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widgitmaster
03-04-2009, 01:27 PM
Is it possible to bend a 1/8" thick sheet of Polycarbonate (Lexan) using a heat gun? I have to make a sliding splash guard for my lathe, and do not want to make it out of several flat pieces!

The sheet I just ordered is 1/8" x 24" x 48"

Any one with experience please let me know how it worked for you!

Thanks,
Eric

LeeWay
03-04-2009, 02:25 PM
It will work okay, especially for mild curves. Sharper bends would need a torch or heat strip to do well. The key is not to get it too hot. It will bubble up on you if you do. The moisture inside starts to boil I think and that creates the bubbles.

I may be best to lay it on something with a similar curve like a barrel or can or pipe or something. Then getting the whole part up to the right temp, it will lay down around it just with gravity.
Once bent, you can quench it with a wet rag and air. Once cooled, it should retain that shape.

Geof
03-04-2009, 02:29 PM
Heat gun is very tricky with polycarbonate. This plastic absorbs moisture into the surface and when you heat it enough to bend the temperature is high enough to vaporize this water and blow bubbles in the plastic. When polycarbonate is going to be vacuum formed or heat bent it is baked for several hours at something like 50 or 60 degrees C to drive the water off.

In addition even when the water is baked off the temperature needed for bending is very close to the temperature at which polycarbonate is so soft it just sags; controlling things with a heat gun is not simple.

But all is not lost; you can bend it very well in a sheetmetal brake. Actually it bends like a charm. You need a brake hat can handle something like 18 gauge steel, the polycarbonate is surprisingly tough. I have found it best to put about a 1/16 radius on the top clamps otherwise you get them digging in badly and almost cut your polycarbonate off. With a much larger radius you get a lot of spring back. The edges of the polycarbonate need to be quite smooth and if you have the teeth marks from saw cutting small cracks can start creeping in from these. Sanding the edges on a good 120 grit belt works fine but do not let it get warm otherwise you then introduce stress cracking.

protman16
03-04-2009, 02:53 PM
widgitmaster,

You can use a break if you need sharp bends. Otherwise if the part is small enough you can put in an oven to heat it up enough and then use a pipe or some other round surface to bend it around.

nervewrecker
12-15-2012, 06:30 PM
sorry to bump an old thread but whats the best way to bend a 1/8" sheet? Looking for a kinda convex bend.

Thermoforming?