lights and the fan. In 15 minutes it went from 91°F to 107°F and then two minutes later it was down to 105°F -What the heck, man? We opened it up and found the fan still moving air but both bulbs were toast. We surmised that we should have run a heavier extension cord to power them or used something other than computer power supply cords to run from the lights to the outlets.
Anyway, a quick trip to Ace to buy some plug ends to add to some 12/2wg wire for the power supply cords and plugging in 12g extension cord and we were soon back in the testing phase. We shut the doors at 1:30 and it was 91°F inside the box. 30 minutes later it was up to 127°F and still climbing. After an hour, it had made it up to 136°F. The box is not loaded and there are some leaks in the insulation joints. I am hopeful that it will get up to temperature and that the fans and bulbs survive.
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This photo was taken prior to rewiring and adding blanks to the electrical boxes.
I have not quite figured out the quote function yet but I guess I need to go to Lowe's to buy some $5 halogen bulbs (YellowHammer's seem to be more durable than mine) and see if they hold up.
Update on the update. The temperature got up to 152°F and in a few hours from 91°F. Then, it dropped to 145°F so I opened it up and noticed one of the bulbs blew. I bought these bulbs off of Ebay a couple of years ago and they have worked well until today.
The fan was still blowing when I pulled the plugs. The 4" server fan seems adequate to keep the air stirred up in the box. Now, we just have to find some bulbs that hold up. We discussed aiming the fan at the light fixtures in order to cool them slightly while still moving air around inside the box.
Are you handling the bulbs with tissue paper or something other than your bare hand? I've been told that your skin oil on the surface of the bulb will cause them to fail prematurely, don't know if that's a wives tale or not but I play it safe and grab them with my old roller dog napkin.
Has anyone tested electric cords for how high temperature they will stand? How much heat can romex take? Do you have to run conduit in the hot box for electric wiring?
I routinely operate my kiln for several days at a time at 150 degrees and have had no issues with the wiring.
I was using nitrile gloves when I installed the bulbs, no cotton gloves here. The wire is now 12/2 wg direct burial. The next plan is to add another fan and put a fan aimed at each light fixture. The box heats up quickly and even a couple of hours after pulling the plugs, the interior of the box was 111°. It think that if we can get the bulbs to live this thing may work. The wires outside the box were not hot so I do not think we had a lot of resistance causing the voltage to drop. The spray adhesive failed that we used to put triangle pieces in the corners but the foam seems fine. Maybe we will use skewers or something else to pin the additional insulation in place.
Who would have thunk drying wood and killing stuff would be such an ordeal?
Quote from: farmfromkansas on June 21, 2019, 08:34:53 PM
Has anyone tested electric cords for how high temperature they will stand? How much heat can romex take? Do you have to run conduit in the hot box for electric wiring?
The insulation on the wires inside the romex jacket are rated for 90°C, 194°F. If exposed it is subject to damage so should be in conduit, which would be thhn wire, it has the same temp rating.
In an empty kiln, the bulbs will get a lot hotter than in a kiln with lumber. The lumber keeps the kiln air cooler, as the lumber "uses" the heat.
But you do need good air flow around the bulbs to allow for the heat to be carried away, with or without lumber in the kiln.
As it appears that your bulbs are over heating, the wires right at or close to the bulb can be over heated too. Check the insulation to see if it is dark and brittle. With the flammability of wood dust at low temperatures, a smoke alarm is a wise choice, if it will work in the kiln humidity and temperature. If the alarm goes off, DO NOT OPEN THE DOOR before you have water running in the fire fighting hoses, as opening of the door adds oxygen and the fire can explode in an instant. Also, make sure you have a gfi circuit and that the fuses at close to the expected amperage draw, so if the wire insulation fails, the fuse will pop off. You might even want to have a circuit that is automatically going to be shut off the bulbs when the fans are not running. Kiln fires do occur.
Using halogen bulbs does have a fire risk if something goes wrong.
Thanks, WoodDoc. I will check the wire insulation for discoloration and probably add another fan and direct the airflow of each fan across the cooling fins on the light fixtures.
I don't recognize those halogens. They may have been intended for a different configuration. They should not be burning out so fast and your wires should not be discolored. They seem mounted awfully close to the back wall.
