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Bruce Clumpner
06-07-2017, 3:05 PM
Just got a call from a client who wants some custom tabletop name holders and it looks like the easiest way to make them is to bend them from a single sheet.. Not having a strip-heater or any experience.. Just how tough is it to bend and form 3/16 cast acrylic? This will only be 10 pieces or so, so I just need an idea if it's worth it to pick up a heater and work the material?

TIA

John Noell
06-07-2017, 4:00 PM
In my limited experience, having a strip heater (and you can make one from an old toaster's heating elements) is extremely helpful in getting a consistent bend.

Kev Williams
06-07-2017, 4:04 PM
They make acrylic specifically designed to be heat-bent, it works MUCH better than bending basic cast. If you can't find any close by, Regional Supply will be happy to ship you some!

for bending, I made a fixture once that worked pretty good for heating plex and Rowmark for bending- it was nothing more than two 1/8" thick aluminum plates about 2 x 8", screwed to a couple of 2x4 'legs', with a 1/4" or so space between the plates. I marked the plastic (tiny speck of post-it note works) where the bend was to take place, then held it in place under the aluminum with the bend marks centered in the slot. Then I ran a 1500w heat gun across the slot for 8-10 seconds. The area to bend gets plenty hot, and the slot localizes the heat nicely so the plastic doesn't distort beyond the actual bend. If you don't want to just hold the plastic in place, stack up a few wood/plastic scraps to make a shelf. But I found keeping the plex against the aluminum localizes the heat better--

looks kinda like this
361595

Bruce Clumpner
06-07-2017, 4:31 PM
Should of said there was a design engraved on the material... so does the bendable material mark as well as cast?

John Blazy
06-07-2017, 5:01 PM
Kev's shield idea is great - never thought of shielding the heat gun heat for line bending. I bought a couple heating elements from mcmaster carr for 25 bucks, wired the ends into a male plug, and fitted them into a holder with a platen on top to hold the sheet of acrylic. The heat goes straight up in a line, and bends are rather quick, but I would go with Kev's idea if you have a heat gun or a torch. Cast should bend fine with enough heat. Extruded is the most common, and bends a tad better, but you want the cast for engraving, and cast still heat bends fine.

Joseph Shawa
06-07-2017, 6:36 PM
You've already got a heat source....https://www.youtube.com/watch?v=arjRtCjI9AQ

John Blazy
06-08-2017, 11:36 AM
You've already got a heat source....https://www.youtube.com/watch?v=arjRtCjI9AQ

Totally forgot about this video. It is one of the most innovative I have ever seen. The laser is a great source for pinpoint heat right where you want it - perfect for line bending.

Pieter Swart
06-11-2017, 7:35 AM
That has got to be the coolest thing i've seen today!




You've already got a heat source....https://www.youtube.com/watch?v=arjRtCjI9AQ

Clark Pace
06-11-2017, 12:55 PM
They make acrylic specifically designed to be heat-bent, it works MUCH better than bending basic cast. If you can't find any close by, Regional Supply will be happy to ship you some!

for bending, I made a fixture once that worked pretty good for heating plex and Rowmark for bending- it was nothing more than two 1/8" thick aluminum plates about 2 x 8", screwed to a couple of 2x4 'legs', with a 1/4" or so space between the plates. I marked the plastic (tiny speck of post-it note works) where the bend was to take place, then held it in place under the aluminum with the bend marks centered in the slot. Then I ran a 1500w heat gun across the slot for 8-10 seconds. The area to bend gets plenty hot, and the slot localizes the heat nicely so the plastic doesn't distort beyond the actual bend. If you don't want to just hold the plastic in place, stack up a few wood/plastic scraps to make a shelf. But I found keeping the plex against the aluminum localizes the heat better--

looks kinda like this
361595

Been bending for over 10 years. And a diy bender is the way to go. No need for any fancy acrylic. Especially if hey are asking for a premium. Plain extruded or cast bends easy and just fine. Just don't over heat and flip back and forth from front to back. You can do just one side also, but the chance increases that you will over heat one side.

Make a jig for the angle so each piece comes out the same.

Bill George
06-11-2017, 1:09 PM
FYI I have a $60 or less? Heat gun (hot air) for soldering and de-soldering surface mount ICs and it works slick for that. Comes with difference size nozzles and can get plenty hot enough to bend acrylic.

Jerome Stanek
06-11-2017, 4:31 PM
Make a bender with a heating element we have been doing it that way for over 20 years. We do set a timer to let us know when to take it off the bender and put it in the jig

Kev Williams
06-11-2017, 6:27 PM
I just have to ask, you guys who state 'no special plex is needed'... Of course, this is dead to rights true, but--I'm curious how many of you have ever used the 'designed-for-bending' plex?

Clark Pace
06-12-2017, 11:29 AM
I just have to ask, you guys who state 'no special plex is needed'... Of course, this is dead to rights true, but--I'm curious how many of you have ever used the 'designed-for-bending' plex?

Are you talking about cold bending? There is an acrylic that you can cold bend? I've done loads of cold bending but using Lexan. It sounds like this acrylic might be an Acrylic / Lexan hybrid. So it might not laser well. Cold bending is a real art, and if you are not experienced you dimension come off wrong. Lexan shrinks a bit when cold bent.

Kev Williams
06-12-2017, 8:57 PM
No, it requires heat-- Not even sure what you call it... Regional Supply and Plastic Fabricating are only a few miles from me. Plastic Fab uses and sells the stuff. They sold me some once (been a long time ago) when I needed to make a bunch of photo holders, which were nothing more than a piece of 2" x 6" of plex bent in half to make 2" x 3". I remember it had a blue plastic masking. But what I most remember was how you could work magic with it when heated up. Took much less heat, and it's very pliable and forgiving. When folding normal cast in half tightly, the bend itself tends to push out on the sides and bunch up thicker. This other stuff doesn't do this anywhere near as bad.

It could be a hybrid, I really don't know. I just remember it was fun to play with!

Clark Pace
06-20-2017, 9:37 PM
Hey kev. I used to work at plastic fab in the fab dept here in utah. The only blue masked stuff we ever used to my knowlege was extruded. Extruded heats and bends easier for sure. They may have been selling it that way. But it was extruded.

mitch stephens
06-21-2017, 7:48 AM
I have done it with a heat gun and some wood. Clamp it in 2 pieces of wood and heat along where you want to bend it. Use another piece of wood to keep it flat and straight.
Mitch