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HDPE for moderators

PostPosted: Tue Sep 06, 2011 7:58 pm
by George Dowell
I like HDPE.

I need to learn how to cut the long pieces shorter.

Paid only $2 per pound but shipping was steep ( by truck)

Geo

Re: HDPE for moderators

PostPosted: Tue Sep 06, 2011 8:21 pm
by Doug Coulter
Yeah, and once you get them to decent size, sell them to us -- a few of us could use more. I stuck myself with a bunch of UMHW HDPE, and boy is it a pain to work. A regular bandsaw, or a metal cutting saw melt it and then it seizes the blade. So far, spade bits drill it well, and a table saw or chain saw seem to be required to cut it. Has to have good wide kerf and fast chip removal to do the job without getting stuck in there it seems. I was afraid to try my woodworker neighbor's wide kerf (offset teeth) bandsaw for cutting up logs, as those blades I wouldn't want to have to replace, but it might have worked. Somehow, I don't think a hot wire would work here, and I know from experience that handsaws and sawsalls don't do it. I did OK but messy work with a chainsaw (needs a powerful one) but you have to stop frequently to keep the chips from jamming up in the clutch and hardening there. Seems like you have to melt it to cut it, a razor sharp japanese cabinet maker's hand saw would hardly scratch the stuff.

(Geo, this should go in materials and fab somewhere)

Re: HDPE for moderators

PostPosted: Thu Sep 08, 2011 1:41 am
by Jerry
A cold saw is the way to go. Once you use one you will never go back to a bandsaw if you can avoid it. I use the one at work to cut delrin and it leaves a near mirror finish. Smoother than I can generally get with a mill.

Of course the machines cost quite a bit. But smaller ones can be found used.

Re: HDPE for moderators

PostPosted: Thu Sep 08, 2011 3:01 am
by chrismb
For the sub-educated of us (well, me then!) what is a 'cold saw'? I could leave mine in the fridge first, if you think that helps! :lol:

Re: HDPE for moderators

PostPosted: Thu Sep 08, 2011 3:32 am
by George Dowell
A cold saw looks identical to a chop saw or radial arm type saw, until you turn it on. The blade goes around incredibly slowly, but with unbelievable torque. Maybe 30-50 RPM. It just doesn't heat up. Usually run wet.

Built strong, like a Diesel engine, so are way expensive. I never owned one.

Geo

Re: HDPE for moderators

PostPosted: Thu Sep 08, 2011 5:39 pm
by Jerry
Yep, like George said. The entire blade is made from High Speed Steel and are can be resharpened. The blade may turn slow, but they cut fast.