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jb8103

Soldering copper tubing

32 posts in this topic

Every now and then this comes up, and it's a skill I can only envy, because I've never been able to do this.

I got some copper tubing and fittings and the tools to practice with. I cleaned the ends with my shiny new wire brush. I put on the flux with the little flux brush. I stick the fitting on the tube. I fire up my shiny new propane torch and adjust the flame to a nice  configuration. I apply the heat to the joint, getting a little green flameout, and hold it there for about 20, 30 seconds.

Right so far?

Then I touch the solder to the joint, opposite the side I'm holding the flame to. According to Scripture, the solder should melt, cling to the fluxed tubing, and wick itself neatly into the joint.

What actually happens is the solder melts, balls up and drips off onto the floor. It's like the tubing is repelling the solder.

Happens every time I've tried it. This inability to solder is having serious detrimental effect on my self-esteem. Not to mention the impression on my wife. She gave me...The Look. You know.

How can I get these tubes to stick together and put the love light back in her eyes?

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Hummm, sort of hard to explain without knowing exactly what you are doing and how....when we braze the copper lines in the window units we have to use the acetylene torch and 15% silver solder....we do not need flux unless connecting different metal like copper to steel....sounds like you are not getting the copper hot enough to let the solder flow, but do not know what type of solder you are using either...the copper needs to glow bright cherry red before putting the solder to the copper so it will flow....perhaps you are trying to do something else I am not failure with however....there is different hardness in the copper for different applications, like plumbers use different kind of copper compaired to what is used in air-conditioning...this takes different type of heat source and solder..believe plumbers do use flux because of the different copper and solder used....perhaps others can shed more light on this when we know what type of copper and solder you are using...

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I'm using plumber tubing, not the AC tubing. Solder and flux is whatever the Home Depot had right there in their plumbing supplies.

Maybe I have to use a hotter gas torch setup, I know I'm not getting the tubing to cherry red. I thought plumbers used ordinary propane.

I have seen that other kind of torch/gas recommended, something used with oxygen, but it's not as hot as acetylene. I can't remember the name right now, I think it's MAPP gas?

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Plummers do use flux (my son is a plummer) to allow the solder to adhere to the copper joint by cleaning it.

I'm not sure what your doing wrong but you need to heat the entire joint, not just one side, especially with a propane torch.  Depending on the flame of your propane torch you might not be getting the joint hot enough, it should be red hot (30 seconds does not seem long enough for a propane torch).  Also there should not be any water in the pipe near the solder joint.

I use MAPP gas if there is alot of copper pipes connected near the joint since it gets hotter then propane.

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Hello

I,m assuming your doing a soft solder joint, not brazing with silver solder. First it sounds like your not heating the pipe up enough. 20-30 seconds is not enough time. Try closer to a 1-2 minutes. Second, use sand cloth or scotch brite pads(the best) to clean the outside of the pipe, the outside as well as the inside of the fitting your putting on (coupling, elbow, etc).

A wire brush just dosen't do a good enough job IMHO:) Apply the flux to the outside of the pipe, the inside of the fitting, and the outside of the joint once you put it together.

As you apply your torch move it all around the joint to B soldered. Top, bottom etc. Don't keep it in one place, and use mostly the middle/end of the flame. Its the hottest part. 

Your flux should be melting (don't be stinjy with the flux), I always put something underneath to catch this. You don't want to get the pipe cherry red or anything, just nice and hot. Once I feel the joint is ready I move my torch to the bottom of the joint, but over on the fitting, not the pipe.

The object is to get the solder to flow into the joint, making a good seal. I then hold my solder on the top of the joint. Once it starts to melt I move my torch away alittle and move the solder all around the joint making sure its being "sucked into" the joint. I'm not stinjy with the solder either. 

I feel the joint is done when the solder starts to drip off at the bottom. Once done DO NOT move the pipe and DO NOT use wet rag untill it has cooled at least a minute on it own. But do inspect it while its hot and make sure you have no misses. Then use a wet rag to cool it down. You should have a nice bead of solder all around the joining point.

Try doing a coupling first. When your done you can look thru the coupling at the inside of the joint. You should be able to see that the solder was drawn to the inside of the joint.

Hope this helps:)

P.S. I use a solder called Stay-Brite. Has a higher silver content for a cleaner joint

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Looks like the consensus is: I'm not getting it hot enough, and the silver solder is recommended.

Back to the basement, and much thanks.

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Cleanliness is next to godliness in soldering. CLEAN! Ahammer's scotch brite is excellent! Flux the male and give a twist if you can,then the outside of the joint.Light your torch(be patient if you're using a propane torch),keep the flame moving all over the joint. Your flux should change a little in look(not real familiar with plumbing soldering but it's essentially the same) as the joint heats up. Then start lightly touching the solder to the joint and keep the flame moving. When the joint is hot enough it will melt the solder and pull it into the joint.CLEAN,did I mention clean! The joint is what actually melts the solder,not the flame. If you do it right all you have to do is just touch the joint with the solder quickly and that's it.Like ahammer suggests practice a few. A joint with the male fitted in from the top is a good joint to start on.Be clean,good fit up(not to tight,not to loose) flux and proper heat,it's hard not to make a good joint.CLEAN, did I mention clean!

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I like it here. This is a great forum.

It'll be a while before I can practice and put this advice to use, since I'm doing a job out of town.

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I would switch to Mapp gas, the extra heat helps alot. I also would use sandpaper or a scotchbrite pad. The wire brushes don't seem to work well, and I think they hold some of the stuff they remove and leave some on the next fitting you work on.

It was easier with the real lead solder.

Nick

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There are plenty different solders for soldering copper... tin based, lead based, copper based, bronze alloys... various silver, zinc etc. content...

