Mig settings for automive repair?

[josejuan]

hi everyone, i bought a simple mig welder to learn with. I have watched tutorials on this site for welding thin metal. I seem to have the technique some what down but i am still managing to blow holes threw the metal. I am trying to butt weld some sections on a 1969 bug. I feel my setup or settings are incorrect. any input would greatly help thank you.

heres what i have.

90 Amp Flux Wire Welder( typical chicago electric, harbor freight junk)
* Wire capacity: 0.035" or 0.030"
* Duty cycle: 10% @ 80 amps, 18% @ 60 amps
* Welding current (2 settings) 63 to 68 amps (low), 79 to 90 amps (high)
* Self regulating feed control
* Thermal protection with warning light
* Carry handle on lid
* Input: 115 volt, 15 amps, single phase

It only has 2 power settings min and max, wire speed i believe has ten settings. Iv tryed running a .030 wire instead of the .035 also.

 

[shenion]

With a minimum current of 63 amps and gasless 0.030 wire, you will have a hard time doing anything other than blowing holes.

For thin metal you want a gas MIG with a minimum current of 30 amps or less.

 

[londonsean69]

* Welding current (2 settings) 63 to 68 amps (low), 79 to 90 amps (high)

That would most likely be the problem. The automotive MIGs over here 'usually' start at around 25-30 Amps.

Any chance you could use a backer? It's a bit lump of metal behind the weld, it will take a lot of the heat.

Also, flux cored wire tends to burn a lot hotter than normal gas shielded wire.

I think you might well struggle with this one, especially on old, thin, metal

Sean

 

[josejuan]

thank you both very much, thats exactly whats happening. Iv got it somewhat decent but have difficulty burning threw. Im going to look into buy a nice gas mig now. londonsean69 iv read about it but have not given it a shot. my friend just recommended the same thing. 30amps and my minimum is 60, i can definitely see the problem there. much appreciated guys thanks again.

 

[londonsean69]

thank you both very much, thats exactly whats happening. Iv got it somewhat decent but have difficulty burning threw. Im going to look into buy a nice gas mig now. londonsean69 iv read about it but have not given it a shot. my friend just recommended the same thing.

What? the backer?

It can be tricky, but there is usually something that can be found that can be shoved down a gap. A flattened bit of copper pipe can be very helpful, as it can be slid in through holes in the panel (the sort of hole a grommet would go in for wiring).

TBH though, it would always be a losing battle/workaround.

Low amps, thin wire, and an Argon mix, it will make life a lor easier.

Glad to be of some help, it was only 18 months ago that I was in much the same boat

Sean

 

[josejuan]

What? the backer?

It can be tricky, but there is usually something that can be found that can be shoved down a gap. A flattened bit of copper pipe can be very helpful, as it can be slid in through holes in the panel (the sort of hole a grommet would go in for wiring).

TBH though, it would always be a losing battle/workaround.

Low amps, thin wire, and an Argon mix, it will make life a lor easier.

Glad to be of some help, it was only 18 months ago that I was in much the same boat

Sean

I was some what confused when i first started all this. Thanks for the clarification. Heres what i am working on, my 1969 bug. there are some sections in the engine bay that needs replacing.

 

[londonsean69]

That looks in pretty good condition. Keep us posted with pics as you go along.

Also, not wanting to teach you to suck eggs, but watch out for fuel lines, batteries etc.

Sean

 

[josejuan]

Thank you, my grandfather and I restored it back when i was 16. Im just going back over things when we didnt get to finish. Im graduating in three months from uti for automotive technician. Body work isnt my niche, but i am learning.