I finally managed to escape the family long enough this evening to practice my TIG skills a bit. I decided to have a go at mild steel this time round for several very good reasons; 1) it's what I've got, 2) I'd not yet given it a proper go and 3) I needed the peace and quiet of DC! I nearly gave up before I started after dropping the power hacksaw on my thumb. 'Ouch' and 'golly gosh' I said.
It took a bit of getting used to the M/S. I find that the timing on ally is very obvious; the pool forms very clearly, you add your filler and move on. With the M/S the pool is smaller and less clear which had me all over the place to start off with. I was also getting the filler stuck to the work but I worked out that that was because I was trying to slide it into the pool, rather than dab it. Actually here I'm a little confused. I'm sure I remember reading that this move, dip, move, dip method is not the preferred method on M/S. Is that so or am I barking up the wrong tree? If so, is the idea to feed the wire in constantly? I'm not sure I get that either as I'm sure I'd have a sod of a time working out whether I was getting the workpiece hot enough or whether I was just laying lobs of weld on top.
My butt welds were reasonably pleasing. On the 80x80x3 SHS I was practicing on I started off at 90 amps but ended up at 80 by the time I'd got round to the last face. I think some are a little proud and one definitely sank a bit!
I was a little worried I was giving it enough oomph but I broke one of the welds (visible in a later photo) and it seemed OK.
Next up was the fillet weld. Thought I'd give this a go without filler first off so as not to over-burden the grey cells. Here I found that once I'd got a pool that spanned the fillet I could move it forward though I kept getting ahead of myself and having to pause to get the pool going again.
After that I tried with the filler. Again, I ran into the problem of rod sticking to work. I had the rod laid flat along the fillet and was rocking the ceramic back and forward along the join. My cure was to twist the rod in my fingers as I pushed it gently into the pool but I can't help feeling I'm just not doing the weld right in the first place!
Finally I tried doing the butt welds left where I had welded to fillets earlier on only because of the radius on the tube corners there was a large gap. TBH, these felt reasonably easy but I was interested to notice that there appeared to be quite a bit of undercutting on the corner of the tube. This had me baffled as I'd have expected to have had problems melting the edge of the other side, not the corner. Anyone brighter than me able to shed any light on this (chortle, chortle)?!
Fortunately the tube has no mill scale on it so I didn't bother cleaing it up. I di have a go on some 30x3 flat and immediately noticed what Darren (I think it was Darren...) was saying about it's habit of jumping up onto the electrode.
All in all I don't think M/S is easier or harder than ally; just different. Although perhaps not having to bother with the pedal takes one thing off the beginner's mind! Thanks to anyone who gets this far through my ramblings! I'd be grateful of any hints, tips or pointers!!!
It took a bit of getting used to the M/S. I find that the timing on ally is very obvious; the pool forms very clearly, you add your filler and move on. With the M/S the pool is smaller and less clear which had me all over the place to start off with. I was also getting the filler stuck to the work but I worked out that that was because I was trying to slide it into the pool, rather than dab it. Actually here I'm a little confused. I'm sure I remember reading that this move, dip, move, dip method is not the preferred method on M/S. Is that so or am I barking up the wrong tree? If so, is the idea to feed the wire in constantly? I'm not sure I get that either as I'm sure I'd have a sod of a time working out whether I was getting the workpiece hot enough or whether I was just laying lobs of weld on top.
My butt welds were reasonably pleasing. On the 80x80x3 SHS I was practicing on I started off at 90 amps but ended up at 80 by the time I'd got round to the last face. I think some are a little proud and one definitely sank a bit!
I was a little worried I was giving it enough oomph but I broke one of the welds (visible in a later photo) and it seemed OK.
Next up was the fillet weld. Thought I'd give this a go without filler first off so as not to over-burden the grey cells. Here I found that once I'd got a pool that spanned the fillet I could move it forward though I kept getting ahead of myself and having to pause to get the pool going again.
After that I tried with the filler. Again, I ran into the problem of rod sticking to work. I had the rod laid flat along the fillet and was rocking the ceramic back and forward along the join. My cure was to twist the rod in my fingers as I pushed it gently into the pool but I can't help feeling I'm just not doing the weld right in the first place!
Finally I tried doing the butt welds left where I had welded to fillets earlier on only because of the radius on the tube corners there was a large gap. TBH, these felt reasonably easy but I was interested to notice that there appeared to be quite a bit of undercutting on the corner of the tube. This had me baffled as I'd have expected to have had problems melting the edge of the other side, not the corner. Anyone brighter than me able to shed any light on this (chortle, chortle)?!
Fortunately the tube has no mill scale on it so I didn't bother cleaing it up. I di have a go on some 30x3 flat and immediately noticed what Darren (I think it was Darren...) was saying about it's habit of jumping up onto the electrode.
All in all I don't think M/S is easier or harder than ally; just different. Although perhaps not having to bother with the pedal takes one thing off the beginner's mind! Thanks to anyone who gets this far through my ramblings! I'd be grateful of any hints, tips or pointers!!!