soldering - prep

[PoorOwner]

putting up some copper airlines soon.

what I got is something like this for the pipe

and a little bottle brush version of the metal brush for inside each coupler or fitting.


Is this enough prep or do I really need to use emery cloth?

can I just use sandpaper I have? 220? what's the difference between emery cloth and sand paper.

 

[Jason280]

I prefer the cloth stuff on the roll, but on the pipe ends I used a wire wheel on a bench grinder when I ran my shop air lines. It takes a little longer, but makes less of a mess. As far as the difference between it and regular sand paper, the main thing is it is a whole lot more flexible,

Regardless of what you use, make sure you get the copper as clean as possible!

 

[Mr. T]

I like red scrubby pads for cleaning the OD (3M 7447 to be exact). And for ID I get a cheap brush, cut off the handle and chuck it in the drill.

For air lines reaming is kind of optional. Best practice is do it, I doubt you’ll notice if you don’t.

I will say that getting the copper clean is the most critical part of sweating a good joint.

 

[pattenp]

Those cleaning tools work okay. The whole point is to clean off oxidation. Just make sure the surface all the way around is clean.

 

[The Cobbler]

and use flux , and don't touch the cleaned area with your hands
I prefer the mesh for the OD of the pipe, and a brush for the ID of the fittings

 

[rlitman]

Those cleaning tools work okay. The whole point is to clean off oxidation. Just make sure the surface all the way around is clean.

They do on new parts that start out relatively clean. If you're using stuff that looks like a decades old penny, then emery is your friend.

On that outside brush, I like to stick a carriage bolt in it, and use it in a drill. The inside brush, I'll cut off and use in a drill. Both are hard on the brushes, but easier on the hands when you're doing a lot.

 

[gungatim]

ditto on the red scrubby pads, but almost anything will work, emery cloth, wire brush, sos pad, whatever you have. you're just cleaning the oxidation off that naturally forms. flux it immediately and you're good to go.

 

[jeffmattero76]

To answer one of your questions, emery cloth is both more flexible and waterproof. Sandpaper is not.

Sent from my SM-G530T using Tapatalk

 

[rlitman]

To answer one of your questions, emery cloth is both more flexible and waterproof. Sandpaper is not.

I've had luck with the screen style sandpaper, both in drywall pad and roll form.
But otherwise, J cloth sandpaper is good for plumbing. Either way, you want cloth. Paper tears way too easily. Especially on burrs. That's an easily avoided way of hurting yourself.

 

[fsae0607]

I like to use emery cloth for the OD. Last time I did this, I plumbed in a wall box for my ice maker. The mock up went ok, but then I had a hell of a time fitting them together after using that tool above even after fluxing.

My guess is that wire brush on the OD acts like knurling and slightly increases the OD so it makes it hard to fit together. Ever since I switch to emery cloth for the OD, no issues.

 

[rlitman]

...My guess is that wire brush on the OD acts like knurling and slightly increases the OD so it makes it hard to fit together...

Never seen that. However, emery will known down burrs that can affect the fitment. whereas the brush won't.

 

[fsae0607]

Never seen that. However, emery will known down burrs that can affect the fitment. whereas the brush won't.

Probably. All I know is that ever since I switched to emery cloth for the OD, I've never had an issue.

 

[Falcon67]

I use the green Scotchbrite, mostly because I can get it by the box at Sams.

 

[dutchgray]

Never seen a plumber use anything other than wire wool or a scotchbrite pad, over here. Then flux paste wiped on with the solder wire, heat the joint until you see the copper change colour slightly and apply the solder which still has a good coat of flux over it. While still hot wipe over with a damp pad which removes any excess solder and helps cool the work.

 

[metalmagpie]

Have you considered silfos?

 

[LS6 Tommy]

In the HVAC world, we clean ID of fittings and OD of the tubing and flux only goes on the OD. ID of the tubing always gets deburred/chamfered to prevent wire threading. Joints are never wiped, as we prefer to build a shoulder on the joint. I prefer the mesh cloth, but the 3M pads are great for odd shaped or small stubs.

Tommy

 

[Schurkey]

I am not a plumbing-solder expert. I did a fair amount of plumbing-solder rework of leaking joints that were improperly soldered by other people. I did a little plumbing-solder work "fresh"; using new tubing and fittings. The stuff I worked on was typically 1" and larger, although I did do some smaller tubing. When I was done, the system was put into use, so any failure was immediately apparent.

What I found was that I needed more heat than I expected. My work got better when I turned the torch hotter and held it on the un-soldered joint longer. Flux doesn't do much if the metal isn't hot enough. I could melt solder into the joint long before the joint was hot enough for the flux to clean it properly.

 

[PoorOwner]

Thanks for the tips guys. Does soldering produce acidic fumes?
Just wanted to know so it won’t affect ac coils and other things in the garage.

 

[The Cobbler]

I could melt solder into the joint long before the .

you heat the pipe and fittings to melt the solder. not the torch to melt the solder

 

[matt_i]

I use the "bottle brush" on the OD of the tubing at times when there's a little imperfection in the tube that's oxidized and the emery is gliding over the top. The wire bristles will quickly remove that oxidation.

I am a big fan of the Stay-Bright #8/Stay Clean flux. Its more expensive but easier to work with and stronger to boot.

