Coated viton or coated silicon?

[Birrofilo]

I was looking around at Aliexpress.

I saw some material which is sold with the choice of silicon gaskets or viton gaskets.

I searched on this forum and I found that viton is not immune to the usual problems plastics have with high-proof alcohol, so I understood that, if I buy viton gaskets, I have to "coat" them in PTFE tape, just as I do at the moment with silicon gaskets.

A question remains unanswered though: is it better a silicon gasket coated in PTFE tape, or a viton gasket coated with PTFE tape?
Considering that viton costs more, what advantage would there be in using it instead of silicon?

[River Rat]

I have a hydraulic equipment background. Viton's advantage in the hydraulic world is that it stands up to synthetic oils where buna and others do not. In that application, that is it's only real advantage. That shouldn't be an issue for our purposes here. I have never used them for stilling. Others might offer more insight.

[tiramisu]

My understanding is platinum cured but not in the vapour path.

[NZChris]

You can buy Viton seals with a PTFE envelope. A search of the forum should find at least one discussion about them. I haven't had to use them myself, so I don't know how well they stand up to multiple uses, but I would try them before wrapping Viton or silicone with tape.

A flange would have to be quite badly deformed for a PTFE wrapped cardboard ring not to seal.

[Birrofilo]

I will look for those Viton seals with PTFE envelope that @NZChris suggests.

I am not very satisfied by my silicon gasket with PTFE tape around them, because the resulting thickness of the gasket is uneven and my column is often not really vertical. I can try to turn the elements until the column is vertical but gaskets to be use as-is would certainly be more practical.

[higgins]

Birro, are you talking about tri-clamp gaskets, or lid sealing gaskets?

If tri-clamp for columns, you can get solid PTFE gaskets for a pittance. I got mine (10 2" for $12) on Amazon ... 2" PTFE Tri Clamp gasket

[Birrofilo]

Birro, are you talking about tri-clamp gaskets, or lid sealing gaskets?

If tri-clamp for columns, you can get solid PTFE gaskets for a pittance. I got mine (10 2" for $12) on Amazon ... 2" PTFE Tri Clamp gasket

I know, the reason I bought silicon gasket is because I read that PTFE gaskets are too rigid and cause problems. But also coating silicon gaskets in PTFE tape causes problems.

I use tri-clamps gaskets, the flanges of the elements have a grove and the gaskets have a protuberance for that groove (I don't know whether this is standard for tri-clamp junctions). That helps aligning and probably helps the sealing, but I think it doesn't help when one has to coat a gasket with PTFE tape.

I will try PTFE gaskets as well.

[Uncle B]

I've dealt with this recently after picking up a bubble plate column from Distillex on AliExpress. (Highly recommended, btw.) The column came with (what I assumed to be) standard silicon gaskets. I ordered a set of PTFE gaskets to swap them out, but those were too rigid to sandwich the plates between the gasket and the tri-clamp flange.

Based on some reading here:

https://adiforums.com/topic/8458-findin ... of-rubber/

...it seems that platinum-cured silicon gaskets are a relatively-decent alternative to PTFE, so I'm using those at my plate joints until I can get some PTFE gaskets sanded down (assuming that will work) to accept the plates.

I think I ordered the gaskets through Glacier Tanks for something like $3 per gasket.

--Unc B

[tiramisu]

If you are using tri-clamp fittings PTFE gaskets are going to give you a seal and safest use.
If you are banging together your own fittings then a more flexible material could help if you can't get a good seal could help but
IF it was me and I had funky fittings then I would either a) Fix my fitting issue OR b) Use flour paste.

I am personally comfortable with silicone outside of my vapor path but it is simplest to avoid any petrochemical that reacts with the solvent.
Will there be health or taste implications. I don't know for sure but I can avoid the question entirely.

Similar issue with filtering at the end. It is simplest not to put off-tastes and funky chemicals into the solvent by not pushing the yeast too hard.
The same goes for the copper discussion. I will reflux with copper as a safety measure but if you don't push your yeast too far then you really aren't going to need to solve the problems that copper solves. I would love to have a copper still because it is pretty, magical, and as a heat distributor it crushes SS but the price of a 12' length of 4" (or even 3" Type L) is pretty obscene right now.

There are lots of heated debates and they go far beyond my ability to determine. Engineers, Chemists, white papers I can't understand.
I know PTFE does not react with any of the solvents created in distilling. I know that EPDM, Silicone, etc do. Is the outcome of the reaction/degradation unsafe/bad tasting? I do not have the expertise to make an educated determination...

But I can sidestep these questions by choosing PTFE and not pushing my ferments too hard. I have chosen to be comfortable with a silicone hose, and HPDE for low wines for fermenting and transferring for convenience BUT If I had a 50-gallon stainless steel barrel and PTFE tubing I would use them as well.

[Birrofilo]

I am using decent quality factory-made tri-clamp fittings.

My next attempt is PTFE gaskets. As suggested, I found them on Amazon.it so I don't have to place an order on some far part of the planet.

If that fails, Viton seals with a factory PTFE coating applied will be the next move.

Thanks to all for the great contributions.

[River Rat]

My setup is a very simple pot still and it has 3 tri clamp connections. I have had great luck with the PTFE gaskets. Yes they are very rigid, but I have never had a leak with them. I think you will be happily surprised with them.