Need advice on raising shower valve height since I’m converting tub/shower to shower. I have no experience with sweating or soldering copper pipes. I’ve watched videos and dont mind giving it a try. My concern is risk of starting a fire. I’ll definitely have fire extinguisher nearby. Any tips/ suggestions? Or should I go with PEX instead- pros and cons, plus cost vs copper? Planning on keeping existing shower head but adding extra line for sprayer between valve and shower head. Any issues with fitting rectangular shower valve to existing lines? See attached pics,thanks.
If you haven't soldered before, get scrap copper and some fittings and practice. Always use the proper flux on both pipe and fitting. Heat the fitting outside of where you want the solder to go. Once the solder has melted, remove the heat. Keep a wet rag tied around the pipe about 10 to 12 inches away from the area heated to cool it down. It acts as a heat sink.
Use some sharkbite fittings to convert to PEX.
Some strong advice from experiance and unfortunate events:
1- do not use teflon tape on threads use thread sealer.
2-Cap off the shower arm and check it under pressure before closing up the wall.
3-Be very wary of the type of shower valve as in your picture. The stuff purchased on the internet is very unreliable and can be a major headache. I have had those type leak after testing, only to find out the reviews were riddled with the same type of complaints. It seams the threads are not cut to any regular US or Canadian standard. Stick with a Name brand sold at reputable store. ( I have had numerous issues with the brand that starts with DEL as well)
Soldering is so much easier than it sounds. There are tons of videos on the net that show exactly how to do it and it really is the best, most reliable solution. You'd be in a wide open space which is really a nice way to learn and you can get heat shields if you're nervous about torching too close to the wood framing. You'll need a torch. You can pick one up at any home store or plumbing supply store. Since you'll be new to this, I'd suggest a propane torch rather than map gas. Propane isn't quite as hot and is nice for learning. You can easily cut your supply lines and install the new valve where ever you want. You can clean off some of the old copper fittings and reuse them. Solder some of the fittings to the new valve before screwing the valve in place since you can move the valve around and then fasten the valve and complete the connections.
As @crip659 stated, leave an access panel on the opposite wall just in case.