Vacforming A-Go-Go, Batman.

John Howling Mouse · May 27, 2006, 07:19:56 PM

Finally got my head back into the vacforming side of things.
Starting out with some small but critical mod's/improvements to my little "Mattel"™ vacuform machine:

Replaced failing flapper valve with the after-market silicone rubber replacement (believe someone here said it was likely from a breast-pump machine):

Then I cut a piece of 1/4" plywood to replace the perforated forming tray that was missing from this used Vacuform Machine:

Believe me, that's a lot of freakin' holes to drill! Could've used perforated screen but I just wanted to get this thing going tonight.

The "footpads" are simply woodscrews that I can tighten or loosen to adjust the height of my homemade, plywood forming table:

And this is how it looks in the machine:

Once the silicone sealant on the new valve sets up, first subject to get formed will be the male pattern for my Morsair canopy. Wish me luck, I know I'll need it!

cthulhu77 · May 27, 2006, 07:44:05 PM

LUCK! after ordering a vac box from a "recommended" company, I've since just started building my own...no way in hell I'm paying out 100 bucks for some plywood.

The Rat · May 27, 2006, 07:49:38 PM

Did step 2 on mine when I got it over thirty years ago, should do step 1 when I finally drag it out again. Never got around to actually forming anything because I wasn't too sure on the exact technique. One part of the frame has all these weeny teeth on ot that probably are supposed to grip the plastic sheet, but they don't seem to allow for much of a seal around the edge. Do you let the plastic get really soft and then squeeze the crap out of it before sucking the air out, or what?

cthulhu77 · May 27, 2006, 07:56:42 PM

the plastic should "droop" in the frame just before you place it over the master, then flick on the machine...suck job!

John Howling Mouse · May 27, 2006, 08:54:23 PM

QuoteDid step 2 on mine when I got it over thirty years ago, should do step 1 when I finally drag it out again. Never got around to actually forming anything because I wasn't too sure on the exact technique. One part of the frame has all these weeny teeth on ot that probably are supposed to grip the plastic sheet, but they don't seem to allow for much of a seal around the edge. Do you let the plastic get really soft and then squeeze the crap out of it before sucking the air out, or what?

The perimeter line of "teeth" hold onto corresponding holes in the outline of the plastic sheets. I buy my .020" clear sheets pre-punched from Ron Callari of "Callari Modelworks."

And Chris is right about the drooping of the plastic sheet over the heater element.
In fact, that seems to be the biggest part of the finesse involved: knowing exactly when to pop the semi-molten plastic into position over the mold pattern.

I've also seen an after-market metal cap c/w a handle that one can put over the heater element side; supposedly makes the element heat up in about a third of the time the little gizmo normally heats up without said cover.

The Rat · May 28, 2006, 06:18:13 AM

QuoteThe perimeter line of "teeth" hold onto corresponding holes in the outline of the plastic sheets. I buy my .020" clear sheets pre-punched from Ron Callari of "Callari Modelworks."

Aha! I figured the sheets had to be special. So I can't just cut out a square of sheet plastic and have at 'er.

More bloody money.

John Howling Mouse · May 28, 2006, 07:59:05 AM

Quote
QuoteThe perimeter line of "teeth" hold onto corresponding holes in the outline of the plastic sheets. I buy my .020" clear sheets pre-punched from Ron Callari of "Callari Modelworks."
Aha! I figured the sheets had to be special. So I can't just cut out a square of sheet plastic and have at 'er.

More bloody money.

I know some people do simply use non-perforated sheets but the original Vac-U-Form ™ toy machine did come with pre-perforated sheets.

With them, you'll get a perfect seal everytime.

Do you have the perforated vacforming tray "table" insert on your machine? I found out the hard way that, without the table insert, nothing will form/seal properly.

The Rat · May 28, 2006, 08:21:39 AM

QuoteDo you have the perforated vacforming tray "table" insert on your machine? I found out the hard way that, without the table insert, nothing will form/seal properly.

Yep. I figured out as soon as I saw it that it would be asking too much for the plastic to stretch that much. Mine doesn't have as many holes as yours, but I'm sure it will do the job.