Freon/oil/concerns?

[Trip59]

Have a small repair job, bracket welded to a side tube on a condenser. The weld I can handle, but never having welded on air conditioning components, is there any concern with vapor/gas release from whatever residue is inside?

I was ASE AC certified, but that was back when the 134a change was just starting, never dealt with it at all myself. I know folks braze on systems that have had it, but what about TIG?

[todmorg]

Phosgene gas can be generated by heating some refrigerants, or exposing them to an open flame.

Do a google search, it's deadly stuff.

[Trip59]

Phosgene gas can be generated by heating some refrigerants, or exposing them to an open flame.

Do a google search, it's deadly stuff.

Indeed, I'm well aware of that, especially with the brake cleaner (though I believe that's the chlorinated ones, I don't heat either type, nor carb cleaner) Wasn't sure about refrigerants or the oils within their systems. The freon I'd assume would dissipate once it was pulled from the loop and open to atmosphere, but I am not familiar with 134a to know if there's any residue and if that residue or oil would outgas toxins.

I have a number of friends who work with AC, but brazing/silver soldering is different in two aspects... much lower temp than TIG, and no Ar to mix into the reaction.

[Gerry]

Indeed, I'm well aware of that, especially with the brake cleaner (though I believe that's the chlorinated ones, I don't heat either type, nor carb cleaner) Wasn't sure about refrigerants or the oils within their systems. The freon I'd assume would dissipate once it was pulled from the loop and open to atmosphere, but I am not familiar with 134a to know if there's any residue and if that residue or oil would outgas toxins.

I have a number of friends who work with AC, but brazing/silver soldering is different in two aspects... much lower temp than TIG, and no Ar to mix into the reaction.

They make a flush for a/c systems to remove the oil and stuff when the compressor fails, you could get a quart can of that and run thru it, BUT Read the can first. I'm not sure if it is flammable or not. Then purge it with air before welding.

[sw2x]

They make a flush for a/c systems to remove the oil and stuff when the compressor fails, you could get a quart can of that and run thru it, BUT Read the can first. I'm not sure if it is flammable or not. Then purge it with air before welding.

Do not! Under any circumstances flush/purge any refrigeration system with air. This will cause a chemical reaction and produce large amounts of phosgene gas which could explode when heated. I am by Trade a HVAC Technician.
USE NITROGEN.

If you feel a light burn in your lungs you are breathing in phosgene. I've had 15 ft flames shoot out of condensing units with accumulators that had not released all their refrigerant prior to trying to braze in a new compressor.

[everlastsupport]

Do not! Under any circumstances flush/purge any refrigeration system with air. This will cause a chemical reaction and produce large amounts of phosgene gas which could explode when heated. I am by Trade a HVAC Technician.
USE NITROGEN.

If you feel a light burn in your lungs you are breathing in phosgene. I've had 15 ft flames shoot out of condensing units with accumulators that had not released all their refrigerant prior to trying to braze in a new compressor.

Do you have any info on plasma , O/A or saw cutting on empty freon containers? Weird question, but for yard art.

[Gerry]

Do you have any info on plasma , O/A or saw cutting on empty freon containers? Weird question, but for yard art.

A lot of those containers at one time were used as portable air tanks when empty. As far as cutting any of them with something that generates heat. I wouldn't advise it. Stay a away from the old R-12 or R-22 containers with heat. There is not a good way to purge those small tanks. Just best to throw them in the scrap pile when empty.

[Gerry]

Do not! Under any circumstances flush/purge any refrigeration system with air. This will cause a chemical reaction and produce large amounts of phosgene gas which could explode when heated. I am by Trade a HVAC Technician.
USE NITROGEN.

If you feel a light burn in your lungs you are breathing in phosgene. I've had 15 ft flames shoot out of condensing units with accumulators that had not released all their refrigerant prior to trying to braze in a new compressor.

Yep the Pag/Ester oil is hard to get out of the system without a good chemical flush and a purge. Like welding an oil pan on a vehicle.
One thing missing is the OP didn't say what the condenser was used on or weather it was removed or still on the piece of equipment.
Nitrogen is used to purge the moisture laden air from the system after it has been open to the atmosphere and to pressure test the system for leaks.
Without more information, maybe a trip the the local ACE Hardware store for a good metal glue would be best.

[Trip59]

Condenser was on a Peterbilt, has been open to atmosphere for a couple months now. There was a thought of repair, but it was replaced, so this is part 'can it be done for next time' and part 'if I fix this, it'll make a nice piece for a TIG cooler.

[Gerry]

Condenser was on a Peterbilt, has been open to atmosphere for a couple months now. There was a thought of repair, but it was replaced, so this is part 'can it be done for next time' and part 'if I fix this, it'll make a nice piece for a TIG cooler.

If you going to use it for a cooler core, I'd just glue the clip back on. It's not going to take a beating like it would on the front of the Pete.
If you want to weld it, I'd do it outside, make sure the inlet and outlet ports are facing away from you and anything flammable . There is still possibly some oil/coating inside the condenser, wear a chemical respirator and face shield. 3 hail Marys & crossing your toes wouldn't hurt.

[sw2x]

If this condensor is removed and has been open for some time you could use acetone and fill the inside of the condensor half way and then shake the crap out of it for a few minutes and then dump it out and let it sit for a few days, then I would think you could weld on it without much risk. I assumed that you were welding on a residential or commercial condensor that was still installed and that is a recipe for disaster. Automotive style systems contain alot less refrigerant and alot less oil than your typical residential or commercial systems..

Why not braze it? I do similiar repairs all the time on Commercial package units in upwards of 50 tons using oxy-acetylene and some Sil-Phos 15% if your trying to attach dissimilar metals you can purchase brazing rods in 56% silver.
Using a Welder is very unorthodox, even the manufacturers use a brazing process except that they do use a electric machine that heats the fitting and melts the filler material into the joints...

[Rambozo]

You can also braze with a TIG. Comes out very clean and no long torch flame, so nothing around it gets burned or needs to be protected with heat shielding.

[jakeru]

I did some welding on an aluminum AC condensor, (putting back on a broken off aluminum fitting onto one for an old mini cooper). Yes, there is a concern regarding phosgene gas when sufficiently heating up (which includes TIG welding) anything chlorinated (including old-school refrigerants - but not the newer "nonchlorinated" ones, just as it does old school "chlorinated" brake parts cleaner and other solvents, but not newer "nonchlorinated" brake parts cleaners or other nonchlorinated solvents.)

I recall verifying that the refrigerant was nonchlorinated as a precondition before taking on the repair. Do some research on the subject for your own safety, and exercise caution. Not a bad idea to weld in a location having good ventilation and keeping your head well away from where any potentially dangerous fumes might be. That said, it welded up nicely. Not sure if I got any pics of it though.