Epoxy Over Fresh welds

[cstrom72]

I would imagine that a little bit of grit or cross hatch would help adhesion, but I have some parts that I epoxied before I welded on the car(floor supports torque boxes) and as a by product of welding I burned off the epoxy. Do I need to scuff the weld or will I be safe cleaning it and shooting more Epoxy? I plan on smoothing out some of them that will be seen but The stuff that buried behind the torque box that will never see the light of day again is what im wondering if I can shoot and forget it. Thanks

 

[crashtech]

The best thing from an adhesion standpoint is to spot blast those plug welds before primering. No matter how you do it, the burnt primer needs to be removed, and the metal should be clean of all contaminants. Sometimes I will hit stuff like that briefly with a Roloc grinding disc, then a 3M #7460 'Clean and Strip' disc, followed by 80 grit on a 3" DA.

 

[Bob Hollinshead]

If you don't have a spot blaster buy one, very very handy for stuff like that and the best way. Even the cheap ebay and Harbor Freight versions will get the job done right.

 

[Senile Old Fart]

If you just want to clean the welds up, get rid of the burnt paint, and scuff the welds up to prime try a 3M Roloc bristle brush.
The 1" 80 grit work great for that task. One will last for a long time doing spot weld clean ups so the $7 isn't to hard to part with.
Just the time saved is worth it.

 

[cstrom72]

Thanks everyone. I have a hand held spot blaster that I will use. I smoothed the welds down last night with my cutoff wheel and epoxied my torque box so that I can weld that in hopefully tonight and be done with the passenger side. Im replacing the floor supports and torque boxes and some small pieces of the floor/toe board on both sides of this 67 Mustang. Im having the whole cowl forward sandblasted once I finish replacing all this metal.