Dissimilar Metals in Air Setup

[MNiceGuy]

I'm planning to install copper air line in my garage this weekend and considering the cost of some of these materials, I want to make sure I get it right the first time. This is my first mixed metal plumbing so I want to make sure I'm paying attention to which metals have direct contact with each other.



Here's my sketch of what I want to do. The copper is there to take the full tank pressure (175psi) to the regulator where it will be reduced for connection to a Maxline setup. I chose copper for its cooling benefit as well as having a little extra piece of mind for the pressure involved (3/4" Maxline is rated to 200psi @ ~70*F). This also allows me to place the regulator at a more accessible location.

Based on my drawing, are there any areas where I should do something differently?

 

[fitter30]

Use unions on both sides of regulator for removal. No air or auto water drains before reg or shut off valve from tank?

 

[MNiceGuy]

Use unions on both sides of regulator for removal. No air or auto water drains before reg or shut off valve from tank?

The regulator is a filter/regulator combination. There is a ball valve on the tank but then nothing between it and the regulator.

 

[rlitman]

You will not have issues with dissimilar metals in air service. Relax.

 

[65ranchero]

You will not have issues with dissimilar metals in air service. Relax.

Unless you run a current through it

 

[GrayFlattop]

No issues whatsoever. Brass is ~70% Copper, so they are basically the same.

Steel, about the only issue there is that will rust given enough time, or a lot of water in the air. You should be ok for the first 20-30 years though. Or just by brass ******* if you are that concerned or if your air is wet

 

[MNiceGuy]

You will not have issues with dissimilar metals in air service. Relax.

Is the rule generally when there is water present (electrolyte)? I have seen water cooling setups where someone combined an aluminum radiator with a copper heat sink and it didn't end well.

 

[ericm]

Aren't the fittings like the hose from the tank and the regulator plated?

 

[ycgoat]

You could put an ati-oxidant or antiSieze at the dissimilar joints

 

[65ranchero]

You could put an ati-oxidant or antiSieze at the dissimilar joints

Pipe Dope!

 

[ycgoat]

Yeh, I use pipe dope on plumbing, anti-seize on bolts, and ant-oxidant on electrical, but corrosion seemed best dealt with anti-oxidant. It may be any of them will work

 

[claymont]

I'm planning to install copper air line in my garage this weekend and considering the cost of some of these materials, I want to make sure I get it right the first time. This is my first mixed metal plumbing so I want to make sure I'm paying attention to which metals have direct contact with each other.



Here's my sketch of what I want to do. The copper is there to take the full tank pressure (175psi) to the regulator where it will be reduced for connection to a Maxline setup. I chose copper for its cooling benefit as well as having a little extra piece of mind for the pressure involved (3/4" Maxline is rated to 200psi @ ~70*F). This also allows me to place the regulator at a more accessible location.

Based on my drawing, are there any areas where I should do something differently?

Look up dielectric union.

 

[rlitman]

Look up dielectric union.

Don't do that. They may have their place in fire sprinkler systems and a handful of other niches, but you're asking for leaks in air lines, with no benefit.