How to Vacuum Form

[Peter Lombardo]

A couple of guys asked to see the vacuum form machine, and how it works, so I thought I would put together a post that shows the process. My son is into “Sci Fi†modeling. He has been scratch building a model of a the LAPD “Spinner†from the movie “Blade Runner†on and off now for about 6 months now.

The top is a modified clear plastic “dome†from the old Pontiac Banshee kit. Since I had one original top, he wanted to make some copies of it for the Spinner, and future Sci Fi builds. The best way to make copies of a clear dome is vacuum forming.

He went on-line a few months ago and found a guy who makes and sells these little vacuum machines. This sold for about $65.00 if I am not mistaken. The machine was sitting around doing nothing for months when I hatched the idea to attempt the vacuum form body of the Aero Coupe a few weeks ago.

Yesterday, he wanted to vacuum form the Spinner top and since it was rather small, I threw in the twin bubble top from the 58 Thunderbird kit, to take up space and see how it would look.

The vacuum machine holds a sheet of styrene that is 12 inches by 12 inches in an aluminum frame clamped down with office clamps. The unit is fairly small and can easily sit on the kitchen counter.

It has an opening where it is connected to a shop vac and that opening is “piped†up to a chamber under the top plate. The top plate has many little holes that allow the vacuum suction to pull the hot plastic down over the item being molded.

As you can see, the two bubble tops are placed on the top of the face plate.

As a precaution, I sprayed the tops with some silicone spray to aid in the removal and help protect the plastic bubble tops from any excess heat that might transfer at the moment of contact.

The sheet of styrene was clamped down and placed in our oven set to 400 degrees.

The frame rested on a roasting pan while in the oven. At first the heat causes the styrene to get real wavy and a few seconds later it snaps back to perfectly straight and tight. The molecules are reacting to the heat and getting all rearranged. About 20 or 25 seconds later, you can actually see the plastic sheet begin to “sag†downward in the middle. A few seconds later and the entire sheet is beginning to sag. At that point the shop vac is switched on and with oven mitts, the plastic is removed from the oven and quickly placed over the items to be molded on he machine. The machine has two little angle brackets that help guide the frame into the proper position as it fits over the machine. I a split second of placing the frame with the hot plastic on the machine the styrene is rapidly pulled down over the molds.

In that second, it is done. “Bamâ€, as that cook on TV used to say, it is sucked down and the form is complete.

The frame is removed and, in this case, the forms (molds) being so light, they were attached momentarily to the newly formed copies, but no worry, they released easily when tapped from above.

Here the originals are still in the newly formed copies, but being that both are clear, it is difficult to see that.

That’s it, the entire process takes about 45 seconds to complete and so far, I have seen no reason to doubt that I will be able to mold the body for my Corvette XP45C. As a side note, I have made a few modifications to the sides of the XP45C. As much as I liked the “throwback C1†side scallops, They just were not working for me, so I filled them in and replaced them with air scoop recesses that are more reminiscent of the C5 and C6 Vettes. All and all, a major improvement. I also re-did the back end design, back to the way the drawing showed and it is also a major improvement…but more on that later.

Edited November 27, 2009 by Peter Lombardo

[Salvo]

Thanks for showing us the process invovled! I'm sure I will have a use for one of those in the near future... Any link to where you got it from? Thanks! Steve

[dencon]

Thanks you very much for posting this. I have been vacuforming for about 20 years and have been needing to do it for some of my resin kits I sell. You just gave me an idea to make it a little more easier and more productive. What I am really interested in is your frame set up for the PETG sheet. Could you show some more pics of that frame and what it looks like unclamped.

Thanks So Much!

Matt

[seeker589]

Peter -

Thank You for shareing that!

That was exactly the details I was looking for.