Bad solder daze

hot_rod · May 12

This was part of my shop system, installed in 2021.

I'm disassembling and repiping, re-using the old sweat fittings.

I remember feeling these joints were not pulling in solder as they typically do. However it was and has been leak free.

I tracked it to bad flux. Maybe too old? Or contaminated with oil or pipe dope? Regardless with a new can of flux the soldering is back to normal. Although many of the joints soldered fine? Certainly a workmanship issue:(

Here is how I reused about 30 copper sweat fittings.

Milwaukee die grinder to clean out the fittings, a 1" belt saner to prep tube and clean outside of fittings.

I priced out press fittings for the rebuild, well over 200 bucks. I'm not a fan of press with glycol, however. Seen too many green fuzz seapers.

One of my colleagues in Germany, a master plumber asks, " why do you Americans still

soul-der copper tube?" press and compression fittings are most common across the pond.

Good question

mattmia2 · May 12

could jsut get a reamer that is the id of the fitting. after seeing that sort of thing on stuff i have done i make sure i brush all of both surfaces with flux.

mattmia2 · May 12

germans also bend and weld…

compression fittings are super expensive, even more so that press. flare can be reasonable up to about 1/2", at 3/4 and above they get really expensive.

hot_rod · May 12

https://forum.heatinghelp.com/discussion/comment/1896384#Comment_1896384

I have used a 7/8 holesaw also, but it can grab easily. The die grinder, at low speed, it's variable, has been my best method so far. I also have fitting brushes for the cordless drill, but they don't remove solder build up too well..

hot_rod · May 12

https://forum.heatinghelp.com/discussion/comment/1896385#Comment_1896385

I still do some bending with a REMS Curvo. But type L copper is crazy expensive. Too much kinking when you try to bed type M.

Drainback solar on right, lines to heat pump on left.

Screenshot 2026-05-12 at 10.31.02 AM.png

mattmia2 · May 12

what if you turn the hole saw backwards? the solder should be soft enough to still cut that way. the reamer might also be super pricey and only chuck up in a lathe or milling machine. the die grinder seems tedious. maybe put the bur in a drill press.

I like the fitting brushes that go in a drill or driver but they are only good for cleaning.

JUGHNE · May 12

Years ago my Father in law took all my scrap copper, brass etc to sort and sell.

He returned a can full of 1/2 &3/4 copper sweat fittings that he had unsoldered to save for future use.

This is when fittings were really cheap and trying to clean up and reuse the small fittings was not worth the hassle. I felt bad that he has burned up his time and gas doing this.

I do usually reuse 1" and larger. Something you can get a slightly damp rag into to wipe out the solder.

And sometimes have to heat the used fitting to get the new pipe into.

mattmia2 · May 12

you can also heat it and smack it on a bench or something similar to propel the solder out or at least most of it.

ChrisJ · May 12

https://forum.heatinghelp.com/discussion/comment/1896397#Comment_1896397

You could also clamp it in a vice lightly, heat it and wipe it with a barely damp rag / sponge real quick. With practice that could probably get most of it out.

Or, in the correct areas heat it up before sliding it onto the pipe and then "backfill" with a little new solder.

Mad Dog_2 · May 12

Every few jobs, I take the cover off the flux and scoop out the nasty black residue with a paper towel and stick a new acid brush in. Mad Dog

hot_rod · May 12

I've tried many way to clean out solder fittings. A fitting brush while the solder is still molten works also.

The die grinder is my current favorite.

When my ship comes in I will buy only press fittings

GroundUp · May 12

I've run into this a few times where a disassembled joint has nothing but a cap on it and been leak free for many years. Reusing fittings makes sense sometimes but if one's time has any value, it doesn't typically work out that way unless there isn't another one onsite and it needs to be done right now. When that becomes the case, however, it only takes but 10 seconds to heat the fitting and wipe the solder out with a dry rag or even smack it on something to hurl the solder out. Same for the pipe. Then clean/flux as you would a new fitting and proceed. Digging out the belt sander and die grinder to intentionally reuse $40 worth of fittings is a retired level of boredom 😂

EBEBRATT-Ed · May 12

@hot_rod

I have had the "contaminated flux issue". A lot of people around here use the "Utility Brand" flux which I don't care for.

I remember being sent to help a coworker finish a job where we were sweating Pex adapters to baseboard. I brought my torch in, and he had flux and solder. Utility flux. It looked okay but I did 3-4 joints with it, and I just didn't like the way it acted.

I went out to my truck and got my container of "Nokorode" and it was fine after that.

I learned through the years to buy flux in small containers (8oz or smaller..) and keep the cover on it. No sense risking contaminating a large container

It can make a difference.

Mad Dog_2 · May 12

Nokorode is the Caddy-lack of Fluxes. Mad Dog

EBEBRATT-Ed · May 12

@Mad Dog_2

I can do 100 joints with Silvabrite solder an Nokrode and have maybe 1 leak. Works for me.

Thats my go to.

Bad solder daze

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