What to seal air compressor fittings with?

[mrsilv04]

I had to replace the control unit on my air compressor. Now I have 4 threaded fittings to re-seal.

It looks like they used a hard, clear liquid (like lacquer or clear nail polish) on the threads at the factory. Is that an option?

I'm not a big fan of old-school thread tape, because I have lousy luck with it.

What else out there should I consider using?

First post since the change over, we'll see how this goes...

 

[cb_13]

They make a teflon paste that is similar to the thread tape. That's what we used on certain front cover bolts on 3.0 vulcan engines.

 

[exranger06]

Hercules Real Tuff thread sealant https://www.oatey.com/products/hercules-real-tuff-268158926
Available at Home Depot in various size containers. I've used it on air compressor fittings and it has no problem holding in 175 psi. I've also had bad luck with teflon tape. This stuff is 1,000x better.

 

[JC1]

You could try pipe dope. I had to do that for my air reel connection that was leaking. Sealed the leak and no more leaks.

 

[Fitter30]

Anaerobic pipe dope doesn't matter what brand

 

[BlueOvalFitter]

RectorSeal Tru-Blu or Leak Lock pipe dope.

RectorSeal Tru-Blu

Features Stays flexible - designed for areas of high vibration and thermal expansion/contraction Contains PTFE Brushable from 20 degree F to 140 degree F. Excellent as a gasket adhesive on flanges. For use with potable water. Lubricates and protects threads, lead free and contains no...

rectorseal.com

Highside Chemicals · Leak Lock

Leak Lock is a state-of-the-art high strength, pipe joint sealant consisting of chemically resistant film formers, plasticers, reinforcing fillers and solvents .

www.highsidechem.com

 

[ABN_CBT_ENGR]

I had to replace the control unit on my air compressor. Now I have 4 threaded fittings to re-seal.

What pressure is expected on these?

Same or dissimilar metallurgy? ( plated or coated fittings?)

Are all threads in good condition?

Are these pipe or other type of thread?

 

[mrsilv04]

I ended up disassembling all of the connections, thoroughly cleaning them with a brass wire brush, and a rag with some acetone.

I then carefully gave each fitting three wraps of teflon tape, being careful to wrap it in the direction that the fitting would be threading in. Then, I applied a thin coating of Rectorseal dope, just to the point where it filled up the threads. I threaded all of the fittings in, snugged them up good, ran the compressor up to pressure, and sprayed all of the connections with some cheap glass cleaner.

I found two problems after re-sealing all of the connections. The pop off valve was ever so slightly bleeding off at anything over 100 psi. It was rated at 140psi, as is the tank. So, it was replaced with another valve rated at 140 psi. The new control stops the compressor at 120 psi, which is right where I want it.

The other issue was the connector at the end of the hose had a slight leak as well. That fitting hasn't been disturbed for years, but it was redone using the same procedure. Also, I drained all of the condensation out of the tank.

Now, the tank won't drop below 115psi no matter how long it sits. I can live with that.