Okay to use stainless wire on bug? What about gas flow rate?

[Raymondo]

Hey guys. Pretty new to the welding, finally decided on a MIG after the advice I got from you guys here. Picked up a Miller 140.

Anyways, the thing is sitting in the garage right now, ready to go, and I noticed something. The welding store gave me a huge 8-inch spool, but it's labled stainless.

I know the steel on a bug is carbon steel. Is this going to cause problems, or affect my weld quality? Should I return the spool?

Also, the manual of the miller says the gas flow rate is optimum at 25cfm, but I've heard that if I'm pulling my welds, I should dial up the gas a bit, is this sound advice?


Thanks.

[MNAirHead]

I run 15# pressure. and push the puddle.

[Bugfuel]

There is very rarely need or an opportunity to lay a continuous weld bead in automotive work. You'll burn a hole through or warp panels in a hurry. Do one spot at a time, let cool for a second, then melt the next spot butt to butt with the previous one. Or if you are welding in repair pieces where there's a high risk of warpage, leave a half inch gap between spots.
You could even have an air gun ready to blow cool air on the fresh weld to minimize heat problems.


Jan

[Raymondo]

There is very rarely need or an opportunity to lay a continuous weld bead in automotive work. You'll burn a hole through or warp panels in a hurry. Do one spot at a time, let cool for a second, then melt the next spot butt to butt with the previous one. Or if you are welding in repair pieces where there's a high risk of warpage, leave a half inch gap between spots.
You could even have an air gun ready to blow cool air on the fresh weld to minimize heat problems.


Jan

Did you even read my questions?

[Bugfuel]

Yes I did. It included a description on your supposed technique, which would most likely have been wrong, and caused you trouble, possibly ruined body panels. A simple 'Thank You' on your part would have sufficed.

On your main concern: Save the stainless wire for stainless work, and get a spool of regular wire for sheetmetal etc. work. You generally should not mate stainless with mild steel based stuff, it creates a 'galvanic pair' and results in accelerated corrosion of the weaker metal. Whether the mild steel rusts through right by the seam after 20 years or 200 years, is too hard to say...

Same thing is more obvious when you look at the corrosion under the nuts of the transmission or engine case. Aluminum/steel contact makes the aluminum erode over time.

On gas flow then, I can't recommend a cfm value, but try to err on the 'too much' side, it won't hurt. Too little will give you porous, dirty, bubbly welds that won't hold, or melt the metals together properly. Higher gas flow also helps with cooling the surrounding metal area. Some better welders have an adjustment for how long the gas keeps flowing after you take your finger off the trigger. Don't move the nozzle away from the weld immediately, let the gas do it's job.


You're welcome.

Jan

[A_67vdub]

You can use stainless wire on mild steel.

[Raymondo]

Yes I did. It included a description on your supposed technique, which would most likely have been wrong, and caused you trouble, possibly ruined body panels. A simple 'Thank You' on your part would have sufficed.

On your main concern: Save the stainless wire for stainless work, and get a spool of regular wire for sheetmetal etc. work. You generally should not mate stainless with mild steel based stuff, it creates a 'galvanic pair' and results in accelerated corrosion of the weaker metal. Whether the mild steel rusts through right by the seam after 20 years or 200 years, is too hard to say...

Same thing is more obvious when you look at the corrosion under the nuts of the transmission or engine case. Aluminum/steel contact makes the aluminum erode over time.

On gas flow then, I can't recommend a cfm value, but try to err on the 'too much' side, it won't hurt. Too little will give you porous, dirty, bubbly welds that won't hold, or melt the metals together properly. Higher gas flow also helps with cooling the surrounding metal area. Some better welders have an adjustment for how long the gas keeps flowing after you take your finger off the trigger. Don't move the nozzle away from the weld immediately, let the gas do it's job.


You're welcome.

Jan

Now that's what I'm looking for! Thanks! I'll return that stainless wire. There's no point in welding on body metal if the weld isn't going to be the best it can be.


As for my first reply, I apologize if it came accross to you as curt. You can't see my facial expression in the text... It pains me to see animosity in a forum about beautiful cars, so no hard feelings, eh?!