Soldering chrome plated copper? Other stop valve options?

[buckyswider]

Hi there, replacing a powder room wall-mount sink with a vanity. Previous plumber left me in a bit of a pickle. He converted the 1/2" copper stub (from crawlspace) to 3/8" chrome plated copper right at the subfloor, and ran the chrome all the way to the faucet (no stop valve....GRRRRR). And then the hardwood flooring crew came along so the existing copper/chrome joint is pretty much buried. with only about 3/4" of the coupling (which, oddly, appears to be chrome) above the floorline. Due to some recent HVAC installs in the crawlspace, access to the pipes from underneath is extremely challenging, so I need to figure out how to do this from the top.

Now my issue is how to connect a stop valve to the chrome line. I made a DIY blunder of not knowing/remembering that 1/2" OD is 3/8", so I bought 1/2" compression stop valves- including a cool dual valve for the cold, 3/8" for the sink and 1/4" for the fridge, which connects thru a wall (this is a kitchen powder room).

My plan was to use a 3/8"-1/2" sweat reducer and use the compression fittings on 1/2" copper. However, after about 10 minutes of scrubbing with #150 sanding cloth, all I'm getting is shinier chrome. Is there a better way to do this? Heavier grit? Can I use a sanding head on a multitool? Optionally, is there a way I can transition to 1/2" compression with some sort of 3/8-1/2 compression fittings? Sharkbites apparently also need the chrome removed, so that just puts me in the same boat I am now.

If I could get my hands on the plumber who didn't install a stop valve.....

Thanks!

 

[James Henry]

use a file.

 

[Sponsor]

 

[Reach4]

You can cut the chromed tubing, and insert a valve such as the Dahl
511-31-31

Compression on both ends.

 

[Tuttles Revenge]

I would avoid using a rotary tool with sandpaper.. you could gouge the copper leaving a divot where you could get a leak. Open mesh emory cloth (not sure thats the exact name) is what I use for something like that.. or a brush on 1/4" drill driver bit might take it faster and more uniformly.

This is an example.. does both inside the fitting and outside of the tubing.. on a drill mount.

https://www.grainger.com/product/2E...ucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231

 

[Terry]

How about a 3/8" comp by 1/2" copper pipe compressions stop?
3/8" OD by 5/8" OD for copper pipe and then you can do whatever you want.

 

[buckyswider]

Thanks everyone! I did try the multitool on a test piece and yep, I gouged it. So that's out. I'm afraid of the same fate with a file. That brush tool looks pretty neat, but pricey! Not sure if it would get the chrome off, though?

As far as fittings go: The issue I have is that the chrome pipe is 3/8" ID / 1/2" OD. And for the life of me I can't find a compression stop valve that size. They're all either 3/8" or 5/8" OD. But I could be missing it, as it's really hit or miss the way the valves are labeled (and/or my unfamiliarity with the naming conventions- OD, Nominal, etc.

I was planning on using this https://smile.amazon.com/gp/product/B00L3W12PQ/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 valve for the cold side, and even that uses two different conventions for three sides! But even if I can find a standard straight stop with 1/2"OD comp and the 3/8" on the sink side, I'll pivot and use another method (no, not a saddle valve!) for the fridge. But alas, 1/2"OD comp seems to be the rainbow unicorn of the stop valve world.

So in the absence of said mythical creature, I've either got to sweat to the chrome or venture down into the crawlspace, and shimmy over a 19" flex return duct in a 30" space and rebuild from the 1/2" feeds. And if I think I have to go back too much for forgotten tools and supplies now, just wait until I have to crest that duct every time I need to get something else!!!

 

[Reach4]

See https://www.dahlvalve.com/products/mini-ball-valves/supply-stops/copper/supply-stops-511-32-31.php

Supply Stops 511-32-31 (Copper)
Product Type
Supply Stop
Description
1/2 OD Comp X 3/8 OD Comp
Material
Lead-Free Brass

 

[Terry]

1/2" OD is often called 1/2" nominal and they do make compression shutoffs in that size. I installed a ton of dishwasher supplies that were 1/2" OD in the 70's.

 

[buckyswider]

Terry, I do have that one triplex (see my amazon link above) that is "1/2" nominal" and it doesn't fit the 1/2" OD chrome- but it does fit the 5/8" OD "half inch" copper pipe. But thanks, since that actually makes me less embarrassed about my confusion, because it does seem that the naming conventions are in fact inconsistent!

Reach4, I found one place that allegedly stocks those dahl valves. I'll give them a shot! Because "OD" cannot be ambiguous, can it?