Pictures of my Robo-Magellan entry

I just put up some pictures of the 'bot I am planning to enter into the Robo-Magellan competition is anyone wants to take a look...
The polypropylene was laser cut by filener.com. The wheels are from a Carnivore R/C monster truck. The axles are Delrin.
http://home.pacbell.net/jkkroll/bigbot.html
Jeff Kroll http://home.bacbell.net/jkkroll
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Jeff, Looks like a nice base!
Any comments on why you chose polypropylene? Personally I think it's a great choice, and has excellent impact resistance. But I was wondering what other criteria you weighed? -- e.g. high melting point.
Any chance of some pics showing lower contrast of the parts? Kinda hard to make out the detail int eh pitch-black plastic.
-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza
robotguy wrote:

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An M.E. friend of mine recommended polypropylene for several reasons: 1. It's cheaper than polycarbonate. 2. It won't crack when you try to tap it. 3. It is plenty strong (and impact resistant as you said) if given enough support. 4. It won't craze if glued or painted like polycarbonate will. 5. I didn't want clear. 6. Can be welded (I just melted the tab/slots together with my soldering iron).
The pictures were real quickies during lunch at work today. As soon as I find my digital camera I will post better pictures. Anyone else have a Robo-Magellan bot to show?
I would like to post an ongoing build journal detailing the design process. Can anyone reccommend blog software that can post to my website via FTP?
Jeff Kroll http://home.pacbell.net/jkkroll
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robotguy wrote:

Your ME friend made a good suggestion, IMO. If you're near a Harbor Freight, you might look into their plastic welder, which needs a source of compressed air. About $20 when they have it on sale, which is regularly. I use mine with a Variac to provide some degree of heat setting. Pretty nice for welding various plastics, including PVC, which has a very low melting point (165 degrees, versus about 500 degrees for polypropylene).
It's nice to see Bruce offering to cut plastics other than the usual acrylic and polycarbonate. I see he's now offering to cut PVC, so I would assume he has some form of hood or vent for the gas.
-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza
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Hi Gordon, I believe you once said that PVC produces **cyanide** gas when burned - as in laser cutting. Would using a plastic welder on PVC also be a problem ??
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dan michaels wrote:

*Burning* PVC releases hydrogen chloride (plus dioxins, CO, and some other toxic gasses like phosgene). I'm not sure if it release hydrogen cyanide to any great degree, though some other plastics do -- polyurethane for one. Phosgene is a nerve agent that causes choking. You don't want to breath it. HCI is very corrosive, and will tear up your mucous membranes in no time flat.
These gasses are released when the material burns, but not melted. The trick is to soften the plastic so it can be thermoformed, but not burn it. With a welder and a heat setting you can dial in just the right temperature. It takes practice...do it out in the open air first! <g>
-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza
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I finally found my digital camera and settled on Meteteque for blog software so for more info and slightly better pictures check out:
http://home.pacbell.net/jkkroll/blog /
Jeff Kroll http://home.pacbell.net/jkkroll
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That is exactly how I built my centipede. Worked like a charm.
Beware of loc-tite, it actually can craze the polycarb.
Nice looking bot.
Mike

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