I have a rod heater mounted in a brass rod and I need to coat the rod with a solid thermal insulator. I have the following options:

  • PTFE
  • Teflon
  • Polyurethane foam

However, I doubt that the foam would be suitable when it comes to be in direct contact with the brass rod. How can I choose the right insulator for this application?

  • 2
    $\begingroup$ This isn't a meaningful question without information on physical space available, on the temperatures the brass rod will reach, and the surrounding ambient temperatures, and the amount of heat loss acceptable. An answer could then tackle the specifics, while illustrating the generalities. $\endgroup$
    – 410 gone
    Dec 17, 2015 at 15:05

1 Answer 1


I would say fiber glass would suffice. It's non-combustable and a good insulator. You can use regular house insulation fiber glass or special shething thats available online. Depends partly on your engineering constraints.

  • $\begingroup$ May I ask you please, can I consider the PTFE teflon is a good insulator, knowing that there will be a direct contact between the teflon and the heated surface of the brass rod. $\endgroup$ Dec 17, 2015 at 13:53
  • $\begingroup$ PTFE Melts at 327$^o$C but the glass transition will be below that. It may work. $\endgroup$ Dec 17, 2015 at 14:08
  • 1
    $\begingroup$ On a related note, if PTFE temperature rises above about 450 or 500 F it begins to degrade into hazardous gases, so be careful. $\endgroup$ Dec 17, 2015 at 18:16

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