Monday, April 18, 2016

Build a Mini Vacuum Former

I built the larger vacuum former first, and then decided that I needed a mini vacuum former for smaller pieces and for the leftover scrap plastic from the big former.
I took a $5 a toaster oven and spent $20 on the aluminum angle, (32) screws & nuts, pop rivets, and corner braces.
I already had the shop vac, wood, and pegboard, as well as the binder clips & clamp. This is a weekend project that won't take very long.

The frames are 10.5"x7.5" overall. It's a total length of 36" which is stock length of the .5"x.75" aluminum angle. I made a top and bottom frame to clamp the plastic. The inside clear size of the frames are 9.5"x6.5".

I mitered the corners of the frames on a miter saw with a metal cutting blade. A miter box and hand saw would also work. The corner braces are attached at each corner. Use a right angle to ensure the frame is square. Make two frames.


I drilled the bolt hole in the aluminum angle for the L brackets. To recess the screw heads I took a drill bit the size of the screw head, in this case .25", and carefully created the recess. I drilled into the aluminum hole for the bolt I had just created, but did NOT drill all the way through. I used a drill press which makes this easier.

I cut aluminum angle to act as brackets for the frames in the toaster oven. I blind drilled a hole inside the oven and pop-riveted the angles in place. Be careful blind drilling, I went very slow so that I wouldn't damage components I couldn't see.

The box is plywood on fives sides with a pegboard top. The box's overall dimensions are 9.5" x 6.5" to fit inside the aluminum frames.The sides are 3" tall to allow for the 2.25" vacuum hose.

I used a hole saw to cut a hole in one side of the box, and a drum sander to enlarge the opening. I then lined the opening with duct tape to create as snug of a fit as possible on the vacuum hose. I notched the aluminum bracket to fit around the hose. You want the top of the bottom frame even with the vacuum surface.

A wood bracket glued to the other side of the box keeps the frame level.

I've got a large clamp to serve as a handle to remove the frames from the oven and onto the vacuum box. Binder clips are on the other three sides of the frame to clamp the plastic in place.

The oven heats the plastic up quite fast. The oven door doesn't need to be shut. As soon as the plastic starts to sag, remove it. Switch the vacuum on and lower the frames over the vacuum box.

On the first pull, I let the plastic get too hot and it was a mess.
 
A vacuum former can't get fine detail. For the second pull, I removed the plastic as soon as it started to sag. 
This pull came out much better. I use .020" plastic for the pulls. A vacuum former does best on a half dome shaped object. Recesses can pose issues.
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