# Galvanized Compression Fittings ?



## BigMikeB (Aug 1, 2007)

KillerToiletSpi said:


> BigMikeB said:
> 
> 
> > No I did not, as a dielectric union does not do that, it is merely thought that it does. Even with the presence of a dielectric union you still have two dissimilar metals and an electrolyte to carry the charge, the fact that they are not in contact does not greatly reduce the problem.
> ...


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## BigMikeB (Aug 1, 2007)

*The Most Effective Method of Preventing Electrolytic Deterioration*








Insulated against galvanic corrosion
Breaks the flow of current to prevent stray current corrosion
All HART Industrial Unions are precision machined
Tailpiece coated with a tough baked industrial thermo-setting epoxy, bonded directly to the metal
Manufactured in all standard metals or combination of metals
Teflon shoulder gasket for extra wear resistance
Insulating properties - exceeds 500 volts dielectric resistance
Specify prefix letter "D"
Example D-3131-5-V-316 (see the "How to Order" page)
Note: Tailpiece side must be FNPT - screwed, however, threadpiece side can also be socketwelded, sweated, buttwelded
Tailpiece side must be threaded otherwise the welding torch would burn off the bonded-on insulation which makes it dielectric


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## KillerToiletSpider (May 27, 2007)

BigMikeB said:


> KillerToiletSpi said:
> 
> 
> > A dielectric union seperates piping of different metals, by means of plastic washers holding the metals apart. Yes the fact that the metals don't touch cuts down on electrolysis.
> ...


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## BigMikeB (Aug 1, 2007)

If you put two metals together in water, one of them corrodes to protect the other. This is known as electrolysis. The action of a sacrificial anode rod, and that of a battery, are both examples of beneficial electrolysis. However, usually in plumbing, electrolysis is something you want to avoid, especially in connections, since it means that the corroding part is eventually going to leak. 
To prevent plumbing electrolysis, dielectric connections are used to separate dissimilar metals.


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## KillerToiletSpider (May 27, 2007)

BigMikeB said:


> If you put two metals together in water, one of them corrodes to protect the other. This is known as electrolysis. The action of a sacrificial anode rod, and that of a battery, are both examples of beneficial electrolysis. However, usually in plumbing, electrolysis is something you want to avoid, especially in connections, since it means that the corroding part is eventually going to leak.
> To prevent plumbing electrolysis, dielectric connections are used to separate dissimilar metals.


Tell that to the CDI researchers, they will laugh at you.


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## BigMikeB (Aug 1, 2007)

KillerToiletSpi said:


> BigMikeB said:
> 
> 
> > I am merely repeating what I was told by the researchers at the Copper Development Institute, I have looked into all forms of fighting electrolysis in plumbing systems in an attempt to get copper pipe approved for use in some high rises. The dielectric union is always the first place in the system that a leak occurs in, because it does not offer the protection many believe it does.
> ...


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