more solar kiln questions

Handy Andy · February 08, 2008, 10:15:12 PM

Weather hasn't been cooperating for building a saw shed, so thought maybe I would build a solar kiln. The ash I have about all has borer holes in it, so looks like I need to cook my ash as soon as it is sawed. Anyway, found a link to the VA Tech solar kiln, answered a lot of questions, but still have more. Have some patio door glass planned for the glazing, measures 34 x 76 , one piece 28 x 76, so on the 45 degree angle, only allows for about 4'4" in width if it hangs over 1" top and 1" bottom. Now could hang it down from the top and fill in with roofing or siding, but what about the gaps between the glass? My experience is that you need something to make a joint out of to seal between the two sheets, rather than just caulking and fastening a board over the crack. Hard to seal, you see. Anybody know of a good way to seal the joints?

pineywoods · February 09, 2008, 10:29:05 AM

Andy I wouldn't worry about air-tight seals. the door gonna be leaky anyway. Just so it doesn't leak rain water. Mine is nowhere near airtight and it still works just fine. There's whole bunch of threads on here on solar kilns. Use the search button to find them..

Handy Andy · February 09, 2008, 08:08:46 PM

I built a solar room once, with slanted glass. Couldn't keep the thing dry. There has to be some way to seal between the glass sheets. Last time just used silicone caulk and 1x3's over the seam and caulked before I put the boards on. The boards warped up and would not stick down, so I caulked again, but never was water tight. OK, it was pretty tight but one drip would drive me nuts. So, I figured there must be some gasket type system that would work. They used to build all kinds of greenhouses out of those sheets. Jim

pineywoods · February 09, 2008, 09:20:23 PM

I sorta cheated on the roof. Mine is polycarbonate sheet (Lexan). regular greenhouse roofing.
Down here in the south, I would be skittish about using glass, too much hail.

Handy Andy · February 10, 2008, 11:03:57 AM

Already have the glass. Waste not want not. I read Ben Franklin's autobiography 35 years ago, still going by his system. JIm

gharlan · February 10, 2008, 07:03:26 PM

Handy Andy just use something besides wood to make the seam. The silicone would work great as you did before but use something that will not warp up in the weather. Just make sure it is clean and apply the silicone ( denatured alcohol works well as a cleaner). The silicone will take about 24 to cure but is your best easiest bet. Gary

Don_Papenburg · February 10, 2008, 09:08:24 PM

Use the windsheild tape for autos/trucks . Clean the glass first ,it sticks real good then .( If you are overlaping the glass.)

Check out Resourse conservation tecnoligies They have skylight gaskets . several types.

Handy Andy · February 11, 2008, 05:22:50 PM

That Resource Conservation Tech co has some cool fittings for using insulated glass.
Just checked out their website. Think I'll go with the windshield tape on this project. Thought if I built a new house before i die I'd like to build a sunroom on it. Those fittings look like they would really work for a dry sunroom. JIm

timcosby · February 14, 2008, 03:42:08 AM

PUT 2X4 rafters in between each sheet and put a rabbit cut on each side for the glass to lay in the silicon caulk.

Fla._Deadheader · February 14, 2008, 07:50:49 AM

Be sure to put an angle or block of wood or something at the base end of those double glass doors, to keep them from sliding down.

When I built the attached sunroom-greenhouse on the south side of our house, in Arkansas, I cut rabbits for the doors to set down in, ala Timcosbys comment. Used Silicon caulk, and a Red Cedar batten, screwed down against the glass, using ¼" lags. Aluminum angle pieces to "hold" the panels. Worked really well. Don't overtighten those battens.

I had glass panels with NO aluminum frame. They had been changed out for tinted.

Handy Andy · February 14, 2008, 08:08:39 AM

Have seen some of these built with the glass just overhanging with nothing holding it but the silicone. Figured I'd have to brace it temporarily till the silicone drys. Mine is glass only. Have picked up some of this smart board, manufactured trim board, maybe it wouldn't warp up and leak. Was thinking of just putting every other panel on, and spacing in about an inch on each side and putting windshield tape on the edges and lapping the between panels right on over the edge of the others. Probably less chance of a leak to just put glass over glass, and caulk with silicone.

Fla._Deadheader · February 14, 2008, 09:40:16 AM

Without the aluminum frame to hold the glass panels together, the extreme angle of the panels, in relation to the suns rays, the glass COULD slip loose from it's sister panel. Mine did. It released the Nitrogen, and the panel would fog up about ½ way, during the day. It would sweat and condense inside the panel, so, I drilled a hole in the sealant to allow the condensation to drain. I would remove the plug every few days, to drain the water, and cut down condensation.

That's why I suggested something to hold the panels from slipping.

What are you planning for the supports to hold the panels ? If wood beams, Tape might not hold ??? One panel on top of another, I'm not experienced with that. :

???

Seems like it's just more to go wrong, if something happens ???

Handy Andy · February 15, 2008, 08:31:46 PM

If you don't like the idea of gluing one panel over the edge of the other, could use some of this smart board trim I have picked up. And just put the grooves in the rafters and then put the smartboard over the seam. Probably doesn't warp like wood. If you examine it, looks like masonite siding, only made into boards for fascia and corners. when you cut it, it has a center of wafer board. Anyway they are using the stuff in place of wood on the new houses around here. Have a friend building, and I raid his scrap pile once in a while. If you lose the seal in the glass, why not just drill a couple very small holes and forget them? Wouldn't leak enough air to really mess up your insulation value would it? Pella windows have holes in the sashes to keep them from fogging up, on their windows with double glaze panels. And storm windows have to have a small vent to prevent fogging between window and storm.

Don_Papenburg · February 15, 2008, 09:17:09 PM

Jim , You will have diffferant troubles with the wafer wood . It is going to swell up and disintagrateas it wicks water into itself. Plastic wood trim subsatutes have to have room to expand as they heat up. Real woods or aluminum would be your best bet all around. Just install them to run wateraway.
That windsheild tape has a tenasious grip it will hold a lot but glass is heavy and will slideif you do not have some sort of mecanical support . such as FDH sugested.
I use windsheild tape to make my own thermal windows . I have a triple pane that has been in service for 25+ years it is holding up great no foging . one other thing if you use silicone to glaze in factory thermalpane it may degrade your thermal seal . Put a metalic tape over the seal area to isolate the silicone from the seal.