bigtim

My Feedback: (13)

thats a huge canopy,good news about the plaster did you use a sealer over the plaster I have done reverse molds as a form to make parts and sealed them with oil based polyurathane so I could use wax as a release agent it took several coats before i got a smooth surface and the poly stopped soaking into the plaster obviously vac forming is a different animal I have been watching this thread for years and I am now eager to give it a try

acerc

I did not use a sealer and don't on other parts. The PoP has a glass smooth finish and the plastics do not have any adverse effect with the PoP. I even glassed over that PoP mold to make the frame and the PoP is still glass smooth.

aspeed

I made a mold from Durabond 90 or something like that for drywalling. It was there and looked like something to try. I painted it with three coats of enamel paint that was also lying around. I went to try it with a pop bottle and it just shrivelled up, so I can't say it was successful. I will get the right material some day though. The pop bottle plastic will use a different method. I think the powdered drywall compound will work though.

tunakuts3d

try looking for ULTRA-CAL 30 a US gypsum product. one source is http://www.reynoldsam.com/p92/USG-Gy...ter/pages.html

bigtim

My Feedback: (13)

one reason I have faith in the Plaster of Paris is when its cured the stuff is like granite, drywall mud even the powdered type is a little bit on the soft side I use it all the time for work so I am really familiar with it the stuff has a tendency to crumble when any stress is put on it when its in larger chunks it also shrinks as its drying plaster seems to not shrink out as it cures, its why I thought it might make a good mold.

aspeed

I found the mixing powder type of drywall doesn't shrink, noticeably anyway. Don't know if it is strong enough yet. I hope it works because the original canopy I took it from has been compromised since then. I use it for a first coat on the drywall because of the low shrink and it dries faster of course.

bigtim

My Feedback: (13)

please post your results I have piles of the SHEETROCK brand hot mud in my garage

aspeed

It may be a year or three, I have a shop to build and a move ahead of me. I think it will be strong enough though.