Solder not sticking while sweating copper


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Old 04-24-16, 04:50 PM
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Solder not sticking while sweating copper

I am attempting to connect two pieces of copper, vertical. Using maps, lead free solder, and flux. Cannot get the solder to stick. Each time I put the flame on, solder melts and runs down the side of the pipe. It does not wick into the opening at all. I also can't seem to get the solder to melt without the maps flame. I am new to this, but have watched videos, read things and seems I am doing things correct.

I've varied the flame size, no,flux, some flux, lots of flux. Cleaned, scrubbed. Not sure what I am doing wrong and not sure where to go,from here. ??
 
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Old 04-24-16, 05:20 PM
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It's really pretty simple once you get the hang of it. I would suggest practicing on a few fittings in a vice.

My way is clean inside and outside, dry fit, flux inside and outside, apply flame opposite from solder (put a crook in the solder to make it easier to swipe around), as soon as solder starts to melt on side away from flame, remove flame and swipe all around joint.

Your problem sounds like dirty connections or water in the pipe. The pipe must be completely empty and dry.

How did you clean?

What size pipe?

BTW...it's MAPP not maps.
 
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Old 04-24-16, 05:40 PM
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Agree with Vic. If the solder is beading up or running down the pipe, you have a dirty fitting. Just as Vic says use clean fine grit sandpaper or emery cloth. Clean both surfaces, spread flux as soon as you clean them. Also clean and flux joint after you fit them together. This will tell you if the solder is sticking if it adheres to the outside of joint. It's a bit of a waste and not necessary once you get the hang of it.
Get fitting near cherry red hot and apply solder to the fitting joint where they join. Capillary effect will fill the joint. Make sure the pipes are dry. If any water or moisture is present, you won't get solder to stick. Once soldered don't touch it. Let cool on it's own. If you disturb it while still in liquid state or hot you will get "cold" solder which is weak or will leak.

You said it's in a vertical position. Are you securing it so that no movement takes place as you solder and when you're done?
 
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Old 04-24-16, 05:45 PM
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You could also have the solder too close to the flame. If all else fails, use Sharkbite coupling.

Click Click
 
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Old 04-24-16, 05:59 PM
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Sometimes Sharkbite can't be used. Had a customer the other day who had to use a solder joint because of space constraints. Even though they are approved for behind drywall, I don't feel comfortable to use them in that scenario. I know a solder joint won't wear out or burst due to a gasket failure.
 
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Old 04-24-16, 06:06 PM
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As others have said, it sounds like water in the pipes.

I use a piece of 1/4" plastic tube to check the water level below the joint. Close off the top of the tube with a finger and the tube will hold water. You can also remove water from the pipe with the tube.

If the water level below the joint continues to rise, stuff crumbled bread down into the pipe.
The bread will keep the water from rising and will pass through any valves. Be sure to flush the bread out through a valve and not an aerator.
 
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Old 04-24-16, 06:13 PM
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Brian said
stuff crumbled bread down into the pipe.
Used this trick on several occasions. Works very well.
 
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Old 04-24-16, 06:37 PM
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Even though they are approved for behind drywall, I don't feel comfortable to use them in that scenario.
That's why God made access doors.
 
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Old 04-24-16, 08:01 PM
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There's no need for any access to push-on fittings, they are designed as a permanent fitting.
Most are guaranteed for 25 years and will probably last much longer.
The first few times I soldered pipe, I couldn't guarantee it for 5 seconds. Anyone having trouble sweating pipe should consider the push-on fittings.
 
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Old 04-25-16, 08:12 AM
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If you don't get it right, including quantity of flux anc timing of when to apply the solder then the flux will have boiled away and the mating surfaces will have re-oxidized. You will need to take the connection apart and re-clean it before trying again.
 
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Old 04-25-16, 09:39 AM
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Originally Posted by Handyone
...(push-on connectors) are guaranteed for 25 years...
Is that seriously all? Does it say so on the packaging? They do work well & I have used them myself in a pinch but would you buy a 25 year old house knowing they were used throughout?
 
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Old 04-25-16, 12:07 PM
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Good question, I never looked at it that way. A 25 year old house isn't old to me.

I look at the fittings as lifetime, could be wrong
 
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Old 04-25-16, 03:04 PM
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They do work well & I have used them myself in a pinch but would you buy a 25 year old house knowing they were used throughout?
My sentiments exactly! Behind drywall I'll stick to my solder joints.
 
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Old 04-25-16, 03:32 PM
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This was a frequent issue I had when I used to use propane before I switched to mapp. I think if you hold the flame too close, you get a carbon build up on the copper that prevents a bond. It is like water sliding off a freshly waxed car.

Others have explained it well, clean both inside and outside fittings, generously flux both clean surfaces, flame on one side, solder on the other and don't overheat the fittings.
 
 

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