help with welding

Hi all. I'm new to mig. I haven't had much trouble with flux core except for burning thru thin stuff. But I'm having a hard time with solid wire and gas. I can't seem to get a solid arc. The arc keeps poping. popopopopopopopop, instead of a steady burn. I played with the gas and the speed and it has come around a little. I can start with a setting and get the pop an inch or so then a solid burn. Stop and start again and get nothing but pop. And the popping doesn't penetrate. My CO2 is at 10psi. I hope someone can shed a little light. Thanks

 

Sounds to me like a polarity issue. Try changing the polarity.

 

Ditto!!
Also as mentioned make sure there are no fans or air conditioning blowing around while your using the gas. If so the gas is pretty much useless.

 

Make sure you have proper tension on the rollers or the wire will slip in the rollers.

My mig is like this weld buetiful but I have to have the roller tension farely high to do so.

Make sure your tip is clean and that it is the proper tip.

 

Agree with all on the polarity, but I'll add that CO2 isn't generally the best for mig with mild steel. You'll get better results with an argon CO2 misture.

 

I did switch the polarity, and there are no fans in the garage. The tension on the feed rollers is as tight as it will get, I pretty sure there is no slippage. Clean metal could be the issue. I would take the grinder and clear a path through the paint for a test bead. I think i need a finer disc for my grinder. A24 seems too course. I'll try turning up the gas. I agree with the flux wire. I had no problems with it. But a patch I made was 20 guage and the flux wire burned through it. I'm having a heck of a time with warpage too.

 

Oh my. If you're trying to weld through paint and rust with solid wire and gas, that's going to be a no-go. You gotta have clean metal for it to work, unlike flux core. Since you changed polarity, make sure it's actually correct for GMAW according to your machine. BTW, what machine are you using?

 

the welder i'm using is a Northern Equipment 125 from Northern Tools. I did use aluminum plate with the flux core for filling 1/2" holes. It worked great. The problem is with the solid wire and gas. The popping doesn't even penetrate the metal. It just lays what bead there is on top. Then I'll start to get a decent arc that penetrates and I can get a decent bead. Then back to popping. I think you are right though, I need to clean the area better. I'm thinking that is my biggest problem. I'll keep playing and practicing. I still have to order panels for the floor and I have to get the tub in the garage to start cutting, so I have nothing but time. I do have a 5'x4' sheet of, I think it's 16 or14 guage steel sheet for the floors. planning on using that for the rear floor.
If the metal is 18 guage or thicker I can use the flux core. That seems to work better for me, but I still want to get the gas mig welding down for thinner stuff. You know with that warpage I'm worried about doing anything on the outside of the tub. I don't want to make it worse. I'll keep practising.
Thanks for all the help and input guys. I love this forum!

Thanks for the link to metal shapers assoc. That website looks like a wealth of information.

 

If your trying to run a bead on sheetmetal good luck. Its going to warp the heck out of it and eventually burn through. You have to tack sheetmetal and cool it after every tack with a blow tip. Yes it takes a long time and is very tedious work but the outcome when its done requires little to no extra work.

 

Try stitching the weld. about an inch, stop move to the other end then another inch. back an forth sort of like the way you tighten the lug nuts on a wheel. Will help the warping, you will still have to flatten it a bit.

 

i was looking at the rear floor today i have my work cut out for me. Thanks for the tips guys. I just hope I dont get impatient and screw it up. I have a tendency to do that. Thanks again.

 

Yeah, I do too sometimes. As trite as it sounds, I find that if I concentrate on what I am doing, and can enjoy simply the process of welding, grinding, filing, etc. and watching the work change I don't get impatient the way I do when I am thinking about getting done.. FWIW...

 

Put your switch(s) to the lowest setting, speed control to the low side of midrange and get out two pieces of scrap the thickness that you are going to work on.
Make sure you have a good, solid ground connection with your ground lead.
Weld a spot - like a three second count- (should sound like frying bacon) move over a couple-three inches and weld a spot. do this the entire length of your weld area. Cuts down on the heat warpage. Clean the spatter up. Go back to the starting spot and do a continuous weld from one end to the other. Or do the spots from one end to the other all over again, reapeating this untill you have welded everywhere you are going to weld.
Different schools of thought on this. Some think the continuous is smoother, some think the spotting method is smoother. The spotting method will cut down on heat warpage, but is a much longer process.
I use flux wire mainly because filling that little tank gets really expensive and I'm on a limited budget.

 

From the sounds of it, you are getting to much wire for the heat range you are using. Most machines include heat range/wire speed settings either on the inside of the machine where the wire is of in the instruction manual. If yours dosen't, you will want to figure out the settings and write them down for future use.

F.Y.I. If possible, try not to use Aluminum Plate as a backer to help fill holes. the Aluminum melts at a lower temp, causing the weld pool to contain both Aluminum and Steel. When mixed togeather, the effect is the same as a steel bolt in something aluminum.

 

As for setting the welder: without being there to hear and see what is happening, I am just guessing so take it for what it is worth.
Take a couple of scrap pieces of the material that you are going to be welding on, then set the welder on an amperage setting that you think is close to what is needed heat wise for the weld. Set your wire speed at a spot LOWER than needed and start a weld. As you weld, you will start with a weld that has a lot of hissing and not a lot of welding. Keep welding and turn your wire speed up as you go. Continue until you get that bacon frying sound that we all know and love. If you go too far, it will start to pop and fart around again and you won't be able to get it very smooth with little to no penetration.

Kepp in mind, this will work assuming you have the polarity right, wire size correct, gas flow correct, etc.

 

Very good advice. Especially on large projects.

 

Clean the metal, but you shouldn't need an extremely fine disc. Just hit the work area with a little brake cleaner and then compressed air and that'll be fine.

Can you actually lay a bead with the MIG wire on thicker stuff or is it only on the thin? The inability to keep a bead rolling points me to the gun tip. You're running a tip, right? Does it match the diameter of your wire? If your tip is bigger than the wire or the tip is corroded/worn/old you can get the sypmtoms you're describing.