Wood? What were you thinking? Yes, I know it is an easy material to build with, but stop and think a minute…you have an open flame that is approaching 3800 degrees F…wood generally ignites at around 575 degrees F…this is not a safe combination.
Yes, I know Michael Barley built his out of wood. Do you have his same experience? Have you been working with a torch for as long as he has? Just because he did it, does not mean you should.
But all is not lost, the hood can still be used, you are just going to have to be a bit creative. You will need to line the inside of the hood with galvanized sheet metal. You will need to ensure that there is a minimum of 1/4″ spacing between the metal and the wood, you can achieve this by using stacked washers. But be sure that there is absolutely no wood exposed anywhere where it could possibly be touched by the open flame of the torch.
Another somewhat common building material used is aluminum faced house insulation board, in fact one particular forum administrator recommends its use for “ease of construction”! WTF??? House insulation board usually contains isocyanates, which, when exposed to open flame, generates cyanide gas! Do you really want to have something right next to your face that will instantaneously poison you if you accidently have the torch flame touch it? I think not. The manufacturer of these boards specifically state that they are not to be used in any situation where exposure to flame may occur.
Please, use common sense when selecting material to build your hood or workstation enclosure.