Weld Through Primer (1 Viewer)

[Pitter Patter]

I’m nearing reconstruction of the tub and want to make sure I do this right. It would be a tragedy to do all this work and paint then have the overlapping panels rust right away.

Nearly every joined panel on the 40 is overlapped and tack welded. I’m attempting to recreate this as true to original as I can. However, I’m all for using better & modern chemicals to make this last. Who has experience with weld through primers or other products? Experienced opinions, preferences or tips are very appreciated.

And we all love pics so here’s some for the wall of rust shame.

 

[ceylonfj40nut]

3M product is good.

 

[A10Driver]

It's tough to get good welds. If you are doing spot welds it's great. Drill holes where u spot weld before welding

 

[wimberosa]

The higher the zinc content seems to be better....but its still a misnomer. If I'm connecting two panels with a spot weld ... I'll drill or punch the hole and then
clean up the primed weld area within the hole with the end of my drill bit. Basically remove some of the primer in that one area. If I'm butt welding in an area where I can't paint the backside later...then I'll just spray it on the backside and weld. Its really the direct contact with the electrode and primer that just doesn't produce a satisfying result no matter what the brand of "weld through" primer. I've done a good bit of experimenting and theres no way its as nice as raw steel.

Thats a beautiful bed panel BTW. Where did that come from? Looks primo.

 

[rkymtnflyfisher]

I used a few different brands when I fixed my rig, SEM was probably in the middle of the field, U-Pol was the best by far in my opinion.

The U-Pol was the best to spray, seemed to weld cleaner, overall a helluva lot easier to work with, but it was a true industrial grade product. Use it outside with a ton of ventilation, I barely made it out of my garage after spraying a small section I was prepping.

All I could see was the big black spots before I finally made it to fresh air.

 

[Pitter Patter]

The higher the zinc content seems to be better....but its still a misnomer. If I'm connecting two panels with a spot weld ... I'll drill or punch the hole and then
clean up the primed weld area within the hole with the end of my drill bit. Basically remove some of the primer in that one area. If I'm butt welding in an area where I can't paint the backside later...then I'll just spray it on the backside and weld. Its really the direct contact with the electrode and primer that just doesn't produce a satisfying result no matter what the brand of "weld through" primer. I've done a good bit of experimenting and theres no way its as nice as raw steel.

Thats a beautiful bed panel BTW. Where did that come from? Looks primo.

It’s the Real Steel bed. Overall their products are pretty good but not wonderful. Still lots of modification that needs to happen but… I’m super thankful these exist. This would be an almost impossible project without these panels.

 

[MaltbyPenn]

I've been pretty impressed with Steel-it, although its wallet draining. You definitely get what you pay for.

 

[vfrer]

Good info. Just putting together a bed myself and getting ready to weld on rear bed supports. I'm thinking self etching primer on the mating surfaces then clean up the spot weld holes as noted above before welding.

That bed is way nicer looking than the one I got from real steel! I got an early style and the rear lip was far from straight and the whole thing is twisted. I can make it flat but just does not look great when not constrained. Do wish they would supply them with the bed supports, same with the mid bed.

 

[roadstr6]

This: Amazon product ASIN B003TQ9NFK

 

[coinoperated40]

Good timing on this thread. I just started back on a long overdue project.

After separating the sections, I see a lot of rust in between. Maybe a little more than a lot. The weld through primer will come into play as I recondition these pieces. Thanks for the info.

 

[rkymtnflyfisher]

This: Amazon product ASIN B003TQ9NFK

Agreed

 

[roadstr6]

Agreed

I've used both the U-POL copper and the zinc (they sell two versions). The zinc is far easier to work with IMO. It almost welds like bare metal. The copper...not so much.

 

[sggoat]

I used a few different brands when I fixed my rig, SEM was probably in the middle of the field, U-Pol was the best by far in my opinion.

The U-Pol was the best to spray, seemed to weld cleaner, overall a helluva lot easier to work with, but it was a true industrial grade product. Use it outside with a ton of ventilation, I barely made it out of my garage after spraying a small section I was prepping.

All I could see was the big black spots before I finally made it to fresh air.

I used SEM initially, but of the two cans I bought-one actually exploded out the bottom when I started spraying--done with that mess--I would go with with what rkymtnflyfisher recommends--

 

[rkymtnflyfisher]

I used SEM initially, but of the two cans I bought-one actually exploded out the bottom when I started spraying--done with that mess--I would go with with what rkymtnflyfisher recommends--

I received 3 or 4 cans of SEM from Summit Racing that didn't spray for more than about 20 seconds, after like the second can I called SEM tech support.

After reading them the code on the bottom of the can they determined that they were actually expired by about a week. Tech support explained to me that large retailers like Summit order a large quantity and they just sit at a warehouse ready to ship. A lot of those cans sit past their expiration date, and they slowly start to solidify.

That's what lead me to a local shop near where I was living, low inventory type of shop, they had a fresh case of U-Pol. After the first can I was sold. Kind of like the difference between UGA and TCU tonight.