Experimenting with vacuum molding

Hi there! This post is about a really simple way of making plastic parts for your projects. Have you ever heard of vacuum molding? It's a method to make a plastic mold of a piece by using heat and suction from a vacuum cleaner. You can easily replicate what I'm going to show you. You just need some wooden pieces to make a box like the one you'll see in the picture, a vacuum cleaner, a heat gun/electric heater/oven and some disposable plastic dishes.

(Click the photo for better resolution in Picasa Photostream)
You don't necessarily have to make the box exactly equal to mine but I'll describe the process to make it:
  1. Cut the top, bottom and side wooden pieces to the desired sizes;
  2. Draw a grid on the top piece and drill a small hole in all the grids' intersections;
  3. Drill a hole with the same diameter as the vacuum cleaner's tube in one of the side pieces;
  4. Screw everything together;
  5. Take your glue gun and fill any cracks with hot glue so that no air flow is possible except through the holes in the top part.
Once you've done the box, it's time for some fun stuff! :) Place the part that you want to mold in the table and cover surrounding holes with some paper sheets. Don't cover them all! Leave some close to the part. Then stick your vacuum cleaner's tube in the hole that you've drilled. Finally, grab a plastic dish with some pliers and turn on your hot air gun or electric heater. Start heating the dish slowly and as uniformly as possible. Once you see that the plastic is almost starting to melt, place it on top of the part and turn on the vacuum cleaner! The suction will remove all the air between the hot plastic and the part that you wish to mold and the plastic will stretch around the part, taking its' shape. Keep heating it at a safe distance until the shape is as you desire. Be careful not to overheat it! Otherwise you'll just get some holes in your mold. If you find the mold too thin, then just grab another dish, repeat the process over the previous one so that they get attached to each other.

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Using this method will work for some small, low profile parts. However, if you want better quality and bigger parts, you'll need to buy plastic sheets for vacuum forming and build a frame to hold it uniformly and then press it again the suction box. If you search for "vacuum forming" in Youtube you'll be amazed with what can be done at home with this kind of setup and some quality plastics.

Oh! A big WARNING... if you use an oven to heat the plastic, make sure that you will not cook food in that oven ever again! I assume it won't be good for your health :P

So, I hope you like it and manage to make your own molds at home! :) If you try it I'd love to see what you've done with vacuum molding :)

Take care! :)

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