I use standard Lowes/Home Depot/Amazon self contained 500 watt work lamps. They don't need forced airflow but it wouldn't hurt. The yellow one pictured below cost $17 at Home Depot, is rated for 2,000 hour bulb life and the bulbs can be bought online for Lowes/Home depot for less than $5. They can be used with extension cords if desired. They only require 18 ga wire and you are using 12 ga, so thats should be plenty for these lights.
The 500 Watt bulbs are available from Home Depot for $6.74 ($3.37/bulb) for a two pack of bulbs, but I found some online for less than $1 per bulb.
The one below looks better, its available at Northern, costs $15, has a one year warranty and comes with an extra bulb.
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They should last as long in your hot box as they would sitting on your garage floor. I routinely get to 150°F chamber temps with these and hold for days if necessary.
Fans are a good idea to move the hot air around the box, and to keep any localized hearing down.
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In this picture, below, where I was working on my L53 refrigeration system issue some tine ago, if you look up on the fan baffle, which looks like a shelf, you can see two of these lamps sitting on the shelf, on either side of aluminum kiln structure. So the install procedure is just put them on the shelf and plug them up. The one on the left has the cord dangling, so is easy to see.
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I checked the wiring today. It looked fine. Tomorrow, if I have time, I will install another lamp, a little further away from the wall (after wiping the bulb down with alcohol-maybe someone in Asia touched the bulb) and add another 12v fan blowing across the cooling fins of the lamps and see what happens. This should not be so difficult. Someone today suggested using the heat lamps, 250w but I doubt they will be any more effective than what we are using.
If this fails, I will just go to the store and shop for some that look like the ones Robert uses.
Yellowhammer, thank you for taking the time to post pictures of your setup and the lights. Those lights look like they should do the trick.
The advantage of these types of cookie cutter halogen work lights are they are fully sealed to prevent dust and corrosive moisture intrusion and also protect the bulb from any wind or breeze.
John bought the last three halogen work lights that the Lake Wales Rural King store had for $4 each today. They are changing to LED work lights. I was going to run up to Zephyrhills, which is 15-20 minutes from my place but the RK there was sold out. I mention this in case some of you have a Rural King nearby and may want a good deal on a work light.
I bought 10 of those yellow frame halogens when Menards was closing them out. Got 10 because did not know how many I need to heat up the old reefer. Hope it is enough.
I didn't realize the halogens were being phased out in favor of LED work lights. It makes sense, but bad news for this application.
I need to stock up if I can find some clearance lights like you guys are finding.
$4 is a great deal, wow.
Caveman, That's a great looking kiln.
Can I see a closer picture of the hinges?
Thanks
Jon
The cords were only about a foot long on the lights so I wired in longer wires so that we could unplug them outside of the building.
The hinges were made out of some metal I had lying around, 1 1/4 or 1 1/2" angle, 1/2" cold rolled, whatever pipe fits it tight and 2" flat bar. I want to make some for our solar kiln and get rid of the access panel and just have two swinging doors.
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After installing the work lights this morning, I turned them on and one of the `3amp fans. It took 3-4 hours to heat up to 152°F while empty. I did not seal up the foam joints. Mainly, I just wanted to see if the lights would live. The work lights use the same bulbs as the light fixtures we were using. The next step is to seal it up a little better, load it with wood with bugs (I laid a cypress board on the ground last week and it has termites now and the carpenter bees are still in a few of our boards) and see what happens.
Thanks to all who offered guidance. Hopefully this thing will work as intended.
Kyle
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Excellent.
You'll have crispy critters before you know it.
might make good snacks for the pig roast!!!
Quote from: doc henderson on June 26, 2019, 08:26:02 PM
might make good snacks for the pig roast!!!
Waste not want not :D
Update on the box. We finally loaded it up with some live oak slabs that had been in the solar kiln until Friday morning. With two 500 watt halogen lights and a small 12 v fan it took until yesterday morning to reach 135° F. By 6 p.m. it was 145° and holding at 146° this morning. I will let it run the rest of today and leave it closed up until tomorrow. The last couple of days have been cloudy/rainy and very humid. That may have had an affect on how long it took to get to temperature.
The next thing to do before using it again will be to add another light or two to bring it up to temperature quicker (like Yellowhammer does).
