I read in another posting that too much flux could cause a failure problem in copper over time.

How would I "clean out" the pipes if they are already in use? I dont know if I put too much flux when I soldered the pipes, but I want to do what's possible to make my work last as long as possible.

thanks in advance for your advice.

The flux left inside will wash out. The flux (which is acid) left on the outside of the pipe can continue to corrode. Wiping joints after soldering should remove the excess.
Deb
The Pipewench

Hot water will flush out the flux fairly quickly, perhaps you can rig something up to temp hot water throught the cold water piping. Flux problems with copper usually occurs with acidic water to the cold water piping. If the ph of your water is close to 7 you probably don't have too much to worry about.

-Steve G

When you get done sweeting and the joint is cooling wipe it off with a wet rag it cool the joint and cleans the flux.
Flux and cleaning is are friend!!!!

Yes, flux is an acid. And many plumbers use way to much of it, leaving behind accummulations of flux residue in the piping they're joining. If you research the matter at the Copper Pipe Manufacturers level, you'ld find that this damage is called 'mitigation of Copper Pipe due to acid reflux'! (A ball of flux will roll down the piping, creating little pin hole leaks). Not so much a problem on hot water systems that can flush the nasties, but 'bad' on the cold water system, or any system not properly flushed after construction! Hire a plumber that doesn't ream the pipe joints and the problem escalates!

I've seen guys dunk the fitting and tubing in a can of flux and then solder them. That's an extreme but, it happens. I've never seen instructions on any kind/type of flux that didn't say 'a light coating and wipe off any excess'. I've rarely seen that done, and although I don't do it either, I only apply a very thin coat that sometimes makes me check that I fluxed. Flushing the lines probably doesn't remove excess flux totally, or it should be thought it won't. Flux in the tubing and not reaming the tubing can cause failure of the system.

Gary
Quality Water Associates

Wouldn't the heat from soldering burn away excess flux?

You can still have some residue even if you use small amounts of flux and that is way alot of good plumbers will use a wet cloth to wipe the joint after solding.

Problem being, you can't and don't wipe it off the inside of the tubing or fittings where it runs out of the joint.

Gary
Quality Water Associates

yes

That is why we flush the system out when we finish the work, the flux is water soluable.



Post Edited (07-10-03 10:25)

Fair enough, then that should prevent excessive flux in copper tubing lines that can develop pinholes but... how about the guys that don't use the right amount of flux and don't wipe and flush or that don't burn up all the internal flux by overheating the joint or get inside the tubing/fittings to wipe up the burned up residual?

Are all brands of lead free flux water soluble? And how long does it take flux to pit cooper tubing while it's waiting to be flushed? Will that time be sufficient to pitting to start that will allow bacteria to continue the pitting to the outside of the tubing?

Gary
Quality Water Associates

PLUMBILL wrote:

> That is why we flush the system out when we finish the work,
> the flux is water soluable.
> Post Edited (07-10-03 10:25)

To the best of my knowledge all flux approved for plumbing by our state are water soluable. I have never seen copper tubing or copper pipe fail because of inproper use of to much flux.

Copper pipe and tube will last well over 100 years with our water in our city and copper will impede the growth of pathogens. If there is a problem with bacteria in dead ends of copper pipe it is a non-factor compared to the cross-connections in the plumbing systems that can occur.



Post Edited (07-10-03 17:14)

One of the best things about the internet, other than it enabling us to expand our horizons, is the information we can get that otherwise would be very difficult or impossible for us to obtain. All we have to do is learn how to extract the info.

Below is a quote from something I found in a goggle search for "copper tubing" + failure + flux. Here's the the search
[tinyurl.com] and the here's the page with the quote:

[environment.copper.org]


"Over the years, analysis of failed copper tubes has been regularly conducted. As shown in Table 5, failures related to flux corrosion are the most common mode of failure and are occurring at an increasing frequency. A great deal, but not everything, is known about corrosion of copper but theories that have little scientific basis are constantly surfacing. Some of these are listed in Table 6."

Gary
Quality Water Associates