My first attempt at soldering copper.

[r00kie]

I've mostly steered clear of copper in my launchers until now, except for the odd piece, I'd always make a mad dash for compression fittings though, as I've been a bit intimidated by soldering.

I found some old flux and solder that I had lying around, I bought them months ago, but never used them. My first attempt came apart half an hour later when I was screwing it into a joint (not a good start!!), but the second seems a bit better.









I hooked it up to a lathe when it cooled down and wet sanded it, which is why it's so nice and shiny.

The issue I'm having now is fear. I don't have the equipment for a hydro test, and I don't see any way to test the quality of the joint without pumping up the pressure and hoping I won't be sodomised by a piece of flying copper.
Is there an easier way to test it, or are my worries unfounded?

[lozz08]

your worries are absolutely founded, If the first one fell apart then this one could burst suddenly and hit you.

Why not just pump it up with your pump around a corner or something? Just shield yourself.

[hi]

If its coming undone then you need more heat.


To hydro test it, just fill it with water and pump it as high as you dare...

[jackssmirkingrevenge]

hoping I won't be sodomised by a piece of flying copper

LOLOL that would definitely make it in the spudfiles unusual accident hall of fame

One word, epoxy!

Though I have to say it does look rather pretty without massive clumps of adhesive piled on to it.

[Technician1002]

Use flux sparingly. Use just enough solder to wick into the joint by capillary action. The puddle of solder is simply due to too much solder being used, too little heat, or poor flux. Solder on the outside does not add strength. The solder wicked into the joint provides great strength.

To test your joint. heat it with a large flame torch (not a pencil tip) until the solder flows and pull the joint apart. Examine for any area of the pipe or fitting that is not wetted with solder. A proper joint should come apart with all the joint area evenly tinned in solder.

Note the photo below. the flame has several tips.. This is a "Turbo" torch, not a pencil tip torch.

Using too much flux can prevent the flow of solder into the joint. Too much heat can burn the flux and oxidize the copper.

Heat the entire joint, not the point where you are adding solder. Note the position of the torch in this photo. It is not on the edge of the fitting, but on the center of the joint where he wants the solder to flow to. Add solder as it wicks into the joint. Stop when the joint is full and no longer sucks in solder.

Capillary action is strong. Gravity is not needed to get solder to flow into the joint.

Edit. Added photo of silver brazing job I did.

When the solder and copper are the proper temperature and properly fluxed, the solder will wet the surfaces. This silver brazing job shows this wetting of the surface. This indicates a good bond. Lumps on the surface is bad.

[Gippeto]

Sweating copper is a useful skill in life...and spudding.

Did the solder wick into the joint? It will if the joint is hot enough.

Hard to tell from your pic, but can you see solder on the inside of the joint?




Small note...Hydro testing should NOT include the use of pressurized gas. That defeats the purpose...buy a grease gun. They're cheap, and able to greatly exceed the pressure you'll get from a bicycle pump.

Edit: Damn I type slow.

[r00kie]

It will be only taken to relatively low pressure (probably a maximum of 300 psi). I could pump it around a corner, but that doesn't reduce the risk of flying metal, which I don't want in a surburban environment.

I really considered epoxy JSR, but as gipetto said, sweating is a useful skill to have and I figured it was high time that I learn it. :p

Technician1002, I think the issue with my first one was too much flux. The flux I have is more like jelly than water, I am not sure if that's because it's been sitting there a while (I stirred it vigorously before using) or just the type I happened to get. The second time, after applying flux I thinned it out with a towel so there was a barely visible layer on it.

I soldered it vertically as I figured gravity would help with the process. I haven't seen anyone solder before, I just looked up a few videos on Youtube. I heated the fitting until the solder melted on contact with the copper, then ran it around the fitting. I noticed it shrinking a bit, I'm hoping that was because it was flowing into the joint. Afterward I cleaned off the excess with a wet towel and let it cool.

I'm not able to take it apart at the moment, but I'll do so when I have the chance to see if there's a layer of solder inside the joint. I thought that when it was heated the solder would just melt away though.

