Welding Question

[CTC]

I have welded for about 6 years now and today I came across a compressor that ate my lunch. It was a 14 ton compressor that was piped to anouther compressor. I could not get the equalizer tube welded to save my life. Heated the metal on the compressor to the point I could see it moving around, RED as fire, Silver rolled off it. Would not stick. I was using 15% silver. Same problems with 1 5/8" Suction and 1 1/8" High Side. What am I doing wrong? I got the equalizer tube closed up, but I would not want anyone to know it was me that welded it.. Looked like a buzzard took a dump on the pipe. Trane compressor and the connections look like steel? Never had this problem before. Am I using incorrect rod or what?

[jpsmith1cm]

Next time, try this.

CLEAN the metal.

Use a good flux and a rod with higher silver content like 45%

Many compressor stubs are copper clad steel. You burned the copper off.

[trouble time]

[Pascone10]

JP Is the man.. Follow his advice!

[dm]

Ditto

[ascj]

Next time, try this.

CLEAN the metal.

Use a good flux and a rod with higher silver content like 45%

Many compressor stubs are copper clad steel. You burned the copper off.

And Trane's Larger scrolls are steel stubs......no copper clad. So follow JP's advise. Or cheat like me and buy the rods with flux on them already. And then when you're done, wipe them down to get the flux off and cover them with a thin layer of high temp silicone. It will prevent the stubs from rusty and getting pin holes.

[Snapperhead]

yup use 45 %

If you have enough play ... cut about an inch off both sides and try again.

[CTC]

And Trane's Larger scrolls are steel stubs......no copper clad. So follow JP's advise. Or cheat like me and buy the rods with flux on them already. And then when you're done, wipe them down to get the flux off and cover them with a thin layer of high temp silicone. It will prevent the stubs from rusty and getting pin holes.

Thanks to all who replied. Glad as heck to run into you as I was thinking I've welded plenty of copper clad and this thing wasn't. Thanks for the info on the silicone as well, I was wondering why Trane had painted all the connections on the compressors.


JP, Thanks for the 45% suggestion. I didn't even know it existed as I trade with 9 different HVAC supply houses in my town and unless I missed it some where, non of them have anything other than 15% Harris Sta-Silv on the shelf. I buddy of mine is a fabricator and he told me he knew of one welding supply in town that for sure stocks 45%. He said they had 5 or 6 grades over there.

I used Sta-Silv flux. Is that ok or should I be looking for something else?

[jpsmith1cm]

I actually use the coated rod, but Stay Silv works well.

[jackintheboxtec]

Coated works the best.

[marvin]

if im using un coated silver i use the harris black flux.
it seems to work better than the white.
im sure you have a magnet in your truck. if it is magnetic i dont
use anything lower than 45% & sometimes use as high as 85%..
flows like hot butter with proper heat control.

[CTC]

Thanks for all the information. I used 45% Coated rod and it worked like a charm.

It seemed to me like I got a lot more coverage out of the 45%. I thought it was expensive when I purchased it, but after using it I thought it was a good deal. In this case you realy do get what you pay for.

[jayhawker]

Preheat the copper coated stub but put most of the torch heat on the copper and let the heat convect up thru the copper coated steel stub for a uniform surface temperature. This will allow the alloy to flow evenly across the two different materials.