I have a shower valve body (brass) and am trying to solder copper pipe to it. For the life of me I can't seem to get the pipe and fitting hot enough to melt the solder. I noticed soldering copper pipe to the drop elbow took more flame heat than normal. Is there some trick when soldering copper to brass? I will say the pipe does not fit snugly into shower valve connector.

The valve body does have male threads so I could get a threaded copper connection, but I am worried about it leaking. If I use a threaded copper connection with teflon tape or cream (is one better than the other?), how do I insure it won't leak - i.e. how much should it be tightened <--- question from someone who has variable luck with compression fittings. If use the copper threaded connection would a week of checking for a slow leak be sufficient time?

Is this a repair or retro fit? The biggest problem I have had is keeping all the water out of the pipe. I don't think even an acetylene torch would make enough heat to solder a pipe with water in it. Many of the stops are old gate or globe valves that let just enough water seep thorough to fill the pipe with water. Try sticking a rope or something down the pipe to push out the water and then get it soldered before more can accumulate. Any time you have something apart, pitch any old gate valves and put in ball valves. Easier to work with and leak much less.

I like Loc-Tite PST better than Teflon tape on threads. Lot of tight joints done both ways. Over tightening can stretch the pipe and make leaks that never go away. Tighten it up less than King Kong would, and see if it leaks. If it does, you can always give it a turn or 2. You can't undo an over tightened joint.

If this doesn't work, do just what Tom says.

This is a retrofit so the annoying water in the pipe problem is not an issue. In fact, I am soldering it outside of the wall.

I'll try the compound you mentioned and wait for any suggestion from Tom.

Try soldering the threaded copper fitting to the short pipe nipple section first, then use teflon and blue block pipe compound, tighten them into the valve body, then solder the short copper nipple sections connected to the valve body to the elbows of the drop legs.

If your shower valve body has threads, (haven't seen one yet with male threads, every one I've seen has female threads), then why solder at all if you're uptight about soldering, ( and no, you can't solder a pipe that has moisture or water in it) why not use 1/2" MIPS(male iron pipe size) to 1/2" compression adapters I use teflon tape on the threads and no pipe dope of any kind on the compression ferrule. As Lab man suggested. " Over tightening can stretch the pipe and make leaks that never go away. Tighten it up less than King Kong would, and see if it leaks. If it does, you can always give it a turn or 2. You can't undo an over tightened joint." Ifyou'redeadset on soldering then skibergers suggestion,
"Try soldering the threaded copper fitting to the short pipe nipple section first, then use teflon and blue block pipe compound, tighten them into the valve body, then solder the short copper nipple sections connected to the valve body to the elbows of the drop legs." using Labs suggestion to remove moisturefrom the pipes. I was just offering you another option. Tom

how about coat the brass fitting with a layer of solder first (the copper tube will fit tight) . Clean it and put the soldering paste to the brass and copper then join them... add a little more solder when brass's solder starting to meld... the solder will look a little messy... I done it like this to a 3/4 valve with a small map tank

I recently replaced my shower valve with a Kohler unit and it has male threads. The unit has the option of using the threaded connection or soldering. The ½” copper pipe fits inside the male nipple and then soldered. Kind of male/female set up. :confused: I’ve also seen this on the new hose bibs. I use both propane and mapp gas, and it soldered right up with propane. You say water in the pipe is not a problem so it should solder. I have learned, at least in my experience, that a very low propane tank will still produce a flame but may not be hot enough to heat a heavier piece like the brass. As for water in the pipe, an old trick still recommended today is to shove some bread in the pipe to absorb and stop the water. The bread will burn up when soldering and flush out when the water is on. I’ve used this many times on vertical drop pipes.

Shader, thanks for sharing.

" You say water in the pipe is not a problem so it should solder."
I didn't say water in the pipe is not a problem. You did in a earlier post when you referred to your "retro fit", (This is a retrofit so the annoying water in the pipe problem is not an issue. In fact, I am soldering it outside of the wall.)
Water in the pipe,any water, is a major problem. If the pipe's loaded with water it will absorb the heat from the torch and if there's even a little bit it will turn into steam from the heat and cause pinhole leaks in the solder joint.
You came up with a old timey plumber trick with the bread. ( Another is to shove a rope or pack string in the pipe and pull it out along with the moisture.)

"I recently replaced my shower valve with a Kohler unit and it has male threads. The unit has the option of using the threaded connection or soldering."
I retired in 1988 and try to stay abreast of any new products and changes that come on the market but missed this one. Thanks for bringing my attention to it.
Glad you're back in business, regards, Tom

Just letting you know of some of the things I have come across during my houses extreme makeover :eek: I haven't tried the rope trick but on several occasions used my shop vac to suck out water from the pipe. Your answers to my questions on the closet flange and toilet supply hookup were very helpful. Thanks...

speedball1, FYI, when I posted " you said water is not a problem" I was referring to the original poster, not you. I learned a long time ago, after using a half a tank of propane on one fitting, that you just can't solder with water in the pipe :o

Shader,

" I learned a long time ago, after using a half a tank of propane on one fitting, that you just can't solder with water in the pipe."

So true!!