Aluminum w/ spoolgun

[Paul Seaman]

I am still having a little trouble with Al burning back to the contact tip on my mm210 spoolgun. I am running .035 on tap6 and wire speed on 70 just like the panel says to. I've tried mixing up and down on both settings, but still have the same problem my welds look very good but still have the burn back and have to replace the contact tip. My local supplier is great and very helpful, their suggestion is to use .030 wire and the .035 contact tips. This sounded odd but I havent tried it yet, does it sound right? pjs

[HAWK]

It won't hurt to oversize the tip. Maybe go to .045 tip with .035 wire.

[Paul Seaman]

Hawk, thanks for the fast response. My local supplier has to order all my tips since I have the only one of these in town, I have 10 of each .030 and .035 but no .045 but I will get some. Another stupid question why did Miller use a different contact tip on the spoolmate from the regular mig gun?

[jeffscarstrucks]

Hi, I am not sure that this will help your situation but I have had this problem at the college where I work and sometimes take welding classes.When I would hold the gun still with the wire sticking out about 1\2 inch and pull the trigger to start the wire would immediatly hit the work and burnback into the tip. One of the guys told me to be moving the gun forward while hitting the trigger to help establish the arc. It did work for me but I'm not sure that I can convey this motion with words. I was using a Maxtron 450 with an XR push-pull feeder(I think, It's been a while). One thing I learned in a hurry was that an accetelyne torch to heat the tip would save it if you heat the tip and push out the AL with a tip cleaner while it was hot. I haven't had this problem with my 30A spoolgun but I think I still use this tecnique.I hope I'm not off base here but it worked for me.

[HAWK]

Jeff,

I think what you are saying is start the arc in a short arc mode with the tip in close to your work piece and pull away to create the spray arc. I have not really thought about it, but that is what I do anyway. I close in to less than 1/2" and pull the spoolgun trigger then pull my tip and nozzle away 3/4"-1" to establish a good aluminum spray. I do the same for ER70S-6 when migging in the spray mode with a hot gas mix 92Ar/CO2 or 95AR/5O2, or tri mix depending on situation. Anyway the longer the stickout the easier to spray with aluminum or steel with a hot enough gas mix.

pj,

Why the different tips? Perhaps an engineering reason we are not aware. Miller and everybody else is always improving on designs. The new push-pull system now has the "fas tip" on the Edge Gun, The 30A has an improved adjustable nozzle with a locknut on the barrel. Why aren't they interchangable? My guess is engineering and marketing. Perhaps Rock or Andy will give us the REAL SCOOP.

[Blondie_486]

Hawk,

Any chance the problem lies in the shielding gas? It's been many years since I've MIG welded aluminum but I do remember using helium as a shielding gas. I remember one machine was using straight helium and one was using a helium bottle and I'm not sure if the other was argon but it was being mixed using a tee at the machine to allow 2 gasses to flow through the gun. One machine was set up with a spool gun and the other had a push pull setup. Since that was in 74 I can't remember which machine was set up which way. The only thing I remember was ending the weld if you let off the trigger at the end it left a little crater not much but enough that you had to fill it. To get around that problem when I got to the end I just moved back into my weld to end the arc. We had no problems with the tips and burn back into the tip though.

Blondie_486

[Paul Seaman]

Thanks for the input, as for the gas I am running straight argon because I plan to do 1/8" and the helium mix is a little to hot and makes my puddle a little to fluid, at least with my current abilities. I rerally do appreciate the help and hope that others can gain from my experience like I gain from others. Thanks pjs.