For people that do restos, welding question.

[The not so tall man]

Do you put anything in between the panels you are welding other than weld through primer. I know some cars have weld through adhesives. Not sure if anything as old as the 60's/70s stuff had anything like that.

 

[Kern Dog]

I've used the weld through stuff.
@eldubb440 would be THE man to know here. That guy fixes everything.

 

[gkent]

Upol weld through primer on the whole flange - not just where the welds are. If I'm welding panels that have been e-coated then I just clean it of the weld area and Upol those spots.

 

[eldubb440]

i've used this, and only this for ever...... used to be able to buy quarts..... I buy a gallon and give a quart to a couple friends..... I brush it on.....gallon lasts for ever, unlike the aerosol cans

https://www.grainger.com/category/welding/weld-fixturing-marking-preparation/weld-through-primer

 

[Bighouse]

Weld-bonding is common of new cars, it’s applied and then squeezed with the spot welder. The idea is continuous connection. It’s relatively new in the last 20 years-ish. It also helps with corrosion between the panels.

I like dubbs brush-on can I be had to chuck dozens of 1/2 used spray cans because they clog- I don’t care how long you shake them for they all suck

When you’re done you can use a cavity wax. SEM makes one that wicks in nicely

 

[eldubb440]

 

[Rich H.]

The best I have personally been able to do is.... coat the entire weld area with SPI black epoxy, allow to cure 24 hours or preferably more, mock up and align the panels in prep for welding, then use small carbide bit (dremel, die grinder) through the plug weld holes to grind the epoxy back. Fully plug weld the panel in place. Then wipe down with wax and grease remover, allow the cleaner to flash off, and using a brush, saturate the entire weld seam in SPI black epoxy again. Epoxy literally running right through the seam and dripping out the other side is desireable.

It's not as easy as a rattle can with weld through primer, but hopefully it will hold back corrosion a little longer.

After it's topcoated, use cavity wax where applicable.

Overkill? Maybe, but I'm from Detroit area, we need all the help we can get.

 

[Cheapsunglasses]

There’s a lot of great people on this forum. If you need video, Chris Birdsong has a YouTube channel, junkerup, he has some very in-depth videos on metal work on these cars

 

[gkent]

The reason for weld-thru primer is that the product is conductive - so you can strike an arc on it. Also, the copper content does not burn off like any surrounding paint would - instead it sort of rolls back protecting the outer edge of the weld puddle. My theory is the heavier the weld-thru coating prior to welding, the better. You also want to coat both sides of any panels you're welding - there's no point in have weld-through on one side and primer that'll burn off on the other. And the tighter you can keep those seams the better.