Welding Tips and Tricks

I'd like to use Select arc 700GS for thin sheet metal... seems to work fine.

I've heard that if you do not clean the weld slag outside and INSIDE (for a car body panel for exemple), it might conduct to premature corrosion. The thing is, sometimes, it's hard to access the inside panel.

I also know that there is different slag PH; it might be a factor.

Overall, it seems a little far fetched...

What do you guys think?

I am not a scientist and yet I get definitely understand flux ph would affect such a thing also moisture holding ability of uncleaned off slag may be an issue as well......but.
But an unpainted solid core will rust the same and I dont think time would be any different. Tig brazing could be an option though but It could be overkill.
If you are not able to get to the back of the panel to treat or paint then it wont mater what weld you use as the heat will oxidise the back of panel to some degree anyway.
I tend to instruct apprentices a fair bit and I notice thier ability to overthink some things. I do it too, It takes awhile to learn appropriateness of application. Longwinded I know, but essentially if you are building or making something you may not be able to use the most ideal method due to cost, availability etc but we can tend to, myself included, not take on projects until its perfect. But things have design life and we can overspend on welds for things that wear out much quicker than our build quality.
Othertimes, if its a good weld and its not at immediate risk of rust and you are curious enough.......give it a crack. Theory and practical shouldnt differ much, but they do.

Rodbelan wrote: ↑Tue Feb 22, 2022 8:41 am I'd like to use Select arc 700GS for thin sheet metal... seems to work fine.

I've heard that if you do not clean the weld slag outside and INSIDE (for a car body panel for exemple), it might conduct to premature corrosion. The thing is, sometimes, it's hard to access the inside panel.

I also know that there is different slag PH; it might be a factor.

Overall, it seems a little far fetched...

What do you guys think?

I can't talk from experience using FCAW on body panels so I probably shouldn't comment but:

• What type of joint is it and how does the slag get inside?

• Any crud left inside (say) a door will accumulate at the bottom seam, trap moisture and lead to corrosion.

I don't know the chemistry of the flux so I don't know if it would lead to corrosion faster than any other door lint.

Jack