Building a solar kiln during this corona virus lockdown

farmfromkansas · March 29, 2020, 10:29:35 AM

Woke up this morning thinking about doors and hinges. Have some barn door hinges, seem pretty light to me. Also have a bucket of house door hinges, 3 1/2" x 3 1/2". Thinking about welding a piece of strap to give them length. They are steel, with brass plating, so could just touch the grinder to them to clean off the brass. Also thinking about doors, seems it would be a good idea to make the doors so the outside layer of ply would overlap the opening, make the framing 1/4" gap all the way around, then add about 1" top and bottom and sides to help with weather sealing. Have some BB form ply, thinking about that for the outside of the doors. 3/4" thick, and very weather resistant. Used once. Would just put a piece same thickness on the wall to make the offset where the hinges mount.

farmfromkansas · March 30, 2020, 10:22:23 AM

Question about wiring, do you put romax in the wall, with a box cut in the outside for a plug, or what? Was looking at btulloh's build thread, didn't see any post about what do do with wiring. Did think I would steal that idea of cutting a 45 degree board on the front wall, probably a 2x6 so the rafters would seat down right, so would have a double plate on that front wall. Will have to cut off all the rafters I have ready, but good idea. Then would not have to cut little pieces between rafters.

btulloh · March 30, 2020, 10:43:51 AM

Wiring is another opportunity for self expression. I put two duplex boxes inside and ran emt. Just ran out through end wall to a disconnect box. I just used disconnect box to control fans at first but now they are controlled by relays which are automated and can also be controlled remotely. I'd say wire it however it suits you and your particulars.

Planman1954 · March 30, 2020, 10:49:35 AM

When I built mine, I put an electrical outlet near the ceiling for fans, and one near the inlet box on one end for a dehumidifier. I used 12/2 w/ground house wire between them. Then I put a weatherproof box on the end outside next to the dehumidifier outlet and connected the two. I mounted a regular male plug to the outside box wire. Then I just run an extension cord from the house and plug the kiln in.

farmfromkansas · March 30, 2020, 02:01:32 PM

Another question, when you paint the interior with the basement tar, do you roll the floor as well?

GeneWengert-WoodDoc · March 30, 2020, 02:28:01 PM

There is so little sunlight that will hit the floor that a floor coating is not beneficial from a solar point of view.

Why use tar? Flat black paint should do the trick. I used a aluminum paint first to form somewhat of a vapor barrier and then the black paint.

farmfromkansas · March 30, 2020, 07:01:51 PM

Gene, the Virginia Tech plan shows 3 choices for a interior coating, and one appears to be plastic roofing cement. Other posts are using basement waterproofing, which I refer to as tar. Have some buckets of both, also think I have a bucket of the aluminum roofing paint, which contains some tar.Also have some white elastomeric coating, which I planned to use as log end sealer, that I could use, but wrong color.

GeneWengert-WoodDoc · March 30, 2020, 08:40:38 PM

Of the three listed, use the one that will be dry, so you do not get black every time you bump a wall.

Marshall7199 · April 04, 2020, 09:47:53 PM

FarmFromKansas, I too am building a kiln during these historical times. I am building a dehumidifier kiln in a previously constructed shed. It is 2 x 4 construction with 1/2" chipboard walls, with R-11 insulation. 6mm polysheeting used as a vapor barrier I am finishing the basic construction and considering the sealing of joints and seams with caulking. As for the interior coating, considering a KILZ primer with an exterior grade paint to seal the 1/2" sheeting.

Have notice the interior coating suggestions and wondering if anyone has used typical exterior house paint. House paint has sealing properties, and is designed for wide temperature and humidity applications.

