Union joint leak

[shadylane]

I’ve been pretty proud of my soldering job, no vapor leak so far. But I cannot stop a little drop of liquid from dripping out this joint now and then,

Alcohol vapor is invisible. It's probably leaking more than you think.

[jonnys_spirit]

Ethanol is pretty explosive too when combined with O2 and an appropriate heat source..

Be safe!

Cheers,
j

[elbono]

Sounds like I have to replace it. It took me many tries to get decent at soldering so I’m really nervous about tearing it apart and doing damage to adjacent joints, but it sounds like that’s the only option. Thanks so much to everyone for their help.

I would try Steve Broady's suggestions first. Surfaces that match well should seal if you take care to get them aligned when assembling.

If you do replace and the nearest joint isn't extremely close wet rags should do the job. I soldered copper/copper joints about 1" apart with no more than that. Set it up with the union facing down, wrap wet rags around the nearby joint, heat the union until it falls off no need to heat the pipe. It all about where you put the heat.

[SaltyStaves]

Ya don't want or need any teflon tape on a union.

The exception to this would be stainless steel unions. Without PTFE tape, you risk galling of the two parts and never being able to undo them again.

[elbono]

If you replace the union, post some pics of the entire pieces so you can get the best approach. Someone probably has done similar jobs

[elbono]

Ya don't want or need any teflon tape on a union.

The exception to this would be stainless steel unions. Without PTFE tape, you risk galling of the two parts and never being able to undo them again.

The only thing I hate more than unions is threaded stainless! Lots of thick Teflon tape on those.

[SaltyStaves]

Ya don't want or need any teflon tape on a union.

The exception to this would be stainless steel unions. Without PTFE tape, you risk galling of the two parts and never being able to undo them again.

The only thing I hate more than unions is threaded stainless! Lots of thick Teflon tape on those.

Yeah it is annoying, but after 8 years, I'm used to it. I can hold my long liebig with one hand and turn the union nut with the other without watching a tri-clover gasket fall out and roll down the driveway.. To each their own.

[still_stirrin]

Screenshot from the video that goes along with the union. Still doesn’t look like the one someone posted above, but definitely has a better cup on the male end than mine.

It looks OK, although maybe from a “cheap” manufacturer.

What I do with copper unions is use fine sandpaper (120 grit or finer) and sand the surfaces of the cup & cone a little. Often when cast, those surfaces have anomalies (raised “bump”) and that keeps the mating surfaces from closing together. You can also put a layer of plumbers tape over the cone as well and it will help glide the surfaces together when tightening. You shouldn’t need to over-tighten the brass nut in order to get the surfaces to seal well enough.

I have several of the unions in service and none of them leak, or ever have leaked once I smoothed the surfaces with sandpaper or emory cloth. Try it.
ss

[OtisT]

Damn, lots of replies so quick. Lots of union experts on-line. I’ll add my two cents.

I think you should try what Steve Broady’s suggestion with the grit paste and pens. If that don’t work replace the joint. That looks like a really cheep union, with such a small union cup. Good luck.

[shadylane]

I would replace it with a Nibco or Mueller brand.

Plus one on that.
First because name brand unions are of higher quality and more readily available.
Second the OP will have more soldiering experience and do a better job.
Third, Ya can't mix and match between different manufactures, best to stick with one.

I vote against SS triclamp fittings that require soldiering or brazing.
Copper unions are much easier for DIY.

[jonnys_spirit]

I’m not proud but it works

Cheers,
-j

[higgins]

I use 2 1/2" unions on my setup below my shotty for directing the takeoff. I have TC fittings everywhere else.

On stripping runs when I angle my shotty I just use the straight section directed into a corny keg.
On spirit runs when the shotty is vertical I add in the L shaped piece.
My unions are NIBCO, and I've never had a leak with them.

[rbsc]

Surely I won’t get this lucky, but I am a bit hopeful. I have used Teflon tape since the very start because I thought it was just almost required. So my routine is to put the tape on, then angle the condenser where I want it. It has always fallen until I really crank down on the union with channel locks. But last night I got curious and assembled it with no Teflon. Hand tightened it and damned if the condenser didn’t stay perfectly in place. So maybe, just maybe, the tape was messing me up all along.

[Lc 1ace]

I use brass fittings.

[MooseMan]

Yeah it is annoying, but after 8 years, I'm used to it. I can hold my long liebig with one hand and turn the union nut with the other without watching a tri-clover gasket fall out and roll down the driveway.. To each their own.

You've been spying on me setting up my still, I knew there was someone watching!

[elbono]

Surely I won’t get this lucky, but I am a bit hopeful. I have used Teflon tape since the very start because I thought it was just almost required. So my routine is to put the tape on, then angle the condenser where I want it. It has always fallen until I really crank down on the union with channel locks. But last night I got curious and assembled it with no Teflon. Hand tightened it and damned if the condenser didn’t stay perfectly in place. So maybe, just maybe, the tape was messing me up all along.

I don't understand how the Teflon tape could do that but it sounds like it's seating properly now but wasn't before. If you have any leak issues now just do some of the lapping procedures and you'll be good to go.

