where to get carbon graphite rod in 1" dia. at a decent price?

[camaroboy383]

k guys,,, this stuff is expensive... mcmastercarr.com is the cheapest i have found it at 40.00 for 12" of 1" rod.....im only looking for a small chunck,,, like 4"-6"... any good source for this stuff that you know of??? or does anyone have i chunk i could purchase??

thanks for any help....

alden

 

[Terry Keeley]

k guys,,, this stuff is expensive... mcmastercarr.com is the cheapest i have found it at 40.00 for 12" of 1" rod.....im only looking for a small chunck,,, like 4"-6"... any good source for this stuff that you know of??? or does anyone have i chunk i could purchase??

thanks for any help....

alden

What's it for? Maybe we could suggest a way to make it, or a cheaper sub?

 

[camaroboy383]

well,,,,its for a flame licker engine,(vaccum engine)... i had put one together recently,,spent hours upon hours on the lathe and such...got it all together and it just wont run...been all over the place with timing,,,lightened parts,,,re-fit the piston several times to make sure,,shortened the stroke,and lengthened the rod,as i thought there was too much volume.... all the elements are there but one.....i made the piston out of aluminum,which rides in a copper bore pressed in the cylinder,,,,now jan ridder,,and jerry howel use carbon graphite to make pistons as the fit can be stupid tight,,,but still glide freely in the bore...plus its self lubricating... jan and jerry are flame gulper engine guys if you didnt know...

alden

 

[Terry Keeley]

Uh hu...

Carbon graphite is quite different than carbon fibre, I only have a little experience with fiber, sorry...

 

[camaroboy383]

no problem terry,,,thanks for chiming in....so ya,,, its basicaly a big chunck of pencil lead... :lol: ... it worked in my head,,it worked on paper,,, but it doesnt work mounted on a slab of wood :lol: :lol: ... its all good i will figure it out in time,,, just drives me nuts :blink:

very cool little engines... figured it would be a nice project...

alden

 

[Ken Gibson]

Carbon graphite rods of all shapes and sizes are used as the electrodes in EDM (electrostatic discharge machining). It's a consumable but I don't know the cost. You might try looking in that direction.

 

[camaroboy383]

ken,,,you are absolutely correct my friend...hence the cost....this is how you will find them listed in mcmaster and msc..listed as edm rods....there are a couple grades,,,i need the one good to 800°f.....

alden

 

[Rudy Formanek]

Try e-bay -- http://cgi.ebay.com/Poco-C3-Graphite-1-Dia-x-6-Length-Round-Rod-/150551751392?pt=LH_DefaultDomain_0&hash=item230d956ae0

a search for graphite in Metalworking supplies quickly gave a bunch o hits. Some EDM guys sell thier leftovers on Ebay. But I have used some of this electrode stuff and can say that I don't think it would work as a high speed recipricating piston like in our 2 cycle engines, maybe I misunderstand what this flame licker engine is exactly.

Okay, I took a look at the other thread, this stuff might work for a mouse fart engine, though I don't see a need for the high temp resistance in this case.I understand the cabin fever thing, I've been bitten by the micro indoor heli bug.

 

[camaroboy383]

ya,,i looked on ebay,,and couldnt find the 1" dia. i need....i will keep looking for sure.... the rpm would never ever be an issue....they rarely exceed 2,500 rpm...

the reason for the high temp stuff is there are a couple grades...one is good to 250°,,,which is border line in some licker cases....the fit of the piston and cylinder must be within .0005 from what i understand.. to get a fit like that with a alloy is near impossible without serious drag...the carbon graphite allows this close tolerance and still glides free in the bore..even oil can be a parasitic drag in these engines...everything is supposed to be lubed with graphite powder...super slippery stuff on metal surfaces...its also a heck of a mess to machine,,,must have a vacuum hose close to the tooling to prevent the dust from going all over... once the dust is on somthing it likely wont come off,,,makes a nasty mess i hear...

thanks for the heads up..ill keep my eyes peeled...

ac

 

[Rudy Formanek]

I thought that link I gave was for 1"??? When I machined the graphite it wasn't any worse than pencil lead (getting it off things). Simple green seemed to work okay for clean-up as I remember, and I don't remember any better than Jerry Dunlap. How you gonna get 1/2 thou fit?? I believe the POCO stuff would easily work then, we used it for aluminum torch brazing jigs, great heat and flux (chemical) resistance.

 

[camaroboy383]

yes the link you gave is good...i was just stating i hadnt turned up any results...as far as fitting that tight....well the piston is machined down to .001-.002 + of the target bore,,,,being a big hunk of pencil lead,,, the method is to lap the piston with standard paper till the piston will hold itself in the bore...this method is used by several from what i have read....

ac