soldering copper pipe

[outofplumb]

Hi,

(Please don't laugh...)

I've got a 1/2 inch copper supply pipe that is coming up vertically from the subfloor that I need to extend. I'm using a standard copper coupling (that 1 inch long hollow cylinder where you stick the pipes into both ends) to attach upon this pipe. The extension piece of pipe will then continue up vertically from the coupling.

My question is, when I solder the 2 ends of this vertically oriented coupling, which end do you guys solder first? The top end or the bottom end?

Also, how much solder to you typically need to feed into one joint? I've read once reference that suggests 1 inch.

My concern is that, because the coupling is vertically oriented, would I end up soldering both joints if I feed solder from the top joint first?

Thanks!


Soldered with No-Lead Solder

[Redwood]

Snicker snicker

No seriously 1/2" uses about 1/2" per joint and 3/4" uses 3/4" per joint.

This isn't a rule! It's not set in stone and I will tell you that I have never in my life measured solder.

You are right If you don't pay attention when soldering the top joint a lot of solder will be dripping out of the bottom joint.

More important than how much you use is cleaning the copper good and fluxing good and not overheating the joint.

[Probedude]

The nice thing is that solder has surface tension - so though it will wet to clean copper wonderfully well, even in a vertical orientation it will form a fillet on the joint when there is enough solder in there.

Go by the appearance of this fillet and not 1/2" or 1" of solder, etc.

You're really going to do both at nearly the same time, but thinking it over I'd do the bottom half first and then the top - for no particular reason other than I can see the top better than the bottom. Finesse with the flame, watching the joint and add just enough heat to completely flow the solder into the joint, fillet a bit and you're done. As Redwood wrote, don't overheat the joint and you'll be fine and done in no time.

[kingsotall]

Just sharkbite coupling it! lol

[nhmaster]

Bottom first, heat rises.

[theplumber]

^what he said.

PS - wipe away any tits as you go. If one forms way below where u do it, put the torch on it till it can be wiped away w/ the flux brush.

[GabeS]

When you are doing the bottom joint it helps to push the solder up into the joint and circle it around to make sure it spreads nicely. When the copper is the right temperature the solder should spread mostly by itself but it also helps a little to do as I just explained.

You'll know when the joint is full because the solder will start to drip out of the joint. That's precisely when you stop, and wipe away any excess drip.

Make sure you use emery cloth to clean the pipe really good and also use the wire brush to clean the inside of both sides of the coupling and apply flux.

While you are heating the pipe, keep tapping the solder against it every few seconds until the solder starts to melt. That's the right temperature. If this is for water supply then use type L copper pipe. It's written on the pipe if you look closely.

[hj]

Bottom first because heat rises, and preheats the top joint. IF you did the top first the bottom would not be hot enough to solder properly unless you were overheating the top. Then when you did the bottom, the heat rising would liquify the top again. No big deal as long as you did not move it while it was loose.

[SewerRatz]

^what he said.

PS - wipe away any tits as you go. If one forms way below where u do it, put the torch on it till it can be wiped away w/ the flux brush.

On the Illinois plumbing test they knock off 1 point for the solder tits, and 5 points if you wipe them away. They key is to use just enough solder to get a good clean joint with out the tit.

[frenchie]

Really? Wiped joints are the standard, here - you recognize a pro job by that perfect 1/4" of silver, looks almost like paint...

[SewerRatz]

Yep, they say wiping the solder joint introduces dirt and such into the solder which can lead to a leak down the road.

[frenchie]

Huh. That's pretty interesting - I'll have to ask my plumber about it, next time I see him...

[hj]

BS. The solder doing the seal is inside the joint and NOTHING is going to work its way into it.

[Redwood]

BS. The solder doing the seal is inside the joint and NOTHING is going to work its way into it.

Yep... Pure BS!
Moving the fitting while wipeing may cause a problem if it is moving at the moment the joint cools from liquid to solid. But, You definitely aren't getting dirt into the joint.

[SewerRatz]

This following part is taken from Copper.org web page about Copper/Alloy Tube & Pipe: Soldering and Brazing. The link will take you to that page. Bold is added by me.

Although soldering and brazing are the most common methods of joining copper tube and fittings, they are often the least understood. It is this lack of understanding that can develop into poor installation techniques and lead to poor or faulty joints. Investigations into the common causes of joint failures revealed several factors contributing to faulty joints, including:

• Improper joint preparation prior to soldering.
• Lack of proper support and/or hanging during soldering or brazing.
• Improper heat control and heat distribution through the entire joining process.
• Improper application of solder or brazing filler metal to the joint.
• Inadequate amount of filler metal applied to the joint.
• Sudden shock cooling and/or wiping the molten filler metal following soldering or brazing.
• Pre-tinning of joints prior to assembly and soldering.

I was taught to wipe my joints after soldering it by my first sponsor. It did not make wiping the hot solder joint to make it look nice right. As I said when I took my plumbing test I seen on the sheet I would lose 1 point for every solder tit, and 5 points for every wiped joint. Now I am not saying after the joint cools you do not clean it off. You must clean off the excess flux after the joint cools on its on.