One of these days we may get around to building proper barn doors for the kiln and then I expect we will use it more. The panel, that I thought would be so simple to remove and install, has been a major pain in the neck. The hot box door hinges were simple to build and with bigger material or more of them, they should work well for the kiln.
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This worked really well in my mind but in operation there were too many variables. The ground and the kiln need to be in the same plane, turning the front tires will move the panel several inches even when not moving forward or back, the sandy ground is easily disturbed by turning tires resulting in holes, our header sagged a bit which makes installation even more challenging and from the tractor seat it is difficult to get it aligned perfectly without a spotter on the ground. I show this to help someone else choose a simpler path.
Glad it worked, but I agree, throw a few more lights in there. Make the circuit breakers groan an little. :D
Since you can hold the temps at 1,000 watts, you can boost the speed with a couple or more lights to get up to temp quicker, then unplug all but two and maintain the temps.
I would think instead of making a full QD plate on the side if you made only a top to hang it may be easier. then it will be more likely to rotate and set into the mount easier.
I often wonder why some of the attachment plates are such a tight fit left to right. That sure makes it a pain to get lined up perfect to lock into the equipment.
Getting the tractor attached to the plate is relatively easy. Getting the wooden panel centered perfectly between the two doors is more challenging.
We added another light to the hot box. It does help bring the heat up quite a bit quicker than two lights. Two lights will maintain the temp around 150°. I would like to seal it up a little tighter as it does have a few leaks.
I opened it up tonight to look at a small stack of maple that I put in there yesterday morning.
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This thermometer pic was taken the other day. Tonight it was 152° after turning of one of the lights several hours earlier.
As I finished looking this thread and decided to go feed the furnace I thought of these as an alternative heat source for a kiln instead of halogen lights.
Its a 450 watt adjustable Trojan Hot Scott heater. Used in livestock waters to keep them thawed in winter. This one is one that w as retired, when the old hog fountain waterer started leaking. New drinker has a different heat system. They are adjustable, hold up to tough damp conditions. Not very expensive. Just a quick thought as it was on the shelf in the basement.
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Those heat coils are intended to be underwater. I wonder how they would hold up in the air?
@Nebraska (http://forestryforum.com/board/index.php?action=profile;u=45256) it looks like it will work. I think cause you mentioned the hog fountain and with the corrosion it looks like it was under water. I blew up the pic to read the label, and it looks like it is designed as a space heater. It is nice that is has a thermostat. I think the brand name implies it is supposed to be covered as well.. :D :D :D :D ;) .@Crusarius
Well the underside of a 20+ Year-old hog fountain is a very wet nasty place.. a hot box or kiln would be a walk in the park for this little dude. I usually only got two seasons out of them . It sat on the cement pad about 3 inches below the stainless water pan. They always go bad when it's zero or worse makes for many magic words when changing them .
I thought those were intended to be in the water?
No with pictures of the old hog waterer unit you'd understand, but at work now. It actually set inside the unit under the water pan, on a a couple bricks and heated the space underneath keeping the water above thawed as well as the valves and supply line that comes up from the bottom through a 12 inch cement culvert, set below frost line. @Crusarius (http://forestryforum.com/board/index.php?action=profile;u=35059) , @doc henderson (http://forestryforum.com/board/index.php?action=profile;u=41041) .
One could also use an old electric range as a heart source take off/prop open the oven door lots of variable controls, but lots of watts, yes it would eat kiln capacity and yes it's ....Redneck.. you betcha... but easy and cheap to a fault. Easy bake oven style, cook your chicken and grits in the kiln. 8) 8) ;D
Nebraska, we don't find too many surplus stock tank heaters here.
I do have a question for those who heat sterilize slabs with bark still attached. Do any of you see fire ants move into the kiln or wood after heat treating?
The last two small loads of bark on, live edged maple we have run in the hot box were held at or above 150°F for over 36 hours. When the heat cycle ended and the slabs were left in the box for a few days, there were fire ants which seemed to be feeding on something between the wood and bark and some frass was present which was not there at the end of the heat cycle. We suspect the ants are showing up to eat dead bugs. After a few days the ants leave but we can't really tolerate them. I am relatively confident that the temperature shown is accurate.
We will probably spread Talstar around and under the hot box before we run another load.
Thank you for your suggestions.
The highest sugar content area is near and between the bark and wood. Heat does not destroy the sugars.
