How to steam balsa wood?

Question

I'm building a bridge out of balsa wood and need to arch the top piece. I already have a thick wood cutout of how i want the arch to be shaped. Question is, how do i steam the balsa wood with enough heat to form it permanently. Someone suggested getting rags piping hot in water, then pressing the rags on the balsa wood. (sandwhiching the balsa wood between my wood cutout and the rags.) any other ideas. I have no clue.

Thanks!!

Answer 1

I agree in part with Mike. Balsa may be light weight but it certainly isn't strictly porous. I disagree in part with rags however. I'd probably soak it and lay it out on a pre deisgned table with blocks and braces to form it to the radius you need.

On a light hearted note I prefer my balsa Boiled rather then just steamed; it's far more digestible that way.

Answer 2

I am not sure I would try, because balsa is so weak and takes so long to water log (see Kon-Tiki - the balsa raft). I would think pine or basewood would be a better choice.
In any case, the easiest way is probably to get a length of PVC pipe big enough to easily hold your wood and long enough and a tea pot or tin can with hole to get a stream of steam off the boiling water. Use rags to stuff the intake so the steam flows the length of the PVC. Add the wood and stuff just enough rags in the other end to allow exit of steam but delay it. You will need rags to support the tube also. Try the flexibility of wood periodically till you learn how much "cooking" is needed. Steam will soften a lot faster (more heat) than hot wet rags and will do it more evenly.

Answer 3

There are several other options you have to steaming the balsa to form the arch.

First, you can try brushing a solution of 50% denatured alcohol and 50% water on the balsa. It causes the balsa to become very flexible.

Second choice is to build the arch using thin strips of balsa laminated together until you get the desired thickness. Put wax paper by your wooden form and glue each strip of balsa with carpenters glue as you stack them.

When you buy the balsa at the hobby shop, buy 1/16 strips or sheets of what is called contest balsa. It is very light and has a good grain pattern .

Answer 4

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