More clarification on pressure cooking the burls:
Pressure cookers (Canning Pressure Cookers) are set at 15 psi. Please make sure that if you use a pressure cooker that it is modern, meaning that you have the rubber plug that will pop off if you get too much pressure. So you have the weight that regulates the pressure and the rubber plug.
Also, you do not want the burl to be sitting on the bottom. The pressure cooker will come with a bottom grate or riser. This is what I use to keep the burl off the bottom.
You do not want the burl to rest in the water but rather steam the block. This is what helps to stabilize the burl and keep the color.
So in my 36 quart pressure cooker I will put about 4” of water in the bottom. Yes it is hard to avoid some of it getting in the water.
Either way waxed or fresh you just place the block in the cooker. I would imagine that if you use the wax blocks you would not be able to dye T-Shirts but never tried it.
Cautions: Don’t let the pot run out of water and make sure the safety button is in place correctly.
The first time I did this I was a bit apprehensive because I had never dealt with pressure cooker. But now it is old hat.
Enjoy! And if you have any more questions just let me know and I will do my best to answer you.
-- Greg, Southern Oregon, www.oregonburls.com What can I say but God Is Good!