I need to bend some acrylic pieces I just cut with the laser.

I believe there are special tools for heating along the desired bend line.

Does anyone know of any sources for these "benders"?
Website, phone, ... ?

Are there different options/features?
If so when is it desirable to pay a little more?

Ken Devory Jr.
Enjoying this forum and
looking forward to having the experience to pass on to others.

Hi Ken,

I know most of the larger plastics companies will sell heating strips for you to use...try Caddilac Plastics, Midland plastics or Cope Plastics if you can find one nearby. I believe we purchased ours from Cope plastics. Any of those three would be worth calling and asking the same exact question.

Good Luck,

Brian G.

Ken,

An industry source for this type of item would be Johnson Plastics.

David, Brian

Thanks, I'll see if I can track a couple of them down.

Ken,

Strip heaters can be bought from engraving supply houses as well. Gravograph (New Hermes) and Ability Plastics are a couple.

Ability = www.abilityplastics.net

New Hermes (Gravograph) = www.newhermes.com

They all work on the same principle. Some may be capable of handling larger pieces of material. A good one will have an adjustable thermostat. They may all have thermostats. I'm not sure.

I have one made by New Hermes, which I acquired in the closing of an engraving dept.

David "The Stunt Engraver" Lavaneri
DGL Engraving
Port Hueneme, CA

I purchased at a garage sale an old 'seal a meal' - removed the heating element and made a small table (2x4's and plywood apx. 8" x 12"). Drew lines for reference on plywood. Cut out narrow rectangle in middle and mounted the heating element in this hole area. Total cost less than $1.00, and I've been using it for 7 years. I know Artisan (800-462-7117) sells just the heating element so that you can make your own.

Zona
Zona's Engraved Creations

David & Zonas

Thanks for the info.
Reading the answers to my original question made me realize some assumptions I made.

Are all heaters for bending acrylic "strip heaters"?

How do you make various sized radius bends?
A sharp bend vs a 5" radius...

Does anyone have any technique pointers?

The system I use has a rod heater. It is a metal frame with a 1/2" x 1/2" depression running down the center. That holds a heating rod, (element). When it gets a dull red hot it is time to put on the acrylic.

The way I time the heating is when the very edge just starts to deform from a square cut, (I use only cell cast acrylic so that starts at about 400*F), it is ready to bend. If you try to bend it and it resists too much, immediately straighten it out and put it back in the heating position for a little bit.

The bending jig is just a slot between two boards. You have to calculate the exact distance to end up with the right bend. Trigonometry. The placement of the plastic on the heater determines just where the bend ends up. You must leave it in the jig till it cools quite a bit, a fan helps a lot. If you take it out a little too early it will unbend a little by itself. Then lots of luck trying to reheat it and rebend it, nearly impossible.

As far as a large radius, never done that. You get a fairly small radius, about the thickness of the acrylic. For a formed bend I would assume that a from is used and the plastic is heated by hand for small quantities with a heat gun.

For large industrial quantities the plastic goes through an oven and then into a forming unit that has a mold and pressure and is usually chilled by water running through the mold.

Oops, more info than asked for again.

Philadelphia, PA (Really Bensalem)

Harvey's Sub Page When you finally understand it completely... it changes.

Harvey,

I like it when people give more information than was originally asked for. When I'm learning something new I don't always know what to ask, or another approach is sometimes better.

You mentioned 400°F for cast acrylic. Is the temperature for extruded acrylic different?

It sounds like: don't heat it enough its hard to bend, heat it too much it'll slump if not supported.

Has anyone on this forum tried using a form? Are there materials to use, or to avoid? (don't want sticking) How do you shape it without distorting the surface finish? Can you cool it with water without disturbing the finish? What am I not asking?

Overheating will sometimes cause bubbles to form inside the acrylic as well as slump. It should be hot enough to just bend without using a lot of force, but a little force should be necessary, it should not just fold too easily, needs a few, (3-5?) pounds of force for about one foot of fold. If you have to go past about 20 pounds per foot, it is not hot enough.

Cell cast acrylic needs the highest temp, continuous cast needs lower temps, extruded needs the lowest. I have seen some extruded that would melt easily in boiling water. If you are using extruded, dip a piece of scrap in boiling water for a bit and then try to bend it. That will give you a good idea on how much temp you will need. I am told that an IR heat gun will not read properly on a shiny surface, but believe that anything stuck on the plastic will leave a mark after reaching folding temperature, so that will not help.

The main difference in the acrylics is the composition. The cell cast is made with mainly polymers with just enough monomer to cover and hold it together. Continuous cast uses more monomer to be able to cast in that method. Extruded has a lot of monomer in order to be forced out of a slot in that manor. Monomer melts at a very low temperature.

Philadelphia, PA (Really Bensalem)

Harvey's Sub Page When you finally understand it completely... it changes.