Di-electric

[fred1949]

I thought there was a post for di-electric pertaining to copper. I did a search but found nothing. My question is I know that you are supposed to use the copper straps to hold copper pipes but what about the screws that you use to fasten the straps with? In my home there are some metal and some are even stailess. What are you supposed to use? Also there has been copper joints sweated and it appears the flux was not wiped off. Will that hurt the copper pipes? Also I have been posting quite a bit. Sorry for asking so many questions.

[LazyPup]

First off Fred..Do not appologize for asking questions,,the only dumb question is the one you don't ask.

In regards to the nails or screws used on the hanger strap. Technically for electrolosis to occur it requires both a direct contact of dissimilar metals and water which works as the electrolyte. The concern about using galvanized strapping on copper pipes is because often the pipes will sweat from atmospheric moisture condensing on cold pipes. The likelihood of the metal strapping condensing moisture at the point where the nail or screw is would be slim to none, therefore the liklihood of electrolisis occuring at that point is negligible, and even if electrolosis did occur it would not present a serious problem to the integrity of the pressure piping. You are correct though, the copper hanger strap should be secured with copper nails, which are readily available at any hardware store. In fact, in some jurisdictions it is a local code requirement to use copper nails, but that is normally only a concern in coastal areas where the pipe and hangers are subject to salt spray in the atmosphere from the ocean.

Failing to properly wipe the flux off the joints will result in a blue or greenish corrosion to form on the joints within 3 to 6 months. Arguably it will shorten the life of the pipe and joint however there is no hard and fast evidence to determine how bad the effect will be. I have seen copper pipe installations where all the joints were almost completle obscurred with the blue/green and a white crystaline corrosion yet there were no leaks, on the other hand I commonly see copper pipe that was installed in the late 50's which show evidence of having wiped the joints and they still look good. If for no other reason, properly wiping a joint is simply too easy not to do it and the end result shows that your are a trained professional who takes pride in your work.

[fred1949]

Thank you once again for all your help.

Fred