Sweat or thread?

My new shower mixer allows for threaded or soldered connections.

The threaded copper connections only twist on one or two turns by hand (without any tape)- does this sound normal? I don't want to wrench it on and ruin the valve threads.

I understand sweating is usually a better joint- but seems like this is not the norm for mixing valves. I figure soldering can be a problem if the joint leaks (hard to pull apart and redo). I understand I have to pull the guts out of the valve so nothing will melt.

Thanks for any advice.

If the fitting only goes in one or two turns before it gets tight, you probably have the wrong fitting!

A properly done soldered joint won't loosen up or leak, and from a production viewpoint, is one less connection to fail verses soldering on a threaded fitting, then inserting it into the valve. Plus, if the thing isn't anchored well, a threaded joint could loosen a little, whereas a soldered joint won't.

The key is cleanliness, even application of heat, flux, and a good solder. All of this is an acquired skill, but not that hard if you are at all handy. To help, you can buy flux with solder powder in it, which can make it a little easier (you still need to add solder to the joint!).

It's safer to remove the cartridge before you solder on the valve. Because the brass body of the valve is bigger than fittings, it will take more heat to allow soldering. A hotter torch helps. A cooler one means the whole thing will end up hotter since you'll have to be on it longer to get the solder to melt.

I agree that you may be using the wrong fitting. The way I prefer to plumb valves is to sweat a nipple to an adapter then screw this assembly into the valve. Then sweat whatever addition fittings and pipe you want to the pipe. That prevents the valve from getting too hot.

If you are threading anything, there should be at least 3 threads of engagement! It wouldnt hurt to use tape/dope as well considering its behind a wall.

Make sure the mixing valve is secured with wood backing to make sure it doesnt move AT ALL. Over the years, the movement of the handle can take its toll on any connections that arent supported.

I double checked the fitting- 1/2" IPS... Maybe the batch of adapters I got is just a little tight. I think I'll try sweating directly to the valve anyway.

Thanks for the tips all.

Solder it. There's less chance of a leak in the future.



Don't argue with me JUST DO IT

just do it

Decisions, decisions, decisions. If the valve has mip connections AND internal solder ports, solder it. If it has female threads, then I solder male adapters into the threads so I NEVER have to worry about leaks regardless of how tight or loose the threads are.