Gipetto, I can see solder when I look inside the threaded fitting, but that could be from where I pulled it apart after it failed the first time. I'm not sure what you mean by "wick into the joint", I took the flame away when it started to melt on contact and guided it around the joint.

[Gippeto]

If the solder was "shrinking into the joint", then it was wicking...terminology.

If you can see the solder at the back side of the joint, and the front side is full like you've got it...it's HIGHLY likely that the entire joint is full.

Give yourself a pat on the back.

Any flux you find in the plumbing section that's made for copper is going to work fine. Most that I've used resemble bearing grease, so your "jelly" is right in line. Apply it with the little acid brushes that are likely right in the next bin.

Like in the picture here;

[r00kie]

That pat on the back will have to wait.

I took Technician1002's advice and pulled the weld apart, and there was no solder in the joint.

I'm not sure what I did wrong, there was a layer of flux on it, and I heated it well.

[jhalek90]

Having quite a lot of experience in soldering and brazing, i think you need to heat the joint more.

You dont need to "Guide the solder into the joint."

If you get the joint hot enough (make sure you heat it even) the solder will flow towords the heat.

I would also say that i think you are heating the wrong part of the joint.
you should apply the heat where you want the solder to flow, which is the bottom of the socket, and be sure to heat evenly.... if you do it right, you will know because the solder will "run" or "flow" into the joint.

solder heated to the right temp, will even flow "uphill" towards the heat.

Maybe i will make a soldering youtube tutorial this weekend.

Hope that helpped. feel free to ask any questions. As i mentioned i have experience in soldering and brazing (high temp soldering) all types of metals. Copper, brass, stainless steel, titanium, and a few others. heck, i've even soldered a few high temp plastics.

[Technician1002]

It was not hot enough. As shown in the photo, heat the joint from the far side and keep the torch moving to heat a large area. When it is hot enough the solder will flow like water and suck into the joint.

Clean the connection area with steel wool, sandpaper or other material to make it shiny, add a light coat of flux to both pieces, assemble and solder it.

If it is clumping and not flowing on the surface, it needs more heat.

[r00kie]

I heated it up to the point where the solder would melt on contact with the copper (after the flame was taken away).

I've heard that overheating it can be bad, so I've tried to be careful.

I've been heating the fitting, not the pipe, as that's where I want the solder to go.

I'll give it another go though, and see what happens.

[Technician1002]

You want it slightly warmer, so it flows on the copper instead of just barely melting. Keep applying heat as you solder, but don't remove the torch, simply back it off slightly to prevent overheating.

[r00kie]

Success! I think.

I found some other flux and solder that I had lying around, I thought I'd give it a go with that. I also took jhalek and technician's advice and altered my methodology a bit.



The flux and solder I was using is on the left, and the stuff I used for this weld is on the right. The solder I used this time is considerably thinner, and I found that it flowed a lot better than the fat stuff. The flux on the right is also completely liquid, while harder to see it was a lot easier to apply.

I took it apart after welding with a bit more heat, and it looks a lot better!



There is a bit of copper that wasn't covered, but I'm pretty happy with the way it turned out. Does it look like enough?
After putting it back together, I got this.





I think I used a bit much, as it dripped down through the inside of the joint.

I'm not too concerned about that as it's not on the threading, but I'll probably sand it off anyway because I don't want it flying off under high pressure and shooting up into the QEV.





That's the pipe up against the piece I cut it off before welding. I think it looks much cleaner around the joint too after a bit of sanding!

Thanks very much for your help guys, I probably would have gone back to a compression fitting in defeat if it wasn't for the advice you've all given. I can't wait to finish putting this launcher together.

[Technician1002]

Much better.. Keep practicing so you get the hang on the right amount of heat. A properly done joint has no voids of missing solder. The entire joint fills.

I hope you got the pipe that nice and shiny before you soldered it. Flux is there to prevent oxides during soldering. It won't properly remove the heavy oxide on your "before" pipe. The joints need to be clean and bright before soldering.