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Question about threaded unions

Posted: Tue Jun 13, 2017 7:38 pm
by Plc Ryan
I recently ordered some fittings from a local plumbing supply place and in my order were a few different sized threaded unions. When they came in some were copper and brass as are most that I have seen before and the others are all brass. Just wondering if either or both of these are safe to use?
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Re: Question about threaded unions

Posted: Tue Jun 13, 2017 7:43 pm
by yakattack
Both look new. Follow simple pickling procedure on both and you should be fine. Check packages to make sure they are low lead brass or lead free brass. If your further concerned you could coat all the brass in the vapor path with solder. But that's just way overkill in my opinion.

Yak

Re: Question about threaded unions

Posted: Tue Jun 13, 2017 10:14 pm
by Saltbush Bill
You can buy stainless ones for about the same price.

Re: Question about threaded unions

Posted: Wed Jun 14, 2017 4:29 pm
by cob
all copper is also about the same price. the nut is brass but the other two pieces are copper.

Re: Question about threaded unions

Posted: Wed Jun 14, 2017 4:50 pm
by Truckinbutch
cob wrote:all copper is also about the same price. the nut is brass but the other two pieces are copper.
That is my choice . The brass compression nut is never in contact with vapor .

Re: Question about threaded unions

Posted: Wed Jun 14, 2017 4:54 pm
by ShineonCrazyDiamond
Truckinbutch wrote:
cob wrote:all copper is also about the same price. the nut is brass but the other two pieces are copper.
That is my choice . The brass compression nut is never in contact with vapor .
I give the seat 1 or 2 wraps of plumbers tape, cheap insurance against contract and leaks. Keeps from sticking tight, too

Re: Question about threaded unions

Posted: Wed Jun 14, 2017 8:17 pm
by cob
ShineonCrazyDiamond wrote:
Truckinbutch wrote:
cob wrote:all copper is also about the same price. the nut is brass but the other two pieces are copper.
That is my choice . The brass compression nut is never in contact with vapor .
I give the seat 1 or 2 wraps of plumbers tape, cheap insurance against contract and leaks. Keeps from sticking tight, too
if they weep a little, lap them a little with some toothpaste and they seal quite well.

Re: Question about threaded unions

Posted: Thu Jun 15, 2017 8:22 am
by The Baker
cob wrote, "if they weep a little, lap them a little with some toothpaste and they seal quite well."

God, what that stuff must do to your TEETH!

Geoff

Re: Question about threaded unions

Posted: Thu Jun 15, 2017 4:39 pm
by nuntius01
they should be fine. if you got them from a plumbing supply house i'm sure the brass is no lead. you can use teflon tape too, instead of tooth paste. not as messy. remeber, that they should go threads to seat with the flow.

Re: Question about threaded unions

Posted: Thu Jun 15, 2017 4:59 pm
by OtisT
nuntius01 wrote:. remeber, that they should go threads to seat with the flow.
Hi Nuntius. Just asking for clarification on this. Does this mean that the end with the nut is the down stream piece and the bare threaded end is upstream?

Re: Question about threaded unions

Posted: Thu Jun 15, 2017 8:37 pm
by cob
nuntius01 wrote:they should be fine. if you got them from a plumbing supply house i'm sure the brass is no lead. you can use teflon tape too, instead of tooth paste. not as messy. remeber, that they should go threads to seat with the flow.
toothpaste is only recommended as a LAPPING COMPOUND for the seats not a sealant.

all my lapping compounds are petroleum based and not food grade.

toothpaste contains very finely ground calcium carbonate, is obviously food grade,

and will work well as a lapping compound.

I don't use brass, I won't use brass.

no amount of pickling will change brass into stainless steel or copper,

and no amount of words (lead free) on paper or in other print media

will convince me that it is safe to use a product that some supplier

will tell you anything to get you to buy. to much new old stock out there

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 6:01 am
by aircarbonarc
Saltbush Bill wrote:You can buy stainless ones for about the same price.

+1! Go stainless!

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 4:09 pm
by nuntius01
yes you have that correct on threads upstream. doesnt normally matter. however if you have it in a horizontal or any back pressure ypu may see it try to weep out of the joint.

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 4:30 pm
by MichiganCornhusker
I bought 1" tri-clamps on eBay pretty cheap. 3/4" copper slipped right in, no tape, no threads, no wrenches!

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 4:52 pm
by OtisT
nuntius01 wrote:yes you have that correct on threads upstream. doesnt normally matter. however if you have it in a horizontal or any back pressure ypu may see it try to weep out of the joint.
Thanks nuntius. I use a 3/4" copper union with brass nut in a horizontal config, and apparently I have it in backwards. Oops!

I'll keep a close eye for any weeping and switch it if it gives me any trouble.

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 5:42 pm
by nuntius01
try teflon tape first. its cheap and usally will fix it

Re: Question about threaded unions

Posted: Fri Jun 16, 2017 6:15 pm
by Truckinbutch
Another word to the wise regarding unions . Don't dry fit an entire run and then solder everything in place unless you are a pro .
Vertical unions have a way of becoming soldered solid . (Don't ask me how I know this . :oops: )

Re: Question about threaded unions

Posted: Mon Jun 19, 2017 4:26 am
by Plc Ryan
Thanks for all the info guys. I pickled them and soldered them into my build. I will definitely be wrapping my threads in Teflon tape as well. I would have loved all copper or stainless but the place couldn't bring them in. Could have ordered online I suppose but but didn't want to get hit with more shipping since these guys didn't charge me any and it's where I bough my copper.

The build is coming along well I will post some pics in my build thread soon. Got it all together and did my vinegar run to find one tiny pin hole leak on one of the unions. Haven't soldered brass before guess it take a lot more heat to really draw in the solder. Oh well I'll pull it apart and fix it and re clean away.

Re: Question about threaded unions

Posted: Mon Jun 19, 2017 1:15 pm
by SaltyStaves
I use a stainless union/nut and support my liebig with an adjustable microphone stand. I only hand tighten the union, so I don't need tools to undo it. Haven't used teflon tape and don't get leaks.