New welder amperage question

Yesterday, I bought this little Harbor Freight 125 amp flux wire welder.
https://www.harborfreight.com/flux-1...psugg_q=welder
One of my first planned repairs is to fix a tear in the mounting hole for one of the wheels on a push mower deck. Last time I did any welding was 35 years ago, and it was using a 240V stick welder on some I-beams, so this little job will require more finesse. Would you use the 60 amp or the 125 amp setting for this job? Any other tidbits of wisdom you can pass along, please do!
Thanks,
Andy

 

Will you be trying to weld on a diecast mower deck ?

 

Nope, it's stamped steel.
Andy

 

It depends on the thicknesses of the metals you are trying to weld. If you only have two amperage choices I would try the lower setting to reduce the chance of burning through the thin sheet metal deck. If the metal is thin you may have to hold your tip in position and just hit it for a second or less leaving a small spot of weld. Let it cool a bit and repeat.

If you burn a hole through the deck you can use the fraction of a second weld spot to build up around the edge of the hole and weld it closed. The key is short bursts of welding with time in between to let the metal cool and solidify before you hit it with more heat.

 

The problem with flux welders is that unlike a MIG or even a TIG you dont produce the shielding gas bubble until the flux burns, by then the arc has already burned through the thin metal.

Very similar to a stick welder they work better on thick material.

Even at that the welds are not going to be very pretty!

 

Can you find a piece of steel to practice on, maybe a joist hanger or Simpson strong-tie? That way you get to make a few mistakes before you take the final exam. You could even replicate the break you're trying to fill.

If you're interested in videos, WeldingTipsAndTricks. com is a great resource. Good luck, let us know how it goes!

 

would start off at 60 if your not burning through look at the weld see if it has good penetration to the metal your welding if not you could turn it up, the 120 flux core welders I have used really do not usually have that much amperage so really doubt it will burn through.
find a piece of copper the same size as the hole and you should be able to weld around it with very little clean up.

 

Welding with flux core wire will make a less pretty weld than gas welded but on projects that are on heavier material as said you will have deeper penetration.
The thing is that the ugliness comes mostly from excess spatter rather than poorly formed welds.
A way of reducing the effect of spatter is to spray anti-spatter spray along the area of the weld.
It won't eliminate it but make a lot of it scrape off.

One thing that is very important is to match the wire thickness with the job.
For sure on thin material you should be using the smallest wire which is .023" and is the most common size for auto-body work.
Because it's thin you would use a lower heat setting.
You would have to change your tip to match .023 wire and be sure the roller is compatible with that size wire.

 

Thanks guys. Not sure when I will actually get to this project, but you've all given me much to think about. I'll let you know how it turns out.
Andy