Vacuum Forming

VashDstampede

Active Hunter

drcrash

Hunter
:p How do you make the molds and make a Vacuuform machine

Here's a draft chapter on how to make a vacuum forming machine that uses a kitchen oven and a vacuum cleaner, which I posted on the aforementioned tk560.com.

http://www.tk560.com/phpBB2/viewtopic.php?t=466

Sorry, there aren't a lot of photos yet, but there's lots of info, including

* how to find a good vacuum cleaner for vacuum forming dirt cheap (shop vacs are overrated; you can get just as good a vacuum for a few dollars at a thrift store if you know what to look for)

* how to make a board with a hole in it work as several sizes of platen, with removable gaskets on tape-down sheets (and why that's as good a platen as you can have if you're making one object at a time)

* several ways to make plastic-holding frames, including mix-and-match-size frames using windowscreen framing material from the hardware store

If you're interested in making a smallish (12 x 20) standalone oven for your vacuum former, very inexpensively you might check out this mini-howto I posted over at rcgroups.com:

http://www.rcgroups.com/forums/showthread.php?t=621858

(If you want to make a slightly more expensive oven that sits over your platen, look in that thread for the link & other info about Ralis Kahn's plans on halloweenfear.com)

If you want to make a big vacuum former with it's own oven, e.g. 2 x 2 feet or bigger, check out the Thurston James design over at tk560.com, including Jim Egner's cost-saving substitutions.

The vacuum forming forum on the discussion board there is very useful and friendly. There's also good info on the vacuum forming forums at hobbymolding.com (but that one's less active) and the one at CNCzone.com (where there are experienced pros as well as hobbyists and noobs).

http://www.tk560.com/phpBB2/viewforum.php?f=1
http://www.hobbymolding.com
http://www.cnczone.com/forums/forumdisplay.php?f=291

As for making molds, start with this recent thread here:

http://www.thedentedhelmet.com/showthread.php?t=16584

You might check out the "similar threads" listed at the bottom of that page.

I'd recommend getting Thurston James's book "The Prop Builder's Molding and Casting Handbook." (You can probably find it in your local library, or get them to interlibrary borrow it for you.) The chapter on vacuum forming in that book is short, but many of the other techniques in the book can be used for making molds for vacuum forming. (It's also got the vacuum former plans that a lot of tk560 folks have used.)

Paul
 

GrottyFurball

Active Hunter
I would have to say the most important thing is to wait until you KNOW you can do it. You have to know how much sag to look for in the sheet of plastic, the last thing you want is moltent plastic ripping and getting all over the inside of your oven.
 

drcrash

Hunter
I would have to say the most important thing is to wait until you KNOW you can do it. You have to know how much sag to look for in the sheet of plastic, the last thing you want is moltent plastic ripping and getting all over the inside of your oven.

Two ways to avoid this:

1. (a) Put a piece of aluminum windowscreen across the bottom of the oven, propped up on something (maybe the bottom rack). If you have a meltdown, the plastic will hit the screening first, not the bottom element, etc. This should give you time to whip it out of the oven before it makes a bigger mess.

(b) Be careful. Start with the oven at a lower heat than you think you need, and see if it's hot enough. Like 200. Bump up the heat 50 degrees at a time, waiting a couple of minutes in between, until the plastic starts to sag. That'll give you a handle on how hot to set your oven so that things don't happen too fast.

2. Build a standalone oven from cheap/disposable stuff, and put window screening across the bottom of that, too.
 
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