In need of advice, brazing joint close to brass fitting

By trweaver89 Date 09-13-2014 21:32

So, I work in HVAC and have been for about two years. This is the first time I've had to braze so close to a brass refrigeration access valve. I'm installing a used A/C I got from a home that was going to be demolished, so our company went out to cut out the units, I figured I'd just take it and install it at home, as it had only been in that house for about two or three years. Our company didn't install it, and the guy who did it before put the wrong size lineset on, so he had pinched the tubing right off of the brass fitting so it could fit the undersized lineset. I had to cut this pinched part off to get on the correct lineset size...now the brazing joint is far to close to the brass fitting, so the silphos won't take.

My question is, does anyone think it would work to use just some silver brazing flux to get the silphos to take? Or should I use brazing flux and a silver solder? Or something else entirely?

Any help would be greatly appreciated.

By Plasma56 (**)

Date 09-14-2014 04:53

Hey, two things to keep in mind, sil fos, or RBCuP doesn't require a flux on copper to copper so if your trying to go copper to brass then yes, the flux will assist with that effort. Problem with using either RBCuP or Silver brazing RBAg alloys is melting and flow temps. More heat into the brass is required and the silver brazing alloy depending on joint design, probably not a good fit due to range of flow between solid and liquid.
Clean the surface well, flux even better, protect what you can from the heat, and focus it more to the brass. Slow and steady rise of heat. Once the flux starts to do it's thing, your off to the races.
Between you and me, it should work. But good luck with that effort.

Attachment: Imgasweldingit..jpg - Some things don't require electricity. (178k)