Is It Just Me - or are new unions hard to get leak-tight?
#1
05-22-11, 04:44 PM
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Is It Just Me - or are new unions hard to get leak-tight?
It seems like I really have to torque them, sometimes with large wrenches - particularly for larger ones, e.g. 1.25" or 1.5" unions in my hot-water heating system. Eventually, I do get them tightened. I wonder if a smooth, thin film of pipe dope on the mating surfaces would help? Maybe that would lubricate the sufaces and allow tightening with less torque.
With smaller unions, like 0.5" - 1", I don't seem to have this problem.
With smaller unions, like 0.5" - 1", I don't seem to have this problem.
#2
05-22-11, 05:08 PM
I wonder if a smooth, thin film of pipe dope on the mating surfaces would help? Maybe that would lubricate the sufaces and allow tightening with less torque.
I actually think the newer unions have less bevel on the nose, compared to older unions.
Mike NJ
#3
05-22-11, 05:35 PM
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Originally Posted by lawrosa
You would put it on the threads which alows you to turn the union more for a tighter seal.
Mike NJ
Mike NJ
#4
05-22-11, 05:48 PM
Would you smear a little dope on the mating surfaces
Thread Sealants
Mike NJ
#5
05-22-11, 06:49 PM
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OK, thanks. I have been using Ace Hardware's dope, which has teflon. After time, it tends to get a little gummy, but works fine. And when I get it on my pants, the wife can't get it off in the laundry - so it must be good stuff!
#6
05-22-11, 07:01 PM
I have always put never-sieze on the threads, that way all of the energy you put in the wrenches goes to torque instead of fighting threads. if you are trying to seal liquids or gases teflon on the faces will work fine. Do not use it with steam the steam will etch right through it and begin cutting away at the union and you will start over. If for steam use a thread lubricant only.
xbank
xbank
#7
05-23-11, 06:17 PM
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Thanks for all your help. My latest union is a new 1.5" Ward (USA). I've got it torqued about us much as I can physically do - and it's still weeping, slightly (with 12 psi boiler pressure). I have another Ward union, and may try it, along with your various suggestions.
Maybe I should try a Chinese union?
Maybe I should try a Chinese union?
#8
05-23-11, 06:59 PM
How big of wrenches are you using? For 1-1/2 inch you need two 24 inch wrenches and you DO need to pull pretty hard on them.
Just because Ward is a US company does NOT mean that all their fittings are made in US foundries OR that any particular one is not damaged. You need to carefully inspect the mating surfaces for any damage BEFORE using a union. I have never used any kind of sealant or "dope" on ground-joint unions or the coupling threads although I will use a drop of machine oil on the coupling threads.
Just because Ward is a US company does NOT mean that all their fittings are made in US foundries OR that any particular one is not damaged. You need to carefully inspect the mating surfaces for any damage BEFORE using a union. I have never used any kind of sealant or "dope" on ground-joint unions or the coupling threads although I will use a drop of machine oil on the coupling threads.
#9
05-23-11, 07:16 PM
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Thanks, Furd. I had been using one 24" and one 18" - to reduce the chance of breaking a foot if one wrench slipped off. I just now tried two 24s, and got a few degrees more turn. But, I'm an old, 185-lb weakling. We'll see how it works.
