Here is what we use at work:
Now in our application, which is a US Coast Guard certified Ferry Boat, the Nelson Transit (mct) is what cables use to penetrate a fire boundary bulkhead.
Red rubber type blocks fill around the wires, in a flange collar welded into the bulkhead. Mineral wool and the red RTV like product are used on older transits.
This company specializes in the application refered to in this post, but mostly buildings and ships.
I think th CLK silicon caulk, and the Puttybar might be applicable to us?
I hope Dan H or someone who is good with MSDS and Tech sheets might find something here?
For myself; I have a RV-8 QB fuse, and have done nothing yet about 'structural fire protection'.
I have an experimental engine, so I know this is important.
Ground running is one thing; I can shut down, jump out and grab the garden hose or fire extinguisher, but now I have an N number and I've fitted the wings, so...I need to get serious about the risks involved.
EAA 668340, chapter 326 & IAC chapter 67
RV-8 N89SE first flight 12/26/2013
Yak55M, and the wife has an RV-4
There is nothing
-absolute nothing-half so much worth doing as simply messing around with Aeroplanes
(with apologies to Ratty)