air compressor output coupling

Mon May 30, 2011 5:42 pm

I picked up a used air compressor and the output threads from the regulator are loose and there is a small crack, so air leaks. Regulator is plastic and the fitting thread is brass. I looked at Loctite 242 blue, but it instructs not to use with plastic. Any ideas as to a thread sealant for this situation? I'd like to try to fix the small air leak rather than buy a new regulator. Thanks,


Re: air compressor output coupling

Mon May 30, 2011 6:41 pm

I have used PVC cement (glue) on threaded fittings as a sealer on water applications. Don't know how it would work with air. The downside is if you use a threaded plastic fitting then you might not be able to get it back out later. A metal fitting screwed into the plastic with some type sealer might work. LOCKTITE make one for gasoline available at auto parts stores. Just my 2 cents. Stan

Re: air compressor output coupling

Wed Jun 01, 2011 10:10 am

First, I would clean out the female plastic threads of any 'junk' that might be in them. Then I would try to put some type of stainless worm gear hose clamp around the cracked threaded area to help keep the crack from expanding as the brass male thread is screwed into it. I would use a liberal coating of 'Permatex' non-hardening sealant (#2 I think?) on the male threads. Do NOT apply too much pressure when screwing the metal fitting into the plastic (that is why you want to use quite a lot of Permatex to do the sealing). The plastic female threads probably broke in the first place because of over torquing. Rely on the 'goo' to do the sealing.

Re: air compressor output coupling

Thu Jun 02, 2011 12:40 pm

Also teflon thread tape woks quite well,---some guys frown on the stuff, but it does work and not a lot of over tightning required either! thanks; sonny