[sbaker56]

Is that typical of pulse programs? or is that high of a spike specific to HTP machines? I feel like pulsing would've been REAL handy when I was making a trailer ramp and had to do all that tacking on expanded metal. I don't know if it has a spot timer or not, but I feel like a quick pulse probably would've done a good job.

[Oscar]

Is that typical of pulse programs? or is that high of a spike specific to HTP machines? I feel like pulsing would've been REAL handy when I was making a trailer ramp and had to do all that tacking on expanded metal. I don't know if it has a spot timer or not, but I feel like a quick pulse probably would've done a good job.

I wouldn't be able to say. I know pulse by definition changes from low-to-high V/A, but how high the other's go is not something that I know. I do know that it kicks butt on my HTP's, with the Pro Pulse 300 being able to utilize peak pulses of ~600A in certain programs!

"Pulse" MIG is not like a spot timer though (the pulses are ultra high speed, 100's per second, to constantly switch between short circuit and axial spray transfer). For your trailer ramp, a spot timer type of mode would have worked out great, no real need for Pulsed MIG there.

[Oscar]

sbaker,

In case you want to experiment further, here are some settings that I found worked well for spray-transfer with Kiswel KX706M (E70C-6M) metal-cored wire. It transitions into spray much "sooner" than solid wire with the right gas mix:

0.035" diameter:

• Shielding gas: : 92/8 Ar/CO₂
  • CTWD: ½" - 9/16"
  • Approx. WFS/V: 318 IPM/22.8V
  • Approx. Transition Amperage into spray-transfer: 145A

• Shielding gas: : 98/2 Ar/O₂
  • CTWD: ½" - 9/16"
  • Approx. WFS/V: 299 IPM/22.5V
  • Approx. Transition Amperage into spray-transfer: 130A

0.045" diameter:

• Shielding gas: : 92/8 Ar/CO₂
  • CTWD: 3/4" - 7/8"
  • Approx. WFS/V: 224 IPM/24V
  • Approx. Transition Amperage into spray-transfer: 180A

• Shielding gas: : 98/2 Ar/O₂
  • CTWD: 3/4" - 7/8"
  • Approx. WFS/V: 200 IPM/23.7V
  • Approx. Transition Amperage into spray-transfer: 168A

On Ar/CO₂, you may be able to bring the transition amperage down, but it wasn't much from what I saw. O₂ on the other hand had a significant effect, even though it did oxidize the weld bead a bit more when it was all said and done.

I will also experiment with using Ar/CO₂/O₂ ternary mixes to see how that changes things.


Also, what etchant are you using to get those spectacular finishes/detail in the microstructure? High-concentration phosphoric acid? Nitric acid? Or is it a polishing technique or both?

[sbaker56]

sbaker,

In case you want to experiment further, here are some settings that I found worked well for spray-transfer with Kiswel KX706M (E70C-6M) metal-cored wire. It transitions into spray much "sooner" than solid wire with the right gas mix:

0.035" diameter:

• Shielding gas: : 92/8 Ar/CO₂
  • CTWD: ½" - 9/16"
  • Approx. WFS/V: 318 IPM/22.8V
  • Approx. Transition Amperage into spray-transfer: 145A

• Shielding gas: : 98/2 Ar/O₂
  • CTWD: ½" - 9/16"
  • Approx. WFS/V: 299 IPM/22.5V
  • Approx. Transition Amperage into spray-transfer: 130A

0.045" diameter:

• Shielding gas: : 92/8 Ar/CO₂
  • CTWD: 3/4" - 7/8"
  • Approx. WFS/V: 224 IPM/24V
  • Approx. Transition Amperage into spray-transfer: 180A

• Shielding gas: : 98/2 Ar/O₂
  • CTWD: 3/4" - 7/8"
  • Approx. WFS/V: 200 IPM/23.7V
  • Approx. Transition Amperage into spray-transfer: 168A

On Ar/CO₂, you may be able to bring the transition amperage down, but it wasn't much from what I saw. O₂ on the other hand had a significant effect, even though it did oxidize the weld bead a bit more when it was all said and done.

I will also experiment with using Ar/CO₂/O₂ ternary mixes to see how that changes things.


Also, what etchant are you using to get those spectacular finishes/detail in the microstructure? High-concentration phosphoric acid? Nitric acid? Or is it a polishing technique or both?

VERY interesting, on while AR/O2 brings the transition amperage down significant from 92/8 AR/CO2, the voltage needed is nearly the same. It kinda makes me think with .030 wire the gas used might not matter much as I burn back towards the tip under 400 IPM anyway. I really want to try that wire though, I should have more than enough voltage and amperage to spray with it.

For polish and etching I use a 120 grit flap disk, I've found you get a slightly better finish if it's been used a fair bit and I finish with a light touch. IF you've done it just right that's enough to see some grain structure as is. But it's better to go a bit further. I've polished it with anything from wet sanding with a palm sander and a LOT of patience and by hand using 320 grit and possibly going up to 600 or 800 if I'm feeling patient. As long as you've gotten all the coarse cut scratches out with the 120 grit flap disk you really don't need to polish it up until you've gotten even the deepest scratches out with the higher grit paper, just until you've gotten most of them out.

For the etchant itself I use Ferric Chloride, just the Radio shack PCB etchant type. It works MUCH faster than phosphoric acid and will bring out the grain structure itself with a lot less polish than naval jelly needs. It would depend entirely on the concentration of ferric chloride used, but I find it really helps bring the grains themselves out if you let it sit a minute and then moisten a Q tip with water and swap the weld again with the etchant still on.

[Oscar]

Thanks for the tip on the ferric chloride, I'll be sure to try that out later on.