forming plastics

[aqua-ed]

this post is kind of out-of-bounds, but it's applicable to this thread.

i coach a robotics team at DHS. we are allowed to use several different types of plastics in the construction of our bot; lexan, abs, acrylic, plexiglas, etc. This year we formed the sheets by cutting them. We'd like to try bending and forming the sheets next year as well. What kind of equipment would we use for this? A heat gun? Any tips?

Thanks!

[darrellw]

I've used a small butane torch, which would let you localize the heat a bit more than a heat gun (which would tend to heat the whole piece). I don't know if the open flame would be an issue in a school environment, though.

 

I think the ideal way is with a "strip heater", a thin heating element that you can set the sheet over, and heat a narrow (and straight) area. Perhaps that is something that you could build?

[newfisher]

Can you use the large oven in the cafeteria?

[aqua-ed]

lol. I'm sure the foods room would love me using their ovens.

Actually, as daryll mentioned, we want to only heat a localized area. most of the work we will be doing involves bending and curving along a straight line. I looked at the strip heaters, that may be the way to go. Thanks for the help.

[h2odvl]

If your going to be forming sheets, I know that acrylic aquariums are made by placing the sheet on a wood frame and heating. When it it at the correct shape they clap the sheet to the form and let it cool. They will use ovens or heating pads/strips. If you use a tube and want to bend it, fill it with sand then cap it the ends it helps keep its shape.

You might also want to put a post in Envision Acrylics or call I'm sure they know a little about what to use;)

[reef165]

Tap plastics or Multicraft sells a heater element that ya use for bending acrylic. It dose strait lines. The last time I looked at one it was $30 ish I think. Ya could basically make one with an old toaster, ya just need to use something to protect the acrylic from direct contact with the element if you go that rout.

[aquariansaltwater]

There are several ways to form it. If you want a long uniform bend in a piece like the front corner of a tru-vu aquarium, you use a tube with a piece of heating rod in it...the type of rod used in an electric oven...you can buy them in straight segments in various lengths. Then apply current untill it reaches the desired temp and the acrylic sheet will drape over the tube containing the rod.

 

If you want a loarge smooth curve you use a form and heat with an oven like previously mentioned. This can also be done with large heaters of different types if no oven is available.

 

If you want to form the part to a complex shape you need very thin material some clamps, a box with some fittings a vacuum source, and a heat source. This will allow you to vacuum form to any shape you want within reason.

 

I've used all these forms of forming plastics/acrylic in model aircraft fabrication.

 

Good luck. Hit me with an email if you have any questions.

 

Matt