dielectric unions

amakarevic

1. the dialectric unions i got at ferguson have an orange rubber/plastic band (gasket ?) between the center nut and the copper portion. when soldering, is it normal/expected to burn/melt the rubber or is that supposed to be avoided ?

2. is the center nut supposed to be tight all the way with joint compund applied ? or does the above-mentioned rubber does that ?

i am using them to connect the new copper piping to the legacy heating radiator pipes that contain water. galvanized steel on the other side.

much obliged,

- a

majakdragon

The gasket should be removed while soldering. After the joint cools, reinsert it. The nut does not require pipe dope. I have always used Never-seez on the threads to make it easier to disassemble later, but it is not a requirement. The gasket makes the seal and seperates the two materials.

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amakarevic

what are Never-seez ?

thanks,

- a

Marlin

Anything with a gasket I try to pre-solder the piece that's going into it.

majakdragon

Never-seez is a compound the prevent corrosion from building up in the threads, including rust. Can be found in Automotive stores. It is also made to protect in high temperature environments to prevent galling.

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Marlin

I wouldn't use anything not specifically made for a potable water supply anywhere that it would get into drinking water.

majakdragon

Marlin, I agree but, you only apply it to the union threads, not on the face.

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Mike Swearingen

If I'm not mistaken, Never-Seeze is primarily made out of some blend of liquified lead and definitely should not be used where potable water can get to it. I normally only use it on engine threads, etc. Great stuff to prevent corrosion, especially in a heated metal environment, tho, and if used carefully, it should be OK in plumbing.
Mike

majakdragon

I honestly do not know what it is made from. I use the copper type most of the time. Only use a thin coating on plumbing threads (union threads only). I don't think it would be anymore dangerous than oil based pipe dope compound that is "squished" inside of the pipe when tightened.

__________________
If you have never made a mistake, you haven't done much.

Marlin

I hope pipe dope isn't toxic, I know I've gotten plenty of that into peoples water lines over the years.

mdlbldrmatt135

http://www.neverseezproducts.com/regulargrade.htm