Vaccuum forming
 

Is there a spot on here for Vaccuum forming? If not, should we start one?

I have a question on plugs. What are people using to make the plugs? If you have a canopy you want to copy, is there something you can pour into it and make a plug from that? I have a great forming machine, but have never used it. Got it from a friends estate and I don't know what he was using. Would love to make some canopies for some of my stuff. Any info would sure be nice.

Thanks.

Vaccuum forming
 

The best thing I have found for copying a canopy (making the plug) is Durham's rock hard water putty, you can get it at like Home depot. Buy the big can, it's a powder you mix with water, mix a big enough batch to fill the canopy all at one time. Make a frame to support the canopy. Once you fill it keep tapping it against the table to get the air bubbles out. It will take 24 hours to cure and it will pop right out. Sand or file off the flashing around the bottom of the plug and give the plug a good sanding with 400 + grit paper otherwise you will have problems pulling a vaccum under the plastic. This is the best stuff I have found for the price, the best thing is Hi temp metal filled epoxy big $$$.

Lance

Vaccuum forming
 

When I already have a canopy that I want to duplicate, I use a powder that the model railroaders use. It is called "Hydrocal". It looks exactly like Plaster of Paris but cures very quickly (gets warm while curing.

I bought my vacuum forming machine because there are so many plans out there that would make very nice planes but without a source for a canopy. In those cases I have made molds from balsa and used strip of 1/64th ply to replicate the canopy framing. The only problem I have had with Balsa molds is that I don't know what to use as a finishing material over the balsa so that it will be 100% smooth. I have used clear dope but that sometimes leaves a residue on the inside of the canopy.