Finished my "solar kiln"

[Wilbursan]

I had to move my wood pile. It was behind my workshop and right next to the woods and was getting infested with carpenter ants and beetles. It had powderpost beetles in it before I even stacked it. I didn't get to split it until this past February so I assumed it wasn't going to be dry enough by November to burn so I decided to give the "solar kiln" a try. Below is a picture (the plastic isn't cut and stapled yet so it's a little sloppy). I was hoping this would help dry the wood and also kill off whatever insects are in it, or at least keep them away form the workshop. The wood was cut for almost a year before I split it, but it was sitting in mud (hence the beetles) and it's been drying in a shaded area that I assume wasn't getting much wind (almost touching the shop and trees not more than 10' away).

As it turns out, it didn't seem to have nearly as many bugs in it as I'd thought so that's probably not a big concern anymore. Also, I split one log to get a reading and it showed only 16% moisture. I've heard sweetgum dries fast but still, I'm pretty shocked. It almost seems like putting the plastic over the whole stack instead of just topping it would be a waste of time, but I already have it in place. I don't really see how it could do any harm though. Does anyone know of a reason I shouldn't do it?

 

[Knots]

How does the moisture get out? I had wood in a greenhouse. Without ventilation, the hot part of the day would pull the moisture out of the wood and into the air. Then, when it would cool down, the warm moist air would hit the cool glass and it would "rain" inside the greenhouse. I had to put vents in the ends up high to move the warm moist air out during the day.

 

[Babaganoosh]

I have a stack that I did with shrink wrap. It gets easily 25 degrees hotter in there than the outside air measured with a probe thermometer. If I had it in full sun I bet it would get even hotter. It also keeps the heat in longer too. I chose not to wrap the bottom of mine so water runs right out the bottom. Just did it as a quick test but it's definitely working. When I do it again I'm going to put a frame around it or possibly just tack some scrap strips of wood against the firewood and then wrap it so the plastic doesn't touch the actual firewood. That would help the moisture running down it.

 

[PA. Woodsman]

Yes like these fellas said you don't want to trap the moisture inside, find a way to let it "drain" or escape but otherwise that looks like a good idea!

 

[Wilbursan]

The moisture should accumulate on the sides after dark and run down to the bottom. I'm waiting to see where it pools up at and then I'll cut it so the water will run out. I'm not sure how well this is going to work with the wood so dry though. I was counting on it being a lot wetter. But at least it will keep the bugs out (or in).

The frame does keep the plastic off the wood. You can't see it but there is a 2x2 running across the top acting as a "crown" which should let water run to the sides instead of dripping on top.

The one mistake I kept making was not making it strong enough. I wasn't looking for anything permanent so tried to go cheap and I kept having to add braces. I wish I had put stronger braces on the ends. Right now they're just strong enough to brace the poles but next time I'll make them strong enough to hold wood. I could have added more wood if I had, not that there is much left.

Oh, I found the carpenter ant's nest. It was in one piece I didn't put on this stack. I've got dead carpenter ants all mover my driveway right now. The stuff that wouldn't fit in my rack I will stack loose on the driveway. This time it will be 20 feet from the shop and surrounded by concrete. I guess it will serve as a control. I'll test both stacks come winter and see if this made a difference.

 

[BoiledOver]

Right on Wilbursan, nice job. I am wondering if the plastic could be laid right on top of your firewood, thus eliminating any pooling and stretching on top when it rains. Do you believe a frame is critical to success? As a side note: I sit down wind of wood stacks to catch the cool air on a hot afternoon. The wood pile's mass acts like a heat and cool sink.

 

[Wilbursan]

I don't think the frame is really critical. I built this after reading about it here and most of those examples didn't have a frame. I wanted one because I wanted to stack vertically as much as possible and I wanted it to look neat. I don't have many places to stack wood so this is going between the house and the shop. Unfortunately the only places I have that get a lot of sunlight are right outside the back door, right outside the front door and the driveway.

 

[Babaganoosh]

Getting the plastic off the actual firewood helps. Where my shrink wrap was touching the firewood water got trapped and was preventing the wood from drying. I removed the wrap for two days to let it fully dry out. Wrapped it up again 2 days later.