La Marzocco GS/3 Steam Boiler Probe Seal - Page 2

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Peppersass
Posts: 3690
Joined: 15 years ago

#11: Post by Peppersass »

Fullsack wrote:]I used to be wary of using teflon tape, on boiler fittings, until Stefano told me he had been doing it for years without a problem.
I was wary, too, until the service department at Chris Coffee told me it's standard procedure for them.

After seeing what happened to the fiber washer over time, it seems to me that anything would be better. British Standard fittings are supposed to work with only a washer -- no sealer of any kind, though some use a metal washer with an internal O-ring. I think the fiber washer can't take the heat. I don't understand why the probe manufacturer uses that configuration. After all, the steam outlet and steam pressure gauge fittings right next to the probe use only a copper washer.

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AssafL
Posts: 2588
Joined: 14 years ago

#12: Post by AssafL »

Fiber seals are excellent. But they require the mating surfaces to be pristine, especially is there is any rotation between the surfaces (as any blemish may tear the seal).

I alway clean and lube the surfaces.

PTFE tape is also recommended, but not as a sealant but as a lubricant. To allow the parallel threads to tighten enough to seal the fiber seal. As the threads age and corrode, tightening them may become more difficult and PTFE tape helps.

Remember that PTFE tape is spec'ed to lube and seal tapered threads and lube (but not seal) parallel threads (which always require a surface seal). That doesn't mean it won't work in some cases...

Personally, I wouldn't seal without the fiber seal. Sometimes one has to use an Emory style paper to clean the surfaces. I like the Japanese rust erasers (red is high grit count) to make odd shaped surfaces shine. And lube.
Scraping away (slowly) at the tyranny of biases and dogma.

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