Rivet options ? Rivnuts?

[Just 1 More]

I'm not a big fan of all the rivets on the firewall and think it would look better with button head screws. Is it ok to use rivnuts or will the head of the rivnut cause the panel to stick out away from the framework too much. What about 1/4"-20 tap the frame work and screw directly in to the frame? Or maybe even smaller than 1/4" maybe a 8/32" or 10/32" button head.

[rthomas98]

you can use any of the above. But personally I would stick with silicone and rivets. limits a heat or water pathway to behind your dash.

[edwardb]

When it's all said and done, the rivets holding the firewall pieces to the frame are mostly obscured by the engine and related plumbing. I wouldn't get too extreme in dealing with that. The frame tube thickness isn't enough for decent threads with 1/4-20. 8/32 or 10/32 would work. But not as strong as rivets. Agree that rivnuts add some thickness that would affect how things fit. For my truck build (exact firewall) I used 3/16" SS rivets. Touched them on a polisher with the stem removed temporarily, and they look fine. Even though mostly buried. These: https://www.mcmaster.com/98780A212/.

FWIW, what is obvious are the fasteners around the perimeter of the firewall where it attaches to the body. There I did used 10-32 SS button head screws. I used these nutserts made for plastic in the body. Worked great. https://www.mcmaster.com/97217A376/.

[Just 1 More]

When it's all said and done, the rivets holding the firewall pieces to the frame are mostly obscured by the engine and related plumbing. I wouldn't get too extreme in dealing with that. The frame tube thickness isn't enough for decent threads with 1/4-20. 8/32 or 10/32 would work. But not as strong as rivets. Agree that rivnuts add some thickness that would affect how things fit. For my truck build (exact firewall) I used 3/16" SS rivets. Touched them on a polisher with the stem removed temporarily, and they look fine. Even though mostly buried. These: https://www.mcmaster.com/98780A212/.

FWIW, what is obvious are the fasteners around the perimeter of the firewall where it attaches to the body. There I did used 10-32 SS button head screws. I used these nutserts made for plastic in the body. Worked great. https://www.mcmaster.com/97217A376/.

Thank you for the info, I'll place an order with McMaster-Carr for the rivets and inserts.

[FF33rod]

As Paul (edwardB) mentioned, nutserts made for plastic around the perimeter. I also added a dab of panel bond on the back side of each just to make sure they weren't going to spin. For the attachment to the frame, I drilled and tapped the frame for 10-32 button head. Worked great. I actually did the firewall in satin black to highlight the engine and used black button head socket screws so they didn't stand out....

Steve

176172

[lance corsi]

Nobody has mentioned adding tabs to the frame instead of drilling a frame member. Then just drill and tap the tabs to accept whatever screw size you need. It’s extra work but I think it’s a better way. This is assuming the framework is rigid enough without the added benefit of the stressed panel. Unfortunately I did not adopt this method before drilling for my cockpit aluminum.