Thursday, June 14, 2012

Small Solar Bamboo Kiln

Love solar stuff!  Here's a cheap and I bet very effective solar kiln idea for small amounts of bamboo or other wood, or make it big as one wants...


It kind of even looks like bamboo haha!  Ok what I imagine is sections of the black metal woodstove  flue pipe from the hardware store, however long one wants, assembled with wooden rings added as spacers on the outside and simply covered with greenhouse plastic.  Caps, maybe wooden plugs on the ends or maybe foam with a vent hole or two, have to experiment and figure that out.  But I guarantee this will get hot enough just sitting out in the sun.  Fill it with stalks and just open an end to check on them periodically. 

Want it hotter?  Make a V shaped trough for it to sit in that's been lined with reflective aluminum foil and align it East/West.  Easier even would be a split piece of larger pipe with reflective lining, sort of a solar parabolic trough though not a true parabola.  Sufficient enough for our purposes I bet.

What's this got to do with boatbuilding?  Well I read we have to cure bamboo by some method. Open air seems to be too long and kiln drying seems to be my personal best option but I don't need a whole big room for it. 

I'm not sure, but knocking out the center culms with a long metal bar would seem the thing to do, to allow air flow and lessen splits.  Will try some knocked out and some not.

Update same day:  Did some price checks.  One 3ft length, 6" diameter section of black stove pipe is $8 at my local hardware store.  Not everywhere is going to have this stuff and it's more expensive than I thought originally.  Got a different, better idea.  Corrugated metal roofing sheets!  Easy to roll up into a cylinder shape and rivet edges together. New is $15 for 10ft locally.  Can spray paint the finished tube flat black.  Just happen to have two slightly used sections with a few screw holes but should work ok.  Stay tuned for updates to this post.

Update later same day:  Did I say easy to roll up into a cylinder? Anything but.  Two or better yet three people would not have any trouble throwing one of these together.  A lone fabricator must improvise.  Started out with riveting both sheets together but could not roll it by myself. Ended up removing the rivets and rolling one at a time.

If you get it this far you almost got it whipped but not quite...


Getting to that point took borrowing a length of 6" diameter PVC pipe from the water dept., used as a form to roll the material around and hold the edge with duct tape.  The pipe also serves as backing when drilling for the aluminum rivets.  Kept feeding the pipe in a bit and drilled close to where the edge was located inside...


All riveted, 19' 4"...


Overlapped 8" and double riveted all the way around and about every linear foot. Nice and snug, very lightweight right now.  Will be cutting out the plywood rings to fit over for attaching the plastic cover and painting the cylinder flat black.  Thinking maybe R-Board foam caps for the ends. Wore me smooth out for today so check back later. :)

Update 6/16/12

Trip to bamboo forest.  All I can say is wow!  It's a huge thing, almost impossible to get to and worse trying to walk out with just a few pieces.  Sorry for the cruddy cell pic...


It doesn't look so big in this pic but it's the biggest I've ever personally seen.  The grove is badly overgrown and would benefit alot by some sound management for bigger and better quality culms.  Came away with five nice pieces at 16ft to try in the kiln...


Update 6/19/12

Kiln is complete and loaded with green bamboo culms.  Pretty hot in there, 120F in just a few minutes so we'll see how hot it gets and how well it dries/cures the fresh cut culms...


To be continued...






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