Viton VS PTFE

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OklahomaShiner
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Viton VS PTFE

Post by OklahomaShiner »

I ordered a sight glass, I asked the seller about Replacing the gaskets with PTFE gaskets and this was their response. What’s your opinion on Viton? For those that have a sight glass and are using PTFE gaskets, where did you purchase these gaskets?
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greggn
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Re: Viton VS PTFE

Post by greggn »

OklahomaShiner wrote: Mon Aug 02, 2021 6:34 am What’s your opinion on Viton?

There are certainly applications where Viton would be preferable over PTFE (where flexibility or compression is important) ... but it's not appropriate for this hobby where resistance to high-temp ethanol is of vital importance.
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still_stirrin
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Re: Viton VS PTFE

Post by still_stirrin »

OklahomaShiner wrote: Mon Aug 02, 2021 6:34 am… For those that have a sight glass and are using PTFE gaskets, where did you purchase these gaskets?
Here: https://www.gvc.net/p/12/ptfe-white-san ... mp-gaskets

Get several for spares.
ss

p.s. - GVC is also a great source for T/C clamps and ferrules.

I strongly suggest using “double hinge point” clamps because they’re all double shear pinned joint, ie - more than twice as strong and won’t bend if wrenched too tight like single hinge pin joints will. A little more money, but definitely better clamps. Here: https://www.gvc.net/p/785/double-hinged-clamps
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jonnys_spirit
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Re: Viton VS PTFE

Post by jonnys_spirit »

I ordered a sight glass..
....where did you purchase these gaskets?....
Referring to the silicone gaskets that seal between the borosilicate glass tube and the stainless housing - not the TC gaskets (which you should also use PTFE for)..

I wrapped mine in teflon tape and re-installed/tested for air/vapor-tight operation.. Keep an eye on em too!

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NZChris
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Re: Viton VS PTFE

Post by NZChris »

If you need flexibility, use a PTFE envelope sanitary gasket.
AlWorms
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Re: Viton VS PTFE

Post by AlWorms »

I used a tri-clamp PTFE gasket at each end of the glass. I sanded the "bump" off the gasket with some sand paper on a glass plate.

Once I had it assembled, I heated it up on the still and tensioned it up a bit more, once the gaskets were well heated. The glass does "sink" into the PTFE a little and seems to seal perfectly well.

I haven't had to touch it since, and have done probably 3 spirit runs and 12 to 15 stripping runs.
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Hambone
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Re: Viton VS PTFE

Post by Hambone »

I bought a set of gaskets that are PTFE sandwiched over voting, as mentioned by Chris. I like them a lot, but they certainly aren’t giving them away…
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Sulaiman
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Re: Viton VS PTFE

Post by Sulaiman »

I suspect that 'purists' will only be content if there is no plastic/rubber in contact with the liquid or vapour,
many may accept ptfe as 'ok if you really must'.

Viton is rated as having excellent resistance to ethanol,
but other chemicals that may be with the ethanol can have a severe effect on Viton.
https://www.calpaclab.com/viton-chemica ... ity-chart/

Viton is a cross-linked polymer so is quite resistant to creep,
ptfe is infamous for it's tendency to creep.
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NZChris
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Re: Viton VS PTFE

Post by NZChris »

Sulaiman wrote: Tue Aug 10, 2021 6:16 am Viton is rated as having excellent resistance to ethanol,
but other chemicals that may be with the ethanol can have a severe effect on Viton.
I've seen Viton seals that have done several runs on someone else's still. They were cracking up. I wasn't surprised. My gasket supplier advised me against using Viton thirty years ago when I was doing my initial research.
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