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1/22/2020 12:12:56 PM
Posted: 9/20/2009 1:50:27 PM EST
I've done a ton of soldering in the last 2 weeks with 3/4'' and 1/2" rigid copper. All of its gone well. I had two leaky joints, I think I neglected to apply flux in my haste.


Today, I'm prepping some joints. I clean them with a brush, apply flux (the same flux I've always used) and then heat and solder. Now, the solder won't flow into the joint. I dumped what appeared to be condensation out of the flux tin this morning before I used it. Could it be contaminated?


This is frustrating... if I could get my hands on them damn sharkbite connectors right now, I'd totally use them.
Link Posted: 9/20/2009 1:51:36 PM EST
Could there still be a bit of water in the pipe?
Link Posted: 9/20/2009 1:57:01 PM EST
It was all new pipe, no water present.

Link Posted: 9/20/2009 1:58:51 PM EST
Make sure you sanded the pipe far enough back

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Link Posted: 9/20/2009 2:18:52 PM EST
could you have heated the pipe way to much and just couldnt see the solder get sucked in, or try new flux and solder
Link Posted: 9/20/2009 2:20:37 PM EST
nah, I pulled the joints apart, and its simply not absorbing solder.


Link Posted: 9/20/2009 2:24:39 PM EST
Your not fluxing enough, and you have to prep the elbow and the pipe with emery wrap. Also you are getting it too hot and burning off the flux so it cannot do the job. Solder should melt and flow without the heat applied.

Also any tap water with minerals in it will do havoc to any solder job.
Link Posted: 9/20/2009 2:27:23 PM EST
Use the flux liberally and be sure to use sandpaper on the ends of the copper, as well as the brush inside your joints. You should heat the joint, not the pipe, and heat it up until solder melts on contact with the copper. If that doesn't work, well, I dunno. It's kind of idiot proof.
Link Posted: 9/20/2009 2:29:45 PM EST
[Last Edit: 9/20/2009 2:30:47 PM EST by sinsir]
one of a few things come to mind

1. the copper was not clean enough
2. your flux may be contamanited/ not enough
3. too much heat, and you're burning off the flux
4. water in the pipe

just my $0.02
Link Posted: 9/20/2009 2:31:24 PM EST
Try "tinning" the end of the difficult pipe first.

Clean and melt solder around the pipe end before joining. Wipe the excess solder off the end with a damp rag, then join the pipes, and resolder.
Link Posted: 9/20/2009 2:33:46 PM EST
this is why I hate plumbing shit....
Link Posted: 9/20/2009 2:39:09 PM EST
I always melt a small amout of solder right onto the fitting so I can watch it melt while heating the fitting, it gives me a good idea when the pipe is hot enough
Link Posted: 9/20/2009 2:41:42 PM EST
As a DIY homeowner - I love soldering copper water lines! -

After I learned that I was heating the pipe TOO much, I've been good to go over the last 30 years. A tip also - when sanding the pipe, sand is in the direction of the solder flow, not around the pipe/

If you are still having a problem, cut off 6 inches of pipe and try again, I've had "difficult sections" of pipe before
Link Posted: 9/20/2009 3:00:18 PM EST
I dunno, I went into the shop and did a vertical joint just fine.


I think this project just wants to kill me.


Back under the house.
Link Posted: 9/20/2009 3:52:25 PM EST
Go buy some new flux.
Link Posted: 9/20/2009 3:57:49 PM EST
If all else fails –– Sharkbite fittings FTW.
Link Posted: 9/20/2009 4:01:00 PM EST
Originally Posted By IchWarrior:
I dunno, I went into the shop and did a vertical joint just fine.


I think this project just wants to kill me.


Back under the house.


Are you sure you don't have any water in the line? If it's working in a controlled environment but not where you're trying to do the work I doubt the flux is contaminated. BTW. 2 things I hate, vertical joints from the bottom and street elbows.
Link Posted: 9/20/2009 4:14:29 PM EST
They probably just need a good cleaning as has been mentioned above, but if you do find that water has gotten into the pipe just ball up some bread and shove it about 6" into the pipe. This will allow the joint to be soldered and the bread will just disintegrate in the pipe when the water is turned on.

Link Posted: 9/20/2009 4:39:57 PM EST
Keep a bottle of acetone handy, and clean the freshly sanded joints with that on a clean rag or Q-tip to remove any traces of oil or grease before applying clean, uncontaminated flux with a clean glue brush Also do the same with the wire solder itself, and never let your fingers touch joint or solder after cleaning them. Sand the outside of the fittings too; it will transfer the heat much better than a corroded or tarnished one.Be sure to have good ventilation and let the acetone evaporate before appliyng flux or heating the joint. Even the trace amount of oil from your skin can screw up a solder joint.
The secret to soldering and brazing is bright, shiny metals, snug dry fits and CLEAN everything.
As others have said, dont heat the solder directly; instead heat the entire joint until the solder runs into it when applied to the copper with the flame an inch or so farther into the fitting than the end to which you introduce the solder. When it flows nicely, pull the flame away, but keep pushing the solder until the joint cools enough to stop taking/melting it.. Quickly wipe around the joint with a clean dry cotton washcloth to clean excess off for a neat, shiny appearance.

