Copper Pipe questions

I am remodeling the master bath. I have a shower pan installed, and will be installing tile walls. I am rerouting the hot and cold lines running to my new shower valve. The old lines don't match the new valve inputs, so I have to reroute them.

Question #1 - 45 & 90 deg joints I'm assuming decrease water pressure. Is there a limit to the number of joints I should add?

Question #2 - I have tried multiple times to sweat a 90 on the cold pipe inlet, but I can't get the solder to sweat into the joint. It just beads ontop of the joint, and rolls off. I have sweated copper joints before, and not run into this issue. The pipe was cleaned real good, fluxed real good too. I heated the pipe w/ the torch, until the solder melts when you touch it to the joint, but it just beads up and doesn't seep into the joint.

Are there any tricks to get the solder to sweat. Just to make sure I was doing things correctly, I tried to sweat the joint to a copper pipe I had removed from the shower, and it went on fine. I just cant get it to sweat on the inlet pipe that I already have installed...

Thanks much,

FlynHokie.

#1 Pressure loss, if any, will not be measurable. Use more than is necessary, the job will definitely look like hack work, but it will operate just fine.

#2 You have water in the pipe near the joint. When that water heats it turns to steam and is drawn to the joint. Basic rule in soldering, NO water.

Make sure that there's an open pipe or valve so the steam can escape rather than coming out the joint. At the joint, it must be dry, but if there's water nearby, the resulting steam from heating the pipe can still play hell with things.

Thanks much! I vacuumed the pipe out, and it worked.

For another pipe, I put solder on the coupling, then heated the pipe, and slid the coupling on the pipe. Solder then would sweat real nice into the joint.

Leak checked the work today, and it looks good! Soldering job doesn't look pretty, but it works. Thanks for the help.

Did you use flux on that joint? I'd like to assume you did, but sometimes we never know for sure. If you did not use flux, you have a bad joint

Yes, I fluxed it. Thanks for checking though! I'm new to this stuff so always love being checked to make sure I don't do something stupid!

FYI - I got the firring strips fully up on the shower wall. 6mil membrane ontop, then the hardi-backer up last night.

Tonight, I hope to get the drywall work finished in the bathroom (at least to the first mudding (it usually takes me 4-5 - cause I really, really suck at drywall work), and get the joints in the backerboard sealed.
Hopefully this weekend, I'll be able to start tile work.

You may find that taping the cbu seams works out better if you do it while tiling. As opposed to drywall where you are trying to hide the seam, in cbu, you are trying to reinforce it, so looks isn't important. If you tape it first, then tile later, you may end up with a 'speed bump', making it hard to get the tile flat. So, do it while tiling, and it works better.

If you were going for a surface waterproofing, such as RedGard, you'd need to pretape the seams, since that needs to have cured before the stuff is painted on. You don't want both a vapor barrier and a surface waterproofing, so it shouldn't be a big deal about the tape. Make sure you use the proper tape for the seams...it must be alkalai resistant tape made for use in mortar, not the same as drywall stuff (but looks like it is!).

I never thought of taping while tiling. You do end up with the speed bump.

I had done the office/kitchen/dining room this way -but I installed heater blankets ontop of that, so that's why I did the joints first.

If I wait to seal the joints till I tile, should I have any worries about the joint not being solid when the tile is installed?

Absolutely no problem doing it while tiling (well, you could catch it with the trowel, just takes a little finesse).

Went there to post tiling question on tiling 12" x 24" tile, and got responses telling me my sub-wall was wrong. Whew! Saved me some trouble down the road before I got tile up!

Check for Leaks

Did you turn on water to valves to check for leaks before CBU went up???

Yup, leak checked the copper pipe. Turned on, off, on off, left pressurized for 24 hours+, turned on and off throughout the day. It worked with no leaks.

will probably recheck, since I have to take the 1/4" CBU down and replace with 1/2". Doh!