Tin and lead solders can be done with propane, and don't even need so much heat, BUT there's a big but coming. For plumbing, you shouldn't use solder that contains lead. You may need to settle with phosphorus copper solder and acetylene torch (the main soldering method plumbers use here).

Mixing highly different alloys for plumbing, you have the risk or corrosion on the more electronegative metal.  If you use lead solder on copper, lead will be dissolved into the water. This will be poisonous, and add up to the gloop-up factor related to water-borne minerals. If you use a high silver content, copper may be dissolved from around the joint. Either way that will gradually weaken the joint.

Tin based solder may become brittle in cold conditions, so it is of no use in refrigeration, especially evaporator side. Bronze solder is recommended, there are grades that can be soldered with propane.

If you are just beginning your plumbing career, you may be easiest off completing your job with bronze bead joints. They are a bit expensive, but they are the easiest way to go for a beginner, and because they need no heat, they're quite safe to do too. Just remember to leave joints to accessible areas if you need to tighten them. they can be used on various tubing types including plastic and iron.

If you need to change from iron tubing to copper, it is recommended that you put a piece of plastic tubing between the two metals. This will slow down the corrosion on the iron side. Best option in an iron plumbed house would be to do additional plumbing with plastic all the way, although it will be expensive.

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Sounds like we're actually talking about brazing.

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Yes, when you're dealing with tubing, you're brazing. If you're wondering about soldering copper tubing using the same techniques as soldering electronic components on a circuit boar, I don't know of any way to solder copper tubing using the same mechanical techniques used in electronics. I do, however, have a nice little handout (attached) which explains basic soldering techniques which you or others may find useful.

How_to_solder_1.pdf

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[user=1]Samurai Appliance Repair Man[/user] wrote:

Yes, when you're dealing with tubing, you're brazing. If you're wondering about soldering copper tubing using the same techniques as soldering electronic components on a circuit boar, I don't know of any way to solder copper tubing using the same mechanical techniques used in electronics. I do, however, have a nice little handout (attached) which explains basic soldering techniques which you or others may find useful.

Saved! That calls for a round of brewskis, on me.

http://www.fixitnow.com/beerfund.htm

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[user=263]jb8103[/user] wrote:

Saved! That calls for a round of brewskis, on me.

http://www.fixitnow.com/beerfund.htm

Sometimes, in my semi-lucid moments, before my medications kick in, I get lucky and give a good answer. Mucho domos for the brewskis! :cheers:

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Right, brazing might be the better word... perhaps the limit of soldering and brazing can be put between tin/lead solder and copper content solder. Some people put it between the methods: solder iron or torch.

I have performed both methods of soldering with tin alloy on copper tubing. Of course the iron method isn't satisfactory on large pieces, and cannot be recommended to a plumbing job, because the alloys contain lead.

Technically, brazing is still part of soldering, because the pieces being joined aren't getting melted like when you weld something. Many people (even professionals) over here talk about just soldering, and the materials determine the method.

Like said, the prhosphorus copper can be considered the copper plumbing standard. copper tubing can be joined by bronze, and this is recommended if you need to join steel and copper.

Note that when using tin solder on copper in high temperatures like with the torch, some of the alloy will penetrate the copper surface and form a bronze alloy. This will happen on your solder iron tip too (which is made of copper and not iron). Especially cheap solder tips seem to corrode and get a golden look. Copper is added to many tin and lead solder grades to hinder this process.

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Domos to you all, and Merry Christmas, too!

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Right back at ya. And Happy Holidays to all!!!!

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[user=10234]Keinokuorma[/user] wrote:

If you are just beginning your plumbing career, you may be easiest off completing your job with bronze bead joints. They are a bit expensive, but they are the easiest way to go for a beginner, and because they need no heat, they're quite safe to do too. Just remember to leave joints to accessible areas if you need to tighten them. they can be used on various tubing types including plastic and iron.

Are you referring to what we in the US call "compression fittings"?

Nick

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probably, "pronssihelmiliitin" or "puserrusliitin".... or whatever each tech/plumber/fumbler decides to call them.

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Have you seen the fittings sold here as "Sharkbite" these things are amazing and have saved my butt many times. Well worth keeping a few on the truck. Not sure how well they'd work around a boiler long-term, I only trust time-tested methods for that. Keino, anything like that make it's way to the "swamp"?

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[user=9503]AccApp[/user] wrote:

Have you seen the fittings sold here as "Sharkbite"

Well there are fittings very similar to these used on plastic tubing in pneumatics... you push the tube in, and it stays there, until you press the rim piece and yank the tube out... quite like pulling it apart. Don't know if that is applied to water plumbing, I always used these compression fittings if I need to alter plumbing, and they're sold as the default thing if anyone "non-pro" goes to buy plumbing stuff. they're quite nice because I don't need to carry the brazing torch or acetylene welding gear etc, or use any very special tools but two wrenches... can do it in a prone-to-burn area, and places where I have no room to rest my bloodshot peepers on the object of work (when both my hands are already in, and the third one would be, had I developed it).

Keino, anything like that make it's way to the "swamp"?

Don't exactly know what this means?? B)

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[user=10234]Keinokuorma[/user] wrote:

[user=9503]AccApp[/user] wrote:
Keino, anything like that make it's way to the "swamp"?

Don't exactly know what this means?? B)

 

It means "Do they sell/allow anything like this in Finland?"

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Those Sharkbite fittings look interesting, sort of like a Robert Guess fitting for metal. Are they expensive? They appear to be solidly built.

Nick

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Well, at least for pneumatics there are very similar fittings. The compression fittings are somewhat the default thing in plumbing, and they are proven to work for hydraulics and pneumatics quite well too.

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