What cause's pitting

[Jack62440]

I was making a tool today to hold the mig gun when I want to set it down for a bit. Nothing fancy just a bit of 1/4" rod on a piece of 1/4" plate. I had the welder set at power E or in other words "Max" and wire speed at 10 or again "Max" Gas was set at 20 The weld had alot of Pitting at the beginning then it was OK Then more pitting ??? Any thoughts ??? Jack

 

[wyn]

I'm sure those "aero" looking parts are down to lack of gas coverage.

 

[malcolm]

I'd agree - could be caused by torch too far away from the job. What units is the gasflow in?

Oil trapped in the joint can also cause that as well as other contamination such as rust or paint.

 

[Wozzaaah]

It does look like the gas coverage was a little low in those two areas. Maybe there was a slight draught just at those two points as the rest of the weld looks absolutely fine.

 

[Jack62440]

The gas was 20 scfh ard there was no draft. I wire wheeled the rod but the plate was rusty. Maybe I didn't clean it enough. I wiped it with solvent and cleaned it with 40 grit pad on a angle grinder But I am thinking now that I worked the centre more than the ends. Must have been the rust. I have been getting alot of pitting in other stuff that I have been welding. I usually just wire wheel things if it's new steel. Do I have to wash everything with solvent first ???

 

[shenion]

Could be oil or scale bubbling through the weld. Rust can do it too.

What wire are you using? ER70S-6 is better for dirt metal then -3.

 

[Drains]

Gas setting "20" may have been high, but as the pitting was at the beginning of the weld, it looks to me like the un-purged gas line was pushing air into the weld, until the gas came through.

 

[shenion]

Si,

20 SCFM is about 10LPM (actually 10LPM is a bit more.)

My torch is 15' long with another 30' back to the bottle from the feeder. If I forget to purge, I only get a very short amount of pitting and it does not look like his. His looks like it is bubbling up from under the weld.

I run mine at 20 SCFM.

 

[Drains]

Si,

20 SCFM is about 10LPM (actually 10LPM is a bit more.)

My torch is 15' long with another 30' back to the bottle from the feeder. If I forget to purge, I only get a very short amount of pitting and it does not look like his. His looks like it is bubbling up from under the weld.

I run mine at 20 SCFM.

That'd be right then

 

[Sparkey]

My first impression about this, would be: you're holding the torch too far away from your work.... (like you did on the other weld on the other side...)
Do you use both hands?

 

[Jack62440]

First off, I would like to say a BIG "Thank You" to All of You for taking the time to answer all these ??? I think Your All Great !!! Sparkey, I don't know how you could see the other side but more power to ya. I think my problem that we are talking about now is a combination of all that has been posted. I am pretty new at welding and I don't weld enough to become proficient. Right now my main concern is to get " Nice " looking welds on my exhaust sytem for a old Hot Rod that I have been piddling around with for the last 6 years. I may just end up using the secret tool from the tutorials Cheers, Jack

 

[Mr peepers]

Make sure the nozzle cup gets cleaned out or use the jelly to keep down spatter so it doesn't plug up, also make sure your not standing on the hose or kinking it Are you pushing or pulling the puddle? What gas mixture are you using? Usually cleaning it up with a grinder is enough it was probably the solvent you used the got trappe

 

[Sparkey]

First off, I would like to say a BIG "Thank You" to All of You for taking the time to answer all these ??? I think Your All Great !!! Sparkey, I don't know how you could see the other side but more power to ya. I think my problem that we are talking about now is a combination of all that has been posted. I am pretty new at welding and I don't weld enough to become proficient. Right now my main concern is to get " Nice " looking welds on my exhaust sytem for a old Hot Rod that I have been piddling around with for the last 6 years. I may just end up using the secret tool from the tutorials Cheers, Jack

Haha! i'll reveal my little secret...sssst! only to you Jack......the weld on the other side had such a lack of gas that it bubbled up....so i could see the weld come over on the other side...
Just keep practiscing! i'm sure you'll do fine!!