USA Weld, Tips, Nozzles, Etc.

Misc:

When I started welding aluminum with my MIG it took a little while to get a feel for it, but within my work envelope I feel like I can get satisfactory results. The one thing I can't seem to eliminate is melt back into the tip of my gun. For a small to mid size project I would go through a couple tips. For a large project tip replacement would get downright expensive. I have a Miller 212 w/ a 3035 spoolgun. I always figured it was just me so I started buying tips from USA Weld (HTP America) in bulk. Someday I figured I would finally master that problem, but in the mean time... I found their tips to perform exactly the same as the Miller replacement tips at a fraction of the price.

A week or so ago I found my spool gun laying on the floor with a bent nozzle. The center tube was bent, and the ceramic insulator was broken. :( I did a little research on parts, replacements etc, and discovered I am not the only one having melt back issues with this gun. One fellow claims that the problem is that the miller tips are too thin at the tip. I don't recall what all the explanation is, but basically he shortened the inner tube and drilled and tapped it to take the regular mig tips which are thicker to the end. He claims he no longer gets the continuous melt backs that ruin so many tips. Interesting. I may try that.

In the mean time I ordered a replacement nozzle assembly for my spool gun from USA Weld. They claim it is identical to the Miller and even made in the same factory. It may be made in the same factory, but it is not identical. I took it all apart and looked it over. For the most part it is the same, but I found two difference from mine. The brass nut that attaches the nozzle to the gun has an easy grip plastic shell over the nut on the USA Weld version, and the hose barb has two ridges instead of one. Both in my opinion are improvements over the Miller Nozzle I have.

When I chase one down I do plan to order a replacement center tube for my Miller Nozzle so I can fix it just so I can do the cut and tap mod to it and see if it really eliminates or substantially reduces melt backs.

Reply to
Bob La Londe
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Aluminum MIG requires 2 setups. For Spray process you want the tip recessed into the cup about 1/4". If you don't recess the tip in Spray process you will eat tips like candy.

For Short Circuit you want the tip flush with the cup or proud by 1/8". Short circuit requires a shorter wire stick-out.

I liked the older Miller 30A spoolguns because you could adjust the wire stick-out by simply screwing the outer barrel in or out of the gun. Not sure why they removed that on the new ones.

Most aluminum MIG systems, such as Cobras or Pythons, use 2 different length of contact tip to accomplish the 2 processes.

Reply to
Ernie Leimkuhler

I looked at my nozzle(s) yesterday, and it looks like the tip is recessed less than 1/8 inch. Maybe 3/32 at best. Since I have a straight DC welder its my understanding I can realisticly only do spray arc for aluminum. That being the case do you think shortening the inner tube and tap chasing as neccessary would improve my burn back problem? (I only use my spool gun for aluminum)

As always, thanks for your help Ernie.

Bob La Londe

Reply to
Bob La Londe

Could be just a case of old production VS new production. So it may be identacal to new Miller parts.

Remove 333 to reply. Randy

Reply to
Randy333

In spray mode if the tip isn't recessed enough you will eat tips fast. Either shorten the tips or extend the nozzle.

Reply to
Ernie Leimkuhler

Try going .005 over on the tips,,,aluminum expands in the gun. This really cured burn back issues with my 3545. Hope that helps!

Reply to
islanduni

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