Brazing copper to steel accumalator ??

[garytreez]

Mitsibushi PU-P1.6VGAA . I was called out to this unit fault today and dignosed a couple of pinhole leaks on top of the accumalator between the factory soldered joint and the accumalator body. I have tried to braze using silver solder and flux but holes keep reappearing. Am i wasting my time trying to braze steel & copper ? or is there another fix. Replacing the accumalator looks like a major pain.

[chemi-cool]

Clean the area to brazed really good, make sure no pressure inside, use 40% silver rods, don't over heat the steel part, it should hardly be orange , it should go nice and easy.

[james10]

If you are really struggling you can pull a slight vac on the unit but be aware that this will pull air into the system and will need a good deep vac pulling before you recharge

[chemi-cool]

If you are really struggling you can pull a slight vac on the unit but be aware that this will pull air into the system and will need a good deep vac pulling before you recharge

Not good practice especially if the oil is POE.

[garytreez]

Thanks all, thats helpful. i was using 5% silver rods today.

[Magoo]

File out the pin holes to remove the impurity and use 40% easiflo rod and flux.

[mad fridgie]

I normally start buy burning of the paint (not to much heat) wire wool the area, then wipe down with a damp cloth (water or a solvent) Nice and clean.
I do not on the first instance go directly for the penetration, I "tin" some solder around the area (like a polo) again do not apply to much heat to one area. I then built up the solder from the tinned area to the place of penetration. i find that this does help with the flux penetration and adds extra stenght to the whole joint. (PS I do lke a shoulder of solder as well)
Trick not a hot flame, but a bigger flame covering a greater area

[paul_h]

Thanks all, thats helpful. i was using 5% silver rods today.

That would be why then.
If you like punishment, you can get away with 15%. But if you want it done easy, use 45%.
Also clean well, removing any oil and paint/ tarnish and rust, sanding back until the copper and steel are shiney.

[Quality]

As chemi said 40% rods and not to hot

[james10]

Not good practice especially if the oil is POE.

No not good practice thats why i said "if you are REALLY struggling" and pointed out that the system would need a good vac , and your right i should have suggested if this was done then an oil change would be a good idea.