Is there such a thing as flexible tube or pipe for fishing through inner walls capable of replacing a very slow running hot water spigot? The old existing galvanized pipe is apparently clogged with years of corrosion, restricting the flow.

Frank, I don't know you expertise with sweating and flaring copper but what I use is 1/2" SOFT cooper.

This comes in 50 ft rolls and is flexable enough to push up walls. You may find shorter length at your DIY stores. It can be bent by hand but I would recommend using a "Tubing Bender" as it can kink easily if you don't have the touch.

You can use regular sweat fittings or you can use flair or compression fittings.

One note here is that 1/2" ID (inside diameter) and 5/8" OD (outside diameter) are the same.

Normal household copper is 1/2" ID so the fittings you would use are ther same.

When using soft copper, it will "Work Harden" if bent to much making it hard to handle. If you need a long piece, stand on the lead end as you roll it off on the floor. This will give a close to stright piece.

Some are starting to use a new flexible plastic tubing good for cold and hot water. I have not used it except for what is in my camper.

Hope this helps.

Thanks, WOW. That was a big help. Now all I have to do is head for Home Depot.

Yes , there is Frank....

Water lines for years and years have been a flexible nylon/plastic lines...and are quite successful...
Only problem is that they are small and do not carry big volume, all tho, maybe they have larger diameter lines now...I've been out of boation for about 12 years now...They use compression fittings and work out very well...
A decent hardware store should carry the parts...
Check it out....

Sorry for the mistakes on my first reply...Think I'm overdose on flu medicine right now....

I was talking about plumbing on boats Frank...Like I said, check it out...Its an easy way out.....