Monday, April 16, 2012
Vacuum forming, commonly known as vacuuforming, is a process whereby a sheet of plastic is heated to a forming temperature, stretched onto or into a single-surface mold, and held against the mold by applying vacuum between the mold surface and the sheet. The vacuum forming process can be used to make most product packaging, speaker casings, and even car dashboards.
But most importantly it's going to help me make helmets and props.
Most of the helmets, and armor seen in the original Star Wars Trilogy was made using a vacuum former.
I have researched many different designs on various websites for building your own Vac Former.
Being that this will be my first attempt to make one, I am going to go for a low-end former seen here..
You can also buy a ready made former from many sites, but it's cheaper to make your own.
Below is a 'sketch' I made in Illustrator of the main Vacuum Forming Chamber.
Since I do not have the tools and work space to cut all these pieces out at home, I will need to have them cut at the hardware store. Essentially, it is just a box with a peg board top on it. The Aluminum foil tape seals up the join areas so that no air can escape, thus making good suction for the forming. The Rubber Gasket will be the same size of the frame, and that should create a good enough seal when the frame is pressed down on it.
Below is a 'sketch' of the Frame.
The Frame is quite simple. For the frame, most people have 2 aluminum window frames held together with clasps and hinges. I would like to do that one day, but for now I am simply going to use a staple gun and staple the plastic (polystyrene) to the frame. I can remove the staples easily and reuse the frame fairly often.
Below is yet another 'sketch' of the process, simplified.
It starts by putting your original in the chamber with your vacuum plugged in.
Preheat your over and heat the plastic. The thinner the plastic, the quicker it will heat up.
When the plastic begins to sag, remove the frame with the plastic, flip it, and place over the chamber so that it fits over the rubber gaskets. Turn on the vacuum and watch the plastic shape to conform to your original.
After a few minutes once the plastic has cooler, remove the frame and turn off the vacuum.
Using a utility knife, or scissors, trim the plastic.
And there you have it.
This is what I am going to attempt to do!
First thing was to get everything I needed from the hardware store. In this case it was Home Depot.
Since I have neither the room, nor the tools to cut lumber, I had to have them cut it for me.
They did a less-than-stellar job, but it will do for now.
Once I got home I charged up my electric screwdriver and assembled the 4 walls of the chamber.
I then drilled a hole for the vacuum attachment.
Then I attached the bottom of the chamber.
I increased the size of the hole so that my vacuum hose fit in snugly.
And then attached the top.
I used aluminum foil tape to seal up all the sides so that the chamber was air-tight.
Then put strips of adhesive door sealer around the top so that when I put down the frame they make a seal to keep air from escaping.
I put a garbage bag on top of the frame to test the suction.
I turned on the vacuum and it sucked the garbage bag down.
Then I put one of my helmets on it with the frame and a garbage bag on top, turned on the vacuum and it sucked the garbage bag over the helmet pretty well.
Guess it works!
For some reason I had a great deal of difficulty finding the proper staples for my staple gun, so me being impatient I decided to screw in the plastic to the frame and attempt my first vacuum form.
I decided to use one half of a storm trooper helmet for the test.
My first attempt was a success, and a failure.
I heated the plastic, put it on the former, turned on the vacuum and for the first second it totally worked.
And then the plastic popped, and the form lost a lot of it's shape.
When the plastic cooled, I removed it from the frame and cut it out.
It definitely has some of the correct shaping. The dome of the top, and the round parts towards the bottom were correct. I took a marker and colored in my new mask.
Some of the reasons I believe this failed was:
1. I did not use staples close together as was suggested on many sites. I wound up using 8 screws which were probably not enough.
2. I may not have heated up the plastic enough - although it did look and feel as was described in almost every site I visited.
3. The helmet I was making a form of laid flat against the former, except for the bottom of the mask where the 'mouth' is. When the vacuum was going, the suction may have been too great and stretched the plastic too far. If you look at the third image above this paragraph you'll see just where I am talking about. This is what I believe the problem to be. So, I am going to put a towel in that area, and behind the eyes to try and keep this from happening on my second attempt.
Towels behind the helmet to keep it from bending too much. Plus now I have the correct staples for my frame.
And as you can see above, my second try was much more successful than my first.
However, as you can see in the photo above and below, there was still some bending of the mask and thus the bottom mouth area is a bit distorted.
Above are the first 2 forms made.
One thing about the staples....they are much better than screws, but boy are they a lot of work to remove. Arg!! I'm going to have to come up with something better.
For my third try I decided to try the whole helmet.
And it did not work out so well. The above picture looks not too terrible, but the plastic is so thin. I would say it's about as thick as a sheet of paper. It ripped easily, and even if it didn't, it wouldn't make a good helmet.
For my fourth try, I decided to use clear plastic with one of my helmets that I made.
This one came out fairly well. The back side of the helmet developed a hole but that was because I left the plastic in the oven too long. Clear plastic heats up very quickly.
But, it did make the visor I have been hoping for, and that makes me happy.
For my last attempt, I tried using thicker plastic (1/8").
I also heated it at a lower temperature (350 degrees instead of broil which was suggested in the video at the beginning of this blog entry).
I also crafted a few pieces of dense foam, instead of towels, to keep the shape I wanted.
SUCESS! This time it worked as I had hoped. Perfect detail. And the plastic is thick and does not bend well.
I eventually replaced the rubber door sealer on the top with a better, thicker garage door sealer since the thin door sealer peeled off too much and ruined the suction.
The newer sealer works much better!
All in all I successfully made my first vacuum former! I will start making my helmets so that they will be vacuum formed. I'm very excited!
When I begin working on a new, bigger vacuum former I will make a new posting.
In the meantime please take a look at some of my older blogs, as I am constantly updating them.
Perhaps you'll see the vacuum former in action again on one of those blogs!
Someone asked me where I get the plastic for doing this....
I get mine from Widget Works unlimited. The prices are reasonable and they ship pretty quickly. Here is their web page for the thermoplastic sheets: