firewall prep and seam sealer

I'm just about done prepping the firewall on my 56 Chev. In the course of stripping and welding holes etc I got rid of all the seam sealer. My questions are:

1. Do I paint then seal or seal then paint?

2. What is body seam sealer? Is this a special product I have to get or is there something else available locally that works as well?

3. Do I even need to bother with this stuff?

Thanks in advance,
Rick

 

I sealed and then painted on my 57 Pontiac. There are various different sealers available, I used brush on for my seams, taped things off so my lines were nice and straight. Any good parts store that handles paint and body products should have seam sealer. They put it on from the factory for a reason, so it would be a good idea to put it back. Seals out water, noise, fumes, heat, etc... I'll try and post some photos later, but check my profile pics or my build thread and you should be able to see where I sealed my firewall.

 

Seal, then paint. See your professional auto body supply house for sealer options, there are many and each has its specific purpose and characteristics.

 

I hate seam sealer, I use pannel bond instead. You will never go back useing seam sealer once you try it, gets hard and it will never crack or shrink.

Get the 10 minute speed, anything faster and you dont get finished before it locks up.

Lay down some etching primer, then pannel bond, then pant as normal.

 

Thanks, guys!

 

Regular seam sealer is air dry, so it takes a while to set up and can be too soft for some applications.
I'd use one of the new sealers that you use with an applicator gun...it mixes and dispenses the sealer in one shot. Hardens very quickly and is tough as nails. The gun is a bit pricey, but if you've got a friend in the body bizz, maybe you can borrow it for a day. Fusor or 3M brand. They have a variety of different hardnesses, textures, dry times.
To make it look like a factory application. I apply it and them brush over it with a 1 in. paint brush, with half it's bristles cut off, so it's stiff.

 

I used 3M Fast N Firm Seam Sealer, #08505, for many years without any issues. It comes in a caulking gun tube-No special gun to buy-and it is designed for just this purpose-sealing seams on body joints. Prime, then seal, then paint...It paints up perfectly, remains flexible, (but not too soft) and, if applied carefully, can reproduce factory like seam appearance in most applications. Like chopolds says, if you're after that brushed-on look, lay a bead on, then just dip an acid brush in some thinner and brush it out, it looks factory. And it's not real pricey, if I recall...Good lcuk!

Eric