If I'm doing 1" or larger I will use a 2nd torch for more heat.

 

[Schurkey]

you heat the pipe and fittings to melt the solder. not the torch to melt the solder

Yes. I could melt the solder on the pipe before the pipe was hot enough for the flux to fully clean it.

 

[rlitman]

Yes. I could melt the solder on the pipe before the pipe was hot enough for the flux to fully clean it.

Then you're melting the solder onto the pipe, and not heating the pipe enough.
Solder melts at a higher temperature than the temperature where the flux is most active.

i.e. if you can turn your torch off, and when touching the solder to the pipe, the solder melts, then you got the pipe hot enough, and by that temperature, the flux WILL have done its job.

 

[Schurkey]

I'm just stating what I found in my experience of (mostly) reworking leaking solder joints.

I needed a shitload of heat--more than it took to melt solder--to get the flux to clean the pipe properly.

The big "secret to my success" was heating the pipe MORE than it took just to melt the solder. As soon as I did that, my failure rate went to about zero. Until then, I was hit-or-miss as to whether or not the assembly would leak.

Goofy flux?

Goofy solder?

Goofy tube?

I have no idea. I needed a lot of heat.

 

[lilscorpion]

The pipe needs to be clean. Using something like what you’ve pictured (or a battery post terminal brush tool ) works well enough.

Some have mentioned having to heat the hell out of the pipe to get it to work. Shouldn’t need to if your using the correct method -

Use flux paste on both the pipe and ID of the fitting. Just a little, 360 swirl with an acid brush. Slide the pipe inside the fitting and then heat the fitting side (OD part) above (or below depending) with your torch. The heat being applied above the pipe will create a vacuum of sorts and the solder will be sucked up into the joint. Pull the heat away just before you touch the solder in...done.

In the event you have a wet pipe (water in the pipe below the joint you’re soldering), wrap a wet bath-like towel around the wet pipe just below the joint your heating. Follow the above steps. Used this method when repairing a main break, in a 6’ deep hole, in a downpour, at 3am. Worked like magic.

A good reference is this video -

 

[WMichelsen]

After the copper air-distribution soldering is completed, do you flush with water to clear out flux inside the piping?

I'm not worried about flux contamination in the air. Instead, I understand that flux is acidic and will erode the copper piping. Isn't that why plumbers wet-wipe joints after soldering?

My apologies if this has been addressed before. I searched the archives, but came up empty.

 

[PoorOwner]

After the copper air-distribution soldering is completed, do you flush with water to clear out flux inside the piping?

I'm not worried about flux contamination in the air. Instead, I understand that flux is acidic and will erode the copper piping. Isn't that why plumbers wet-wipe joints after soldering?

My apologies if this has been addressed before. I searched the archives, but came up empty.

I didn't flush my last build because some of the pipes are soldered in place. years later I opened the filter to found it looks crazy, like thousands of droplets of acid has been sent to the cup. (aluminum + acid = crud) Inside the pipe looks ok though and nothing made it pass the filter. I even reused some of the already soldered joints.

This time I am doing sections and flushing it when possible.

The flux I am using this time is called C-flux and it doesn't really seem to rinse well, not a bunch of foam comes out like traditional flux, they stay more like an oily residue and is even hard to wipe off if you let it dry. Not sure if it is really going to keep corroding the pipe or not.

 

[Jlbc212]

I use the "bottle brush" on the OD of the tubing at times when there's a little imperfection in the tube that's oxidized and the emery is gliding over the top. The wire bristles will quickly remove that oxidation.

I am a big fan of the Stay-Bright #8/Stay Clean flux. Its more expensive but easier to work with and stronger to boot.

If I'm doing 1" or larger I will use a 2nd torch for more heat.

^^^ use good quality flux! Apply the torch flame to the fitting, not the pipe. The fittings usually have more mass than the pipe and when the fitting is hot the pipe inside will be too. The solder will be drawn up into the fitting. After applying the solder and removing the heat i wipe the joint with a dry cloth to remove any residual flux while the joint is still hot. Any residual flux will eventually turn the copper green.

 

[no704]

If you can’t get the inside of the pipe completely dry due to a leaky valve etc. shove a balled up chunk of bread up it as a temporary cork. It will flush out.

 

[LS6 Tommy]

After the copper air-distribution soldering is completed, do you flush with water to clear out flux inside the piping?

That is why you only use flux on the OD of the copper.

I'm not worried about flux contamination in the air. Instead, I understand that flux is acidic and will erode the copper piping. Isn't that why plumbers wet-wipe joints after soldering?

You should use THAT much flux. Plumber's wipe the fitting to make it look nice.


My apologies if this has been addressed before. I searched the archives, but came up empty.

Tommy

 

[WMichelsen]

Thanks PoorOwner and Tommy,

I don't think I'm over fluxing. And, whatever bubbles out of the fitting when soldering boils-off and hardens.

I know with water plumbing, it seems like the water tastes a bit funny for a while (whether DIY or professionally worked). I always assumed this was a little flux residue tainting the water until it flushed out ??

With condensate moisture in air-lines, will the residue slowly continue etching (that's my concern)? But, I'm getting the impression it's a practical non-issue to stop thinking about?

Thanks for the feedback.