Made a bead of Loctite 5399 around the lower perimeter of the firewall. I was unable to buy firewall sealant on this side of the ocean and Van's is not allowed to ship it anymore. Other Dutch RV builders adviced me to use Loctite 5399. What a mess! The stuff sticks like hell and dries quite fast. Besides that it's hard to work in that area even with the fuelage on his side. After installment of the interior you will not see it anymore.