Weld through primer..

[proxlamus©]

Soo.. finally getting around to welding on my bad dog 280z frame rails.. I coated the inside of the factory rails using Eastwood's Internal Frame Coating.. then coated the outside of the chassis/frame rails with self-etching weld through primer as well as the inside of the bad dog frame rails with weld through primer.

 

I've noticed.. with the weld through primer.. the welds seems to be a bit messy and look contaminated. A good weld to me sounds like a sizzle, but this sounds like splattered bacon. I sand blasted the area first then coated with weld through primer. After I took a wire brush to the primer, the welds were nice and smooth again.

 

Any reason why this may be so?

Edited January 16, 2012 by proxlamus©

[Xnke]

Weld thru primers are just generally garbage to weld through. I have used them, but really prefer to not use them, and go back and spray inside the frame rail or behind the panel afterward.

[redneck1545]

^ same,

I found that welding through paint, is well...welding through paint. The hot arc typically burns through any paint and splatters pretty bad.

 

I just painted the surface with Zero-rust and when I needed to weld something in an area I already painted I hit it with a wire wheel to expose bare metal and sprayed it with paint after I welded and it cooled.

[proxlamus©]

Hurm.. not what I was hoping to hear. Sigh

 

Not sure why a company would sell a product that is even pictured and advertised to weld thru.. when it barely welds.

 

[Tony D]

I would clean parts and coat them with weld-thru primer. As well as on any bare metal on the car.

When I tacked it in place, being able to strike an arc onconductive primer was a plus.

Then once I was satisfied with the position, a quick wipe with lacquer thinner, or a quick whire wheel and away I went with the final welds.

 

Don't know if that's the way you're SUPPOSED to use it, but it's the way I always did.

[zero]

I recently had a similar experience. What I ended up doing was coating the inside of the frame rails (except near the welds) with POR-15, then spraying the 'tabs' of the frame rails with weld-thru primer, as well as spraying the area of the floor I had wire-wheeled the undercoating off of. Once I discovered how annoying it was to actually weld through I basically did the same thing as Tony.

 

I took a good rag and wiped most of the primer off of the floor where I was going to weld. Basically anything I could get at with undercoating later was wiped off and the inner surfaces that I couldn't still had the primer on it. Also, switching to high heat on a better welder helped. I have some pics here if you're curious.

 

http://southbronxspeedshop.blogspot.com/2011/11/112911-frame-rails-pt1.html

 

http://southbronxspeedshop.blogspot.com/2011/12/122111-plugging-along.html

 

http://southbronxspeedshop.blogspot.com/2011/12/122711-frame-rails-pt2.html

Edited January 16, 2012 by zero

[palosfv3]

It appears there is confusion on the proper usage of weld through primer . It should only be used in the immediate area of the plug weld . It is not to be used to replace ecoats or for rust prevention on parts other than the immediate heat affected area where the weld is being made.

 

I have posted a link to the ICar website where all of the tech articles about welding are listed . Take some time to review these as they are great sources of info straight from the people that test correct repair processes on todays cars. This info is directly transferable to use on older cars.

 

http://fms.i-car.com/advantage_search/FMPro

 

 

For the

Weld through PDF follow this link .

 

http://www.i-car.com/pdf/program_support/advantage/1996/julaug96.pdf

[ModernS30]

I would clean parts and coat them with weld-thru primer. As well as on any bare metal on the car.

When I tacked it in place, being able to strike an arc onconductive primer was a plus.

Then once I was satisfied with the position, a quick wipe with lacquer thinner, or a quick whire wheel and away I went with the final welds.

 

Don't know if that's the way you're SUPPOSED to use it, but it's the way I always did.

 

This is how I always did it, I would coat it, fine where I wanted the part, wire wheel the area directly where I was welding, then weld.

[johnc]

The issue is the term "Weld Thru." It does not mean you can "Weld On", only that it helps protect the metal from corrosion when the weld penetrates through the backside of the panel. You still need clean, bare metal at the weld bead.

[RB240zDET]

Never used the stuff, but have heard from enough local people and friends that it is crap. I always just coated the inside of the area with POR15 and the outside area with POR15 then I simply removed the POR15 from where ever I needed to weld and laid my weld and then repainted with POR15.

[proxlamus©]

I was able to get some better welds today..

 

I used a bit more heat.. at the start of the bead I waited a few more seconds until the puddle got nice and big.. then I could weave my way along the bead with fairly good results. I started getting better welds with more heat and more time which is good. But.. I won't be doing the rest of the seams for my stitch/seam welding with this product.