I'm at the step that I'm supposed to seal all the rivet heads on the firewall with tank sealant. Does anybody have a suggestion on how to to this so it looks neat and clean? That stuff sticks to everything you don't want it to stick to....
I have to admit that I've never really understood why sealing the rivets is a big deal when you have that big cabin heat door in the firewall. It's kind of like "spitting on a fire". I'm not saying don't do it, but I get enough leakage through the cabin heat door that I'm not too worried about the rivet heads.
The type of blind rivets used are not a liquid seal.
Sealing the rivets helps reduce the level of mess should there ever be a coolant or oil leak.
Fuel tank sealant is flammable and gives off noxious smoke when burning. There should be something better to use to seal a firewall.
I used the little punch hole donuts that are for fixing papers in binders. Very happy with the results. The hole fits the rivet perfectly and they really don't stick that well. You should already have some for your kit build book
My conclusion for the sealing is that oil will eventually blow through the firewall as it makes it's way around the engine compartment through general use. Not sure how much the Rotax will blow out but the Lycoming does enough to warrant a solvent cleaning firewall forward every couple years.
That's one of the most significant differences between a lycoming and a rotax. My engine does not drip a single ounce of any kind of fluid. My firewall is as clean now (245 hrs) as it was new.