I'm making an exhaust for my old Panhead and I really need some help with laying down a tack without using wire. The tube is .062 and I've tried low amps (30) and high amps (75) pulse and spot and my confidence is in the shitter. My machine is an HTP 221, using the peddle and 1/16" tungsten. Ideas and help would really be appreciated.
A filler-less tack (autogenous weld) requires perfect fit-up. If you have gaps at the seam, you’ll need a dab of filler.
Even though the tubing might be mild steel, I find it best to purge while welding. The purge gas pressure from behind helps push the tack/weld up and keeps the tubing cooler.
I’d be using 60 amps, foot pedal, and either blast it (if the fit is good) or ease into it with a dab if you have a gap. To weld it out, I’d be running 70-75 amps, pulse at 1.2pps, 50% on time, 25% background. This is my go to recipe when welding exhaust tubing. You can run a root bead with filler, let the whole thing cool off, then come back with pulse and make it look really clean.
Even though the tubing might be mild steel, I find it best to purge while welding. The purge gas pressure from behind helps push the tack/weld up and keeps the tubing cooler.
I’d be using 60 amps, foot pedal, and either blast it (if the fit is good) or ease into it with a dab if you have a gap. To weld it out, I’d be running 70-75 amps, pulse at 1.2pps, 50% on time, 25% background. This is my go to recipe when welding exhaust tubing. You can run a root bead with filler, let the whole thing cool off, then come back with pulse and make it look really clean.
fit up needs to be near on perfect. spending a few minutes with a file getting just right makes life so much easier.
jody likes the blast tacks, i tend swirl the weld. eg move the tig torch like your mig welding, i do circles. this drags the metal across from one side of the other. this helps stop the metal shrinking back because the fit up isn't quite perfect.
jody likes the blast tacks, i tend swirl the weld. eg move the tig torch like your mig welding, i do circles. this drags the metal across from one side of the other. this helps stop the metal shrinking back because the fit up isn't quite perfect.
tweak it until it breaks
Thanks, I try to make my fits tight, my biggest challenge is applying the tack. If I go with 60 amps I'll blow through before I can move. I try to stay away from the joint and work into it with the puddle, throttling my heat as I go, but more times than not I blow through. If I stay on the joint I blow through with any amount of amps and I think this is because I'm not reacting quick enough to back out before it gets to hot. I just think it's operator error. More practise!
If you are hitting the joint directly, even with a good fit, lower your amps to 45. Be prepared to move away quickly. You can also use a dab of filler resting on the joint, and hit that with your arc. This can provide just enough extra material to avoid blowing through.
One thing that is critical: you must use a VERY tight arc. If you are long arcing, you will blow through immediately. Check that aspect on yourself. BARELY above the work surface (like .5mm) works best without filler.
One thing that is critical: you must use a VERY tight arc. If you are long arcing, you will blow through immediately. Check that aspect on yourself. BARELY above the work surface (like .5mm) works best without filler.
I was thinking that if you had your heat set, that a one second pulse might be the ticket. I tried it to frustration and turned it off. I think that I might have found a way that works for me most of the time.A tight fit and light up just off from the joint and as soon as it puddles bring it into the joint.
Sure sounds like newbee stuff but getting the little stuff done really makes the task easier. Thanks
Sure sounds like newbee stuff but getting the little stuff done really makes the task easier. Thanks
a crude way is to weld a dob of weld next to the edge of the joint while its apart. then hold that into position and light up on that bit of weld and drag the weld metal with the arc. at lot easier if gravity helps. ie weld a bit of filler on the edge, place the part of top, weld on that filler and let it flow down across the joint. downside is its not pretty, so do it where you can grind it off later.
tweak it until it breaks
All good welders are cross-mated with an octopus. What’s the issue???
Seriously, a “third hand” clamp is frequently used if you can position the work pieces on a table. Just give it a Google to see examples. But there are so many times that another pair of human hands or fingers would be quite helpful… Tweake gave another option for making a pile of filler nearby that you “borrow” from to get your tack.
This is great as I've been screwing this part up myself. TY!cj737 wrote: ↑Thu Feb 01, 2024 10:57 am If you are hitting the joint directly, even with a good fit, lower your amps to 45. Be prepared to move away quickly. You can also use a dab of filler resting on the joint, and hit that with your arc. This can provide just enough extra material to avoid blowing through.
One thing that is critical: you must use a VERY tight arc. If you are long arcing, you will blow through immediately. Check that aspect on yourself. BARELY above the work surface (like .5mm) works best without filler.