Cowls,@#*^#spot welds,and seam sealer?

[67 GTA]

I just finished tearing off the cowl cover and the cowl panel also. Luckily just some pin holes around the hats. It will all get blasted and epoxy primed before reinstalling. Is it crucial that the seam sealer goes in between like the factory, or will a coat on the outside seams work? I know my mig welder will not like that stuff. Also, I am losing sleep thinking about the carnage left after the spot welds burn the primer off inside the seams (shudder). Is there a solution or am I just being the usual paranoid perfectionist? I will try the "hat" repair since the metal isn't eat up. What about the studs that hold the fresh air vents to the cowls under the dash? Will they come off with the hats?

 

[John Z]

You're using weld thru primer, right?

 

[67 GTA]

I am going to use PPG DP40. I drilled the spot welds all the way through and will use a piece of copper under the hole to fill them back in. I have never used weldable primer. Will weldable primer burn off inbetween the panels around the spot welds?

 

[67 GTA]

I am going to use PPG DP40. It is a two part self echting epoxy. I drilled the spot welds all the way through and will use a piece of copper under the hole to fill them back in. I have never used weldable primer. Will weldable primer burn off inbetween the panels around the spot welds?

 

[67 GTA]

I am going to use PPG DP40. It is a two part self echting epoxy. The whole car will be stripped to the metal and coated with it. I do not want to put anything on it that is not self echting. I am doing variuos repairs before I put it on the rotisserie. I drilled the spot welds all the way through and will use a piece of copper under the holes to fill them back in. I have never used weldable primer. Will weldable primer burn off inbetween the panels around the spot welds?

 

[67 GTA]

That's funny

 

[John Z]

You want to use a special primer in the areas that will get welded. Here is an example
http://www.levineautoparts.com/upwelprimaer.html
I'm not recommending this brand, I just pulled it off the internet to give you an example.

 

[67 GTA]

The use of weld-through primer is being hotly debated throughout the industry, but some manufacturers, such as DaimlerChrysler, are starting to make statements against its use in certain applications,” he states. “The concern is the integrity of the weld, which is weakened if weld-through primer is present. Porosity in the weld nugget can result, causing zinc evaporation and burn off at the weld site. These conditions make the sheet metal vulnerable to corrosion because it is not protected adequately.”

As an alternative, Olson prefers epoxy primer, which burns off at the weld site like weld-through primers, but provides better corrosion protection qualities. “Epoxies stick to bare metal with a minimum of preparation and provide the kind of corrosion protection that comes closest to the OEM e-coat,” he adds. “They performed far better in salt and corrosion tests conducted by I-CAR
www.abrn.com/abrn/article/articleDetail.jsp?id=148443


I have read mixed reviews about weldable primer. I have never really looked at it. I will have to check into it.

 

[Red5oh]

I wouldnt expect an epoxy to provide a decent weld at all... the weld throughs are hard enough to get a good weld.

I would practice a bit on some test panels with cured epoxy inbetween them and see what results you get.

 

[tos]

I always use weld thru primer with no problems or corrsion showing up. If you use epoxy primer or any paint or other than weld thru primer you will have alot of trouble welding especially now that you have to fill the holes you drilled. The good thing about weld thru is it kinda seals around the area as you weld where other primers or paint will burn away and leave the area vulnerable to corrosion around the weld between the panels. All the self etching primer you can pile on wont help you there. Have you thought about a panel adheasive instead of welding. There are several on the market that body shops swear by and most are using now for door skins and panel replacements. One that comes to mind is fusar, but there are others that would bond, seal and fill your holes all in one. I still prefer welding though.