Thanks, that is what I was thinking too, but I wanted to read it from the expert (s).
I have had fire ants get in my kiln dried pine that was shot full of dehydrated pine borers and eat them.
I also routinely have to put spetracide fire ant killer around the bottom edges of my kiln where I must have some slight leaks because the fire ants really seem to like those edges.
Does anyone else think this post has been extremely informative. The forum has a wealth of detailed info on kilns and drying which I refer to regularly but this last step, while it gets mentioned regularly, does not seem to get as much detailed info and ideas. I have found this one to be very beneficial on detailed practical application of building a hot box. Just wanted to thank everyone that participated.
Was at the local Good Will store a while back, and they had a couple of hot plates. Would those work for a heat source?
YellowHammer...Fire ants like dry, dark places especially when raining. So, your kiln with a nice roof and maybe good drainage, provides a good nesting spot. They also like to eat plants or animals...they are omnivores. So, maybe the area around the kiln was turned up when building and so it attracts earthworms.
@farmfromkansas (http://forestryforum.com/board/index.php?action=profile;u=36643) I don't see why not. I bet they aren't expensive, and you won't be out much for trying. My little heater (hot scot) from the old waterer is 18.00$ new at the local hardware store, I was curious after I posted about it before so I went and checked. On line they are higher. I also decided I need a clone to do the projects that appear in my head while I read stuff in threads like this.
Quote from: YellowHammer on November 09, 2019, 09:55:57 PM
I have had fire ants get in my kiln dried pine that was shot full of dehydrated pine borers and eat them.
I also routinely have to put spetracide fire ant killer around the bottom edges of my kiln where I must have some slight leaks because the fire ants really seem to like those edges.
Borax mixed with sugar is much cheaper
Got any pictures of finished kiln?
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These are what I have for now. The inside was lined with 4" thick Styrofoam and the top initially had 4" also but a week or so ago, we removed the tin and added 4" more just because we had more foam. With temperatures in the low 50's outside it was no trouble to get to 160° with three lights to set the pitch on some heart pine recently. We may make another similar to this but next time we will probably cut the foam to fit between the studs, now the foam is just pushed up to them. The box is not air tight but it does the job. The slabs on the bench are some maple slabs that we were sterilizing.
I'm glad the lights worked out for you, I have tried many different things but these just seem to work best with the least amount of fuss.
So 3 lights, or 1,500 Watts is all that's required for you. You didn't even have to use any chickens. Nice.
Very nice 👍
Oh, he better hold on to the chickens. He will surely need them.
How dry was the lumber you used?
The pine we just pulled out of it was air dried as low as it would go here and was at 9% a week after we pulled it out. It probably gained a little moisture over this week in the shop.
That's a good point, the hot box can be used like a conventional kiln by venting the moisture laden heat periodically. I do it post sterilization as a way to fine tune my finished moisture levels.
So, it is all about money.
1500 watts of electricity is 5000 BTU per hour. In an insulated box with vents (or a kiln), about 1/2 the energy input goes into evaporations for water, 1/4 into building heat losses, and 1/4 into vent losses. (A dehumidifier will eliminate or greatly reduce vent losses, adding the savings to the amount of evaporation.) A typical batch of lumber of 500 board feet will lose about 14 pounds of water for a 1% MC loss. (Oak is more and soft maple less, etc.) Each pound requires 1000 BTU for evaporation.
So, 1500 watts of energy (lights or strip heat, etc.) or 5000 BTU per hour of gas or oil heat (not counting losses in the heating device, such as a gas furnace) will in a kiln or typical hot box evaporate 2.5 pounds of water per hour or 60 pounds per day or about 4% MC loss from 500 BF per day. Note that 1500 watts might cost 15 cents, which is $3.60 a day 90 cents per 1% MC loss. For air-dried lumber coming in at 27% MC and ending at 7% MC, that would be $18 for 500 BF. (A dehumidifier would reduce this to $10 but a DH unit has higher capital cost than bulbs or strip heaters perhaps.)
@GeneWengert-WoodDoc (http://forestryforum.com/board/index.php?action=profile;u=20498) I really appreciate how you are able to speak in practical terms as well as scientific specs. thanks for all the knowledge you bring to the forum. And Merry Christmas to you and your family! :christmas:. how about solar with fans, is there a ballpark on 500 bf, and cost to run the fans?
