fittingplumbing
I removed what I didn't realize was a compression fitting on a copper pipe for my kitchen cold water supply. Is it possible to reuse the compression fitting or do I need to buy a new one to replace it?
It looks like it's some kind of plastic. It took a tremendous amount of force to loosen, and a fairly cursory attempt at re-tightening resulted in a leak. Also, I assume I should wrap everything in teflon tape when replacing the connectors?
Swagelok fittings are different than compression fittings and will not work. Both are very different than flare fittings, which have a tapered nut and require the tubing to be formed in a "flared" taper at the end (using a special tool) and do not use a sleeve (ferrule). They also use a different thread:
You may find that regular compression fittings are labeled "tube" fitting in your locale. Home Depot Canada has them, they include a brass insert (for plastic tubing) and ferrule (for all tubing applications; for your purpose do not use them.
Why don't you take your connectors down to the local mom & pop plumbing / hardware shop instead of going to the "big box", they likely have the part and will be full of good advice as well.
here's the link to the part at HD: 3/8 comp. x 3/4 mip adapter
1-2 wraps of teflon tape, then use pipe dope. You can't go wrong. Too many wraps of teflon only distort threads.
Same theory as your idea of epoxy, but more 'plumbery'.
Best Answer
If it hasn't been tightened many times, it should be okay to reuse.
Clean off the mating faces thoroughly and don't use tape, putty, or anything else. And don't be gentle tightening: The seal is formed by forcing the surfaces together and "bending" them to mate.
Even with threaded steel pipes, it can take a day or two for the tightened fittings to form a good seal and they can drip at first. The essential observation is whether the drip rate slows hour by hour—if it does, it is probably okay and going to seal.
If it doesn't drip more slowly, try tightening a little more with water pressure applied until two consecutive small turns (1/8 turn) doesn't immediately decrease the drip rate.