Newbie has questions on vacuum forming

[Sunshine]

Hi to everyone!
Yup, I'm new and have read thru many of the posts and now I'm so confused!
I would like to make molds for cement stepping stones and sculptures. I am tired of the same old things and would like to creat my own. A HA ! Vacuum forming! But I'm really confused as to building my own machine....I keep reading about the additional pump or vacuum tank.

""Vacuum Forming" or "Thermoforming" is a simple process where you take a flat plastic sheet, and heat it until it's soft. Then you stretch it over a mold or pattern, and suck it down tightly with vacuum. The plastic cools quickly and retains that shape. "

I read this in all the 'how to's' and and it sounds easy enough that even I can do it........and I thought I could just take an old 10amp vacuum apart and use it. Do I need additional draw?

I found an electric grill at Wally World for $30

I would like to make items about 14"x14" x 2.5" thick.

Thanks
Sunshine

[spektr]

Ok heres the reality of your situation. You are going to be using something like 3/16th inch thick ABS to make the molds. This isn't going to pull down with a vacuum cleaner. You will need a vac pump/tank/valve as well as a heater that can get the abs to temp without charring the surface. The open ovens here have a drawback in that they heat from the bottom, and as the material sags, the center gets a disproportionate amount of energy. I have a 2 x 2 oven box with a 220 oven/broiler element in it. 3/4 plywood faced with hardiboard. It is 12 inches tall. I run it wide open/full power and use the distance to prevent overheating. I run bottom heat and run 3/16th abs manually with decent results. Heat times are around 90 seconds and i have a metal pie plate on the center of the element to reduce center heat soaking. The center of the sheet is about 15 degrees hotter than the corners. For a simple frame, use 1/2 x 1 furring strips on end and make a frame. Cheap gate handles make it easier to lift off the oven. I use a 5 cfm robinaire pump pulling on a 25 gallon propane tank (the old heavy ones) with a McMaster Carr p/n 4625k63 with the squeeze lever arm to run the vacuum on a foot pedal. put a T on the tank, one side to pump, one side to the valve. The other side of the valve to the plenum box. Simple, cheap, effective. Hard to go wrong. Ask more questions and I'll try to aim you a bit better............ Scott.

[Sunshine]

Scott,
Thanks for your answer....
My hubby is the one building this for me. He understood what you were saying! (At least he thinks he does)
He came home today with a small, 10"x11" (inside demensions)
propane camping oven. 1/2 price sale. Says it holds temps to 400 degrees....has 2 racks, of which I could use for holding my plastic rack set up....but do you think there would be a problem with 'gas'? I don't know if the fumes are combustible?

He is thinking he would like to build the table area like a drawer, so it can be pulled out to be used and tucked away when not in use. The oven can sit on the countertop in the shop. Does that make sense?
Thanks for all the help!
Marcia