Stainless threads galling.

[Pnutapper]

Hi all,

I have just become a victim of thread galling or "cold welding." I had never heard of this phenomenon before, but it is truly terrifying.

For those not in the know, it is when a thread that was screwed in just past finger tight, seizes when unscrewing. It will no longer move either way.

My beloved supplier has told me I should have been using an anti seize paste on the thread at time of installation. They are now my ex supplier as this has never before been necessary in 20 years of using their product line - they "forgot" to issue a tech bulletin when they started using a different grade of stainless steel for fittings.


Anyway, do any of the engineer types here at AHB know a method, or a contractor who can remove the thread from my manifold? I need to get the nipple out of the pipe manifold. It would be nice to get the other end of the nipple out of the block manifold as well, however this is not crucial. I am Melbourne based. Inner Nth suburbs.

 

[homebrewnewb]

aww man, that is terrible news!
side note, oooooh shiny.

 

[Pnutapper]

side note, oooooh shiny.

You should see it after I have cleaned it!

 

[homebrewnewb]

this isn't your personal gear is it? also, would it be safe to say it's friction welded not cold?

 

[Droopy Brew]

Cold **** in a can?? "Freeze your nuts off" or what ever it is called might be worth a go. Worst case it doesn't work and cost you $5.

 

[Pnutapper]

this isn't your personal gear is it? also, would it be safe to say it's friction welded not cold?

Nah, not mine... A customer I have had for around 15 years. Doing the same thing for them year in year out, and doing nothing different this time.

It could be called friction welding mate... Dunno. I know that aside from pressure, nothing could have caused any friction. Screwed the fittings in by hand, and just nipped them up a little with a spanner when they were finger tight. Certainly no bicep bulging torque applied to them.

 

[Matplat]

The curse of stainless!

When using stainless fittings, your ex-supplier is right, thread lubricant of some description is required. However some fittings will have a silver coating applied to one of the threads so nothing is actually required to be applied.

I must say I'm surprised to hear of this happening at low torque though, I normally find it occurs when there is some pressure on the thread to get things going.

DB has the right approach I reckon, alternatively, apply heat from a blow torch to the external portion of the thread while applying torque to the nipple.

 

[Mardoo]

I actually just experienced this for the first time this week, too. It galled me no end . Fortunately mine was just a retainer bolt on a 3-piece valve I cleaned for the first time. The threads were shocking! Rough as guts. I just cut the bolt off and got a new one.

 

[MHB]

There are lots of anti-galling products (collectively known as Silver ****), probably plenty of food grade ones to if you do a bit of looking.
Its really messy, sticky and if you get it on anything but the thread you will spend forever getting it off.
Mark

 

[Mr B]

Noting the cause, perhaps a little Penetrene may also assist?

 

[Pnutapper]

The curse of stainless!

When using stainless fittings, your ex-supplier is right, thread lubricant of some description is required. However some fittings will have a silver coating applied to one of the threads so nothing is actually required to be applied.

I must say I'm surprised to hear of this happening at low torque though, I normally find it occurs when there is some pressure on the thread to get things going.

DB has the right approach I reckon, alternatively, apply heat from a blow torch to the external portion of the thread while applying torque to the nipple.

And that is fine IF they advise long standing customers of a need to suddenly change installation practices because they have changed their manufacturing processes. For these types of fittings in this application, there has never been a need in the past to use a thread paste or lube of any description.
I am tossing up whether to use heat or cold. All the reading I have done since this happened suggests heat, as the two surfaces will expand and then contract at different rates allowing a window of opportunity to move the thread a little at a time.

 

[Pnutapper]

I actually just experienced this for the first time this week, too. It galled me no end . Fortunately mine was just a retainer bolt on a 3-piece valve I cleaned for the first time. The threads were shocking! Rough as guts. I just cut the bolt off and got a new one.

I see what you did there...

Trust me... I am feeling your pain

I am around 1900 bucks out of pocket on this little clusterfark!.

 

[Pnutapper]

There are lots of anti-galling products (collectively known as Silver ****), probably plenty of food grade ones to if you do a bit of looking.
Its really messy, sticky and if you get it on anything but the thread you will spend forever getting it off.
Mark
View attachment 108091

Yes, thanks. I have a food grade Loctite product I will be pasting away with, with great abandon in the future. My task at the moment is to get this bugger out. Unfortunately, these types of paste will not work retrospectively!

 

[Pnutapper]

Noting the cause, perhaps a little Penetrene may also assist?

When this happens, It is like a weld. I really doubt that any lubricant will get me out of this. I have tried a copper & lead lube carried in a very light penetrating oil that is usually my "go to" on seized threads, but it made no difference at all.

 

[Pnutapper]

Cold **** in a can?? "Freeze your nuts off" or what ever it is called might be worth a go. Worst case it doesn't work and cost you $5.

As noted above, I have been tossing up whether to apply heat or cold to see if it gets me out of this. I may test on some of the block manifolds I did manage to get out of the pipe manifold to see how it goes. (For those interested, this one in the pic is the last of 24. I got the other 23 out.)

 

[Matplat]

You could potentially use both heat and cold, to maximise the effect. Heat on the outside, cool on the inside. Applying heat to the outside will be easier given the shape of the components.

Try to apply heat evenly around the entire thread, and have an assistant apply constant torque on the nut while you are on the blow torch.

 

[Pnutapper]

You could potentially use both heat and cold, to maximise the effect. Heat on the outside, cool on the inside. Applying heat to the outside will be easier given the shape of the components.

Try to apply heat evenly around the entire thread, and have an assistant apply constant torque on the nut while you are on the blow torch.

Yes, this is the way I was leaning as well. The equipment is in a cool room with a nominal set point of 2.5°C, and I was initially thinking of introducing boiling water internally. After rethinking this, that is not clever as I have glass and rubber components in the manifold to consider as well. I will try introducing a sacrificial solution of glycol and water internally on a recirc at around -3°C, and put the propane torch on the thread today.

 

[homebrewnewb]

you're ganna need an extra pair of hands i reckon.

 

[Pnutapper]

you're ganna need an extra pair of hands i reckon.

All unnecessary leave has been cancelled! I don't know whether to give the apprentice the torch or the spanner. He will hurt himself either way.

 

[TheWiggman]

Stainless is a prick that way in that once it wants to pick up, you're basically snookered and efforts made to remove the nut compound the problem.
Penetrene - won't work, very effective on corroded nuts but not on bound stainless
Heat - worth a shot but not common practice that I have seen on stainless threads. If you don't have an oxy or similar don't go to extraordinary lengths to get one, as it probably won't work.

First option is to give it more force - put a bar on the spanner and use all your might to try and remove it. You'll damage the thread, but chances are if it's tapered you might be able to get away with it. Obviously tap the thread out after you're done.

If you absolutely must remove the component then the option is limited to cutting the nipple, grinding out the remaining nipple with a die grinder until you can see the female part of the thread, then manually trying to remove the thread remnants from the nipple. This will be frustrating and laborious and not guaranteed to work depending on how fused the threads are. This will certainly damage the thread in part and you'll need to run a tap through it with liberal cutting fluid.

Personally, I would cut out the bound socket and weld in a new one. $20 for the socket and a few hours' labour for a welder.

Anti-seize is absolutely a preventative solution to binding threads and there are sanitary options out there. I haven't used them in brewing before so can't recommend one beyond a web search.