Cleaning flux off copper after the crew leaves.

swvawethead

After searching the internet and the forum I have couple of questions.
The installation crew is gone and final inspection passed on a Buderus GC144/4 installation.
Many sweated copper joints for splicing in the new pumping away scheme to the old copper lines.
I have no idea if the (young) crew properly wiped the joints right after sweating or what type of flux/solder was used.
Instead of calling the installer to ask I just want to wipe down the new connections before insulating the pipes.

Lots of online comments on flux residue causing green surface corrosion and this can show up immediately or over time.
By the way the installation overall looks good and running well - The AquaSmart is an amazing gizmo and fascinating to observe.

1. Read some comments NOT to wipe with white vinegar. I've been using white vinegar/baking soda paste to clean green corrosion from leaky bleeder valves that were replaced. Maybe I should have just used water for the paste.

2. Will wiping with Simple Green help clean off the flux residue?

Just want to go around and clean all the new sweated joints and I am about to leave to pick up a supply of pipe insulation.
During initial filling and purging the system after the installation the debris trap screen on the return was coated with what had to be flux residue. I sure hope the closed system helps prevent flux induced corrosion inside the pipes.

ChrisJ

How much flux did they leave behind?
Can you share some pictures?

swvawethead

Sorry no pix yet and I will try to post a few. It does feel a bit surface tacky around the sweated area. And where they spliced a 1" to 1-1/4" the fitting is visibly 'wet' and that is kind of bothersome. I would not call the sweating job 'clean' and meticulous. It will be best for me to just wipe them down with whatever works and be done with it. Friend suggested damp clean rag while the pipes are running hot during heating. Baking soda water mix? Simple Green?

swvawethead

Also reading cotton towel/rag and soapy water (dish washing liquid) for wiping and wringing in clean water. I have a two compartment bucket that will be handy for this. Will hit some of the mildly green surface spots with baking soda/water. (They are not from water leaks, thank goodness.)

Alan (California Radiant) Forbes

Don't go overboard. Wipe it down with a wet rag until there is no more residue.

swvawethead

re - Don't go overboard.

Thank you and I am all for that. If the flux residue will wipe away with a damp rag that would be great and I can do this when the boiler is running.
I just don't know what this flux stuff is made out of and if it is water soluble which is why I was getting all antsy over how to wipe off the stuff.

NY_Rob

Try to use a cotton shop towel dampened with warm water, it will be easier to clean when the pipes are warm too.

swvawethead

Yes, cotton it will be. Thank you.
I did a major boo boo making baking soda paste with white vinegar instead of water for cleaning off built up green corrosion from two leaky bleeders (that are now replaced) Unfortunately some of this paste dribbled down under the floor where the pipe drops down. Will have to deal with getting that stuff cleaned up.

hot_rod

As hot as you can stand the water on the cloth to remove old flux

Ideally right after the soldering hardens with a wet rag. The flux acts as the cleaner

Avoid soaps

swvawethead

re - Avoid soaps

Ok, water only. Thank you.
It is too late obviously for me to clean this right after the joints were soldered.
And I will clean during the boiler in operation.

EBEBRATT-Ed

Because it is a heating system you won't have any internal corrosion the hot water will wash the flux away. I have only seen that on cold water lines.

This is the reason I use "NOKARODE" flux made by Rectorseal.

And the reason I don't like "Utility" flux which is all our shop provides. I hit the supply house and stock up on my own.

Plain how water is all you need to wash it off

swvawethead

Ed and all: Back at the house from next door where I am cleaning flux. Worse than I thought, with one fitting with shutoff and two pipes joining with flux actually forming a drip if that's possible. Lots of wet sheen at most of the sweated joints.
Anyway, since this will require steady cleaning I have a portable induction burner with a pot of hot water. Turned up the thermostat to get the boiler going. Half a dozen small towels soaking and a bucket for rinsing before back in the hot pot. It is going well so far except I have to trust this is cleaning off most if not all traces of flux.
To make sure the towel is hot enough I am using silicone gloves and changing towels frequently.
Anyway, thank you all for pointing me in the right direction and should be done in another hour or so finishing up around the boiler piping which has the most number of new sweated joints.
Yes, I saw a shelf full of Nokarode along with the other usual brands but I have to assume that is not what the crew used.

rick in Alaska

Why don't you just get the people who put the joints together to come back and clean them up? Anyone who leaves solder joints dripping with flux should be flogged. It is considered as a bad installation technique. And, it makes them look like a hack. All joints should be cleaned immediately after soldering. And, if there is flux that is drippy, they have used too much anyway.
Rick

hot_rod

Hopefully they flushed the system well, probably a lot of flux residue inside also?

