Best way to join copper pipe for compressed air?

by Lyn
(Oregon)

Hi Jody, Thanks for your site I have learned a lot and I truly appreciate the obvious time and effort you have invested to make us all better welders.
I am building a compressed air piping system for my shop out of 3/4" copper tubing. I was all set to sweat the joints with solder like you do for plumbing but then I read a recommendation from the pipe mfg saying that brazing was preferred for compressed air.
I am brand new to TIG, in fact, I get my Everlast PowerTig 225LX welder tomorrow. (My choice was heavily influenced by your videos of Everlast products, thanks!) Is brazing copper pipe a reasonable thing to try for a newbie? If so can you give me some pointers as far a settings, filler, technique, etc? If not, can you recommend alternatives? Thanks again!!

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Lyn,

personally, I think that a good soldering job would hold up fine.

I know folks who used pvc without issues also and a good solder job would be much stronger than pvc glue.

but to be safe, if you want to braze , you can use silfos also called silphos

it does not require flux so the inside of the joint is cleaner and the job goes quicker.

its what hvac guys use a lot for brazing copper lines.

you will want to get some copper pipe and practice a bit, you can look on youtube and find a few decent vids to get an idea of how hot the pipe needs to be before adding rod etc.

hvac guys doing it for a living use either oxyacetylene or air acetylene torches but you could probably get by with a small propane torch, it will just take longer to heat each joint.

one key is to use a torch that will let the flame wrap around the joint to spread the heat more evenly. you want to avoid hot spots so keep the torch moving also.

what happens if you overheat an area is that it gets oxidized and the braze metal wont flow.

so clean the joint with emery cloth also on both surfaces to be joined.

good luck,

jody

ps, I really hope your everlast machine does well for you... please let me know