One could make an mast autoclave from steel piping. Not sure what the cost is now but should be around $1000 for a 40 foot section in structural pressure steel 0.4' in wall thickness.. Flanges each end will give a seal to a few atms.. make the mold to slid inside .. a long heating element small fan .. compressor and a few hours work by a boiler maker. just dont ask me to pick it up!