Will there be a loss if I use some 1" pex to replace a leaking 1" copper? It is a small piece that is leaking maybe 1 foot

 

What do you mean "loss"? Are you asking about leaking or the difference in the ID diameter of the pipes?

 

Volume is proportional to internal diameter so the smaller the internal diameter, the smaller the flow. If the leak is small I would try soldering the pipe to cover the hole. I have drilled a 1/16 hole in copper pipe many times ( DC powered drill) to drain water from low spots and just solder over them when done. Assuming the internal diameter is the same for both copper and pex, I would think the cost of pex to copper transition pieces to be considerably more than 2 copper couplings. If you can't get the couplings without the internal stops (you need to slip them over existing pipe before inserting the replacement piece and soldering), get a semi-round file and file them off. Hope this helps..

 

Thanks for the reply but as I had to get working I decided to rip out some of the old tubing and replace the Ts and Valves with Sharbites. Went together extremely easy and worked perfect. Other than the Sharkbite version of everything is twice the size they do really work well. I had used them a few years ago and they worked great. No fluxing, sweating, just a quick push and done. Love it.
Oh and used the copper.

 

I agree with Bob, a 1 in. x 1 ft. copper “L” pipe is about 10 bucks. Two copper no-stop couplings @ approx $3 ea. and a little solder and you’re done in a half hour. No transitions. More reliable soldered connections. More consistent – and copper is the tops (unless your water is very aggressive).

But Sharkbites are a good choice if you don’t want to solder. I’m using one now that’s been on for years with no problems, and I’ve been forced to use them before (but your repair is a case in which it would be beneficial to know how to solder).

But - All IMHO!!