Are you thinking of squirrel cage fans? With one or two gerbil power? Thanks for your comments
:D maybe a dog chasing a cat, or cat chasing a mouse. Tom and Jerry comes to mind. I was really thinking of the standard VT kiln with box fans x 3, and such. I was surprised at how cheap even the dehydration kiln was to operate. It suddenly was clear, and I was hoping to add the comparison of electric cost to operate the solar kiln. I assume it is cheaper than a DH kiln. Best regards Sir.
Generally, the fans for a given amount of wood will be the same whether a hot box, DH kiln or solar kiln. In the VT 1200 BF solar kiln, a 20" box fan, high quality, will use perhaps 70 watts, so running 12 hours a day and using two fans, would be 17 cents a day (or 6 cents per day per 500 BF as the previous posting was for 500 BF) or three fans, 25 cents (8 cents per day per 500 BF), assuming 10 cents per kWh. In a DH kiln, the fans run 24 hours a day, so double. Of course, the DH kiln dries every day, while a solar only works when outside is above 50 F and the sun is shinning.
The lumber you used to build your kiln was air dried down to 9%?
Is it a must to put foam board insulation over fiberglass?
Foam board (closed cell so it will not absorb water) that will withstand 160 F or hotter without "melting" is fine by itself. Or else fiberglass by itself is ok with an added vapor barrier to avoid any moisture in the insulation, destroying its R value and getting so heavy it will sag and decay is also likely. I have seen some fiberglass used, but it is put into a big, thick plastic sealed bag to avoid moisture issues.
Dean,
The wood we used to build the kiln was a combination of green and somewhat air dried. We just overlapped the boards for the exterior walls. If we do another we will probably do a proper lap siding or at least cut rabbets. There is no fiberglass in ours. We put some 2" chicken house foam between the floor joists and lined the inside with 4" Styrofoam. The top now has 8"-9" of Styrofoam. The front foam panels are just pulled out before the box is loaded and installed afterwards. It has leaks but I think that helps any air dried wood we put in there finish drying.
I think we paid $70-$80 for all of the Styrofoam as found on CL (8-9 4'x8' sheets). If it eventually breaks down we can probably get more. The guy who sold it evidently has it regularly after they use it for its intended one-time use at his job. It has small, melted, very precise lines cut about every 4" that are about 1/8" deep.
We have been talking about building another box but making it a solar kiln that we can heat sterilize lumber in. Our solar kiln is such a hassle to open and close that we don't really use it much even though it does a great job of drying wood.
Wood Doc:
Appreciate the hard data on drying costs ( 12-9-19). My question is: Is the drying of green lumber a linear or exponential function ?
Thanks for the help.
Drying time for lumber twice as thick takes about 2.5 times longer. Drying costs go up in that proportion as well, which is why we seldom kiln dry thicker species starting at a green MC, as the time is too long. A rough rule would be that the kiln dried lumber needs to be about $25 per day more valuable than green lumber...example, 10 days of kiln drying x $25 means the KD lumber should be at least $250 than if the same lumber was sold green. This same approach is what makes air drying so attractive...save two days by air drying the wettest piece of lumber that much drier will save $50 per mbf.
We had a pile of cedar slabs and cookies that were air dried down to around 15% but there were small, scorpion looking bugs between the bark and the wood so we gave them a few warm days. We were not quite able to get all of the cookies and slabs into the box but we pulled them out today and there was no sign of bug life.
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Cool. The oniy good bug is a dead bug. Cook em all.
now you gave me an idea. I have been paranoid to sell any wood because of the bug situation. Maybe I need to build me one of these hot boxes just to sterilize it. Then I will not feel bad letting some go.
has anyone tried those livestock heaters in a similar system?
There is a ton of information on this thread. As a longtime lurker on this site I appreciate the depth of experience that you all bring to the table.
Has anyone considered mounting a propane wall heater like you would put in a barn or workshop. They make them vented and unvented. They put out a ton of heat and require no wiring. They do have an open flame inside the cabinet but I wouldn't think this would be a huge safety hazard since they do have a thermostat so the unit comes on and off. Even though you are heating wood the environment is not dusty with a lot of airborne dust.
I would love to hear your thoughts.
