Vacuum Kiln Construction

[BuffaloJones]

Looking to make a vacuum kiln. I have access to some 24" diameter corrugated outer and smooth inner HDPE for free. Does anyone know if this is a suitable material to use to hold a vacuum? I have access to a machine shop to cut ends flat and fabricate some steel plate to cover the ends. Just not sure if HDPE is suitable.

[Posty]

Hi
I tried that this past summer. It didn't work for me. It sucked it in like an accordion at 20hg.

[Erik A]

Part of the strength of hdpe pipe is the material compacted around it to hold its shape. Put something around it to hold its shape and it may work! 

[Erik A]

2nd thought, cut open the spaces in the ribs and fill with something like concrete, and I think it would hold its shape.

[nativewolf]

We built a prototype.  The only thing that I know to really survive a vacuum is a propane tank.  There are previous threads on another propane tank conversion effort, from England I think.  
Once idry came out we scrubbed our effort .  That product works and the price is very compelling for what it offers.   I consider the idry the most interesting product in drying in years

[Stephen1]

Sometimes it is better to let the experts build and I use. 
Years ago we put a stainless 45 gallon drum under vacuum for the sugar bush, it didn't make it .
I do know now, vacuum is more destructive than pressure in tanks. 

[ronwood]

A friend of mine and myself built a small vacuum kiln using a stainless steel tank. tank was 18 in in diameter and 36 in length.
Even thou it is small we cut out the wood  for a project and put it in . Trying to refine the process and working to add additional  instrumentation to the kiln.  Will provide some pics when I can get them.

For our use it works great. If I was drying larger amounts of wood  i would consider the idry.

Ron