SonexBuilders.net

Posted: **Tue Aug 14, 2018 4:10 pm**

Fellow builders,
I would like to insulate the space between the forward end of the fuel tank and the upper firewall as well as the whole rear side of the lower firewall. Has anyone done the same and if so what product did you use?
Blue Side Up!
Sherm

Posted: **Tue Aug 14, 2018 11:05 pm**

You might look at intumescent paint. A common one is from Contego and often goes by the name "The Fire Stops Here". Its a latex paint with little suspended bits of a fire-retardant material in it. Some folks have tested it with blowtorches (on scrap material) and have shown that it gives you some decent extra time before things start to burn/melt through.

I applied some on my Sonex firewall and found it to be relatively easy to work with, albeit with some caveats:

It doesn't adhere to slick metal on its own, so you need to scuff/sand/scotchbrite (and then thoroughly clean) the stainless steel. Otherwise the paint will flake off easily.
It doesn't spread and coat the substrate very well; so don't brush it on thick and expect it to "run out" nicely. Instead I found it much better to brush it on in thin coats and use 2-3 coats to get solid coverage.
The suspended particles mean you need to really thoroughly shake/mix the can before painting. (Its not a problem, but something to remember)
It can still be chipped off after it dries, so use care when hanging your engine or accessories on the firewall.
I've found that the material will get stained by oil or other liquids, so don't expect it to remain a uniform pristine color like a powder-coat or true top-coated paint job would. And of course you don't want to ruin the paint's safety properties so harsh chemical cleaners (to try to remove stains) is not recommended.

Enjoy,

--Noel

Posted: **Wed Aug 15, 2018 6:03 pm**

Sherm I used Thermi Guard FR by Thermo-tec.com. It is a one sided foil insulating pad. Part #14130? I adhered it to the cockpit side of the fire wall with a spray on adhesive I believe by Loctite. The above part number is a 24x48 inch piece. There was plenty left over and I cut pieces to tie wrap around my gascolater and my fire sleeved fuel lines. I probably sourced it from an auto parts store.

David

Onex N951X

Posted: **Thu Aug 16, 2018 10:24 pm**

surfly wrote:Fellow builders,
I would like to insulate the space between the forward end of the fuel tank and the upper firewall as well as the whole rear side of the lower firewall. Has anyone done the same and if so what product did you use?
Blue Side Up!
Sherm

What is your purpose for insulating? That will determine what you use. If if's for thermal comfort there isn't much going on at the firewall so it may be a waste of effort. If you're worried about cold, most of the air comes in through the wing roots (and blows on your legs), not the fire wall. If you're worried about heat, not much comes through the firewall.

Posted: **Wed Aug 22, 2018 11:40 am**

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