[rbsc]

I’ve been pretty proud of my soldering job, no vapor leak so far. But I cannot stop a little drop of liquid from dripping out this joint now and then,

Alcohol vapor is invisible. It's probably leaking more than you think.

Somehow I missed a whole bunch of these replies, including this one. I obsessively look for vapor leaks every few minutes with a flashlight and mirror as I have read on the site to do. So is that pointless if you’re saying alcohol vapor is invisible?

[acfixer69]

Surely I won’t get this lucky, but I am a bit hopeful. I have used Teflon tape since the very start because I thought it was just almost required. So my routine is to put the tape on, then angle the condenser where I want it. It has always fallen until I really crank down on the union with channel locks. But last night I got curious and assembled it with no Teflon. Hand tightened it and damned if the condenser didn’t stay perfectly in place. So maybe, just maybe, the tape was messing me up all along.

I don't understand how the Teflon tape could do that but it sounds like it's seating properly now but wasn't before. If you have any leak issues now just do some of the lapping procedures and you'll be good to go.

Rincles in the tape can be enough for steam.

[elbono]

I’ve been pretty proud of my soldering job, no vapor leak so far. But I cannot stop a little drop of liquid from dripping out this joint now and then,

Alcohol vapor is invisible. It's probably leaking more than you think.

Somehow I missed a whole bunch of these replies, including this one. I obsessively look for vapor leaks every few minutes with a flashlight and mirror as I have read on the site to do. So is that pointless if you’re saying alcohol vapor is invisible?

Not when it hits a cool glass mirror the mirror will fog.

I've had liquid drips with no vapor escaping. All depends on where it's at how big a leak it is and the temperature around the leak.

[acfixer69]

A leak is a leak fix it.

[Saltbush Bill]

Iv'e never found a leak with a mirror yet......maybe it's something that only works well for you cold climate fellas.

[acfixer69]

Iv'e never found a leak with a mirror yet......maybe it's something that only works well for you cold climate fellas.

The mirror just needs to be colder then the condensing temperature. Not the best indicator but is valid. I've chased leeks for so long I can say I know I never found them all. With home distillation you need to find them all.

[elbono]

Ok, how do you find a leak?

I've had mixed success with any method unless it makes a drip, that's pretty easy. I smell alcohol anytime the still is running so that's not an alternative. The best results I got with a mirror was when it was cool but not cold enough to fog up from ambient humidity kinda touchy.

Got to find it to fix it.

[jonnys_spirit]

I’ve used a mirror, my glasses, and the shiny end of a spoon. They all work as long as they’re not like 180*F. Vapor will condense and fog it up.

A spray bottle of water might bubble a little but I probably wouldn’t use dish soap like you might to locate a leak in a tire.

Using PTFE tape on union joints also makes it a bit slippery for me too and I need to tighten it excessively. Grips better when it’s copper to copper.

Cheers,
J

[shadylane]

Rincles in the tape can be enough for steam.

Trust an Air Conditioner fixer to know how to prevent leaks.

My 2 cents worth on the copper union vs SS tri-clamps
Unions work great for 1" and under. It's cheaper, easier to connect to copper tubing.
No additional seals are needed, unions are lighter in weight and complexity than tri-clamps.

[shadylane]

Iv'e never found a leak with a mirror yet......maybe it's something that only works well for you cold climate fellas.

I've tried the mirror trick on known leaks and it didn't work very well.

[Steve Broady]

My 2 cents worth on the copper union vs SS tri-clamps
Unions work great for 1" and under. It's cheaper, easier to connect to copper tubing.
No additional seals are needed, unions are lighter in weight and complexity than tri-clamps.

While I’m not about to argue with someone with so much more experience than myself, I will throw my opinion into the pot as well. I’ve used both unions (that’s how I know about lapping them) and tri-clamps. I agree with the advantages shady mentioned for unions, and if I was going to build a rig that was always going to be assembled in one way, I’d probably use them again.

However, tri-clamps are more versatile which is a big bonus for me. I’ve assembled my still all sorts of ways, depending on what I’m making, what I’m making it in, where I’m making it, and what the product is going into. Having tri-clamps on everything and a small selection of spools, elbows, etc. has been a huge help. And I haven’t had any trouble finding ferrules that fit a range of copper pipes. If I remember correctly, 1” ferrules fit 3/4” pipe perfectly, and 1.25” fits 1” pipe almost as well.

[shadylane]

I'm not a fan of tri-clamp fitting that are 1" or smaller. SS is too difficult to attach to copper tubing.
2" and bigger, tri-clamps and SS spools are the way to go.

[googe]

When the still heats up, things will expand and the joint will do what its meant to.

[OtisT]

Ok, how do you find a leak?

I've had mixed success with any method unless it makes a drip, that's pretty easy. I smell alcohol anytime the still is running so that's not an alternative. The best results I got with a mirror was when it was cool but not cold enough to fog up from ambient humidity kinda touchy.

Got to find it to fix it.

Add some dish soap to a small glass of water. Use a brush to wet the joint area with the soapy water and look/listen for bubbles.