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-   -   Tips for Soldering "up"? (http://www.diychatroom.com/f7/tips-soldering-up-12520/)

moneymgmt 10-18-2007 11:17 PM

Tips for Soldering "up"?
 
Well the galvanized to copper change has been going excellent, I'm thinking of just leaving the walls open since the shiny new copper looks so dang nice (kidding). I have a couple of spots along the lines where soldering before putting the pipe into place was not an option and I need to solder up, or, against gravity. One place in particular, I have to solder an elbow onto a piece that comes up through the floor only about 4 inches. I have the kevlar blanket to protect the area around it but getting the solder to creep up into the void worries me. Any tips?

scorrpio 10-18-2007 11:59 PM

Use emery tape to thoroughly clean the pipe and a wire brush for the fitting. Don't touch clean copper with bare hands. Make sure to apply flux all around. I prefer the 'tinning' flux (green cans in HD). Now, I prefer a MAPP torch, it heats things faster than propane, especially when working with pipes like 1" type L.

The biggest mistake most beginners do is heat the spot 'in where the solder goes'. That is, they point flame at the gap between pipe and fitting, usually heating just the pipe. What you have to do is heat the fitting - in particular, the portion containing the pipe. Even better is to assemble and solder all fitting outlets at once, in order to avoid reheating an existing joint.

Once you heat the fitting enough, and touch solder to the gap, it will be drawn in by capillary action towards heat. Gravity has nothing to do with it, hence direction not important. In fact, as soon as solder stops being 'sucked in' and starts forming a 'bulge', remove the solder. The smaller the'bulge' , the better. Repeat with other outlets, then wipe down with a wet rag. It usually takes less than a second to apply enough solder when the fitting is heated well enough.

When soldering valves, or any other components that might have non-metallic gaskets, either remove non-metallic parts or tie a wet rag around the valve to absorb excess heat. This is one of reasons I prefer MAPP - shorter heating time gives heat less time to spread.

moneymgmt 10-19-2007 07:17 AM

That's pretty much what I figured; thought there may have been a 'trick' to it though. Thanks.

moneymgmt 10-19-2007 05:42 PM

Either you're a good teacher or I'm a good student (or both) but we did 2 joints like this and success! Have a great weekend!

RippySkippy 10-22-2007 10:46 AM

Not that you'll need this now....but if someone is searching and runs across this later...

Another little trick, that helps when soldering is to take a hammer and lightly tap either the fittings or pipe, the goal to make them "slightly" out of round, so when they are connected they will stay connected. I have had tight fitting connections fall completely apart when heated due to the heat expanding the fitting. BTW don't try to catch a falling, heated fitting...you'll probably catch it!

sz8 10-23-2007 10:31 AM

I don't think being "up" or "down" will not make too much difference since
the solder is kind of sucked in. Gravity does not play too much role here.

However, I found that when soldering "up" fittings, if you put too much
solder, extra solder will drip down more easily making it look ugly. It is also
bit harder to see if the solder melted is enough to fill the gap. Fortunately,
extra solder does not hurt execpt for looking.

majakdragon 10-23-2007 01:17 PM

The solder goes to where the heat is. As long as the pipe and fittings are cleaned and fluxed, gravity will have no bearing (as stated). If I have joints that may move while soldering, I give them a squeeze with my channel-locks once in place. I always wipe the joints after soldering. Makes it look more professional.

scorrpio 10-23-2007 04:04 PM

Actually, dripping solder is very bad. Consider following: take a piece of glass, tilt it about 45 degrees, and deposit a small drop of water - likely, it will 'adhere' to glass and stay put, forming a thin dome. But put a large drop, and it will skate off, leaving very little on the glass, since surface tension is stronger than water-glass bond. Same with solder. When you have just enough to fill the gap, it sits there. But if a large droplet forms, you essentially have a 'surface tension sack' filled with nolten solder, tugging at what is inside the gap. This droplet has a potential to pull solder out, resulting in a weak joint. This is why one should immediately stop adding solder as soon as the droplet starts to form.
In this sense, sweating 'up' or 'sideways' is better as you immediately see the droplet forming. Whereas sweating 'down', you might keep adding solder without realizing that you have it dripping inside the pipe. In fact, you might have seen this effect: solder first appears to fill the gap, but then, if you add more, it seems to get 'sucked down'. That's a droplet inside the pipe pulling it. Right thing to do it to stop adding solder as soon as gap fills.

moneymgmt 10-23-2007 04:32 PM

All good info.

Now a different question which I pondered: what is the purpose of flux?

majakdragon 10-23-2007 05:51 PM

Flux cleans the pipe and fitting and helps the solder to adhere.

scorrpio 10-24-2007 08:35 AM

Flux 'eats' away impurities left on metal that might interfere with solder adhesion. It also protects the surface from oxydizing when you apply heat.


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