Graphite piston material

[Chuck in E. TN]

What are your sources of graphite rod for pistons? I’m building a ‘tin can stirling’ and have used a 1” steel tube for the cylinder. I need to find piston material that I can turn and lap to fit.

Chuck in E. TN

[NickG]

Hi Chuck,

I asked the same before I started my tiny stirling build and somebody suggested this place:
http://www.nogginend.com/index_files/GraphiteRound.htm

I had some graphite donated by a very kind member, I have some left but it's not big enough to get an inch dia out of. I didn't get my stirling working but I'll try again 1 day. Will be trying the graphite on the two flame lickers I'm building now too.

Nick

[Chuck in E. TN]

Wow, pricey. I imagine shipping will add quite a bit. I think I will experiment with casting a piston from epoxy.

Chuck in E. TN

[sorveltaja]

Chuck, have you asked, if any EDM company has some leftover pieces?

Graphite is quite expensive, as I ordered two 20mm(0.787") bars long time ago. Despite that, it has unbeatable heat expansion factor, so it won't stuck on the cylinder, when heated(cylinder might expand more, than graphite piston, depending on cylinder material). Also it is totally self-lubricating material.

If you manage to get suitable size graphite rod, be sure to have a vacuum cleaner running, when machining it, to protect your lathe and other electrical devices, as graphite dust is indeed an electrically conductive material. 

[Brass_Machine]

Ebay Chuck. That's where I got mine

Graphite rod on Ebay.

Eric

[Dean W]

Chuck, I get mine from Jerry Howell.  They're in the States, so shipping is not a problem.  Check the link.
http://www.model-engine-plans.com/partskits/miscsupplies/index.htm

[boatmadman]

If you know an industrial electrician, ask if they use carbon brushes on motors or generators. They get replaced regularly and there is always a nice bit left.

Ian