GeneWengert-WoodDoc · April 04, 2020, 11:15:27 PM

The coating should be flat black in color and reflectivity. It would be helpful if the coating had some water vapor resistance to transmission. Can you find flat black acrylic latex? That would work. Otherwise, use aluminum paint for the sealer and then flat black interior latex for the top coat.

farmfromkansas · April 05, 2020, 10:46:36 AM

During my building days, the paint companies advised builders that latex paint did not seal, and when we used bare wood, we were to coat both sides, edges and ends with oil base primer, as the primer is a sealer. The paint lasted a little longer over oil base primer than over latex primer, but still was not great. That is why this engineered wood trim is selling so well, as the paint lasts. I would think a product that is water proof would be a better interior sealer than latex paint. Can you paint over the white elastomeric roof coating? Menards has it on sale occasionally for 49.99. My project is getting near a coating, have insulated 3 walls, put on the plastic sheeting and have part of the interior covered with sheeting. Battery gave up on my truck yesterday, spent half a day getting it replaced at Walmart. The computer would not let them replace it under warranty, finally gave me a receipt and said I could go. Only guy in automotive was in the bathroom when I got there, must have fallen in and couldn't get out.

GeneWengert-WoodDoc · April 06, 2020, 12:39:18 AM

Today, acrylic latex does a nice job of sealing. The old-time latex paints were not acrylic.

tacks Y · April 06, 2020, 07:45:14 AM

I used basement coating. It is latex went on good and does not rub off, 5 gal and black.

farmfromkansas · April 11, 2020, 09:33:35 AM

Thinking about fans this morning. Have a couple 20" fans with metal blades I bought at Menards last year, but also have a used furnace blower. The blower is a squirrel cage fan, and I used one like it to push air through my solar collectors on the big wood dryer, and it moves a ton of air. Would one of the furnace blowers put enough pressure on the solar kiln to circulate enough air? Maybe better than 2- 20" fans?

GeneWengert-WoodDoc · April 11, 2020, 09:42:43 AM

Two fans are better than one, as they distribute air more uniformly than one. On the other hand, with lumber under 25% MC, air flow numbers are not very important...you need some air throughout the kiln, but the amount does not influence drying speed at low MCs.

DDW_OR · April 13, 2020, 12:07:30 PM

late to the party, as usual.
Following. mine will be in a fixed location on concrete blocks
estimate 540 blocks available to use. 4 in a four foot square
should i use tar paper between the blocks and the un-treated wood
longest i can cut on the mill is 21 feet. yes i know i can cut longer by sliding the log on the mill, or buying or making the extensions.
also have some 4x6 box steel that my dad was going to use to make a frame machine to straiten car body's for his autobody shop.

so a kiln 24 feet by 10 feet. short side at 4 foot

Sedgehammer · April 13, 2020, 06:23:29 PM

Quote from: farmfromkansas on March 25, 2020, 08:34:13 PM
Doc, Menards has the twin wall poly for 40 some dollars per sheet, but it is only 6 mil. Plan to pick it up on a 11% off day. Have not purchased it yet. Last thing to go on the kiln. Got the floor laid today, forgot how hard it is on an old coot to work. All I can think of is laying out the walls and framing, but too tired to start.

The VA Tech plan is 8' 6 3/4" slope if I'm readin the plans correctly. That take a 10' sheet. Either 4' wide or 6' wide. $67 and $100. Not sure where you are seeing it for $40.
How does that hold up to hail? Anyone know?

farmfromkansas · April 13, 2020, 07:41:49 PM

It is a 4x8 sheet. Stock stuff. Special order is more expensive. The paperwork says it has a 10 year warranty, fine print says 5 years, and then is prorated for next 5. Last year is probably about zero. Warranted from hail, etc. I am thinking of shimming above the first sheet, and overlapping a piece from top down over the first sheet.

Sedgehammer · April 13, 2020, 07:44:25 PM

Ahh k. That'd sure be cheaper. Long shim though, but easy enough. Over lap 6" with 2 beads of caulk?

farmfromkansas · April 20, 2020, 08:29:37 PM

Want to check if there is a recommended way to butt or overlap, but just figured to over lap a couple inches and use screws through the lap, having a 2x4 on edge under the joint. Someone recommended no caulk, just screws through the sheets. Working on my doors, have 3 pieces built, allowing 1/4" between the sections, bifold doors. Wonder if anyone could post what the gap between the doors in the middle should be? Probably will just hang the 3 pieces ready, then take a piece of 2x4 to try to figure out what the 4th piece should measure. Trying to keep them close enough to use weather strip between the sections.

farmfromkansas · July 23, 2020, 09:14:17 PM

Wet weather has allowed me to get the kiln close to finish, ready to build the baffle, would it be better to run it straight up and down, or angle it to push the air down along the glazing?