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Section 27 Firewall. Priming & sealing questions.

WayneJ

Member
I have all the firewall parts de-burred and was getting ready to prime everything except the (4) stainless steel parts. Then I realized that maybe for the same reason the stainless parts shouldn't be primed or painted, the aluminum parts directly attached to the firewall shouldn't be either.

Also, I ordered some fuel tank sealant for use where indicated and then noticed that Van's sells this:
"Firewall Sealant 3.5 oz. price includes shipping MC-CS-1900 W/SHIP $115.00"
How is this different than tank sealant? What are others using? Why is it so expensive?

I plan to call builder support about this but wanted to get your opinions too.
 
Firewall sealant

Used Proseal tank sealant. Did not know any better. Hopefully I shall be back on the ground in one piece before the Proseal fails and allows smoke and flames into the cockpit.

Related topic. Firewall insulation on the engine side. Look into that before you hang the engine. First time I flew with short pants, I was surprised how hot the footwells become.
 
Thanks for the replies guys. Seems there are many options for sealing the firewall. All are likely good options. Some have even used Hi Temp Red RTV which I would not use. I think I'll go with the tank sealant since that is what I have and what is specified in the KAI. Still not sure what the Firewall Sealant is all about or how it's different from Tank Sealant tho. I talked to someone in Van's builder support about this. He was unaware of the Firewall Sealant or that it is sold on their store. I now remember reading other posts about 3M Fire Barrier 2000. I think someone did an extensive test using actual flame and instrumentation. I will try to find that for review. If someone is aware of that test please help me find it.

No comments so far about priming the firewall structure parts. I understand paint on the firewall is a no no because of the smoke issue in case of fire. But what about the structural parts directly attached to the aft side of the firewall? Seems heat would quickly transfer to those parts and produce smoke as well if they were primed. Maybe since they are a relatively small area it would be insignificant but any amount of smoke in the cockpit would be bad. I just don't remember this being discussed here before.
 
DanH did the test you refer to. Do a search on his user id and maybe about 1 or 2 years ago. Material such as a flammable insulation on the back side of the firewall is a bad idea.
 
3m 2000+

I also purchased a tube from Spruce of the 3M 2000+ fire sealant, and it worked out great. Rivet right away though, don't let it set overnight or anything in my opinion as it hardens and you want all of it to ooze out as much as possible.
 
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