Seam sealer?

[johno]

I'm planing on removing the footwells in the rear seat area and welding in flat panels, for exhaust clearance.
I'm not a welder, but will practice a bit before i attempt this, I have a 110v mig i just bought.
My plan is to make new panels with a stepped flange, which will have holes drilled in it at regular intervals, and to spot weld thru them to original floor pan.
I then have to seal the complete joint to keep out water dirt etc.

Can any one recommend a good product, or for that matter can anyone see a problem with my proposed plan?

Thanks for any help.

 

[larry_g]

When i did this I went to the auto part store and they had Seam Sealer. A can of tar like stuff to brush on. There is also another thread on the board that addressed this point.

http://www.garagejournal.com/forum/showthread.php?t=78706&highlight=seam+sealer

lg

 

[romoman]

You want **** joints so the panels can not rust between them.

As for seam sealer, there are lots of types and methods. Runs from stuff in a caulking tube, to a quart can that you paint on, to spray on. SEM products are usually pretty good. Check out your local body shop supplier.

 

[e-tek]

**** welds are nice, but not necessary in many situations - especially this one. Too hard to do here and you'll get extra strength from putting the floor pan on top of the edge flanges.

Make sure you grind the flanges clean (rust, e-coatings, oils from new metal), then use a weld-though primer before attaching. I would then use screws (either drill and screw or self-tappers) to seat panel pefectely, then weld your spot-welds. Just start in the middle of the hole and work in circles until you reach the outer edge. You'll get a nice rossette.
As for seam sealer, I've been using the black tubes from Pro-Form - goes in your caulking gun. The brush-on stuff skins so fast it's hard to get it to stay smooth.
Good luck - and take pics!

 

[johno]

**** welds are nice, but not necessary in many situations - especially this one. Too hard to do here and you'll get extra strength from putting the floor pan on top of the edge flanges.

Make sure you grind the flanges clean (rust, e-coatings, oils from new metal), then use a weld-though primer before attaching. I would then use screws (either drill and screw or self-tappers) to seat panel pefectely, then weld your spot-welds. Just start in the middle of the hole and work in circles until you reach the outer edge. You'll get a nice rossette.
As for seam sealer, I've been using the black tubes from Pro-Form - goes in your caulking gun. The brush-on stuff skins so fast it's hard to get it to stay smooth.
Good luck - and take pics!

Thanks for the input, sounds good to me.
Do you think it makes any difference weather patch panel sits on top of floor pan or vice versa?

 

[firehawk7]

I do collision work and the best I have come across is urethane sealer, it stays flexible and is strong, so strong you could put the patch panels in with it but I am not recommending that. 3M makes some as do many other companies.


But do not use fast and firm from 3M, that stuff is junk.

 

[lilredex]

I do collision work and the best I have come across is urethane sealer, it stays flexible and is strong, so strong you could put the patch panels in with it but I am not recommending that. 3M makes some as do many other companies.


But do not use fast and firm from 3M, that stuff is junk.

Along the same line, how did Chrysler (and others) manage to seal up the front fenders on their RWD vans then weld through it?

 

[firehawk7]

Along the same line, how did Chrysler (and others) manage to seal up the front fenders on their RWD vans then weld through it?

Resistance spot welders? We had that capability at my old shop, glue and weld. It is used a decent amount today.

 

[lilredex]

Resistance spot welders? We had that capability at my old shop, glue and weld. It is used a decent amount today.

Maybe, then just covered up the obvious mess with seam sealer. It worked whatever the method. Never seen one leak on that joint.