Shower Stall Work

[Joey Arispe]

Hi everyone.

I'm replacing my grandfather's shower valve. I soldered the coupling and left a piece of a roof flashing rain diverter metal behind the pipe to keep the 2x4 from getting scorched.

Well, I soldered to the pipe to the metal. I can't get it out from behind the pipe now.

Will the steel corrode the copper pipe? Or is it okay?

331381

[Clint Baxter]

Steel contacting copper will cause corrosion. You should be able pop it loose. I wouldn't think the solder would hold it that well, round to flat like you have. If you have to, put the torch to the flashing to get it hot enough to break it loose. Just don't direct your flame directly on your coupling. Good luck

Clint

[Larry Frank]

It looks like it is galvanized steel. The only thing that might eventually corrode is the galvanized steel. If you can not get it off easily, do not worry about it.

It is like connecting galvanized pipe copper pipe....it is the galvanized pipe that corroded. If the piece of galvanized steel in your case corroded, what difference will it make....none.

[Pat Barry]

I think you really want to remove the galvanized sheet metal before you close that wall up

[Tom M King]

I don't know what's in solder these days, but lead and zinc are close enough that it's not a worry. I've seen stranger things in walls. If it really worries you, put some heat on the flashing while shaking it back and forth, and it will probably come loose without disturbing the pipe joint. At worst, you will just have to redo the joint, which isn't That bad.

For next time, the felt heat shields, sold in the plumbing aisles of the box stores, work really well. I've used them in some much tighter spots than that.

[Prashun Patel]

If you cannot lever that out with vise grips, then I'd reheat the metal sheet near the joint, just enough to be able to hammer the piece loose.

[Jay Nossen]

Agree with Tom on using a fabric heat shield in the future. I have a few of these (http://www.homedepot.com/p/9-in-x-12-in-Hands-Free-Heat-Shield-314002/100345508) floating around and have really liked them for tight spots like that.

[Chris Padilla]

If you can't removed the metal, is there room to jam some heavy cardboard/paper or plastic something or other to isolate the two metals? I'd hate for there to be some irritating noise generating by the two metals rubbing when that copper warms up and cools off a zillion times over the years and also it'll help with wear.

Ideally, try to remove it.

[Pat Barry]

I don't know what's in solder these days, but lead and zinc are close enough that it's not a worry. I've seen stranger things in walls. If it really worries you, put some heat on the flashing while shaking it back and forth, and it will probably come loose without disturbing the pipe joint. At worst, you will just have to redo the joint, which isn't That bad.

For next time, the felt heat shields, sold in the plumbing aisles of the box stores, work really well. I've used them in some much tighter spots than that.
If its actually just stuck together I wouldn't like the possible galvanic reaction between steel and copper even though there is a small layer of zinc or what not in between. Galvanized pipe connections to copper pipe use dielectric fittings to prevent issues.

[Morey St. Denis]

Reasonably confident in your work and that this area should likely now remain dry?.. Then you can leave that galvanized steel sheet metal in contact with the copper pipe. For any appreciable galvanic cell potential that would rapidly drive corrosion, requirements typically are two dissimilar metals of differing galvanic series potential wetted by a conductive electrolyte. Zinc and Copper are reasonably close in standard electrode potential amounting I believe to about only -0.3V. In molten form, these two readily alloy into brass. Another benefit for easing your concern is that conductive water pipes are typically grounded to earth. You may wish to check near the water main supply valve to confirm that this is the case here and that all supply line fittings leading to the bathroom are copper, bronze or brass without insulating bushings or plastic adapters. Since that difficulty appears to occur on the mixed water line leading to a shower head, you'll not experience condensation forming there. That copper pipe temperature will very quickly match or be above that of any entrained moisture. You may wish to put some flexible moisture sealant around the overhead wall penetration and check the fit of that shower escutcheon plate to better avoid any mild backsplash trickling down that particular pipe. You can also rest easy knowing that it's the Zinc that will function as the sacrificial anode with this coupling; the zinc would likely erode before copper. On the wild chance that we may have misread that brightly reflective plate and it's not galvanized sheet metal, but stainless or some unknown bright metal coating such as cadmium, then do try to jamb some plastic shim material between those two.

[Chris Padilla]

If its actually just stuck together I wouldn't like the possible galvanic reaction between steel and copper even though there is a small layer of zinc or what not in between. Galvanized pipe connections to copper pipe use dielectric fittings to prevent issues.In that case, reheat it and bang on it with a hammer to separate and then remove it.

[Morey St. Denis]

Properly done galvanized pipe to copper pipe connections do indeed utilize dielectric fittings to prevent issues between the wetted surfaces. On the exterior, nominally dry side, there also needs to be conductive clamps and a copper ground wire jumper across such a joint.

[Joey Arispe]

Thank you everyone for your advice, tips, and interesting information on the contact of solder/copper/galvanized metal. I took the torch and some channel locks to it and wiggled it out.

No leaks!

[Chris Padilla]

Glad to be of service, Joey! I always find it interesting how a (seemingly) simple question can get so many varied responses. :)

[Joey Arispe]

I completely agree! Go Broncos!