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J187 01-17-2007 07:42 AM

Strange strange problem, could it be the flux?
I know this sounds weird but could I have some bad flux maybe? I've sweated a fair share of copper pipes so far and I really haven't had a problem. Recently I moved my water heater which required me to sweat a few joints in both hot and cold sides. For the passed two nights I have battling a strange problem. Every joint on the cold sold, and the two extension pieces straight off the hot side are fine. However, on the hot side, right at the 90 degree elbow going down, I haven't been able to get ANYTHING to hold. Every time I make a new joint there it leaks! Its so frustrating. I'm not resoldering the same joint, rather making up new sections each time, each time it leaks. The joints that are leaking are the new ones I make and I make them on a bench vise, so its not a water/moisture issue. After racking my brain, I realized the ONLY variable between the pipes that held and the ones that wont, is that I opened a new can of flux after the cold side and two other joints that hold on the hot side. Thats when I ran out of flux and used a new can. Everything since the new can won't hold. Could the flux be bad or something? I'm going to try a new can tongiht, but I was just curious.

harleysilo 01-17-2007 09:02 AM

Wow, that is strange. Their are different types of flux's but I didn't think it mattered.

I'll assume you are cleaning your pipe ends and connectors, right?

When you remove your bad work, were you getting solder in the connection?

J187 01-17-2007 09:39 AM

Well, for the most part, I'm not desoldering the bad work. I'm cutting and starting over. But I did desolder a couple of joints to have a look and it doesn't look terrible, but i'm not getting a completely even coverage. I'm definitley cleaning right, I've soldered over 100 joints(not a ton, but enough to get the hang of it) and never had a problem until this. I'm not thinking its the "wrong" flux, its the same stuff I"ve always used, I'm thinking something might be wrong WITH it.... Can't think of anything else. thanks.

harleysilo 01-17-2007 09:58 AM

So are you soldering a section (the one that fails) on your bench, and then soldering it in place? Or are you using unions or something to attach it?

If you are soldering near the failing joint a second time you could be heating it up too much and causing the solder to not form a good bond.

I usually run all my pipe and fittings and then start from one end and work to the other doing all soldering at once as to not heat the joints up multiple times.

I am not a plumber.

Mike Swearingen 01-17-2007 10:56 AM

I think harleysilo hit the nail on the head.,,,overheating.
Heat the fitting not the joint, and heat it just enough to draw in the solder, then quickly back off the heat.

majakdragon 01-17-2007 11:13 AM

I agree with Mike and Harley on the overheating. Since you are using the same brand flux, it SHOULD not be the problem. Along those same lines though, I have seen flux seperate in the can from being kept in too warm a place. Try stirring the flux up a bit or get a new can. I am preferential to Oatey flux. I have seen homeowners buy the cheap flux and wonder why they have bad joints. Wiping the solder joint with a gloved finger can also help alleviate problems plus making the joint look better.

J187 01-17-2007 02:22 PM

I am open to ANY suggestions, but I gotta tell you, I don't think it's overheating at all. I am making each section at the bench. I don't put the union on until I get to the house pipe. Then I solder both ends of the union at once. I know what part of the flame to use and I heat my flux to a gentle sizzle w/ a slight green hue and then I go in. I've done many, many flawless joints. There HAS to be something different here. I used bread in the pipe. I cleaned thoroughly, I wiped the joint after, I know enough to heat the fitting and not the joint, I heat the fitting where I want the solder to flow. I learned all that stuff the hard way before, lol. I made the cold side the exact same way and its fine.

Ron The Plumber 01-17-2007 02:25 PM

Is there enough room inside that pipe for heat to expand, lack of space will cause solder to spit out of the socket making it leak everytime.

KUIPORNG 01-17-2007 02:28 PM

Did you try to use those pre-soldered parts? I used them together with new solders to get double insurance that there are solder falls in the joints....

Brik 01-17-2007 03:52 PM

One time I used a different brand of flux. I couldn't get it to work right. Back to the green Oaty cans and never a problem. Also, could solder be a variable?

gitnerdun 01-17-2007 07:08 PM

What Ron said. You may have some moisture in the line trying to escape as you are closing up the last few joints. Try leaving a mechanical joint cracked to let off any pressure that may accumulate inside the pipe when heated.

J187 01-17-2007 08:33 PM

Ok, so I stopped and bought some new flux on my way home tonight. As soon as I got home I made up a new section and sweated it in. No problems whatsoever. Heater is working fine, no leaks...........I wasn't going to leave it at that. I broke out the first can of flux and sweated on a male adapter and an elbow to a spare couple of sections of pipe. I hooked up a hose and ran it. I swear to you, it leaks. Strange, huh?

Thanks everyone.

Brik 01-17-2007 08:41 PM

Same brand/type?

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