TheSamba.com :: View topic - Can I use flux core wire to weld body panels?

Sat Sep 23, 2017 11:47 pm

Getting ready to weld in some patches and my new front floor on my bus.

I have a SMAW and a gasless MIG (flux core wire). I've gotten pretty good with the stick welding, but MIG has been a bit more trouble.

I read that if you paint over flux core wire welds, it will show through the paint after a while. Is that really the case? Do I need to invest in yet another welder (gas MIG or TIG) or can I use my gasless MIG?

If I can use flux core, what kind of wire do you guys recommend? I saw there's something called Easy Grind wire, but I think it's only for gas MIG.

Sun Sep 24, 2017 12:02 am

MiG... as gas shielding is the best and most universal welder you can have.. and do the job right and cosmetically more friendly.. flux and mig are like night and day.. you will not regret the investment.. and you want a large tank.. yes they cost more.. but the investment will pay for itself in the long run.. as less trips to get filled.. get a bunch of cheap harbor freight right angle grinders with different wheels on them.. and some with wire wheels.. and go to town..

Sun Sep 24, 2017 7:25 am

Mig all the way! So much more control over the job. Try to find a mig 135 from Eastwood, great welder at an affordable price.

Sun Sep 24, 2017 11:34 am

I don't really want to buy another welder if I can help it. So you guys don't think I can get away with flux core?

Sun Sep 24, 2017 11:41 am

esotericsean wrote: I don't really want to buy another welder if I can help it. So you guys don't think I can get away with flux core?
what is your end result goal?
Yes.. you can use the flux core.. but only really really good welders with years of experience can make the welds look nice.. are you good? show us some pictures of some scrap you welded together.. both flat and 90deg.. and we will tell you

Sun Sep 24, 2017 12:07 pm

esotericsean wrote: I don't really want to buy another welder if I can help it. So you guys don't think I can get away with flux core?
I highly doubt it... but it's always possible. We need pics of what you've done.

Sun Sep 24, 2017 12:13 pm

Thanks guys. I'm not the greatest yet, but I'll post a picture later today (in a couple hours) when I stop by my studio. I guess my biggest concern was the flux weld showing through the paint.

I've been practicing on 22 gauge sheet. Though I'm pretty sure most panels in the bus are slightly thicker than that.

Sun Sep 24, 2017 1:35 pm

Your bus likely has 19ga. thick metal. But practicing on 22ga. will get you a better feel.

Listen to ct67bug. He started with flux core and switched to mig after much trial and error. He's wise for all of his 16-17years of age. :shock: <<Not a shot at ya ct. :D

And if you do buy a mig welder. Do as vwjetboat said. Get the biggest cylinder that you can afford. I started small and burned through it in an hour. Then I doubled the size and wish I had gone with a larger size. But I'm just a home garage hack that once in a while drags out the welder to glue something together. 8)

Good Luck.

Sun Sep 24, 2017 1:49 pm

I want to see... overlap.. one laid ontop of another.. I want see butt joint and 90 degree...
I mean.. if ya want a honest opinion.. get some clean metal same thickness as what stuff you will be doing on bug.. and do as I said up there ^^^ as you will need to do all three.. and you will get honest feedback.. now no grinding.. I want to see just the weld with scale knocked off..
NO i am not a certified welder.. just been doing it for 30 something years.. owning my own Lincoln 175 mig for over a decade and shop always had one since they first became affordable in the early 80s... when we restored vws at shop.. no more brazing pans in..
Peace out..

Sun Sep 24, 2017 2:33 pm

My neighbor at the studio has a motorcycle repair shop and he's offered to let me try his MIG, so I'm going to take him up on that offer soon.

In the meantime, I've been practicing my FCAW. I'm terrible at it compared to SMAW, but with a little more practice and a lot of body filler I think I might be able to eventually get away with it on my bus. I want it to look nice, but I don't intend for it to be a show car or anything.

Here are my welders:

And this is how I'm practicing:

And with a heavy coat of primer, just for the heck of it:

I'm absolutely not proud of what I'm showing here. I've yet to lay a nice looking bead on sheet metal with FCAW, but it's better than my first attempt.

