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Old Jun 14, 2012, 05:09 PM
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Freddie B's Avatar
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Thermal forming, Vacuum forming methods & devices.

My new Vacuum Forming table device for Thermal forming plastics into shapes and aircraft parts is a success.

I have tried the traditional box with holes in it, as a type of forming device with somewhat limited success. Complicated construction is a turn off for many. So I decided to try the One Hole Vacuum Table Idea. Maybe this is not new to you, but it was to me. Very easy to make and use, sounds like it fits the bill! I can not take credit for any of the ideas I will present, but did some extensive research before trying my ideas on this new device.

What the object here is to allow anyone the ability to copy my ideas and be able to Thermal Form, or say Vacuum form their own parts and expect success for those efforts. I do hope many will try this as it now seems so much easier and the results are great so far.

The actual device is so easy you may just be amazed, so here we go, as I make my One Hole Vacuum Forming Table, and thermal form some plastic sheets into aircraft parts.

Fred
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Old Jun 14, 2012, 05:10 PM
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We need a flat table with a single hole.

The basic process is fairly simple in nature. So should be out equipment, right?

So I started with some junk plywood about 1/2" thick, and cut it into a 12" x 18" piece. This could be larger, but it fits my needs for now. I cut a 2 1/4" diameter center hole through this with a hole saw.

Next some old 2'x4' material was attached to the bottom with liquid nails and some screws. This can now be clamped onto my cheap WorkMate clone from Big Lots, and then no huge table with stationary legs is sitting around the shop. Slick.

Fred
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Old Jun 14, 2012, 05:10 PM
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I used mostly old discarded materials that I could find, but a few things need to be purchased. One of these is shown in the first photo, a drain kit from Lowe's, for a laundry sink. It is basic plastic in construction, fine for this, and cheaper that way. I also picked up a 1 1/4" tail piece to attach to the drain (White Pipe) as this fits into the vacuum hose of my Hoover Vacuum Cleaner that I use around the house. You will also see some weather striping tape I bought, more on that later.

I added two pieces of 1/8" thick Masonite to the top because it is smooth, and flat. I had some laying around, but if I had to buy it, get 1/4" thick becaust that is what we need to clear the drain parts. Cut a 3" Diameter hole through with your hole saws, and glue them to the plywood with Liquid Nails. I used some cardboard as a glue spreader here.

Weigh it all down with something heavy, and let it dry. Last photo shows what we have so far. Acetone cleans up any Liquid Nails mess you might encounter.

Fred
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Old Jun 14, 2012, 05:11 PM
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And photos should explain. Bayh caulk was used to seal the drain piece. Had to open up some room for the attachment nut, so a 4" hole saw was used. After tightening, I made the caulk bead smooth with a wet finger.

Fred
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Old Jun 14, 2012, 05:12 PM
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Last I opened up the dran by removing the webbing so the airflow would be unobstructed. Then I attached the tail piece.

The last photo shows how my Vacuum Cleaner attaches via hose to the drain tail piece. WOW the Vacuum Table is done, ready to thermo form some plastic sheeting.



Fred
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Old Jun 14, 2012, 08:36 PM
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Wellll ..mate that's One way of doing it... using a bathtub drain .
But perhaps you might consider.. buying some Vero board from a local(or not so local) Electronics supply house.. Hundreds of precise holes and the strength of an Epoxy/glass substrate. Affordable too :-)
Thousands have used this.. Happily .
You might too :-)
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Old Jun 14, 2012, 08:44 PM
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Frames to hold plastic sheets. Bottom frame first.....

OK, back so here goes this edit.

We need frames to heat and form the plastic sheets with. These frames need to capture the plastic and hold it tight. There is no secrets and anything from wood to metal can be used. From staples, bolts, to clamps, the plastic can be held while working. I used to use plywood and masonite frames, heavy staples to hold the plastic, and that went well. Problem was the staples damage the frames and are hard to remove. So I evolved to simple enough metal frames.

I want to make several frames for different part size ranges. But for now, I settled on a frame and plastic size of 7" x 12". This size will make many foamie parkflyer size parts, and this is also the size of the Plastistruct Brand of pre-cut plastics available at the local hobby store (again, expensive).

The bottom frame needs to seal against a gasket (weather strip) so it should have little ability to leak air. A vacuum can overcome some loss, but not much. So I picked up some 1/2" x 1/2" 'U' channel at the Home Improvement store, and the wall thickness is 1/16". An 8 foot length cost me $8.00 and change, plus tax. I could afford that. Besides my frame took less than 4 feet of material, so I can make 2 frames in different sizes. About $4.50 a frame.

