Question welding SFC's. Welds are garbage, can't figure out why
 

By no means am I an expert welder, hell I'm probably not even an "OK" welder but I for the life of me, can not figure out exactly what the problem is.

I'm trying to weld in a set of MWC SFC's into my 2000 Firehawk and regardless of what I do, the welds are absolute garbage, it act's like it has contamination. I'm grinding everything down with a 2in 36grit 3M disc on an air grinder

Hobart 140 Handler MIG
Argon 75%/25% CO2(new tank)
Regulator set to 30cfm
.030 wire

I've changed the settings on the welder and it hasn't made an improvement, There are only two settings, power level 1-5 and wire speed.

I've changed where I put the ground clamp at, doesn't make a difference.

I tried using the Hobart anti splatter gel, didn't make a difference.

I can not get a good weld pool started. It just pops. Again, it acts like there is contamination, but everything has been ground down.

I can weld exhaust pipes, brackets, etc, decently, again I'm not a "welder" but I know what a decent weld should look like.

However, trying to weld the SFC's onto stock sheet metal has been a nightmare and to be quite honest, embarrassing.

I am tired of grinding this shit down and trying again only to have the same results.

The only thing I haven't done is wiped everything down with acetone. For the basic entry level welding I do, I've never had to, but I've never had this issue either.



Is there some weird goofy shit with the metal on these cars?

What is an SFC? That might help get an answer

subframe connectors

OK thanks! Should have thought of it. Must have been in wrong frame of mind....
Is it possible they are of a different grade of material than you think it might be? I know they're usually mild steel, but the question seems valid

Lets see some pics.

I'm off work tomorrow, I'll take some.

I wish I would have taken some sort of welding class when I was younger. Not to do it as a profession, but to be halfway good at it. I can do a lot of things pretty well, welding is not one of them.

My welds are good 60% of the time, every time. :D

maybe hire a welder.

@LilJayV10 Have you practiced these welds using scrap of 1/4" and 10 gauge, to test your settings and that the machine is feeding correctly, out of position exactly as you'd do on the car? Since this is a 140, your probably maxing out for the horizontal and overhead, and then dial back to 1/8" or so for the uphill welds.

Thank for the reply. You've been a lot of help.

The popping could be be a feeding problem, so I assumed you're maxing out settings (incorrect settings can also cause popping). Sorting this all out on scrap, including your technique, focusing the nozzle on 1/4" plate, flow rate, wire and voltage, will give you assurance you can repeat the approach successfully on the car. I've accumulated many hours creating "art" built from lowes, homedepot, metals depot, and weld metals online sourced metals, working out settings in different processes, positions, thicknesses, and joint configs.

Do Not Despair: Could be a simple overlooked obscure problem.

FIRST: Occasionally, a bad batch of shielding gas appears, I've seen contaminated BlueShield ( trade name for mixed gas) Why not try a fresh CHEAP bottle of straight CO2 ?
Second: Any chance of a HOSE leak, rupture, or bad fitting anywhere in the gas system? Even a loose fitting INSIDE the box at the gas solenoid valve can let air in= bad juju.
Third: Hail Mary to bail you out, TRY reverse Polarity.... CERN's Large Hadron Collider may have fucked up your timeline, you could be welding with Posi-Trons for all we know.

I had a similar issue once and it was the wire. The wire had been sitting for several years and I think some water from a snow shovel that was hanging above it on the garage wall dripped onto it. It wasn't very noticeable but the wire had some rust/corrosion on it. I fought with it an entire day wondering why I couldn't get a good weld. I was getting lots of spatter and blow outs. I changed the wire and all the issues went away.

Does that machine also do flux core? I think it does,but not sure. Check your polarity.

I have an Ironman 210 and have sometimes forgotten to change the polarity from going from flux core to mig and it welds horribly.

A properly set up machine should be really easy to initiate an arc, and the sound should be somewhat like bacon frying.

Double check your shielding gas flow is correct. Insufficient shielding gas usually results in a lot of porosity.

Try on some scraps. No sense in trying to weld something critical if you can't get scraps to look good.

If you can't get it correct, try welding with flux core. I'll have a bit more spatter but that can be ground smooth. Weld penetration is always better using flux core, for the same amount of welding amps.

Good luck.

Gas flow set to 30scfm is not helping. Excessive flow can cause turbulence and have the affect of little to no gas coverage.

I would find the Hobart web site and do a Q and A with their tech support guys for advice. Give them as much info as you can. Wire size. Material type.
Any chance you are welding in an area that has a lot air flow that would blow away the shielding gas?
I also suck at welding. But if you trying to weld let's say 1/8" tube to car sheet metal which is maybe 20-22 gauge it's not going to be easy.

Just one more thought.
Maybe take your car to a local muffler shop that welds thin sheet metal everyday and has a lift for much easier access to the SFC's.

I had the same problem years ago when welding SFCs on my GTO. Turns out the brand new tank of gas was contaminated. Those welds still look like shit 20 years later, but they are still holding up just fine. It was late at night so they were finished with the bad gas. A new tank made the next day's welds back to normal. Never had a bad tank of shielding gas before or since.

Thank you for all the replies. Work has been busy and the little time I've had to work on the car, I've been doing other things.

From some of the YT videos I watched from Hobart they said that would it should be at.

I have raised it, but I don't think I have lowered it.

Without seeing what's going on directly it's hard to say. You're out of position welding, welding thick to thin (though I think the lca torque boxes are close 1/8", so that's not quite as thin as the front points). It's possible if you're over penetrating you're pulling trash in from the back side, but you'd know (You're blowing holes at that point).

Some of my YT favorites
WeldingTipsandTricks
TimWelds
Making mistakes with Greg