Sun Sep 24, 2017 2:42 pm

difference between a mig and flux.. I can cut out a rusted part.. form a piece.. weld in and grind.. and well.. pretty much wont need bondo.. spot puddy about it and very very little.. with flux.. its going to look like shit no matter what and will need some filler of some sort.. yes you can do it.. its just so so so so much harder.. once you try the mig.. you will be like.. ok..i gota have one..

Sun Sep 24, 2017 3:12 pm

Hey avenger thanks! You got the age wrong though, I'm a little younger than 16 :lol: sorry to bring the thread off topic though. Those welds don't look too bad. I would take your friend up on the offer though.

Sun Sep 24, 2017 4:16 pm

67ctbug wrote: Hey avenger thanks! You got the age wrong though, I'm a little younger than 16 :lol: sorry to bring the thread off topic though. Those welds don't look too bad. I would take your friend up on the offer though.

Just read through your 67 Bug post, amazing work so far! You've done way more than I have on my bus. I saw you started out with flux core. You're using MIG now?

Sun Sep 24, 2017 4:39 pm

67ctbug wrote: Mig all the way! So much more control over the job. Try to find a mig 135 from Eastwood, great welder at an affordable price.
If you can wait until Black Friday, you might get lucky and find a promo code on-line for a deep discount on the Eastwood MIG 135. I was able to score one last year (2016) for $199 + free shipping. It is a very nice welder for the hobbyist with infinite adjustability and an included gas regulator.

Sun Sep 24, 2017 4:42 pm

esotericsean wrote: 67ctbug wrote: Hey avenger thanks! You got the age wrong though, I'm a little younger than 16 :lol: sorry to bring the thread off topic though. Those welds don't look too bad. I would take your friend up on the offer though.

Just read through your 67 Bug post, amazing work so far! You've done way more than I have on my bus. I saw you started out with flux core. You're using MIG now? Thank you! I started out with a harbor freight flux core welder. There was no control really and the heat settings were hot and hotter. I would burn holes on OG and replacement metal. I bought an Eastwood 135 and a 40 or 60 size tank for 75/25. Now my welds are looking top notch.

Mon Sep 25, 2017 2:11 pm

you want to be practicing butt welds your example above look more like lap welds.

Tue Sep 26, 2017 6:47 pm

These were done with a infinitely adjustable volt setting type welder.

Wed Sep 27, 2017 6:06 pm

After reading everyone's advice on here, reddit, and watching lots of YouTube videos, I think I've really improved my flux core welding. I still plan on trying a proper MIG as soon as I can, but figured I might be able to get away with my FCAW for a little while.

How does this look? Here's the front:

And the back:

After grinding:

I really took my time between each tack and made sure the angle of my welder was correct. What helped a lot was using a piece of copper pipe as a backing for each tack to absorb the heat.

The metal I'm practicing on is already all warped, which made it more difficult and it's 22 gauge, which is thinner than the few areas I checked on my bus. So I imagine welding the actual metal on my bus will be a little bit easier. There's a metal supply shop in Irvine that I might try to go to soon to get some more sheet to practice with.

Wed Sep 27, 2017 6:26 pm

So, question. What are the steps I should be taking for each panel I weld?

Cut out the old, fit the new piece, weld it in place, grind it down, use seam sealer? Primer? Do I need to clean the weld perfectly after grinding? What about body filler, when do I use that? What about rust remover?

Thu Sep 28, 2017 9:13 pm

based on your photos, I highly recommend not proceeding with your existing setup and skillset.. you will not be proud of the results. To answer your first question.. NO.. you cannot use flux wire MIG on sheet metal. Your sample photos are all horizontal welds to boot... the easiest position to weld. Most body panels are vertically welded.

there are quite a few shortcuts or alternative solutions in automotive work.. some are acceptable, some are tolerable, some are not recommended at all, and flux welding a body panel falls under the last category.

it looks like you plan on doing it anyway despite several other folks leaving comments from their own experience.. so do yourself a favor and start with the smallest possible repair. Leave room for cutting out your mistakes and welding in a little bit bigger piece.

agree or disagree, that is my experience.