ORIGINAL: LesUyeda
Dion. From the looks of your plastic frame and fasteners, we might have read the same book.
This was my first attempt at vacuum forming. The task was a challenge, but the results were gratifying. I glued up the flat pieces, turned it upside down, filled it with plaster, shaped the "dome" and pulled the plastic. Instead of molding the frame into the canopy, I pulled two canopies, cut out the "windows" in one, painted it and glued it in place.
Les
Thanks Les for adding your canopy technique! I agree that the easiest and best way is to add the frames later with a thinner white styrene. I wanted to make my canopy look more commercial, and having ridges built in makes it stronger, but again it's not necessary. Your's looks very nice!
-one question though, after you make the plaster plug, do I have this straight that you cover the plaster plug with the styrene? Then the styrene makes the clear canopy smooth and doesn't melt from the heat?
thanks again.
Kelvin.
Good question Kelvin, in my experiments if you pull .040 white styrene over the plug and sand it, then glue it on with 3M spray adhesive it will last for up to 3 or 4 pulls before it has a tendency to bubble. If you get the PETG to hot and over the 120 degree working temp then it could harm the styrene you have on the plug. If you use a lighter PETG like .030 and .040 white styrene on the plug then you can pull as many as you want, I never found the limit and I made a bunch of them. It's when you have the same thicknesses on the plug and clear that you will run into problems after a few pulls.
The frame to hold the plastic, is that just Aluminum angle?
Does the depth of the Vacuum Box make a difference in making a good pull (4" depth is better than 2"?)
What is black on the top of you vacuum box?
YAT-28E I got the frame idea from Chad here on RCU, it's just aluminum angle bent and pop riveted, works great.
You should not make a deep box, the less air your vacuum has to take out the quicker it will draw the plastic. In fact you don't need a box at all, just a board with a hole in the bottom. You will need to use small sticks or something to keep the canopy up so it won't block the vacuum hole. Use weather strip as a seal. My box is about an inch and a half deep and it works great.
The top is 1/8 inch tempered Masonite, I took the time to drill all the little holes! It's important to have enough holes in the top for a good pull, also it must be supported from the bottom with some small posts.
YAT: Micro Mark sells a book for about $15.00 on vacuum forming, that is well worth the price. Answers all of the questions that you haven't even thought of yet.
Wish I would have got the book instead of learning on my own! Here are my latest experiments with plugs, one major failure to report! I thought that I would first cover the plug in resin, spot putty and primer, got it real smooth (should have stopped there!). Next I painted it with Ford Blue engine paint, it says it takes the heat, up to 500 degrees, what I didn't know was that it also sticks BETTER than glue to PETG plastic![X(] Look at what it did to my plug!
Next picture, what kind of advanced finishing system would one need to finish a plug for a clear canopy? You must be thinking that it's some space age finishing system? NO! Try Wal Mart $1.79 a can dirt cheap primer, Brite Touch! I was getting frustrated so I finished the Corsair canopy quickly, first I cover the plug with finishing resin, hit it with some primer, not even finishing it with more primer, just got it real smooth... it worked! I could not believe it, I had my other plug in the same primer and if I had just sopped there I would have had a perfect plug for forming[:@]!
Well that's it on this, if I do anything else I'll post it here. Please post your work on this thread also, I would like to see what others are doing, maybe we can learn some new techniques!
Thank you everyone,
Dion