UHMW polyethylene more abrasion resistant than carbon steel?

I had high hopes for this stuff. Ordered UHMW polyethylene tube part number 8705K141 from McMaster-Carr. Banged it on the end of a bolt and it left marks on the tube. So the high impact resistance is relative to HDPE polyethylene, fine. I read that you can't drive a nail through it. I drove a nail through it several times with no problem. Then I read it's supposed to be 15 times more abrasion resistant than carbon steel. So I put it on a smooth concrete driveway and laid a brick on top of it. Pushed back and forth in the tube slid on the driveway. Pick up the tube and noticed lots of abrasion. So what do they mean by "more abrasion resistant than carbon steel"? Does that mean like if you rub it with your thumb for

15 million years it will last longer than carbon steel would? Are they using a narrow definition of "abrasion resistant" and "outlast"?

Thanks for any translation of what they're talking about.

Reply to
John Doe
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Wherever you got your information from was totally wrong. It's a low friction material, meaning that an object will slide much easier on UHMW than it would on another material. However, low friction and abrasion resistance are two different things. In general, if you have something sliding over a surface, coating the surface with UHMW will reduce abrasion to the PART, but possibly at the expense of the UHMW wear surface. For example, it is often used in jigs and fixtures, such as custom fences and cutoff sleds, to create a surface that allows the part to slide easily without expensive ball or roller bearings.

The nail thing is ridiculous. I use woodscrews and other pointed fasteners to fasten to UHMW and Delrin all the time.

Is this coming from a manufacturer's spec sheet or some internet fact file of dubious value?

Reply to
woodworker88

Assuming that you are not a troll....

One possible translation would be, if you go to the trouble to buy something from a fine company like McMaster-Carr, you probably shouldn't beat it to death and try to destroy it.

Almost any product they sell can be damaged. Such torture testing is both discouraged and bizzare. This sound like some of those weird reality shows where they destroy stuff and call it "science".

Reply to
Lee Michaels

It is used to line dump truck beds, gravel chutes and such. It will outlast steel in applications where the pressure is not too high. I have it to make drawers open easily by putting it on the runners.

Dan

Reply to
dcaster

Take a strip of UHMW and a strip of carbon steel of the same dimensions. Run both through a sandblaster loaded with aluminum oxide media. Repeat. The UHMW will still be there long after the carbon steel has been abraded to nothing. And some grades of polyurethane will still be there long after the UHMW has gone away.

Yes, I have done this. No, you won't find the results online, they're in a United Technologies internal document.

Reply to
J. Clarke

I'd say it all depends on how the test is defined. It sounds like your test is a good example of the phenomenon of differential cutting. I bet if I repreated the test by abrading both samples with a steel saw blade, I'd get different results.

todd

Reply to
todd

Re: the nail thing - UHMW has enormous compression resistance, so if you're trying to drive a nail through the plastic without drilling a pilot hole first, and the plastic is thick enough ( say, 3/4" thick or better), odds are you'll bend the nail instead of pushing it through.

Same thing with screws - you have to drill a pilot hole first or you'll likely snap off the screw in the hole.

That's what they're talking about in those areas. You probably had a thin piece.

Re: the abrasion resistance - UHMW is more abrasion resistant that steel, but abrading it on a driveway is like taking sandpaper to it. Sine the carbon steel you're comparing it to is harder then the driveway material, it's not a fair test - with the steel, you're actually abrading the driveway surface. With the relatively softer UHMW, you're actually abrading the plastic.

Here's a link to a discussion group that has more information on UHMW;

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Reply to
eric h

Assuming that I'm not a troll? You do woodworking or metalworking (apparently woodworking) and the materials you use cannot be stressed or tested? Only if what you make gets put on a shelf, maybe not even then.

Apparently you live in a very small world.

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Reply to
John Doe

...

Sandpaper is the definition of "abrasive".

So it's more abrasion resistant than carbon steel, but only maybe if you're rubbing it with something soft.

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Reply to
John Doe

Or something hard.

Reply to
J. Clarke

Not really. It works well in abrasive conditions and usually will outlast steel. For example, a brick company was having issues with tail sprockets on a conveyor - couldn't get a month out of them. I sold them some UHMW sprockets and they lasted 6 months and were still running fine although they were showing wear. They just put them on a

6 month PM and were happy as they could be. I know of a log deck that had UHMW sprockets that lasted 13 years with all the bark, dirt, sand and everything else dumped on them.

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REMOVE

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