In general, if one were doing a root weld with a back-up strip on mild steel using dual shield with 100% CO2 for shielding gas that was to be UT tested, would it be possible for a needle scaler to "pound" in flux that would show as inclusions on an inspection?  I can probably give more tech specifics and some parameters but it was years ago at a barge builder I worked at and there was a big debate over grinding it out vs using a needle scaler.  I used a grinder and think you can see pinholes and other junk while grinding but not so much when just "chipping it off". It seemed the guys that used grinders always moved on and the needle scalers  headed for the nearest air arc...  just thinking back and wondering.  Scott.

Scott: When I was in trade school learning to weld plate and heavy section we didn't use wire feeds and either hammer chipped or used needle scalers and brushed.  We learned that properly laid and chipped root pass doesn't leave inclusions when over laid by a 70xx series rod and that tends to chip itself.

It's been a long LONG time since school but how could 100% CO2 be dual shield? I run 75 25 in my little wire feed, isn't that dual shield? 

Or is my schooling THAT dated?

Frosty The Lucky.

  Sorry frosty, flux core with CO2.  I've seen the flux just peel off the weld when you have it set right and under perfect conditions so perhaps its a combination of things.  It was actually weathering steel, under less than perfect conditions.  Sometimes the flux would be stubborn and wouldnt just chip off.  All full of bubbley holes and stick like you now what.   I think just running over it with a scaler or chip hammer may leave flux around the undercut (which may or may not burn out on the next pass) or may drive it in deeper.  As an aside, it is fun to dig out a weld with an air arc or grinder just to see if an inspector knows what to look for.

I must be out of the loop, flux core and CO2 eh. What makes it better than just flux core?

Welding rusty steel and you're wondering about porosity? Brush the rust off before you weld. Undercutting welds, especially multiple pass fillets was a BAD thing when I was welding. Slow down on your pass speed and flag a little wider, maybe a J weave. 

I don't know if just a needle scaler would clean the inclusions out of porous undercuts. We used to keep dental picks in our pocket. That was 46 or so years ago though and I never worked as a certified pro welder. Ain't that life for you spend a couple few years learning and going to school for a profession and find a different career. Makes me wonder if my opinion is worth anything after so long.

Frosty The Lucky.

11 hours ago, Frosty said:

 Makes me wonder if my opinion is worth anything after so long.

Frosty The Lucky.

  Surely you jest!  I should have had my ducks in a row when I asked my question.  Learning experience...  Every body tunes in when Frosty message comes through the hemisphere and lands here!  

Oh PULEEEZE Scott my hat is tight enough already! I was referring to how out of date my welding trade schooling is, I don't recognize half the stuff I see at the welding supply anymore. 

Frosty The Lucky.

The pipeline welder I know uses a Stringer type wire wheel to clean off the flux when stick welding.  He always grinds the steel clean before welding.  Always grinding off the mill scale before welding.

 

 

Short answer: no.

A needle scaler is not going to pound soft slag under the surface of hard steel. Any subsurface discontinuities were formed in the weld pool before solidification. Poor technique will give you slag inclusions, undercut, lousy bead profile, etc.

Longer answer: welders with poor metal cleaning habits and poor technique blame the tools. I have tested welders to the bridge code on 1" plate, vertical & overhead, no air or power tools allowed after fit-up. Hand file, hand wire brush, chipping hammer only.  Zero defects = expert craftsmanship.