Alrighty, I'm fairly new to this project, but I've been reading up on the bots for about a month. I'll be building a McWire CartBot sometime soon, and I'm hoping to get either parts or money for them for Christmas. I spend so much time on my high school robotics team in the Spring that I can't have a job; Leav can vouch for me on the time it takes up.

Anyhow, onto the topic of the post, I've got no idea whether or not my local hardware stores will carry the Teflon rod. My question to you all is whether or not this can be substituted with another sort of plastic. I know for a fact that in our shop there is a long rod of Delrin that I could use, but I'm not exactly sure if it would be safe to use.

Thanks,
Parker Francis

[www.smallparts.com]

Parker, et al,

I would NOT advise using Delrin. It has lower melting and heat-deflection temperatures. Google:
delrin maximum temperature
and
teflon maximum temperature
and note F vs. C data.

Both give off nasty fumes if you get them too hot (Teflon worse than delrin, if I recall correctly.) There are some other plastics that can be used, but they're typically less available than teflon (PEEK has been used by the metalab folks; I suspect Ultem would also work.)

I think small parts is probably higher price than other online suppliers; I bought some from McMaster Carr. I think MSCdirect.com also carries it. (And these two aren't even mainly plastics suppliers, but will sell by the foot.)

HTH,

-- Larry

You need something that will take the heat. Teflon can take temperatures up to 500

John,

In Googling, I see a *wide* range of maximum temperatures for polycarbonate -- many well less than 475 deg. F! This may be a plastic where getting the exact product is important to getting the expected performance. I've used Lex for a some projects, but never yet in a high-temp application. Have you?

-- Larry

Alright, thank you all very much. I'll look into ordering some then.

Cheers,
Parker Francis

Parker, I bought 12 feet of the stuff, as that was the minimum order at the local plastic supplier. I can ship you small pieces of it for say $8 a foot, plus whatever shipping charges are from Toronto Canada to wherever you are. I haven't looked, but McMaster might be cheaper, but those guys won't ship to Canada anymore #()@*$!!!

I bought .625" and .75" diameter PTFE rod; the .625" works perfectly in the clamps I printed from from the Darwin v1.05 files. My original BFB teflon pieces are slightly larger though, about 16.5 mm if I remember correctly.

I'd get enough for a couple extruders, as you're bound to mess at least one up.

I'll put this stuff on the for sale forum too.

Wade

I thank you for the offer, but it looks like I can get a foot of this stuff from McMaster for $6.02, and I'm sure the shipping from Toronto to Texas isn't very cheap. If my mother pays me as she's said tomorrow, I may be taking a trip to my local Lowes for McWire parts!

Thanks again for the tips and advice guys.

Yes, McMaster will be a much better deal, and simpler.

I'm temped to move back to the US just so I can order from McMaster again.

Wade