Vacum, forming tips
09-10-2008, 10:33 AM
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Vacum, forming tips
I am about t6o have to make my own windows for my cub what is the best plastic and easyest to get for making these parts, Can Plexiglass work for this?
09-10-2008, 08:05 PM
#2
RE: Vacum, forming tips
You can use almost any type of plastic for vacuum forming. My personal choice is PETG. I get mine from US Plastic - their trade name for it is Vivak
http://www.usplastic.com/catalog/cat...ookie%5Ftest=1
US plastic also has some very good prices.
Tips:
Get about 5 - 6 times the amount of plastic you think you will need for your first pulls. You WILL BE MESSING UP.
If at all possible make your plugs from pine (or use plaster of paris to make a plug - plaster of paris will need to dry in the mold for several days, then after removing it from the mold put it in a 150 degree oven for 2 - 3 hours, or let it sit for about 10 days to completely dry ).
In any case, you will want to add a 1/2" - 5/8" REGULAR PLYWOOD to the plug. The backing should taper from about 1/32" - 1/16" at the plug to about 1/4" out from the plug. The backing helps make the plug more rigid, provides a cut line and give you something to put screw eyes in for pulling/leverage if the plug decides it doesn't want to separate from the plastic. I use a GENEROUS amount of thick CA to fasten the backing to the plug.
Make your plugs as smooth as possible. The least little defect in the plug IS GOING TO SHOW and if the plugs are not smooth they will be harder to separate from the plastic.
I typically use about a 2" "slump" in the plastic for forming my parts (I normally use .030 and .040 for forming parts).
I also keep my heat gun right next to the vacuum box so I can heat any problem areas immediately so they will pull in.
If your part is "webbing" (forming wrinkles) the plastic is too hot.
If the plastic is not pulling down completely the plastic is not hot enough. I use a 5 gallon shop vac (minus the bags and filters) for a vacuum source.
It will be a trial and error thing for you to determine the correct amount of slump for the type and thickness of plastic you are using.
http://www.usplastic.com/catalog/cat...ookie%5Ftest=1
US plastic also has some very good prices.
Tips:
Get about 5 - 6 times the amount of plastic you think you will need for your first pulls. You WILL BE MESSING UP.
If at all possible make your plugs from pine (or use plaster of paris to make a plug - plaster of paris will need to dry in the mold for several days, then after removing it from the mold put it in a 150 degree oven for 2 - 3 hours, or let it sit for about 10 days to completely dry ).
In any case, you will want to add a 1/2" - 5/8" REGULAR PLYWOOD to the plug. The backing should taper from about 1/32" - 1/16" at the plug to about 1/4" out from the plug. The backing helps make the plug more rigid, provides a cut line and give you something to put screw eyes in for pulling/leverage if the plug decides it doesn't want to separate from the plastic. I use a GENEROUS amount of thick CA to fasten the backing to the plug.
Make your plugs as smooth as possible. The least little defect in the plug IS GOING TO SHOW and if the plugs are not smooth they will be harder to separate from the plastic.
I typically use about a 2" "slump" in the plastic for forming my parts (I normally use .030 and .040 for forming parts).
I also keep my heat gun right next to the vacuum box so I can heat any problem areas immediately so they will pull in.
If your part is "webbing" (forming wrinkles) the plastic is too hot.
If the plastic is not pulling down completely the plastic is not hot enough. I use a 5 gallon shop vac (minus the bags and filters) for a vacuum source.
It will be a trial and error thing for you to determine the correct amount of slump for the type and thickness of plastic you are using.
