Padding Question

admin

Machine: Lincoln Electric AC225Tap: 90ARod: 3/32" 7024 (I do not know the exact brand, they were spare rods that were given to me)Material: 1/4" HRSTo all,I was practicing padding yesterday, and I decided to make triangles, as my drop off was cut that way.  However I ran into problems with the joints, see the attached sketch.  The legs of the triangles is about 4".  I could make the initial outline with no problem, however I would always wind up with little dips in the beginning of my bead.  I know that this is due to the angle that the rod was being held at at that specific point, but I am unsure of what the correct position would be.  Any advice would be helpful.  Some additional observations:The majority of my beads were sized slightly over 1/4"  The width was pretty consistent down the length of the bead (about +/- 1/32" excluding start)In the portion with the dip the puddle was obscured by the slag, when I could see the puddle the consistency was good.I tried to clean out the portion with the dip with my hammer and brush, but as the dip got smaller, it became harder to do effectively.My initial rod angle is a 15* travel pointing directly into the corner.  I rapidly change to 15* travel with a 5* work (from vertical) with the rest of the bead.
Reply:Hello Ace86, your progression for padding this part could be considered as a part of the problem that you are having with the "dip" that you speak of. Another item to consider is the rod that you are using, not to say that it is a poor choice,yet. E7024 electrodes have a thick/heavy slag coating on them. This is due largely in part to the additional powdered iron that becomes a part of the finished weld bead. You need to run on the upper end of the amperage scale with these to allow the force of the arc to assist you with keeping the puddle clear of slag (the part positioned so that you have no downward welding angle, level or slightly uphill is ideal). A more pronounced drag angle with this rod can be beneficial to keeping the finished weld bead free from toe issues (such as your "dip in the bead" item and "fish eyes" (this can occur when you are welding fillet welds into and out of inside corner welds).  With reference to your padding progression choice, you may find that if you start on one end of your part and weld across the edge as you initially did, but then make your next bead start where you ended the first bead and then ran this bead in the opposite direction and continued to alternate directions that this sort of progression may reduce the likelihood of having bead start issues and will also provide for a very even build-up all around on the surface that you are padding. With your start, strike it away from where the bead will actually begin and inline so that after you have begun the weld it will consume this strike-up area and move on to make the rest of the bead. This slight "preheating start technique" will assist with preventing a humped and less than consistent bead width at the start of your beads. Good luck and best regards, Allanaevald
Reply:Aevald,Thank you for the response.I think that I am running these rods close to their upper end of Amperage.  I found a data sheet for Inweld 7024 3/32" their listed range is 60A-100A.  I could try to bump my amperage up to 105A if that may help a little bit.  I can also give a larger travel angle a shot.  I actually prefer to just run straight parallel lines when I am padding.  Once I get past the start, I think that I am actually doing really good.  I am getting the slag peeling up by itself, I can clearly see the (back of) the puddle, and the slag swirling around behind it, and I am keeping the arc close enough that sometimes I can't see my line or the previous bead (I am not sure how to explain it, I can see where I am on the previous bead by watching the puddle).  The triangles were simply because I was using a random drop from work, but they have show me a deficiency that I was not aware of.When you say strike ahead, how far ahead do you mean?  If I was using 6010 I would burn right through the slag and not really worry, but with the 7024 is that possible?  I think that part of my problem with the dip is that I can't see the puddle when it initially forms, the slag starts building up , and I move away too fast without being able to really see what is happening.