brazing a compressor into a loop.

[the_new_guy]

hey guys i had started my ss, i am having problems brazing copper pipes to the terminals of the compressor.( discharge, suction etc.)

i cannot get the filler to flow, either its to cold or to hot and the pipe melts. i am using 45% silver rod. should i use brass instead.

help me out guys any tips or tricks that can help me????:stick:


thanks
mohit

[Xeon th MG Pony]

what type of flame are you using? Highely fucused or distrobuted?
MAPP, Propane, Oxy/Acetle, Oxy/Propane?
How fare are you holding the tortch?

and perhaps 15% be more fiting? Did you remember to sand & clean off the joints with aceton or Alcahol, Add flux?

To realy help we need this info, as this simply may be a technique problem or a physicle surface problem, or like you said a pure heat problem.

[ayrtonsenna]

you need to concentrate the heat on the compressor pipes first as the heat is conducted away into the compressor body. get them really hot and the pipe you are trying to join will heat up quickly when you come to braze it.

[Xeon th MG Pony]

http://hvacwebtech.com/brazing.htm < Nice set of tips

[wdrzal]

If the copper tube is melting your to hot. First clean joint till shinny,I use scuff pads but you can use sand paper of steel wool. I like the scuff pads because no debrie comes off them.To clean the inside of a swag joint you should have a wire tube brush. The compressor will "still" heat so you will have to apply more heat to the compressor side. with 45% silver rod no flux is needed. You can use flux but you may burn it causing more problems, Do not use any thing elese on the tube

[Stewie007]

No flux for 45%?

o.O

The only time you should follow the no flux rule is is your filler contains phosphorus (i.e. phos copper) With anything else you need to be using flux. No flux with 45%? That is a no no, in the industry; and a no no for the DIY. Use flux.

In fact, that's most likely why your alloy isn't bonding. Without the flux, silver tends to bead and run off a joint. I do this every day. If you want pictures, I'd be more than happy to provide them.

[Xeon th MG Pony]

as stewie said ALL WAYS USE THE RIGHT FLUX! this is true in any industry be it electricle, plumbin soldering/brazing or brazing steel, SilFos is its own flux as it where.

Well it's true long as you're not using flares lol

[the_new_guy]

i have esab silver brazing flux should i use or not?

[PetrolHead]

You need to use it, you won't be able to make the joint without it.

[the_new_guy]

thanks guys

i ran out of oxy so will try again in few days

[aussie_guy00000]

Just another quick question while we're on this topic, how does everyone purge the compressor inlet and outlet whilst brazing to avoid oxidation in the pipes?. Cause you can't purge with nitrogen/propane as it can't flow thru the compressor. Just curious what everyone does to solve this?

[Comp-Freak]

Don't purge? ;) Only purge the evap, you won't have to worry about oxidation in your pipes I suppose.

*Disclaimer :D: I didn't ever build a unit, so it isn't based on my own experience, only what I think ;)

[hatemi]

You have acces valves on suction and discharge side of your loop so you can use them. Then when I'm brazing some pipes that arent in the loop yet, I use a ~1m piece of captube brazed to a schraeder. I just stick the captube to whatever tube or piece I'm brazing.

[Xeon th MG Pony]

yes you can (pending where the piston is) you apply pressure to the low sides and the gasse flows happily through the velves (Naturaly this won't work in revers!) then Hatemi's idea comes in perfectly.