pyrolytic graphite vs copper as welding backer heat sink?

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anyone ever use pyrolytic graphite as a heat sink. it's supposed to be 3 to 4x more thermally conductive than copperI was planning on getting some copper bars off ebay as heat sinks when we weld really thin aluminum sheet .032I'm still not 100% sure we will weld the sheet metal. it might be more economical to use epoxy and a piece of aluminum angle on the inside corners to attach together.anyways I was a bit fascinated by the pyrolytic graphite thermal properties and never saw it mentioned here, so maybe it's just one of those useless scientific facts that does not carry over to real world usage.
Reply:Is it cheap? Got a link?Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Pyrolytic graphite can be 3-4x as thermally conductive as copper, but mainly in the plane of the sheet (x-y).  Natural graphite varies, but can be a bit better than copper.  However, in the thickness direction (z), the thermal conductivity is poor. See page 2 here:  http://www.graftechaet.com/getattach...eat-Sprea.aspx"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:It's pretty interesting.http://www.google.com/url?sa=t&rct=j...81449611,d.aWwDifferent one - with pictures http://www.google.com/url?sa=t&rct=j...81449611,d.aWwIt's "new" and fancy, and I probably can't hit it with a hammer, therefore I'd rather use copper Last edited by MinnesotaDave; 12-09-2014 at 09:23 AM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Putting a piece of carbon in contact with a molten weld pool would probably lead to serious weld contamination.
Reply:mcmaster has 1 sq ft for $100, 1/4"thickprobably too expensive compared to copper is the reason it's not used?
Reply:I got my copper plates from the scrap yard.One of them is about a 7x7 1/4 inch thick square the other is about 13 inches long and 6 inches wide, same thickness.Don't remember what the total was but I didn't pay more than $1.30 a pound.So this graphite conducts heat faster.But does it hold more heat than traditional heat sink material?The answer is NO!A volume of copper holds more than double the heat than a similar volume of graphite.So you could use a 1/4 inch copper plate as a heat sink or go look for about 5/8 plate of graphite to hold the same amount of heat.Iron also holds about the same amount of heat per volume of copper, but you have to keep the rust off it, plus iron and steel don't conduct heat nearly as rapidly as copper.Aluminum, which is cheaper than copper and graphite, will conduct heat faster than iron but doesn't hold as much heat, so you would need about a 1/2 inch aluminum plate to equal copper for heat capacity.I would just stick with copper and aluminum, there is a reason why when you open up something with heat sinks inside you always find the heat sinks are always made of copper or aluminum. It works.I would think that the graphite sheets would be easy to break and gouge, making them wear out faster. I don't know how tough they are.Get a block or 2 and try it, you may be on to something. But don't drop $100s in it till you know its going to be better than copper and aluminum.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder