Firewall and f672 skin question

[billytime1]

Making holes and thinking , has anyone used a sealant like pro seal to help keep any kinds of liquids from getting into the fuse floor board area, right at firewall and thinking of a small very thin amount of pro seal to make this possible.
And while on this area the firewall to angle metal row of rivets calls for subcut / draw dimple ? Its 040 bottom skin f672 ,,, would countersink the 040 be acceptable. I get that nesting is a bit better.. just a few questions I guess.
Thanks vaf community
I’m happier here than on tech support from vans mountain…

 

[PaulvS]

Yes it is a good idea to seal the edge of the firewall to prevent gas and fluids e.g. engine oil from seeping into the cockpit. Van's is OK with Proseal on the firewall but some builders prefer to use a fire rated sealant.

The skin F-672 should be dimpled for the row of AN426AD4- rivets in the firewall angle because the skin is too thin to machine countersink for 1/8 rivet. There is a bit of vibration in this area so it needs to be as strong as possible.

 

[billytime1]

Thanks

Thank you for the draw dimple explanation. In school and on videos online we were shown that 040 is ok to cs for fastening . I found a video made by “ Walt Disney” that completely explains all the dimple processes in a cartoon.. I’m sure someone else has seen it and posted..
thanks again