lml@lancaironline.net Mailing List Archive

Pipe thread sealant does more than lubricate the threads. It seals the spiral leak path that exists between the root of the thread and the crown of the mating thread. Without this sealant, excessive overtorque is required to try to create a metal-to-metal seal which damages the threads and overstresses the fittings (specifically the female fitting) which can then crack.

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On May 23, 2012, at 11:17 AM, "Bruce" <BGray@glasair.org> wrote:

OK, let’s talk about “thread sealants”. Usually pipe thread to pipe thread joints are lubricated by Teflon paste or tape. You’ll notice I said lubricate not seal. The purpose of the “sealant” is to lubricate the joint and prevent galling, not to seal. NPT threads are tapered not straight. The taper is what provides the seal.

Bruce
WWW.Glasair.org

-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of rwolf99@aol.com
Sent: Wednesday, May 23, 2012 8:17 AM
To: lml@lancaironline.net
Subject: [LML] Recoseal

I recall the reference to Recoseal as well, but I could not find it in the manual this afternoon.

For Bruce's benefit, this was a thread sealant called out for the NPT pipe threads on the AN fittings going into the hydraulic cylinders. There was no suggestion that it be used on the flared fitting connection. Your suggestion is correct -- if you can't get the flared fitting to seal, remake the flare.

I used Loctite 565 pipe thread sealant for screwing the fittings into the NPT holes in the cylinders. Rated to 10,000 psi and can handle gasoline and hydraulic fluid. Available in a lot of places, although I don't recall whether I bought it at Home Depot or the local auto parts store.

- Rob Wolf