Should the gun tip and nozzle be flush or should the tip be recessed or proud. When should tapered vs. straight nozzles be used. Specifically when welding aluminum with 170 amps .035 wire 5356 alloy and 25 helium 75 argon gas. I found that a straight nozzle which extends past the tip seems to work better but I want to know if this is the way it should be.
On Sat, 24 Apr 2004 12:47:24 GMT, Ernie Leimkuhler vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email
Today I was welding and started to weld a bit "hot". IT was behaving ike spary, with a "flame" rather than the usual crackle. I was running
220A. The welder is not really designed for this at all. I have "faked" the spray at lower current settings before, with good results.
The wire kept welding to the _base_ of the tip, where it joined to the liner steel atop the gun. It would stick, and in the end I had to change tips. I tried adjusting tip-to-work gap quite a bit, but it still gave trouble.
When you say "the tip too far out", do you mean too far from the nozzle/gas shield, or simply with too long a tip distance?
I am always trying things. This "spray" mode gave beautiful welds after I changed the tip. Really smooth and deep. I was working in fiarly heavy stuff, and was able to "go for it"
**************************************************** I went on a guided tour not long ago.The guide got us lost. He was a non-compass mentor.........sorry ........no I'm not.
With aluminum MIG welding the machine settings are critical for each combination of joint design, materiels thickness and direction of travel. When you find a combination of voltage / wire speed that works, you write it down for future use. The welding itself is pretty easy, once the machine it dialed in.
Spray is very good for materiels 1/4" or thicker, but it runs much hotter and will eat tips quickly if you don't have the balance of settings just right.
By sight and sound. Globular transfer produces lots of spatter, spray doesn't. Short circuit makes a "frying bacon" sound, spray makes a hissing noise. The differences are distinctive enough that once you've seen and heard them, you'll have no trouble recognizing them.
Your voltage, wire speed, wire thickness, and shield gas will determine which mode you get. Spray requires the highest voltage, short circuit the lowest, with globular in the middle. High CO2 can't get to spray, so you'll only be able to do short circuit or globular with CO2. Argon is needed to spray, a fairly big welder is required too, since you need close to 300 amps to get into spray with the usual wires. (Small wire lets you get into spray at somewhat lower current, but there will be problems with the wire welding to the tip.)