Aluminium hot pipe welding issue

admin

So I'm trying to weld the BOV flange on my hot pipe and for some reason it is just not cooperating.I've sanded the parts thoroughly, SS wirebrush, and acetone and still I'm just getting issues.Any help or suggestions with what I could be doing wrong?I'm using 1/16" 4043 Filler, 3/32 Red tungsten electrode. Syncrowave 180SD.If I don't go to max cleaning I get black pepper like stuff, but the ball really doesn't let me get a stable arc.
Reply:Wrong balance setting, wrong tungsten and wrong size filler.Switch to a 3/32" or 1/8" Lanthanated or Ceriated tungsten.  The Thoriated (on the Sync 180) should be used only for mild and SS.  Not good for AC welding with your machine.  The Thoriated will tend to split and form multiple small balls on the end of the tungsten.I'd recommend going up to 3/32" filler also.  The 1/16" is hard to keep in the gas envelope without melting.  You're probably pulling it back too far (to keep from melting) and contaminating the filler.  Then when you add filler, you're contaminating the puddle.I'd recommend a balance setting, in this case of between 6 and 7, since you say you've throughly cleaned the material.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Great advice. The flange looks a good bit thicker, you might also want to start the arc on the flange, and try to center more of the heat on it so your pipe won't keyhole much or burn away. I think once you get the puddle going well, you will see a better result. That might take all the heat you have with a 180, and some fast filler adding (along with the bigger filler). If you have one, try a practice flange.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:The contamination doesn't look like a show stopper to me; it looks like you are still able to get a puddle to flow there.I am also a little doubtful that more DCEP (more cleaning on the balance setting) is actually helping get rid of the contamination.  But I am certain that its helping to melt your tungsten tip. It looks you you may be having trouble focusing the heat into the the corner of the fillet though.  A little pre-heating (such as with an air-propane torch) will help you get away with using a smaller, sharper tungsten, which will help you concentrate the heat more.If you're worried about excessive contamination (could be coming from oils in the metals that haven't been baked out) put on a small, sharp tungsten and using a very low current and high cleaning setting, run your torch over the area to be welded to etch and clean the area to be welded, even without forming a puddle.  It should help bake the contaminants out and clean them.Strive for keeping the tungsten very close to your work also, to focus the heat.  You may need to vary your cup size too if you aren't getting good gas shielding.  If you are sticking the tungsten out farther than about 1/2 of the inside diameter of the cup, try a gas lens or different cup size (smaller that will fit in closer to the work, or larger that will permit more stick-out.)  Do a dry run on a piece of scrap to test your gas flow rate and gas shielding.Welding the fillet in between the tube and the flange looks like a challenge.  If you can't "aim" the tungsten at the fillet there, you may have to resort to building up a wide bead until it gets high enough that you can flow it into the flange.You might consider welding inside the pipe, around the of the flange to the pipe connection, rather than trying to do it all on the outside, it might be easier to access all the way around the joint.  (You could also weld both the inside and the outside.)
Reply:Out of curiosity, what is your previous experience with aluminum.Have we all gone mad?
Reply:Gnentemen, does this power supply (Syncrowave 180SD) have an adjustable hi freq?  it looks a little diffused, I only know the Dynasty and I'd crank the hifreq to get a more 'focused' or concentrated arc.  Also arc length may be too long, so the arc is wider than needed for the weld?  Since d'man12' is trying to get in tight; small cup, lots of hifreq, short arc length and sharpened electrode would all go to help reduce the arc cone foot print and the wide puddle.I think the salt and pepper is coming in on the filler rod or too much gas and 'underskirting' some atmoshpere onto the puddle?  I'd suggest you scrub the filler with ScotchBrite (tm) pads just before  you light up, keep the cup small and tight and see what happens.  Sanding the parent metal can also embed contaminates, instead of really cleaning, I'd use SS brush after the acetone and skip the sanding unless the grit were 220+?A wide cup can keep the gas flow over the inside fillet so wide it drafts atmosphere over the wet metal and keeps the electrode too far from the puddle by the width of the cup.  If this is the case I'd add some stickout and get tight to the puddle at the tungsten tip; 1/8" or less.Cheers,Kevin Morin
Reply:Originally Posted by sn0border88Out of curiosity, what is your previous experience with aluminum.
Reply:Thanks to close reading by SundownIII, I'd like to make my post about the arc adjustments more useful by separating the terms I used- way too loosely.I'm welding on a power supply with an adjustable rate of AC (from 20 to 250) and I called  that adjustment of the AC rate of change by the same term as the arc stabilizing frequency used on the Syncrowave 180SD power suppliy.  I called the increased AC rate 'high frequency' as in greater than 60 Hz therefore a 'higher' frequency.  What I should have made clear, and hope this post helps in that direction, is to use the term AC rate increase instead of just 'hi-freq'.By calling the AC rate adjustment  on the Miler Dynasty power supply by the same term, high frequency, as the arc stabilizing feature on the other power supply, I have implied that the weld shown above would be improved by adding "intensity" to the high frequency are stabilizing wave form, that is not correct.If the intensity is increased the problem shown, too wide arc and possible arc wander with a wide puddle is made worse; not reduced.  On the Dynasty type power supply the increase in the AC rate (adjusted to a higher frequency) would narrow the arc cone, and make the weld bead fusion track less wide. On the Syncrowave 180SD the increase in intensity setting wouldn't help, in fact it would probably stick the filler rod to the flange when it was being fed.  The difference in the two results, increasing an adjustable AC rate, and increasing the  induced arc stabilizing 'high frequency'----- is 180 degrees apart. Thanks SundownIII for the heads up. Cheers,Kevin Morin
Reply:I think the problem is more with the weldor than the welder in this case.  With the machine and filler you noted anyone competent with aluminum should be able to make this weld.  No offense, but sometimes you need to know when your outside your limits.Welding thin tubing to a thick flange is not something a novice should be doing, regardless of what parameters you are using.Go and get some more practice, get some pictures of that up here and go from there.Have we all gone mad?
Reply:Late response but I ended up taking a different route. I welded the top part instead and just sanded the welds flat with a block and sand paper so that hopefully it doesn't leak now.Anyways, here's how it came out afterwards.
Reply:duffman,I'm not sure you'd have ever gotten a torch cup between the flange and the manifold?  I think socket/inside welding the stub was the only way to get this done now that I see this picture.When you say "welded the top part instead"  I'm taking that to mean you welded from the flange face fusing the tube to the inside of the bore in the flange?  Then you faced the flange by smoothing the welds' crown so the flange was as shown?Nice job.cheers,Kevin Morin