Tape on hydraulic connections?

[whistlepig]

Yes on the cure time. The fitting should be clean and oil free as much as possible on application. Loctite 567 was created for high pressure industrial applications. Primarily for industrial assemblers fitting hydraulic connections and forgetting to tighten them all the way. Even with the NPT threads not tightened Loctite 567 will seal. Loctite 567 isn't a patch. Its a permanent fix if applied properly and allowed to cure.

 

[Chilly807]

We use 567 at work, I used it on my air compressor fittings at home. I was surprised when it leaked when I put air to the lines right away, then realized I hadn't allowed for cure time. It's great stuff if you don't happen to have anti seize on hand, as long as you don't have extreme temperatures to deal with.

Sean

 

[mmurphy]

I have never used locktite on hydraulic fittings.
I have used the locktite on 230 degree temp feed line to boilers that was running at 125 psi. It did not work any better then tape and paste together for me. But, it does bring up the fact some times if you over tighten, you damaged the fitting before even starting.

 

[Rocwin]

A lot of people don't realize there are many types of paste, so they use the first they see, (of course they used it improperly) had a bad experience and stick to tape.

The type of paste most people should be using does not cure, its a lubricant, not a sealant. If it gets into the hydraulic system it should go through any valves without an issue.
The cure type of paste is not meant to be used in maintenance fittings. You set the fitting, let it cure, then test. It is an utter disaster to remove, those are fittings you throw away.

 

[MtnViewRanch]

A lot of people don't realize there are many types of paste, so they use the first they see, (of course they used it improperly) had a bad experience and stick to tape.

The type of paste most people should be using does not cure, its a lubricant, not a sealant. If it gets into the hydraulic system it should go through any valves without an issue.
The cure type of paste is not meant to be used in maintenance fittings. You set the fitting, let it cure, then test. It is an utter disaster to remove, those are fittings you throw away.

So the type of paste that you are suggesting that should be used is one of 2 types.

A paste that is a lubricant only, I assume to make the parts go together easier, but has no sealing purpose or a paste that does get hard and does seal, but if for some reason those 2 fittings need to come apart for some reason, then you should just throw those fittings away and use new fittings because it is so difficult to clean the hard paste off.

I think that I will stick with using the tape, I seem to have good luck with it.

 

[whistlepig]

So the type of paste that you are suggesting that should be used is one of 2 types.

A paste that is a lubricant only, I assume to make the parts go together easier, but has no sealing purpose or a paste that does get hard and does seal, but if for some reason those 2 fittings need to come apart for some reason, then you should just throw those fittings away and use new fittings because it is so difficult to clean the hard paste off.

I think that I will stick with using the tape, I seem to have good luck with it.

Loctite 567 is both a sealer and a lubricant. I have taken fittings apart sealed with Loctite 567. A couple of swipes with a wire brush and a rag dampened with mineral spirits are all that is needed to reuse the same fittings. Its not a hard paste and easier to remove than ribbon dope in my experience. The negative side is the cure time. Paste is not a 5 minute fix. Cure time must be allowed. I much prefer the paste. It covers a lot more sins in the NPT threads, both male and female, than ribbon dope does. I have never had to redo a fitting or had fitting leak after using 567.

 

[J_J]

Opinions vary, and here is mine.

There are those that think a lubricant should be used on threads. Not true as the threads are being distorting in an NPT fitting, and a lubricant allows more torque, than should be applied, further distorting the threads. A sealant does just what it says, seals in the voids caused by the distortion. Limited reconnect capability.

A lubricant is usually used on metal that have a tendency to gall like stainless steeland certain other metals.

 

[whistlepig]

Opinions vary, and here is mine.

There are those that think a lubricant should be used on threads. Not true as the threads are being distorting in an NPT fitting, and a lubricant allows more torque, than should be applied, further distorting the threads. A sealant does just what it says, seals in the voids caused by the distortion. Limited reconnect capability.

A lubricant is usually used on metal that have a tendency to gall like stainless steeland certain other metals.

On galling it depends on the metals (non lubricated):

Stainless to stainless galls is by far the worst.
Mild steel to stainless second worst.
Mild steel to mild steel the third worst. Very close to mild steel on stainless.

Non galling (non lubricated):

Cast iron to stainless doesn't gall.
Cast iron to mild steel doesn't gall.
Cast iron to cast iron doesn't gall.
Brass to anything doesn't gall.
Aluminum bronze to anything doesn't gall.

I have very limited experience with aluminum.


I am the machinist that had to remove the broken bolts and fittings that galled.

 

[Rocwin]

For us it is about economy, is it worth us having a mechanic @$90/hr cleaning adapters or the under $2 cost of a typical adapter? Being in service no customer is willing to wait 24 hours for anything to cure, downtime is money and is just not acceptable. Using a lubricant might not be necessary, but it is a bit of insurance towards preventing disassembly after testing if a leak does happen.