Some fluxes contain chlorides, need to get that flushed out after running the system up to hot temperatures.

Most flux is water soluble, easily cleaned out with hot water.

swvawethead

I chose not to call back the guys - for various reasons I am just glad the job is 'finished' and the system itself is running as I had envisioned. And with the sloppy flux mess I cannot assume they will properly clean the stuff. Best if I take care of it for peace of mind. I think the sweated joints will hold up but I think I would have done a cleaner job.
There was quite a bit of water that was run through the system and drained out during my initial fill and purge sessions but running cold water and before the gas was connected.
After the heating season is over I may drain and fill the system. But not sure how the flux behaves when the water is cooled down. Will it remain suspended in water after circulating in the system during heating?
Do I want to push out the old water with the fast fill? I cannot do this while the boiler is producing heat.
And not sure about simply draining the system of heated water - will that do the job without it being forced out?
All sorts of questions while I understand the need to change out the water.

swvawethead

Around the boiler there are some green corrosion on some elbow joints where vertical and horizontal pipes intersect. The metal rail clamps around the circulator pipes I will need to undo to clean. Some sloppy sweat jobs with 1" pipes. I may have to take care of this in steps and methodically. Been adding straps to properly support some sections that they neglected. About to head back with the Dremel to shorten some of the threaded rods that are too long and touching the copper pipes.
Anyway, not all's lost because I get to learn by taking care of this stuff.
I will at some point - just for the fun of it - redo the boiler room piping by increasing the header to 1-1/4" (from 1") and install the indirect.

Alan (California Radiant) Forbes

Any corrosion that you can't get off with a wet rag can be removed with some open-mesh sand cloth which you can buy at a good hardware store or plumbing supplier. Mill-Rose makes a good product.

swvawethead

Alan - thank you.

Took longer than expected but I think I took care of the flux. Need to go back and sand off traces of green at some spots.

Was using wet baking soda and stainless steel brush at heavily greened section where the old bleeders were leaking.

I do have a question:
Stuff is stubborn and not sure if the green itself will continuously degrade the copper if not removed. This if there is no more leak and conditions are dry.

Tinman

Plumber's sand cloth or grit cloth will remove it in seconds.

swvawethead

Thank you.

Is the green corrosion itself - if the source of leak is stopped - a continuous ongoing problem if not cleaned off?
I am mainly concerned about the section of vertical pipe after it drops down below the floor.

The leaky bleeders were replaced and everything is dry but to follow the pipe below the floor to do a thorough job of cleaning off the green corrosion would require cutting out the floor around the pipe.

swvawethead

Edit: 70154 is open mesh and slightly finer grit. 70174 is the 'sand cloth' you mentioned. Thanks!
------------------------

Mill-Rose 70174 150 grit. Blue Monster Ultra Flex Premium Mini Strips Abrasive Cloths, 2-Inch 10-Yard,

Mill-Rose 70154. 21 x 21 Mesh - Has larger holes than other open mesh products. 165 grit white Aluminum Oxide cuts and scores surfaces faster for more effective cleaning and debarring.

swvawethead

Found this info regarding the existing green 'corrosion' and if it is a continuous process that further degrades the copper - if the damp water source is eliminated such as in my case.
I will go ahead and clean off the green but maybe not obsess over the section below the floor.
------------
The patina actually protects the copper below the surface from further corrosion, making it a good water-proofing material for roofs (which is why the roofs of so many old buildings are bright green).

