how do i make a vacuum forming mold?

Question

i am trying to make a vacuum forming mold for something but im not sure how to make the mold. can any one tell me the best way to make a mold. i have been trying to make one out of m.d.f. but i dont seem to be able to make it work any ideas anyone.

do i have to make a possitive mold or a negative mold for vacuume forming and how does vacuume forming work

Answer 1

What are you trying to form? If it's a simple shape AND you're not pulling too many forms off the tool, you can use MDF.

Remember that you will need a minimum of 2-3 degrees draft on any "vertical" surface to be able to pull the form off the mold.

One useful trick I learned to increase the hardness and toughness of an MDF vac-form tool is to saturate the surface with super glue. You'll need to use the very liquid type of glue. While wearing gloves, you can put some on the surface and rub it around and in with a tissue. It will create a hard shell on the surface that will minimize chipping and damage you would get to the MDF otherrwise.


Edit: Look at this website with lots of videos of vacuum forming in action. http://www.imperial-armor.com/videos.html It should be helpful to see.

Answer 2

I used to fabricate Vac Form molds for the defense industry, for models, using a 4 x 8 vac table.

My molds were all Maple, often laminated 2x whatever size, sanded, finished, and polished smooth to allow RELEASE after the fact.

The issue is ANY voids in whatever material you use that will allow the material to be contained into the voids in the vac process.

Without knowing what you're actually attempting to form, the mold issue should be similar to fabricating a mold to lay up Fiberglass. Again,,,Release is the major issue.

Steven Wolf

Answer 3

Styrofoam can be cut or melted to vertually any shape