soddering threaded fittings

I am moving a washing machine . I have soddered the copper pipes and I had to thread a male 1/2 in. nipple( brass with ball valve) in to a female 1/2 copper threaded joint , that I soddered on . all of the sodders are tight. I have a leak at the threaded site. I had used pipe compound first and it had a small leak. I took it apart and used teflon tape and resoddered. It still leaked. I am frustrated and I want to sodder the brass male threaded nipple from the ball valve shut off to the female copper fitting on the water feed pipes.
1. Is this the way to go?
2. Can I sodder over the teflon tape without flux?

Lars

There is a reason they put teflon on frying pans! Nothing sticks to it.

Basically, flux and teflon tape will keep solder from wicking into th ejoint and creating a good seal. It is one or the other (solder - not the norm for a threaded connection) or tape and/or pipe dope. You can use tape and pipe dope, or each by itself, but never one of those and solder.

For a soldered joint to "take", it needs to be clean and fluxed. The tape and dope will preven the solder from bonding.

soldering threaded fittings

thanks for the replies.
For clarity. I only soldered a female threaded fitting and then screwed in the male nipple for the washing hoses to that fitting. I used teflon tape for the male fitting and tightened it very well. I did this two different ways with the same result: a leak. It is very difficult to get apart because of side by side hot and cold water fittings. If I take it apart I want to solder the two threaded fittings together. I think I have to take off the female adapter and just put the 1/2 copper pipe into the male nipple and then solder it.
I only want to do this one more time.
I have soldered multiple other fittings and they are fine. I see the threads as a weak leak. If I ever need to change it I will just unsolder them

Can I do what I mentioned about soldering a threaded connection: they do it with outdoor faucets.

Sometimes the threads are very poorly made with dull cutting tools. So, to get a good connection, you may want to buy a small tube of pipe dope. It will seal the joint. You may not have run enough wraps of teflon on the pipe or wrapped it the wrong way round. Or, it may not have been tight enough. Either should work, but some people use both. If the pipe or fitting is oval rather than round, that can make it really tough to get a good seal.

lars said:

thanks for the replies.
I think I have to take off the female adapter and just put the 1/2 copper pipe into the male nipple and then solder it.
I have soldered multiple other fittings and they are fine. I see the threads as a weak leak. If I ever need to change it I will just unsolder them

Can I do what I mentioned about soldering a threaded connection: they do it with outdoor faucets.

Click to expand...

I don't know the clearances between the copper and the inside of the male nipple, but I would not do that. I assume that it is a brass nipple, but I still wouldn't do it because of the unknown fit.

You could probable solder the threaded parts of a male and female assembly, but they are so heavy that you would probably need a lot of heat. If I had to do it I would:

1. Unscrew the fittings and clean both the male and female threads with a sharp brush. You want them to be clean of grease, pipe dope, and corrosion.

2. Liberally apply a tinning flux, such as Oatey No. 95, to both the male and female threads.

3. Screw the two parts together loosely, just finger tight, because you want the solder to wick into the joint.

4.Apply heat to the parts, especially the female part, and apply the solder when both parts are hot enough to melt the solder when you touch the solder to the joint. Let it cool after soldering before moving it.

lars said:

Can I do what I mentioned about soldering a threaded connection: they do it with outdoor faucets.

Click to expand...

They don't do what you think. Many hose bibbs are made with half inch IPS male threads, for people who want that application, and the inside of the casting is machined 1/2" CTS so a 1/2" copper pipe can be inserted and sweated. You see this a lot in new construction, and they usually opt for the sweat connection. Delta shower valve bodies are constructed in the same way.

I only soldered a female threaded fitting and then screwed in the male nipple for the washing hoses to that fitting." ~ What male nipple? Washing machine hoses are meant to be attached to a garden hose thread. Not a pipe thread. Different number of threads per inch, and no for-certain area for the hose washer to seal against, if you try it with a pipe nipple.

soldered threads.

Thank you again for all of the replies. This is a good site for advice. To wet boots I am talking about the bottom thread of the valve not the part that goes to the washing machine.
My old washing machine threads are screwed into a female nut that is soldered onto the 1/2 in supply. This is why I did it that way. It made sense if I need to change it in the future. However , I now realize that the joint will be hidden behind the wall and I will have to cut that out to change it and I will have to unsweat the joint to move it.
I took another look at the directions that came with the box and the valves. Of course stupidly , I missed the picture of the lines going into the bottom of the threaded nipples and not with a nut. There was nothing written so I missed it but it is clear that they want you to solder it.
I am going with Jimbo. I saw a video where the threaded frost free faucet was soldered and not screwed to the line.
I wish I would of looked closer, it would have saved me an afternoon of frustration. Bottom line I will solder the joint and deal with it in 10-20years when and if it fails.
thanks again