In fact, the weathering and oxidation of the Statue of Liberty's copper skin has amounted to just .005 of an inch over the last century, according to the Copper Development Association.

j a_2

Where has all the pride gone...here is the problem ,they think they did a good job......Let them know there solder job sucked...Cut up an old pair of jeans and buff out the ugly areas....A bit of rubbing compound and auto polish details very nicely

swvawethead

j a - I am mainly wanting to prevent problems down the road in the aftermath of the young crew's less than ideal craftsmanship. Overall I feel fortunate to have survived the installation by getting the system configured and functioning flawlessly so far and they went along with my request to split out a zone and change the scheme to pumping away which they were not familiar with (in our part of the country.) Although they were good to work with the crew is done and gone and don't want them back. After wiping down the flux residues I am now focused on cleaning off the green corrosion that formed around the old leaky bleeder valves (that were replaced) using the sand cloth.

hot_rod

ScotchBrite (pot scrubbing) pads with some water works well also, less dust to breathe and they wrap around the pipe and fitting nicely. Latex gloves preserve the skin, yours.

I do some copper art work and the pads put the final finish on before buffing with a cotton wheel and polish.

bob_46

I'm a little disappointed HR I figured that with your extensive hydronic background you would build a water cooled bike !!!

swvawethead

Yes, do have the green scotch rite pads as part of the arsenal I am nearly finished with the section above the floor starting below the old bleeder and about 4-5" vertical before dropping down below the floor. Please tell me if I need to follow the pipe beneath the floor to completely remove the green crust. There no more water seepage that contributed to this. Is the green crust itself the byproduct and not necessarily cause ongoing corrosion?

hot_rod

The green crud could be caused by the solder flux, or by a small leak over time. Once you have it cleaned up, and the system leak free, you should be fine.
Stored chemicals, like pool chemicals in a room will can copper to discolor also.

You might have the boiler water tested, if they left that much flux on the outside, you could have a flux sludge inside the pipes. Most flux is water soluble, hopefully they ran it up to temperature and purged the junk out. As you have discovered it is tougher to get off after it sets for a bit.

Sometimes it is wise to run a hydronic cleaner in a system that has flux and oils left over inside. These hydronic system cleaners are basically a strong detergent to dissolve and clean systems and balance ph.

Tinman

@hot rod I'll trade you the lamp for the bike?

hot_rod

Stephen Minnich said:

@hot rod I'll trade you the lamp for the bike?

Keep your eye out for unique radiators and we can talk. I'm looking for a circular and or cabinet type.

Here is a Caleffi two cylinder water cooled version

Tinman

Very cool.

swvawethead

hotrod - thank you.
The green crud I am cleaning is from when there was a leaky bleeder valve at the end of a loop before dropping back down below the floor to head back to the boiler.
I am mainly concerned about the section of pipe after it drops down below the floor where I know there has to be green crud on the pipe at least several inches before hitting the L to travel horizontal under the floor.
If there is no more leak and everything is dry, should I be concerned about the green crud I cannot reach unless the floor is cut around the pipe to get down below?
Sorry to persist in this question.

And thank you for the suggestion to purge the system which was not done with the system water heated. Tons of cold water was run through during the initial fill/purging of air.
With the system water heated to high limit, will simply gravity draining be enough?
Specifically I am wondering about opening the fast fill to push out the heated water one loop at a time.
No way to push out the heated water with more heated water in my setup because the hose bibs on the supply and return are on the wrong side as Paul48 pointed out in my other thread. (But works great for cold filling system loop at a time using the fast fill.)

Now it makes sense that I should have a hose bib AFTER the boiler supply shutoff for forcing hot water into the system for flushing.

hot_rod

Some people wait or pay big money for that green patina on copper! it does serve as a protective layer, and should not be a problem out of site.

Sure you could purge the system after running it to temperature.

Take a sample in a glass or jar, let it settle overnight and see what, if any, crud is swimming around inside.

Only a water analysis could tell you what exactly is in the water. High chloride levels are one concern, most fluxes contain chlorides as the cleaning agent, so that level in addition to the chlorides in the fill water could put you above what the manufacturers are comfortable with.

swvawethead

Hotrod - Thank you for putting my mind at ease about the green crud blow the floor. Believe me I would rather not get carried away trying to get to it.