I have photos below showing the metal, miter box, X-Acto razor saw (you can use hack saw). Look close, I cut so the standing wall is to the inside. Cut to that bottom wall in the 'U', and then I bent it over my table edge. I cut the 12" side 11", and the 7" sides 6" to compensate for the material width. Finished frames is 12" x 7".

At the end, I cut 1" extra, and shaved off the two outside legs as shown. This created a tab to bend and sit in the channel. I used some CyA to bond while drilling for some small screws to lock it in place. Pop Rivets would work well too if that is what you prefer.

Fast forward below and lets cover the top frame.

Fred
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Old Jun 14, 2012, 08:47 PM
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Quote:
Originally Posted by Bare View Post
Wellll ..mate that's One way of doing it... using a bathtub drain .
But perhaps you might consider.. buying some Vero board from a local(or not so local) Electronics supply house.. Hundreds of precise holes and the strength of an Epoxy/glass substrate. Affordable too :-)
Thousands have used this.. Happily .
You might too :-)
Thanks Bare, and hang in there as this may surprise you without all those tiny holes, or finding Vero Board, let alone pay for it. My chepo unit is going to perform well, and cost little, which is good. Also can make big parts without big boards with holes all over them........



Fred
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Old Jun 14, 2012, 09:28 PM
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Good stuff Freddie. I'd love to see a video of this in action with good pictures of the results. I may have to build one of these. The possibilities this could give to really dress up a simple foamy cheap and easily intrigues me. BTW, what kind of plastic do you use for the final product and where can you get it?

Thanks,
Nole
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Old Jun 14, 2012, 11:30 PM
skumgummi dave
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Fred:

Watching and learning...

Dave-
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Old Jun 15, 2012, 12:25 AM
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I believe some of the pro use holes only where the part to be formed is.
Keep up the good work this is interesting.
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Old Jun 15, 2012, 09:43 AM
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Nole,

Thanks. Plastic is everywhere! (Haha ) Actually I often use the plastic that shrik wraped products are sold in (toys, tools, and just about everything else) when I can find either large flat surfaces, or some areas that are pre-drawn but fit the frames. Also hobby stores sell some (expensive) and usually some plastic suppliers are located close to everything, or will ship. There are many suitable types and I will cover that later............

Dave,

Welcome and thanks for watching.........

Brihoo2k,

You are right. From Vero board as Bare pointed out, to peg board, to a favorite, 1/16" diameter holes drilled in key areas, these are the more intense, expensive, or labor intensive ways, and they work. Problem is why would you want to cover pre-existing holes that are not needed, make seperate top boards drilled for one type of part to form, etc. Hang in and watch how this plays out, very cool........

And video, well there is a short one to come anyway. maybe we will get Mrs. Freddie B to become a camerwoman for something more encompasing.....

Fred
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Old Jun 15, 2012, 10:17 AM
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Top frame for holding plastic.

Now, the top frame does not need to be air tight, and as such we can save even more money here. (I love that, saving money so we can buy more motors, batteries, and such).

I bought some window screen frames made from aluminum. Now these were less than $4.00 for 8 feet. That is $2.00 a frame. (sort of). Best of all.
I found some old discarded frames and salvaged them for parts and didn't even touch my new material yet. Your challange is to salvage too, but don't get caught. The wifey or neighbor will kill you......

The important part is we would like to have metal corner joiners. Many screens have plastic corners. Seems Lowe's and Home Depot have cheaped out, but Ace hardware, and others have the quality metal ends. (so does my neighbor, JK). The plastic corners will fail over time because they are, well plastic! Plastic will heat and soften, so find metal ends. (see photos).

I wanted the inside of both frames to match, so this time I miter cut the parts as 2x 12.5", and 2x 7.5". This gave me just what I was looking for. It is pretty easy just to overlay and mark the material to cut (no rocket science here).

Photos.....

Fred
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Old Jun 15, 2012, 10:21 AM
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Frames and plastic mounted in frames.

So a couple photos showing you how the metal frames worked out. These show a sheet of plastic mounted in the frames using medium Binder clips. The box of 12 binder clips was $1.37 plus tax at Walmart. This is a very strong holding frame and you can see how it has clearance on the bottom frame to seal to the weatherstrip and heat won't affect the metal!

Fred
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Old Jun 15, 2012, 11:16 AM
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Beauty in the one hole system....

Here is part of the beauty in the one hole system. We make a mask out of cheap plastic that will go on top of the table. To this we will mount weatherstrip fro sealing our frame. This mask will tape to the tabletop to seal it's edges, and remain removable. Now we have a frame and mask that is specific to this size, and others can be made to suit larger or smaller parts.

For sale sign (large), Walmart $2.20 plus tax (or there abouts). Cut as shown in the photos. I believe this is a PVC material, but it doesn't matter. Thin, flexable, and easy to cut is the trick!

Fred
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