heat conductive material

How about DensoTape?

You could go to

www.Mcmaster.com

and look at thermal grease, or you might just try heat sink grease (Newark or DigKey or probably RadioShack)

Try automotive engine laquer.

Actually, I am trying to replace roll formed or extruded aluminum as a heat transfer medium in a hydronic heating application. I hoped maybe there was some "goop" that would do the job as well, but not have the price volatility of aluminum.

So far the leads have been interesting, but no home runs.

High Temp engine (auto) paint

I'm thinking a compound such as terrazzo or the epoxy resins that are normally used these days as a binder for terrazzo could well provide the medium you're seeking.

You do not want to do with anything that (might) have solvents in it. Such things, including greases might / will destroy the plastic PEX. I understand your concern with the extruded Alu heat exchanger.

Go to the Fine Homebuilding magazine:

www.FineHomebuilding.com

They have advertisers for subfloor heating based on crosslinked plastic (like PEX) pipes and bent Alu sheetmetal heat transfer from it to the floor, attached from below. It seems to be built just for the task you are asking about.

Just for example, see; www.radiantec.com www.warmboard.com

I understand the concept of the terrazo binder or overpour of gypcrete or the like. Was hoping to avoid the need for leveling and the themal mass effect of poured concrete.

Maybe I need to go back and review my physics and heat flow. Heat sink grease seems likely, but you buy it by the ounce and I need gallons.

I'm getting the idea you are not using hydronic heat on the floor?

There are heat exchangers designed for heating areas say for raising chicks or baby animals and for use in automotive application. It would be a tube with tin fins, a plethora of sizes available, www.Globalspec.com

Anyway if you are the old terrazzo binder maybe more fitting, it was a combination of poly and vinyl resins. I have used it in past to cover landings and if mixed right was self leveling though that mixture took longer to set.

You could use Lucite which is the original plexiglass but soft and easily scratched though conductive and under floor covering may suffice; available in sheet form up to 4'x8'.

Thank you for making think of this I am upgrading a century old hydronic heating system. It is conceivable to put three layers of sheeting illuminating the mill work of cutting grooves. I can use a .250" whole sheet on the wall and use strips of Lucite thick enough to shelter the PEX, fill remaining space with resin, cover with another whole sheet creating a radiant panel to replace the old time standing radiator.

Cheers!

Use the mil spec # and order bulk supply of thermal grease from Standard oil.

I suggest using a heat sink compound that can be found in any electronic component store.

or search on GlobalSpec: "heat sink compound".

Good luck!

I forgot to login.

The heat sink compound is used in electronics for thermally coupling a CPU or other power component to a heat sink or cooler. I think is the right stuff for your application.

You guys are off the track. The grease is designed to be used to even out heat conduction between mated metal pieces or metal to glassfiber epoxy. Neither this material can be bothered by most solvents. Any fat or solvent will attack the integrity of the PEX or any other plastic over time, causing it to rupture. So, it is not a useful idea to get near that with any of this stuff. Additionally, he needs thermal coupling by the GALLONS, and cheap. That leads back to home building techniques.

On the attack of PEX I am willing to take a small bet for bragging rights. To put some fairness into it, I am relying on long experience. I did not test this case before placing the bet offer.

Leveles, you are spot on. I am trying to avoid aluminum extrusions or roll formed pieces for cost and squeek potential. Also, would like to avoid lightweight concrete if at all, due to the weight and heat sink grease sounds "not so hot".

Options are dwindling. Does anyone know if acrylic aluminum paint will conduct much heat? It is sold as a radiant barrier, but so is aluminum? So far the info off the web doesn't address heat conductivity of the paint. Think it would eventually eat away at the PEX since it has no VOCs?

Inexpensive readily available good conductor of heat = table salt or the result of sulfuric acid added to salt = carbon

Glass is also good conductor of heat, beads without sharp edges from broken tempered glass.

Clay and or ceramic pastes

Quartz crystals after deburring.

Bauxite

Basalt

Bromide in solution

Aluminum paint of any kind is a heat reflector for radiated heat. I have no clue, how it will behave in a conducted heat. I, for one, would leave that to the laboratories to figure out, and go with a true and tried solution in my case for now.