EDP coating

[72cudamaan]

Does anybody have any experience with edp coating and spot welding. I don't know if I have to remove the coating before welding or not.

[Moparal]

I do not know much about painting, but thought I'd bump you back up in the newer posts for some advice from the guys

[shawge]

I think EDP is like paint in that you'll need to grind it away until you get to bare metal before doing any welding.

[gkring]

remove it. That is what spot sandblasters are for.

[Lunchbox]

I was told that with EDP you don't have to remove. Then again with the weld through primer it sucks trying to put a nice weld down as with EDP, either way I remove the EDP or don't apply the weld through primer. It is a much better weld in the end.

Lunch

[wagesofsin]

i agree with lunch.

[elitecustombody]

remove the coating only at the spotwelds,welder will not weld through the E-coat

[E-Body Products]

The E-coat will contaminate your welds.  I don't have the same problem with 3M weld thru, it turns out nice.

[72cudamaan]

So, Daniel, you're opinion is to remove the EDP and spray on the 3M weld thru primer?

[Lunchbox]

I use the SEM weld through primer and some no name stuff of the automotive shelf at the local store. Both bubble from the welding process, and that is if the can isn't clogged up from the zinc. I stopped using it, and go back after the weld and get regular primer between the joint the best I can.

Lunch

[MoparCar]

I've been using U-Pol weld thru. Not much better. I find if I take a small wire wheel in a drill and remove the weld thru primer thru the overlapped punched holes before welding this really helps. This will only burn off at the spot weld area anyway and this way everything else underneath still has full zinc primer.

Store your cans upside down I've been told. It's supposed to help the clogging issue a little. Not sure if it really makes a diff, but worth a try.

Wes

[nick68]

I put little stick on dots where the spot weld is going to be, then spray primer, then remove the stick on dots. Hit it with degreaser and I have some protection under the panel.

[shawge]

That's a great idea.

[E-Body Products]

Yes, remove the EDP around the area that you plan to weld.  For plug welds, generally 1" diameter.

As far as the weld thru primer, I like 3M Weld Primer II.  The II version does not clog as easy as the original.  Also, bump the weld current up on notch when welding through the weld thru primer.

When your welds are growing like volcano magma it is because of contamination.  Causes are as follows from my experience:
1) Wind from natural causes or even a fan.
2) Rusty metal
3) Oily / dirty metal
4) Primer and Paint
5) Lack of shielding gas (clogged nozzle / low tank pressure)

I always use a tank with 75% argon.  I can't go back to flux wire.   

I am not a pro welder, but we do quite a bit in the factory and I have done my share on these old cars.  If you lived close to KY, I would invite you up and show you what little I do know...   

[Lunchbox]

Some good tips