As for the flux dissolved in the system, in my other rather rambling thread I mentioned the debris trap screen had a coating of semi translucent slime which some members guessed as being flux. This was discovered (after quite a bit of cold city water was run through the system during the fill/air purge) while the crew was rotating the trap to be in the 6 o clock position after installing it wrong at the 12. (This was pointed out during the thread discussion - thank you.) I asked them to remove the screen for examining it. And this was before the gas service was connected and boiler was test fired.

So...back to my question about dissolved flux:
Short of chemical treatment will simply gravity draining the heated water help remove a lot of the dissolved flux? If I have to the only way I can force it out is using the fast fill/cold water because of the way the isolation valves were placed at boiler supply/return and I cannot force heated water into the system via a hose bib.

After the first heating season run of the new boiler install I plan on correcting the misplaced isolation valves at the boiler supply/return and attempt to clear at least some of the dissolved flux.

hot_rod

Not to alarm you, it is possible most of the flux got purged out with the work that has been done. It is best to get it out quickly and dissolve it with hot, boiler at 180 temperature water.

Until the heating season is over or you make other piping changes, let 'er run, as you suggested.

Rhomar and Fernox sell easy to use aresol cans of cleaners & conditioner in a kit. Connect the hose to a boiler drain or hose thread and pull the trigger. One 12oz can treats about 35 gallons. Run it for a few days then flush.

Check you water for ph and TDS, get DM water if needed, refill and squirt in the second can of conditioner.

hvacfreak2

EBEBRATT-Ed said:

Because it is a heating system you won't have any internal corrosion the hot water will wash the flux away. I have only seen that on cold water lines.

This is the reason I use "NOKARODE" flux made by Rectorseal.

And the reason I don't like "Utility" flux which is all our shop provides. I hit the supply house and stock up on my own.

Plain how water is all you need to wash it off

To each his own I suppose. I swear by Utility and refuse to use the other. Either way , if it don't leak it has to be good.

GW

Some guys don't appreciate a good looking solder joint. Others do.

Since I was a young man I took great pride in soldering and it cost zero added time. I was 20 or so when I rolled the work truck back to the shop one sunny afternoon. The twitchy boss barked out while I was parking the truck, "Wilson, the inspector shut you down, you forgot to solder a joint on the tub/shower valve!"

This was a rough plumbing inspection

I drove back to see what I missed and the valve was indeed soldered. What it was lacking was gross smears of solder wiped all over the place. I proudly reported back to the boss that the inspector was mistaken.

Some heating guys don't get it, some plumbers are a joke.

I wipe the joint while it's hot. I do NOT smear the wet solder all over the place.....why why why do this? Someone please explain what prompts someone to wipe wet solder like it will actually benefit something. I'd your joints bites is this gonna stop a leak? Pulease!

Now if it's a vertical pipe and you have running solder them by all means wipe(fling) the running solder.

I use my finger, my nerve endings are well adjusted

Anyway, to answer the question, I would sand the crud off with sand cloth or better yet open mesh that we plumbers use .

hot_rod

I suppose we all have any idea of the perfect solder joint. My best is a joint that is fluxed
so there is no need to wipe solder.

If it is over fluxed and the flux runs down, the solder will follow

With practice, and luck you should be able to keep all the solder in the socket and cap it off nicely

Wipe it with a wet rag only after the joint sets. Cooling it with a wet rag when the solder is still liquid is not so good

swvawethead

Thank you.

I would be happy not to see any hardened driblets of solder, obviously not wiped in due time.
As for wiping, I have seen very 'clean' looking solder jobs with about 1/8 - 1/4" of solder wiped around the pipe where it joins the connection. No driblets. Good practice or not, it does look tidy.
The crew who installed the convector runs in the 1950s, all the sweat joints have cleanly wiped solder at nearly all the connections, some as much as 1/2". Unmistakably noticeable touch with the shiny solder on the copper pipes.
On the just finished boiler install - zero signs of wiping with plenty of driblets. But some joints have solder only inside the joint with none oozing or running out.

Anyway, the only thing I can do is to make sure all the flux is wiped clean and after this heating season attempt to drain out some if not all of the dissolved flux using the hot rod's suggestions.