Weldable Primer

[jboswell11]

I have not used weldable primer before and several of my spring projects need it (I think).

I have read that the primer should be applied to steel after removing the rust and wiping it relatively clean of grinding residue (nowhere that I have looked indicated steel required a wipe down with acetone, brake cleaner or similar) and that prior to welding the primer should ideally be removed from the direct area to be welded (applies to the MIG process I will be using, other processes may not require scraping or grinding the primer from the directly welded area).

First question: Do the directions above match the process that is normally used with success? It would be nice to weld through the primer and not have to grind the areas to be welded but I certainly will if this will effect the weld.

Second question: Does the brand of weldable primer matter too much or will any zinc based etching primer work (assuming it is advertised as a weld through primer)? If the brand matters what brands have you used with success?

 

[pc1p]

I have two different weldable primers that I use:
Seymour PBE (https://www.amazon.com/gp/product/B0088LVJTE/?tag=wranglerorg-20) - my go to

and SEM (https://www.amazon.com/dp/B000PKZ3IY/?tag=wranglerorg-20).

I had success with both and have no hesitation using one over the other. Both are self-etching but some common-sense surface prep is important (as you stated, wiping off the majority of surface ruse, and cleaning residue, etc.). I often use acetone as the final degreaser/wipe but any good solvent will do the trick. Acetone is great but is very volatile and a wide ignition range, which can be annoying or even dangerous in small or enclosed shops.

I recently used some Seymour during my spring perch relocation. I never had any issues starting an arc or getting a good penetration at the weld-points. I will double check what the back of each can says and see if they recommend grinding the weld-points. It would seem counterproductive to have a "weld thru" primer that you must first grind away to weld through

 

[jboswell11]

It would seem counterproductive to have a "weld thru" primer that you must first grind away to weld through

that was my thought as well... might just go for it anyway if its working for you to just burn it through.

Thanks for the links to the products, I will look locally for them. The prices on amazon seem high to me but I have never purchased this stuff before... do they seem high compared to what you can source the stuff for from a hardware store in your area?

 

[someguysjeep]

there can be chemicals in some brake cleaners you don't want a wiff of if you spark a welder and vaporize it.

 

[Alex01]

I used the product below when doing the raised body mounts on my jeep. It worked great.

https://www.amazon.com/gp/product/B0088LVJTE/?tag=wranglerorg-20

 

[Mike_H]

I've used SEM with decent results. I did find that the welds that had to penetrate the SEM were not as "pretty" as the ones with out. I don't believe it affect the strength at all, but there was a difference. I need to get some more.... I'll probably try the PBE this time.

 

[Mrhp]

I have used the SEM with good results as well. I did not remove the primer before welding. I had no issues mig welding over it.

 

[pc1p]

that was my thought as well... might just go for it anyway if its working for you to just burn it through.

Thanks for the links to the products, I will look locally for them. The prices on amazon seem high to me but I have never purchased this stuff before... do they seem high compared to what you can source the stuff for from a hardware store in your area?

They are consistent with the local sale prices. The only place I can find it locally is a bit of a drive, so the $$ difference isn't worth the ~40 minutes of driving/shopping/driving back...