Copper pipe at the cabin we bought

[gear jammer]

I tore out the tub, toilet and vanity in the bath. I have them put back in and trying to use compression fittings. The pipe is old and I clean it before trying to put on the fitting. They don't
 seem to hold. I tighten them as far as I can and they still wiggle. What am I doing wrong. Old pipe and new fitting?

How hard is it to sweat on fittings?

[MKepke]

I tore out the tub, toilet and vanity in the bath. I have them put back in and trying to use compression fittings. The pipe is old and I clean it before trying to put on the fitting. They don't
 seem to hold. I tighten them as far as I can and they still wiggle. What am I doing wrong. Old pipe and new fitting?

How hard is it to sweat on fittings?

You can wrap the compression-olive and/or male pipe end in teflon tape to improve the fit. Pipe dope can be used the same way - just check the dope is suitable for potable water.

But sweating fittings isn't too hard normally. Get some pipe and fittings to practice with before tackling the real joints.

Another option is sharkbite fittings.

Of the three, sweating is the best long term if you have the option.

-Mark

[fredhargis]

I noticed there are fittings now available that already have the solder in them.....you clean the male end of the joint, stick it in the fitting and heat it up. While sweating pipe is fairly easy (cleaning is the big thing) the pre-soldered seem to take to a new level of piece-of-cake. Unless the pre soldered fittings have been discontinued, it's been some time since I looked for copper fittings.

[carwashguy]

 While sweating pipe is fairly easy (cleaning is the big thing) 

Clean, Clean, CLEAN is the key.  Apply some flux and heat the pipe using MAPP gas.  If you use a propane torch you'll get frustrated because it take too much longer to heat the pipe and joint.  
watch a few youtube videos for some tips but CLEAN CLEAN CLEAN!!! the pipe and inside the fitting!

[pprobus]

I tore out the tub, toilet and vanity in the bath. I have them put back in and trying to use compression fittings. The pipe is old and I clean it before trying to put on the fitting. They don't
 seem to hold. I tighten them as far as I can and they still wiggle. What am I doing wrong. Old pipe and new fitting?

How hard is it to sweat on fittings?

My recommendation would be to just use Sharkbite, or equivalent, and be done.  Just make sure you knock down any burrs on the outside of the pipe because the only real leak I ever had with a SB type fitting was with copper pipe and I found that a burr knicked the o-ring and caused the leak.  My only other leak was due to not pushing the pipe in all the way because I trimmed it too much and it blew out when I brought the system up to pressure, after loosening the pipe hangars to give me slack to push the fitting on all the way on that one side (the other two held fine) I have not had an issue since, its been 3 years (I did re-arrange some of the pipe hangars to keep from stressing the pipe.  Since this second case was in my compressed air piping and SB fittings are technically not recommended for CA, I will not go into whether they are appropriate for such use or not.  

There is one thing about these fittings that is both a strength and at the same time a weakness.  These fittings do not give you a rigid connection in that you can rotate the fitting even though it is fully seated, which makes changing the direction you want the pipe to run easy, however, if you need a rigid connection for a hose bib to screw into, to hook into a sink, etc. you need to add blocking to your framing to screw additional pipe anchors or a specific fitting to (there is a SB fitting that offers a 90 degree elbow that has a female thread outlet and a built-in area with screw holes to support the fitting).

[Flat Lander]

From my experience of using compression fittings, it sounds like there is a size difference, using a 1/2" fitting on 3/8" copper. Just tossing it out there.

[arthropod98]

I tore out the tub, toilet and vanity in the bath. I have them put back in and trying to use compression fittings. The pipe is old and I clean it before trying to put on the fitting. They don't
 seem to hold. I tighten them as far as I can and they still wiggle. What am I doing wrong. Old pipe and new fitting?

How hard is it to sweat on fittings?

it's really not difficult . . . as was mentioned, practicing is definitely recommended.

if you've got the clearance to get to things, i'd sweat 'em.  

[crokett™]

If you don't have the tools already (torch, solder, etc) then the sharkbites are going to cost the same and be much easier to do. If you only plan to do this once or twice then I'd get shark bites and be done with it.

[blackhat]

I’d probably do just enough soldering to put PEX adapters on what has to stay and crimp PEX for all the replacement stuff. In fact, that’s exactly what I’ve done dozens of times.

[EightFingers]

Beware putting Shark bites on old copper....