Humm information on the fire performance of paxolin (or FR-2 or FR-4) seems rather thin on the ground (or thin on Google at least) - "self-extinguishing" seems to be a specific as I can find, which as I recall is about the standard that plastic CU cases were supposed to meet, which might not be that reassuring.

   - Andy.

To be declared FR4, the material has to meet UL 94 V0 - when a flame is applied to a vertically held sample and then removed, it must not keep burning for more than 10 seconds, and if anything flakes off or drips off it must not be burning. Paxolin type material generally does not meet this though some brands do claim to meet the easier FH1. Similar classification ratings occur in IEC 60695-11-10.

We used to use a lot of sheets of Tufnol in varying thicknesses - if it got hot it just used to char and give off a awful smell, same when drilling and cutting the stuff. No idea if it is still available though.

We used to use a lot of sheets of Tufnol in varying thicknesses - if it got hot it just used to char and give off a awful smell, same when drilling and cutting the stuff. No idea if it is still available though.

I've also used Tufnol in the past for different applications. A quick look on RS shows they still sell it in various types. Whale is cotton weave and Kite is paper based. I seem to remember Carp being a variant as well.