How to seal fittings on compressor tank.

[conor1n]

Hello all,

(I am talking about the brass fitting that screws into the tank)

Quick one here. On my compressor there is a slight leak on the connection that threads directly into the tank and received the air from the motor head..

Part of the issue is the considering the solid pipe that feeds into it the fitting needs to stop at a specified position, meaning I can't just crank it until sealed.

I tried to fix it by removing the fitting and taping the threads with PTFE. But then when I closed it up again, the leak was worse than before. (Tested with soapy water).

When I removed the fitting I noticed some kind of compound in the threads that went hard. Was that thread locker, or is there some kind of compound I can get to seal the threads? Or is it a case of just using more PTFE?

My OCD is killing me when I know this is leaking and it having to run every time I turn it on.

Thanks a lot guys
Conor

 

[anto44]

I use this stuff on any threaded fittings like that

I've used normal thread lock in the past and that works just as well

 

[Hitch]

Loctite 577 will sort that.

 

[Trevorleach]

Any thread sealant should work.

 

[conor1n]

Hmm thanks guys, I don't have any thread sealant knocking around, but will use that if needed.

Now, just a quick silly question if you don't mind. Would RTV sealant work? The kind of stuff that's used as liquid gasket for car engine rocker covers etc?

Cheers

 

[Wildefalcon]

Liquid PTFE from a decent hardware store, or b&q.

 

[Erie Fred]

You are needing to "Clock" or "time" the fitting.
I have used RTV in the past.

Carefull, do not glob too much on, the fitting probably has a check valve down in the tank, so you don't want it getting on it.

 

[RWD3M]

Hi Conor,

Assuming that's a taper thread then Loctite 55 is my goto. It's like an industrial version of dental floss!

 

[indy4x]

I used liquid PTFE on mine, I'd stripped and painted the tank so all fittings went back in using that as its what I had kicking about

Purchased from Screwfix and intended for plumbing but has worked ok so far

 

[graffian]

Loctite 577 will sort that.

Or save money and buy the one with a T on the can, might be T2?
it came from a plumbers merchants and so far seems to work just as well as loctite.
I used to use loctite 565

 

[GRW]

I reckon Heldite might work (though not great for getting undone again. Great stuff for fuel pipe fittings.

 

[timgunn1962]

Flomasta Liquid ptfe from Screwfix is what I tend to use on pneumatic fittings now, even when someone else is paying. Used fairly liberally and being careful not to go too far and have to wind the fitting out to clock it, it doesn't seem any less effective than Loctite 577, which is what I used to use.

If the fittings tighten, it can be pressurized straight away. If clocking things means the threads don't tighten, I try to give it an hour before pressurising.

There is also a Flomasta anaerobic pipe seal, again from Screwfix, that will fill and seal the threads then set. I can't fault it and use it when I don't intend to have to take things apart again. The liquid ptfe allows for much easier disassembly.

 

[doubleboost]

Hemp and white lead used to be the stuff to use .
Ant modern pipe sealing compound will be fine .
We use Rocol Steam Seal on everything .
Including air .

 

[Ross365]

You don't say whether the leak is on the broken joint or the one with the spanner on it. The broken joint looks like a parallel thread, and that should seal on the flare/cone on the end of the tube; sealant of any kind should not be necessary on the thread of a parallel fitting and probably will not help (adding a little tape may help loosening it in the future.)

 

[MattF]

When I removed the fitting I noticed some kind of compound in the threads that went hard.

Did you remove all traces of the original sealant?

 

[maroon]

What is the washer like? Perhaps a new copper washer may help?

 

[Jack Ryan]

You don't say whether the leak is on the broken joint or the one with the spanner on it. The broken joint looks like a parallel thread, and that should seal on the flare/cone on the end of the tube; sealant of any kind should not be necessary on the thread of a parallel fitting and probably will not help (adding a little tape may help loosening it in the future.)

I agree. Anything with a tube and a nut is probably flared and thread sealing will have no effect.

Which connection is leaking and what sort of connection is it? Lift the nut for a photo or two.

Or is it the brass to tank connection that is leaking? That is probably tapered and will need sealing.

Jack

 

[conor1n]

Hi everybody..

Thanks for the input from you all.

I bought some liquid PTFE from Screwfix and it sealed it right up. I ran it up to pressure and powered off.. i've been turning it on over the last few days and not once has it kicked in to build pressure which means it's holding well. Fantastic!

Thank you all.