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Union surface just metal to metal?

sunlight33
sunlight33 Member Posts: 301
The contact surfaces on the Viega union fitting is just metal to metal, I presume this is going to be watertight after tightening but no gasket is needed?

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,851
    Yes, metal to metal, no gasket needed. The Viega unions are usually very good high quality and don't leak. They shouldn't for the price they get.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,091
    A modern marvel of precision engineering! And they had metal to metal unions even before NASA was around! Check out that radiator valve
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • Jamie Hall
    Jamie Hall Member Posts: 15,742
    Just remember that a union will not correct for misalignment, either laterally or vertically or angularly. And don't be a gorilla when you pull it together!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    PC7060
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,091
    @Jamie Hall... I have used Gorilla in the past for many things. Some even use it for hair care.
    Have you tried their Bikini Wax product?
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • Jamie Hall
    Jamie Hall Member Posts: 15,742
    As they used to say about duct tape... it's like the Force. It has a dark side and a light side, and holds the universe together...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 14,753
    metal to metal unions usually have some taper or bevel, not a flat surface. If it is flat to flat, I think a gasket would be needed?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JUGHNE
    JUGHNE Member Posts: 8,263
    Always had good luck with brass/brass unions.
    Stainless steel on the other hand can be tricky.
    Steel is hard unlike brass that might conform just a little to the match up.

    Gas and water meter spud unions use a flat washer gasket.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,851
    @JUGHNE

    Copper sweat unions are problematic. The cheap copper-copper ones if you put 10 of them in correctly a few will drip. The you dope them and hope for the best.........does not make me happy. I usually don't dope any unions unless I have to but like using never seize.

    On copper I have much better luck with the Nibco where 1 end is copper and the other end is brass, forgot the # Those are pretty good.

    Of course, because the are more $$$$ some supply houses don't stock them. Big Box forget about it.

    The propress unions are big $$$$. I don't think I have ever had a leak on one of those. Quality counts
  • JUGHNE
    JUGHNE Member Posts: 8,263
    Those NIBCO brands have been pretty good.
    I have salvaged some old (30-40 years old) that performed well.
    I did learn to not assemble the unions before soldering....a little solder in the wrong place will ruin your day.
  • pecmsg
    pecmsg Member Posts: 1,964
    JUGHNE said:

    Those NIBCO brands have been pretty good.
    I have salvaged some old (30-40 years old) that performed well.
    I did learn to not assemble the unions before soldering....a little solder in the wrong place will ruin your day.

    Again a little never seize goes a long way in preventing that!
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,851
    edited April 1
    @JUGHNE

    Tell you the truth in my younger days I soldered many together :) NIBCO makes the good ones and the cheap ones @pecmsg that sounds like a good trick with the never seize.

    I always solder them when apart just to avoid that problem.

    Finally learned to much (or how little) solder to use
  • mattmia2
    mattmia2 Member Posts: 2,869
    I had to wipe the solder off of the taper of one...

    I had a 1" black iron union from home depot that i had to replace with one from the real hardware store because it was leaking. A lot of times the iron ones have a brass seat in them.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,851
    @mattmia2

    You only had to wipe the solder off one?? Your better than me!! :)
  • mattmia2
    mattmia2 Member Posts: 2,869
    I have only used a couple dozen...
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