"John Doe" wrote in message
...

I'm looking at 3/16" thick polyethylene sheets. Can it be bent 180°
to an outer diameter of about 1 1/4"?

This will require heat, but the good part about forming PE is that it melts
easy and doesnt require drying.

If you have a waffle iron with removable grids, you can make your self a
strip heater very easy. Lay out the iron flat on a surface that will not be
affectd by the heat, remove the waffle grids, and using foil make your self
some heat deflectors. (If using kitchen foil, fold it over several times.)

Position the foil so there is an open gap about an inch wide, and hold the
area you want to form over the gap in the foil about an inch or so above.
You may have to flip it a few times to heat it evenly.

In the natural state PE is sort of milky white. With the application of
heat, it turns clear and s then ready to form. To make the bend you
describe, get a length of rod about 1 inch in diameter. You can use wood,
copper or aluminum sucessfully but if yu use metal be sure to pre heat with
a torch or the metal will suck heat out of the plastic too fast. Polishing
helps also. If you use wood, sand it really smooth. If you decide to use
metal as a form heat it gently untill you can touch it but only for a short
time.

While heating the plastic, move it back and forth so the area you heat to
clear is about an inch and a half wide. When you have a clear spot in the
plastic an inch and a half wide lay the center of the clear spot over the
rod and fold it.

It will give you a better form if you have a 1 inch board under the rod and
some spring clanps to attach it too while the melted plastic cools.

It will deform aroung the edges so form a piece that is longer and wider
than you want to end up with.

It will probably be a little funky where the melted part meets with the part
that wasnt melted but for a skid plate this should not matter too much.

A fan will speed up the cooling process.

When the PE is cear it will burn your skin so be careful.

Once you have the plastic clear, that is the time to take it away from the
heat. If you continue to heat it will go from soft to liquid pretty quick.

I didnt meat to make this sound too tough, you might practice on some scrap
to get the hang of it before you do the full size piece.

You do not need to worry about the smell. It will not hurt you like other
stuff might.




I suspect some form of HDPE if not UHMW is available at the local
hardware Borg. Will check tomorrow, but I'm not confident about
getting good information about what the material there really is.

Look for milky white cutting boards that have a waxy feel to them. These
are usually UMHW PE. I have not seen PE as a raw product at the borgs.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.