Thermal compound for heating element

[Circuitous]

I had to repair the wife's Capresso milk frother, and there's a thermal cut-out that has white thermal compound on it that connects it to the back of the heating element.  But, naturally I touched and disturbed the compound during the work and now I'm not sure that the cutoff switch has a proper thermal connection to the element.

I was looking at various compounds, but I want to find one that can take the heat and won't migrate much.

Here's a couple on my list:

• MG Chemicals 860-150G
• Chemtronics CW7250

Any recommendations?

[vtkkorhanjoh]

Ever heard of JB weld? it might be a little too much for what you need, but will inarguably handle the temperature in your milk frother! The stuff basically is like an epoxy whitch when done becomes an analogue to iron! Ir does not corrode, does not interract with water (or milk) in any way, and when it has set, it has set! If not, some standard cpu cooling paste might do it, as long as it is not in contact with any milk as it may dissolve into your delicios coffe cream!

[Whales]

Almost any solid/liquid is a magnitude better than air.  Keep in mind pretty much any liquid or solid will work well enough, provided:

• It stays stable at the desired temperature ranges
• It is thin (ie squeezed out under pressure, not used like a lump of glue)
• It won't dry out[/i]
  

Have a look at this entertaining comparison, from a writer for Atomic magazine before it started going pretty bad.  Toothpaste and Vegemite work as well as almost anything else, but will dry out.
http://www.dansdata.com/goop.htm


If you have ordinary silicon on hand that is rated to keep integrity at these temps, it will probably be fine.  Ensure it does not release gases when curing, however.

EDIT:  Keep in mind your heating parts will get hotter than the water!  It takes a while for thermal conductivity to raise the temp sensors above trip point.  YMWV

[SeanB]

Do not bother, it will work in any case so long as there is still some compound there. It is a safety cutout, a 5C higher operating temperature will not affect it at all. Most of those switches do not even have any thermal compound, but if you are worried use the cheap white zinc oxide in silicone grease used in cheap amplifiers and available in any computer repair shop as the free tube with the cheapest PC CPU heatsink.

[Circuitous]

@seanb Thanks.  I have some decent heatsink compound, I'll give that a try and check it for migration.  I won't worry about finding a high-temp stuff for this.

[nctnico]

IMHO you only need compound if you need to transfer heat energy. A thermal switch just senses heat and very little heat leaks away throught the plastic housing.

[IanB]

I had to repair the wife's Capresso milk frother, and there's a thermal cut-out that has white thermal compound on it that connects it to the back of the heating element.  But, naturally I touched and disturbed the compound during the work and now I'm not sure that the cutoff switch has a proper thermal connection to the element.

I was looking at various compounds, but I want to find one that can take the heat and won't migrate much.

Here's a couple on my list:

• MG Chemicals 860-150G
• Chemtronics CW7250

Any recommendations?

Much cheaper to locate something like this at your local auto parts store:

http://www.amazon.com/CRC-5351-Caliper-Synthetic-Grease/dp/B000M8IF1Q

(I just searched for "high temperature silicone grease" and looked at what turned up.)

As noted above, all it has to do is withstand the high temperatures without baking solid. Since air is an insulator, the job of any thermal compound is simply to fill in the gaps and exclude air from the mating surfaces.