Then go out and buy a few.PEX tools and fittings and switch over to that much superior plumbing system!
Link Posted: 9/20/2009 4:43:21 PM EST
Originally Posted By out-a-ammo:
They probably just need a good cleaning as has been mentioned above, but if you do find that water has gotten into the pipe just ball up some bread and shove it about 6" into the pipe. This will allow the joint to be soldered and the bread will just disintegrate in the pipe when the water is turned on.



Yep, learned this from an old school plumber a while back. It really does work.
Link Posted: 9/20/2009 4:54:33 PM EST

Originally Posted By flatfender:
Go buy some new flux.


+1 If your flux is contaminated, you will not get a good solder joint.



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Link Posted: 9/20/2009 4:55:22 PM EST
Thanks for the great tips.

I'm replacing gray plastic shit... its always broke on me and been a pain in my ass.


Copper is a new pain in my ass... but damn is it strong


I went and just soldered all my joints, with some water in the pipe and they all held.


But I found new leaks, in shit I soldered in the shop and couldn't leak test before I put under the sink.


Great.
Link Posted: 9/20/2009 4:57:39 PM EST
Try S39 flux instead of that paste junk.
Link Posted: 9/20/2009 5:03:31 PM EST
[Last Edit: 9/20/2009 5:07:53 PM EST by offctr]
edited to remove double tap
Link Posted: 9/20/2009 5:04:01 PM EST
[Last Edit: 9/20/2009 5:04:33 PM EST by Dumpster_Baby]
Trust me on this guys - the ONLY thing that can be used to clean copper before soldering is sandpaper, the red or tan abrasive kind that has ONLY MINERAL abrasive glued to it. You CANNOT use a stainless brush, black iron brush, steel wool, or stainless curly scouring pads to clean a copper joint. Metal from the brush, steel wool, or curly pad will transfer to the copper and form a MICROSCOPIC METAL FILM on the copper that SOLDER WILL NOT STICK TO. When you use METAL to clean a copper joint you leave behind a MICROSCOPIC METAL FILM ON THE COPPER, no matter how clean and shiny the copper looks.

Metal abrasives on copper is a 100% guaranteed soldering failure.


Link Posted: 9/20/2009 5:06:12 PM EST
Originally Posted By eric496:

Originally Posted By flatfender:
Go buy some new flux.


+1 If your flux is contaminated, you will not get a good solder joint.



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+1 again I just spent the end of last week and the week end roughing in a new house for inspection tomorrow (yeah homeowner was a little late calling in a plumber) Fri nite my flux tub got left out and was wet sat morning after three-four joints like you had I said f-it and dug thru the truck for some more flux and violla! no problem. When sweating joints cleanliness is next to godliness and if your flux or anything else is off ––forget it no matter how much heat you apply. The thing I hate is those little bar code stickers they put on everything now the adhesive residue can mess you up if you don't get it completely off. The acetone trick works the best especially for that ––I have seen the oil from one fingerprint screw up a solder joint so you gotta make sure its clean.
Link Posted: 9/20/2009 5:11:42 PM EST
Originally Posted By Dumpster_Baby:
Trust me on this guys - the ONLY thing that can be used to clean copper before soldering is sandpaper, the red or tan abrasive kind that has ONLY MINERAL abrasive glued to it. You CANNOT use a stainless brush, black iron brush, steel wool, or stainless curly scouring pads to clean a copper joint. Metal from the brush, steel wool, or curly pad will transfer to the copper and form a MICROSCOPIC METAL FILM on the copper that SOLDER WILL NOT STICK TO. When you use METAL to clean a copper joint you leave behind a MICROSCOPIC METAL FILM ON THE COPPER, no matter how clean and shiny the copper looks.

Metal abrasives on copper is a 100% guaranteed soldering failure.




Well, I've been using it so far and no ill effects. But I'll head your advice that its not the BEST sanding medium. I'll get something better, some new flux...

... and some fuckin shark bite connectors.
Link Posted: 9/20/2009 5:24:43 PM EST
Originally Posted By Dumpster_Baby:
Trust me on this guys - the ONLY thing that can be used to clean copper before soldering is sandpaper, the red or tan abrasive kind that has ONLY MINERAL abrasive glued to it. You CANNOT use a stainless brush, black iron brush, steel wool, or stainless curly scouring pads to clean a copper joint. Metal from the brush, steel wool, or curly pad will transfer to the copper and form a MICROSCOPIC METAL FILM on the copper that SOLDER WILL NOT STICK TO. When you use METAL to clean a copper joint you leave behind a MICROSCOPIC METAL FILM ON THE COPPER, no matter how clean and shiny the copper looks.

Metal abrasives on copper is a 100% guaranteed soldering failure.



I've used steel wool, emery cloth, silicon carbide abrasive paper, aluminum oxide abrasive paper and wire brushes to clean joints without any problems.
I don't see why they should pose problems, since many other metals besides copper can be soldered with the correct flux, etc. I wonder if it's actually some of the glue used to bond the abrasives to the papers that causes more problems than the actual choice of abrasive material.
Not disputing your experience, just wondering out loud..
I do suspect that the detergents in steel wool scouring pads would certainly cause problems, though...

Link Posted: 9/20/2009 5:32:55 PM EST
my kit looks like this except i use a torch on a 4 foot hose
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