Having an open flame in an enclosed box of dry wood would concern me to the point that I would locate it well away from anything else that could burn in the event that it does catch fire. That way you will not burn up your barn, workshop, yourself, and your loved ones.
Quote from: WDH on February 16, 2021, 07:40:37 AM
Having an open flame in an enclosed box of dry wood would concern me to the point that I would locate it well away from anything else that could burn in the event that it does catch fire. That way you will not burn up your barn, workshop, yourself, and your loved ones.
As a commercial HVAC guy I agree completely. If the oxygen supply is not correct the heater won't work properly anyway. They require proper clearances and ventilation to be safe. Not worth the gamble.
If proper installation procedures, material restrictions, and backsets are maintained it should be work as an extra heat source to sterilize wood. They have heated many spaces safely, ( we used to heat the old hunting camp with a couple of them) They actually sat on the floor with some feet on the carpet never thought much about them. They had a low oxygen shut off and the old trailer house we had leaked plenty of air. The combustion by products of burning propane properly are water vapor and CO2. The space would have to maintain fresh air venting to function. I don't know how/if it would effect the drying process via raising humidity and such in a kiln, solar or otherwise.
The climate in a kiln is extremely corrosive. I've had many different heat sources that I've tried and the only ones that didn't fail relatively quickly, from days to weeks, were the completely sealed systems, like halogen lights. Otherwise, switches corroded quickly, wires rotted, not to mention relays, thermostats, fan housing, bearing, pretty much anything that could corrode, would corrode. Also, the elevated temperatures in a kiln will cause the life of normal parts to shorten drastically. A kiln of a hot, acid place for a machine to operateI. I would be very careful about putting any heat source that could fail catastrophically and cause your kiln to burn down. Electric systems have external breakers, internal breakers and such.
Thats why I am partial to the Halogen lights. They get very hot, put out heat, they are completely sealed, even the switches and can be operated in a harsh environment.
When I posed this question my thoughts were along what Nebraska had said as far as my experience with these heaters. Reasonably safe when used with some common sense. However I had not considered considered the corrosive issues of the environment or the issue of adequate oxygen to burn. I just figured the Btu's per dollar were cheaper in the long run.
It sounds like halogens are the way to go. However with all of the halogen lights getting replaced with LEDs I'm afraid they will become as rare as the old corkscrew light bulbs. I guess all we'd better stock up on them while they are available.
there are also the little 20 buck heaters you can get at WM. plug in, no flame, some forced air. tip over switch, I am not sure if they cut off at a high temp. handle on top. we have one in our pool house for the winter.
I bought some one dollar halogen bulb replacements at Harbor Freight a while back, they were a dollar each or 2 for 3 dollars. Thought that was funny. I bought the dollar ones. Can't help it, i'm Scottish.
This is the first run of the hot box since John and I redid some of the insulation inside. One of us ran it a little too hot and melted some panels. It seemed to do okay. I turned on the lights (heat source) when I got home Wednesday afternoon. The air temp was in the 70's. It was getting down to the high 40's-50's at night. Yesterday afternoon it was sitting around 148° and late last night had only dropped to 143° while it was in the high 40's outside. Today, the inside temp was 154° and the outside air was in the 60's although up near the metal it read a little higher.
We still need to seal it up a little better. When I walk out there at night, I can see a little light shining through the cracks. (https://forestryforum.com/gallery/albums/userpics/22883/278311CC-F8D7-4B4B-B2E3-B22455FEA823.jpeg?easyrotate_cache=1642191303)
Has anyone tried the ceramic heat lamps as an option just asking :)
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Paul Q,
What are ceramic heat lamps? I have not heard of them unless we use different terms around here to describe them.
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They are used for reptile cages as warming or basking lamps. Theu are on Amazon. They come in several wattages. They screw into a light socket like a light bulb. You can use the old fashion ceramic socket.
I am putting the finishing touches on my kiln and heat for sterilizing is the last thing. I thought about those ceramic heat lamps, but went with a 1500 watt 6 foot baseboard heater with a clothes dryer type 155 degree shutoff switch to replace the one in the heater.
Going to install it this weekend. My fans alone generate enough heat to get to 100 degrees. My kiln is very well insulated and sealed.
I'm not an electrician, reading YH's post and looking at the specs on this, would you put a 15 amp breaker on the black line outside the box? It should carry it running but if it corrodes and shorts to case it'll pop the breaker just above that normal running current.
