iDRY Vacuum Kilns

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Hot Box

Started by caveman, June 07, 2019, 08:53:44 PM

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YellowHammer

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.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

K-Guy

@YellowHammer 

Are you their dealer or just the cheerleader?  :D ;D
Nyle Service Dept.
A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
- D. Adams

caveman

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.
Caveman

YellowHammer

Neither, 
But I did stay at a Holiday Inn once. :D

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Don P

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.

caveman

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.  


 

 
Caveman

samandothers

Nice looking fans.  I am watching with interest your results.  I feel I need something to treat lumber with.

caveman

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.


 This photo was taken prior to rewiring and adding blanks to the electrical boxes.
Caveman

caveman


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.

Caveman

Don P

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.

farmfromkansas

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?
Most everything I enjoy doing turns out to be work

WDH

I routinely operate my kiln for several days at a time at 150 degrees and have had no issues with the wiring. 
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

caveman

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?
Caveman

Don P

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.

GeneWengert-WoodDoc

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.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

caveman

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.  
Caveman

YellowHammer

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.  



  

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.



 

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.  



  

YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

caveman

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.

Caveman

caveman

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.  

Caveman

YellowHammer

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.  
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

caveman

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.
Caveman

farmfromkansas

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.
Most everything I enjoy doing turns out to be work

YellowHammer

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.
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Weekend_Sawyer

Caveman, That's a great looking kiln.
Can I see a closer picture of the hinges?
Thanks
Jon
Imagine, Me a Tree Farmer.
Jon, Appalachian American Wannabe.

caveman

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.

 

 
Caveman

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