Flux-core/MIG for frame welding?

Most new welders move far too fast when learning to MIG weld. Cut that wire speed and slow down to get good penetration! With proper chamfering on thick stock you can easily get perfect keyhole penetration with even a cheap mig. Same with stick. Most people try to move far too fast with small buzzbox welders. The key is to turn it up, slow it down and watch the puddle, not the slag.

Exactly what maniac57 said.

I tend to do the opposite. I run too slow. Most of my welds look piled up but have great penetration. I tend to move just slightly faster than when the puddle will fall through.
I have tried going faster only to find undercutting. That I really do not want to see.
Yeah, I am still a noob at welding but nothing (knock on wood) has ever fallen apart on me yet.
I am a big fan of angle grinders and flap wheels! They polish down my welds nice and smooth.

I'm with you GearNut.

I have been welding with all types of machines since around 1974 as a kid and then did it for a living in 1979. I closed our shop down for family health reasons in 2006 and My house doesn't have 220v so I cant run my machines at home. Instead of wiring up my house I bought the Harbor Freight 99a Flux Core machine and you can get decent looking welds with it and the welds are strong. You can even weld heavier materials if you pre-heat with a torch. They are not the best machine to weld with but the comments that they don't make strong welds are incorrect. If you have welding experience they work fine they just aren't the best welder there is but at $100 they are a good little machine. I just built a 20" BMX bike with a china girl on it with one.

The key to using any welder is practise, you have to get used to the way it operates. If you take a few pieces of tubing that are close to the frame tube size and make a few test joints you can learn a lot. Welding is an art and I'm no artist, that's what they make grinders for!

i do all my welding for this hobby with a lincoln electric flux core (fcaw) machine - i have access to other tools but choose this for portability and just because so many people tell me it "can't" be done. I can always make reliable welds, but on a good day i can make 'em fairly purtty too!

Welding bicycle tube, particularlly butt welding bicycle tube, is tough. It is thin and has got paint or chrome covering, it burns athrough fast.

getting the settings correct is critical

prep is critical

steady distance is critical

extra lighting on your work can improve your output

Sometime i use inserts.


I like my FCAW machine, and it is super portable