Welding Tips and Tricks

I am just asking what someone would do to repair the newer pure aluminum refrigeration coils by Tig welding? The problem is the refrigeration oil that has been in the coil. All of this fancy welding online is beautiful, but most of the repair work I get on aluminum has been contaminated with oil like cast aluminum blocks and coils. I rarely get a clean piece of metal in the real world. I would just like to know how someone would clean these coils inside before welding? Thanks.

TIG requires clean metal. I would find some way to flush with acetone.

I do this regularly. I use shellite (naptha) with a feeder pot and either compressed air or nitrogen. Outlet of the coil covered with rag so you don't spray oil everywhere.
After the oil is out, keep the air running to evaporate all the shellite so no flame outs. Shellite is good because it removes oil and also neutralises any acids in the system (common).

I did one a few years back. Local repair guys burned a hole in the tubing by not unplugging the fridge when using a heat gun to thaw frozen parts, whatever they were. Heat gun touched and POOF.

The refrigerant IS flammable, so that'll make a hell of a mess as soon as you get near it with an arc. Definitely try to purge those lines. Ask me how I know...

I cleaned it real good with Dynaflux alum cleaner, and used 1/16 4043 rod. Super low amps, I forget how low, but really low. Used .040" tungsten, might not have been necessary but a sharp point sure is. Mine turned out super nice, almost invisible. Pure luck, but I was sure proud of it!

Good luck!

It's easier to braze it. This is what I use. It flows like butter and can bridge a decent size hole. I like to brush and clean with acetone, but I have done it with less than ideal cleaning.



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WTXOffroader wrote:It's easier to braze it. This is what I use. It flows like butter and can bridge a decent size hole. I like to brush and clean with acetone, but I have done it with less than ideal cleaning.



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What heat source did you use?

I've seen similar repair demo'ed at a refrigeration exhibition. They used a small hand held butane torch a bit larger than a jeweler's torch. Worked nicely.

Also seen it done with oxy acetylene but with small tip and using only the very end of the flame to avoid overheating. I did not know this at the time of the exhibition when I was invited to try. I was given the opportunity of the butane torch or the oxy. I chose the oxy and became very sad.

ran into a guy at a flea market selling same type stuff. Watched him reseal a pop can using hand held propane torch, stainless brush...bought some. Ran into same guy at another flea market...he had me do the repair on the pop can...didn't buy any more, still had the first batch.

G-ManBart wrote:

WTXOffroader wrote:It's easier to braze it. This is what I use. It flows like butter and can bridge a decent size hole. I like to brush and clean with acetone, but I have done it with less than ideal cleaning.



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What heat source did you use?

I use a oxy/acetylene porta torch with a brazing tip.

It doesn't take much heat. I'd say the heat input is similar to soft solder on copper pipe, but flows more like 15% brazing rod.

Propane or mapp might work, but I like the precision of o/a without cooking everything in the area.

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Here's a video I did a while back. I was seeing how well it would bridge a larger hole.

That was a used piece of scrap that had oil in it and minimal cleaning.

https://youtu.be/z5ZmQuy6xGk

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