Sealing air lines

[OllyK]

Spent the evening messing about with the compressors, adding quick connects and couplings (PCL) to lines and the compressors. Trouble is, it sounds like a vipers nest. I've put 3 or 4 turns of PTFE on the threads before doing them up as tight as I can with spanners but it's still hissing away. Does anybody know of anything better to use than PTFE, I was pondering on silicone or decorators caulking. Anybody got any bright ideas?

 

[oddsocks]

I've used Boss green jointing paste together with PTFE tape and that worked on mine. Spec focuses on water (I bought it for plumbing compression joints) but it goes to 7bar

link

 

[mickster]

As a former mechanic with most of the types of airtools ever produced, I have had some experience with PCL connectors. As the threads have a slight taper, the tighter they are bound, the chances of leakage decrease, but usually not on the first assembly.

I used to tighten, loosen, then re-tighten the couplers a few times to get a gas-tight seal without any PTFE or sealer, because you don't want any of that going through to the rotor & jamming the vanes.

HTH,

Mick.

 

[Another Dave]

Loctite Air Brake Sealant.

Great stuff. 25 years I've used it on commercial air tool installations and never a problem.

Dave.

 

[white_sw]

I used liquid ptfe on all my BSP fittings and not one leak... It's not cheap, but sure does work and is really easy to use. I used the 50g bottle which still has 1/3 left. I have 6 outlets dotted around my workshop of which all are BSP PCL quick release fittings.

http://www.toolstation.com/search.html?searchstr=34357

Cheers,
Sam

 

[OllyK]

Thanks for the responses, I'll try the no sealer approach first and if that doesn't cut it, I'll try out some of those mentioned above!

 

[Hitch]

I usually put a few turns of the gas grade ptfe then screw it in tight.

Im wondering if you have a slight mismatch on the threads...?

Perhaps the difference between BSP and NPT. I wish theyd just make stuff standard! :roll:

 

[Woody Alan]

I have seen on other forums trade plumbers/heating engineers complain about cheap PTFE tape. I usually wind loads around fittings such as radiator tails and have tested up to 7 BAR and still get leaks. I think you need to use more tape more elbow grease. I would also suggest as someone else did, the gas grade tape it is much thicker tape.

Cheers Alan

 

[jonny boy]

I would re-check the thread sizes, i've never had any leaks after sealing with ptfe tape and it should be the right thing for the job in hand. It is the threads that are leaking isn't it?

jon.

 

[Woody Alan]

I've just re-read OP and realised it said hissing not leaking, the leaks I have had can only be detected by pressure test and micro leak test spray, so you must have some sort of mismatch.

Alan

 

[carpenteire]

Gas grade tape (yellow) in colour is good stuff I reckon. As already suggested I don't think you should be using a compound on those joints and I wouldn't rate the Boss Supergreen anyway. If I'm using compound on regular plumbing I use an American paste called LACO which is PTFE based.

 

[OllyK]

Been re-doing things with liquid PTFE over weekend and it's massively improved.