Quote from: farmfromkansas on February 16, 2021, 09:55:24 PMCan't help it, i'm Scottish.
Prove it. Wear a kilt through the winter and be regimental(no underwear). smiley_jester ;D
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Don, Your observation about breaker size and current draw are only a guess at this point.
There is not enough information given by Broncman relating to the 1500 watt baseboard heater. That heater could be 115 volt plug in type (although I have mostly found 4 foot [1000 watt] in the real world) or it could be 230 volt hard wired type of heater that is designed to be permanently mounted to the wall.
In my kiln I use 230 volt heaters that are mounted directly to the wall and hard wired in place with conduit.
YellowHammer is correct in observing the harsh area inside an operating kiln. I also use halogen light fixtures that plug into outlets. All of my heat sources are controlled by thermostat.
Back to Don's math exercise and that 1500 watt heater. Let's pretend that the heater is 230 volt unit. 1500 watts divided by 230 volts = about 6 1/2 amps. We are not allowed to load a circuit more than 80 % of the breaker & wire size capability. So the smallest breaker (fuse) would be a 9 amp double fuse (2 pole breaker). . . . awkward.
Since most folks have normal fuse boxes or breaker boxes in use, we will probably use a 15 amp 2 pole breaker and 14 gauge wire size (or larger wire size is ok). The breaker would connect to the black conductor as well as the red conductor. No white conductor. The green conductor is for ground.
The breaker box and all control circuits (electronics ) will be outside of the kiln chamber in ambient fresh air.
On the other hand (four fingers and a thumb) we need to ask how much heat is needed for what purpose . Is 1500 watts enough to sterilize wood? This is a topic for another day.
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I'm about where y'all are at...picking the best heat source for the final bug-killing phase.
For context, I'm a hobbyist, a knucklehead, and low-volume (lumber, that is). For you "production" mavens with customers and ledgers, none of my thoughts are remotely useful. I'm also focused on Red Alder 2" slabs for now b/c, A) I have lots of them, and B) if I can dry them w/o horrendous splitting, then my Doug Fir slabs should also be fine. The slabs have been air drying outside for 1.5 yrs in about 75% relative humidity, so I'm likely looking at mid-teens moisture content to start with.
So I'm making a smaller version of this dude's garage dryer from "Logs-To-Lumber-Now".(Simple DIY Wood Drying Kiln - YouTube (https://www.youtube.com/watch?v=FVdteRwTPIQ&t=0s))
[FWIW, I was focused on the Virginia Tech (VT) solar kiln for quite a while, but 4 things talked me down: 1) I'm not doing a lot of wood, nor for a long time (just wanna remodel the house, so counters, some furniture, island...); 2) VT dude says solar kilns are not great for bug killing; 3) VT dude also says solar kilns are not great for thick slabs; and 4) I live in the PNW, so optimal solar kiln running conditions are less frequent.]
So assuming the garage dehumidifier version, I'm going to go with just the dehumidifier to begin with, and maybe a small fan. The dehumidifier (which we run in the house regularly) produces a good deal of heat and air flow all on its own. Not too fast, not too slow, that's what I'm looking for. There's so much natural tension in Alder grain, it will be most unforgiving of impatience.
Once the dehumidifier has done its thing, I'll do the fan + heat source thing with a temp controller set at 150 degrees. If I can hold 140-150 for 12 hours, I'll consider the slabs clean.
That's my plan! I'll follow up with results when I get some. Any wise, "Ohhhh, that's not going to work b/c...", I'd really love to hear it!
I have a dehumdifier kiln I built from USDFA plans. It has back wall chamber that acts as an air diffuser for the stack. Fans mounted on top.
I took a long baseboard heater, bypassed the high temp cutoff. Use an inkbird controller.
The controller has a programmable function that will hold heat cycle to a programmable temp for a programmable time.
I set it to 150 degrees for 24 hours. It has a display to show you how many hours left at temp.
I also have a 4 inch vent fan I can program for high temp or put on a timer if needed.
So far the baseboard heat mounted by the fans has worked good.
I think 150 for 24 hours is the standard, and that is likely for 4/4.
For hardwoods I recommend 140°F for 24 hours.
K any increase in time for thicker slabs?