aluminum ac coil repair

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my dad found a pin hole in a small diameter (maybe 3/8") home air conditioning coil.  Would the aluminum stuff you use with a propane torch work well?  Would tig be ok to repair the line?  The inside of the line is not able to be cleaned so I guess it could easily contaminate the weld.Thermal Arc 185TSW
Reply:All the ac tech's I know (a lot) use Oxy Acetylene to braze them. But it may work, I can't say that it won't.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:I can't remember the name, but esab  had a paste designed for bonding aluminum.  It was sort of a welding/brazing paste.  I used to have some I used to patch thin wall aluminum irrigation pipes.  you could clean the material put the paste on it, and an aluminum patch covering the hole and take a torch and heat it and it would bond like crazy.  I haven't used it in a long time, but it did come in handy to keep around.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:JB Weld........
Reply:Depends some on which side of the system the hole is on. There can be some pretty high pressures with AC. Better check with an AC guy on this one. I always wonder, how'd that pin hole get there? Corrosion?? Thin spot??
Reply:I have repaired ally ac pipes on vehicles by tig welding. They usually corrode under one of their mounting brackets. The repairs are never pretty but as I remind myself every morning when I look in the mirror, you dont have to be pretty to work. Regards from sunny Cornwall__________________www.iancarey.co.uk
Reply:It depends.Most of the AC coils out there are copper with aluminum fins, but there are all aluminum coils.  If you want to repair the coil and maintain some kind of efficiency, damage as few fins as possible.  Oh, most leaks I have found are at the ends where the tubing goes through the steel plates.The problem is that this leak is probably just the beginning.  There is a type of corrosion ( called formicary corrosion, http://www.edwin-fine.com/air_con/fo...formicary.html) that will not stop, no matter what is done, outside of replacing the coil.  You can get a 'coated' coil that is less likely to leak in the future, but they are expensive and not easy to find.  Most techs have no idea they are available.For what it's worth, AC systems, which include heat pumps, have a life expectancy (according the manufacturers) of about 15 years.  Furnaces have an expectancy of 20 years.  House hold water heaters, the standard gas and electric ones, have a life expectancy of 12-14 years.Hope this helps.Second post, back to lurk mode.Last edited by heatman; 08-06-2007 at 07:40 AM.
Reply:Excellent post, Heatman. You nailed it 100%. I used to do A/C for a living, I remember cleaning off the aluminum coating from the copper, patching it... and having another leak in a few months. No fun.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Originally Posted by TEKJB Weld........