OT HDPE/UHMW polyethylene?

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.

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.

A second idea might be to get a 1/4 inch sheet larger than the whole board, remove the axel trucks and form the PE over the bottom of the board. When cool, trim the edge level with the top of the board, drill holes for the trucks and screw them back on. This will make the whole bottom of the board a skid plate. It will add some weight however so doing the board flipping stuff will be a little trickier and when you bash your shins there will be more mass to impart a bigger bruise.

Good luck.

I've examined those for other purposes, didn't know what they're made of, thanks.

I'd probably wear shin guards.

Not that it matters, but I'm making a very small skid plate for in-line skates, not for a skateboard. The front 80 mm wheel will be replaced with a 125 mm wheel. That leaves a little more distance between the front wheel and the second wheel, and I want a stopgap between those two wheels so the second wheel doesn't get caught up on stuff the big first wheel rolls over. After an obstruction gets beyond the first two or three wheels, it's no longer a major hazard.

Without the skid plate, it will look like this but with a bigger front wheel.

Subject: in-line skate big front wheel Newsgroups: alt.binaries.phish

The only problem with what you're suggesting, Roger, is that the plastic won't be UHMW when it cools.

UHMW requires heat and pressure to form. Heating it without pressure turns it into something different ( not sure WHAT it is, but it's not UHMW.)

As for differentiating it, cutting boards are usually made of UHMW or HDPE. HDPE is usually high gloss in finish and a solid white - UHMW is a semi-transparent while and semi-gloss at best.

If you really need the material to remain UHMW, I'd suggest cutting it out of a suitably-sized block and drilling out the center.

If you need small blocks of UHMW, you can get them online at;

I've been working with UHMW for 25 years and have never heard this. Do you have a source?

I don't have a source for it, ned, but I do remember reading it - I believe it has something to do with the difficulties you encounter when UHMW is extruded.

I did experiment with UHMW myself to find out more about what I was selling (I sell it on ebay as surplusdealdude), and I do remember weighing a piece, heating it up and re-weighing it after it had been pressed and cooled. It weighed less afterwards.

eric h fired this volley in news:990dff51-3c37- snipped-for-privacy@u10g2000prn.googlegroups.com:

And it took over forty thousand years to cool, too!

LLoyd

I worked for a company that had the capability of injection molding UHMW. Lots of folks said it couldn't be UHMW but a major chemical company that makes the resin tested it and said it had all the properties of UHMW. If it looks like a duck and quacks like a duck ......

I don't think there is a problem injection molding UHMW any more than there is HDPE. If I understand my plastic chemistry, (As a non chemist.) the heaver density varieties of PE just have longer molecular chains. Soda bottles are the same stuff where the molecules are crosslinked so they will hold higher pressure without bulging.