Thermally conductive potting compound

[Tom]

I need to fill hundreds of test tubes about half full with a thermally
conductive material that will harden. Thermally conductive epoxys work
perfectly but are very expensive. Is there a lower cost product to use?

The test tubes will be use to test a heater in a piece of test
equipment. There won't be anything added to the test tubes. Just need
a solid mass to transfer heat.

Thanks, Tom

 

[James Meyer]

I need to fill hundreds of test tubes about half full with a thermally
conductive material that will harden. Thermally conductive epoxys work
perfectly but are very expensive. Is there a lower cost product to use?

The test tubes will be use to test a heater in a piece of test
equipment. There won't be anything added to the test tubes. Just need
a solid mass to transfer heat.

Thanks, Tom

There are low melting point metal alloys that are often used by
machinists to hold odd shaped pieces to be machined. These alloys come in a
wide range of melting temperatures. Some as low as 180 degrees F. Melt some
and pour it into the test tube. You can recover it and use it again if you need
to.

http://www.hitechalloys.com/hitechalloys_002.htm

Jim

 

[John Larkin]

I need to fill hundreds of test tubes about half full with a thermally
conductive material that will harden. Thermally conductive epoxys work
perfectly but are very expensive. Is there a lower cost product to use?

The test tubes will be use to test a heater in a piece of test
equipment. There won't be anything added to the test tubes. Just need
a solid mass to transfer heat.

Thanks, Tom

Lead? Solder? Wood's metal? Epoxy filled with aluminum filings? Epoxy
filled with sand?

John

 

[[email protected]]

Lead? Solder? Wood's metal? Epoxy filled with aluminum filings? Epoxy
filled with sand?

How about the sealant you can buy at Home Despot (latex caulking
compound), or the many similar products?

Max

 

[John Popelish]

I need to fill hundreds of test tubes about half full with a thermally
conductive material that will harden. Thermally conductive epoxys work
perfectly but are very expensive. Is there a lower cost product to use?

The test tubes will be use to test a heater in a piece of test
equipment. There won't be anything added to the test tubes. Just need
a solid mass to transfer heat.

Thanks, Tom

A little epoxy and a big bag of B-Bs should do it. If you don't need
that much conductivity but more heat storage, epoxy and very coarse
sand or pea gravel should be better.

 

[Rich Grise]

I need to fill hundreds of test tubes about half full with a thermally
conductive material that will harden. Thermally conductive epoxys work
perfectly but are very expensive. Is there a lower cost product to use?

The test tubes will be use to test a heater in a piece of test
equipment. There won't be anything added to the test tubes. Just need
a solid mass to transfer heat.

What are you trying to accomplish here? Your second paragraph sounds
like what you're really looking for is test-tube-sized and -shaped
heating elements. If that's the case, then just shop around for
heating elements. If it's sensor probes, then (all together now)
shop around for sensor probes!

If it's something much more arcane and sophisticated, then please,
do tell!

Good Luck!
Rich

 

[Active8]

A little epoxy and a big bag of B-Bs should do it. If you don't need
that much conductivity but more heat storage, epoxy and very coarse
sand or pea gravel should be better.

What about cheap plaster, at least for the binder?

 

[Al]

There are low melting point metal alloys that are often used by
machinists to hold odd shaped pieces to be machined. These alloys come in a
wide range of melting temperatures. Some as low as 180 degrees F. Melt some
and pour it into the test tube. You can recover it and use it again if you
need
to.

http://www.hitechalloys.com/hitechalloys_002.htm

Jim

Very expensive stuff. Eight ounces costs about $12 retail at online
retailers like MicroMark

http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catal
og&Type=Product&ID=83092

Al

 

[Clifford Heath]

Very expensive stuff. Eight ounces costs about $12 retail at online
retailers like MicroMark

And the density is very high, so 8 ounces is a very small volume.
It's the high indium content that makes it expensive.

There's an LMP alloy of bismuth, tin and lead, which melts below
the boiling point of water. It should be possible to make it using
bismuth shot (sold to replace lead shot) and, wait for it, solder.
Might need to tweak the tin/lead ratio slightly to get the lowest
MP, but if that's not critical... at least it's cheap.

Clifford Heath.