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Mon Mar 26, 2007 10:03 am

This has probably been covered a million times but I've been reading and reading and haven't found it.

I've heard flux welders will case defects in the paint after time. is this true?

Mon Mar 26, 2007 2:04 pm

juki48 wrote: This has probably been covered a million times but I've been reading and reading and haven't found it.

I've heard flux welders will case defects in the paint after time. is this true?

That's a good question. You can use a flux core welder but it splatters like crazy and creates a lot of mess that you need to clean up before doing body work. I would think that if you got a good chemical cleaner on the area before attempting the bodywork you'd be okay. I'd then be sure to seal the area in an epoxy primer.

Just for the record, I have no concrete experience with using a flux core welder. I only use a MIG welder for all my needs. It's the cleanest next to TIG.

I yield to anyone who has first hand experience with flux core welding and bodywork.

Scott Faivre

Mon Mar 26, 2007 2:22 pm

The flux is an impurity which paint is not to fond of.. may have a tendency to flake off around any left over flux.. I would be cautious using flux.. but that is just me!

Mon Mar 26, 2007 3:23 pm

People who do this for a living and who value their time and take pride in their finished product use gas, not flux core.

That should tell you something.

Mon Mar 26, 2007 3:31 pm

^ that being said I have used mig/flux core .030 wire in my mig for over 15 years and never had a problem... sure it leaves some spatter... BUT... I grind down the welds and wire wheel the areas etc etc during the prep work and so there is not much of a change for any "flux residue" to react... check out my gallery for pics of some stuff I have posted.

Mon Mar 26, 2007 5:49 pm

the biggest problem(next to just hearing the same thing over and over) is the flux wire burns a bit hotter.... heat control is more of an issue.... i've used fluxcore for 15+ years (came from stick welding background) and never had any paint failures... along the lines of what keifernet posted, the "normal" treatment of any welded panel removes the flux residue.... MIG is obviously easier to a novice and most folks....

EDIT: sorry Keifernet, misspelled your name.

Tue Mar 27, 2007 6:35 am

I've never used flux core, but I have stick welded. The welds are not nearly as clean as my MIG & TIG welds. There's too much slag.

Tue Mar 27, 2007 9:18 am

Personally, I have found that controlling the heat is the biggest problem when using flux-cored wire. I welded a patch in the center of my drivers' side door using flux-cored wire and ended up warping the area around the new sheet metal. My technique (right or wrong) was to place small spot welds on opposite sides of the patch until there was almost one continuous weld around the patch (allowing each one to cool), then grind the welds down. I was able to smooth most of the area using filler (after grinding, of course), but the end result is a 2nd rate job at best.

This could have been due to my inexperience with welding sheet metal, though.

We learn by doing!

Tue Mar 27, 2007 10:50 am

I found flux core usefull but thats cause I have to work outdoors and its windy here by the airport

but if i had a garage i would be using a mig with gas

Tue Mar 27, 2007 12:23 pm

wow, thanks for all the replies. It looks like flux welding is an option for body work as long as you grind and clean it well. Obviously MIG would be better. I've also read that welds on bodywork should be filled with a fiberglass filler to prevent moisture from comming through and rusting the repair. maybe this would also help keep any flux left behind from comming through the paint?

As you can tell I'm a newb when it comes to body work.

Tue Mar 27, 2007 1:56 pm

juki48 wrote: wow, thanks for all the replies. It looks like flux welding is an option for body work as long as you grind and clean it well. Obviously MIG would be better. I've also read that welds on bodywork should be filled with a fiberglass filler to prevent moisture from comming through and rusting the repair. maybe this would also help keep any flux left behind from comming through the paint?

As you can tell I'm a newb when it comes to body work.

My post mean MIG with flux core wire VS gas sheilded ( which is better but not entirely neccesary)

Not sure what you mean by FLUX

Tue Mar 27, 2007 1:58 pm

Sorry, when I say mig I mean with gas. flux is no gas.

Tue Mar 27, 2007 4:35 pm

there is a lot of confusion in these answers . In mig welding you can use what they call flux core wire or welding wire with argon gas shield. When using flux core wire you do not need to use argon , to create a sheild around the weld . As mentioned before it does spatter all over the the place , it has to be really well cleaned before any plasctics ( bondo type products) or paint are applied over top of it and it looks horrible . If working outdoors , you may have to work with flux core , due to the wind will blow the argon away ,faster then the weld will take place. The weld must take place in an oxygen free environment . that is the purpose of the argon or flux .

Tue Mar 27, 2007 8:48 pm

CarreraRS2.7 wrote: I've never used flux core, but I have stick welded. The welds are not nearly as clean as my MIG & TIG welds. There's too much slag.

stick welding does indeed produce a lot of slag.... using a fluxcore wire does not leave the large amounts of slag that stick welding does, but it does leave residue. Definitely not as clean as solid with shielding gas.

Tue Mar 27, 2007 8:49 pm

winston the browndog wrote: and it looks horrible . If .

a good weld looks good no matter what type of shielding you use.