Copper brazing on a moonshine still question for you welding gurus
 

Mornin, DTR.
I have a friend of mine that runs a distillery, one of his stills has sprung a leak at a seam. I know a couple of things about welding, but not copper repair other than soldering pipes together at joints.

With my limited knowledge, I assume I could separate the seam in the damaged area, clean it, place some BCuP or Bag alloy in the seam, warm it slightly and hammer the pieces together, then apply full heat with a MAP torch. (cheaper for me to get than an oxy/acetylene setup for this small repair)

I may be way over my head here, if so, that's cool, but I figured I'd ask.

TIA!
mad

Also, it's 16ga copper, and the whole bottom is off of it now. Guess I just need to use my education benefits to go to welding school and learn how to tig.

Duct tape?

My first thought would be to run a tig without a filler and just melt the copper back in place.
Otherwise, there is probably some copper filler metal for TIG.

16 ga means light work, heavy seam.

not knowing if it is a 35 gallon or bigger, guessing if you can still access seam from the stovepipe (past apron to the kettle bottom) down to the seam fit.

copper is flat light metal hammer, almost child like toy hammer weight. but you still need a body wedge to hammer against, the curved knuckle.

align seam rotating just before leak bulge, get a tension fit.

close look, light touch, hammer with a lot of light taps not moving hammer surface over a two inch spread of seam. no bulges? good, done hammering.

it is a high pressure weld so thick flux on steel wool rubbed seam. air blast seam the pre heat with flame spread about four inches of seam line before and after actual repair site. you want a constant temp on this line and
see color change. sweat it from bottom up. that fills in more and tends to
cover wider seam area. work is fast and light touch once (no back and forth heat or weld) and have plenty of solder off the spool, almost like you are laying the cold tin over the seam, plus two inches.

welding is eyes, steady hand or support and timing experience for heat and material. with your focus, it might be easier than you think madson.

put a strip of masking tape over your weld when the pot gets fired up.
if it falls off, run. [whistle] I can neither confirm or deny about this process.

I would test with just a straight water run first to make sure the repair holds. If it fails and there's any methanol being run it will turn ugly quick.

If possible try and find a plumber you both trust and let him solider it up

Heidi... yeah. lol thanks for the post.

I was thinking about calling a plumber. I'm gonna go take a look at it this weekend and see what's up. I may just bring it home and monkey with it.

I know you can get a self fluxing rod for copper repair, I have some left over from my air con days. It has a fairly high melt point so you need at least propane and O2 better yet Oxy+acetylene, it does go down very smooth though.

Don't use soft solder. If it's leaded it's poisonous. It'll fail when things start moving around anyway.

I'd use a silver solder and flux designed for copper. I think what I have on hand is called Harris Sta-Silv 15. It ain't cheap, and is best applied with an oxy-acetylene torch. Sil-Phos 15 is about the same. Harris Dynaflow is their latest 15% Silver Phosphor bearing brazing allow, and is like Sta-Silv except more tightly controlled in alloy. None of them are very cheap, but when a copper joint performance is critical and fit is uncontrollable. these are my g-to fillers.

silver solder.

Mad,

What episode of moonshiners is this going to be on?

Silver solder with the correct flux. Clean everything very well first.

Thanks for the replies. I've done a little reading, I won't use any led solder, for sure! I'm going to have to look at it, I may learn about copper shaping as well... I think he got a cheap build, and he was moving it around a lot, so it's probably busted pretty good.

I'm not sure what episode of moonshiners it's going to be on, but I don't really watch it... I live it!

I just finished running a sweet feed and getting ready to run an all sugar wash.
cheers!