PTFE Tri-Clamp Seals

[GCB3]

I had a safety issue arise two days ago that I thought might be worth mentioning. During a spirit run in full column mode, I developed a significant vapor leak between the two column sections. Tried tightening the tri-clamp but no dice. Had to shut down, disassemble and put it all back together to resume. Sure am glad I wasn’t using the “flaming rag” leak detector in that old Poteen video!
My point is that this is the first time this has happened to me and it really got my attention. I discovered it doing my usual walkaround in between cut jars etc. The lesson for me was, don’t assume everything is OK, pay attention, and look for problems. This is a serious hobby.

For those who want more background:
When I bought my Brewhaus CM column still, I was a little disappointed in all the silicone seals and plastic product tubes. Searching here ,I instantly found the US Plastics PTFE tri-clamp seals and set about getting some copper tubing coming off that condenser.
While discussing another issue with Rick at BH, I told him I had replaced the column seals with PTFE and inquired about a source for the kettle seal. No luck he said. I then wrapped it in PTFE tape.
He cautioned me about using the Teflon seals due to their rigidity. He didn’t recommend them. In fact he said I should be very careful and be sure to check my clamp tightness during runs. He was concerned about leaks due to torque on the joints.
The condenser arm does create some torque and then add a couple of feet of copper and bam! The leak was exactly opposite the condenser arm. I’ll do some reconfiguring before the next run in an attempt to neutralize the torque.

[spiff]

That was my experience as well. Those rigid PTFE gaskets suck ass, even if wrapped in PTFE tape to give them at least a bit of squishiness. When I reported this here literally everyone replied that they had no issues with theirs. Take that as you will... I also tried grinding them down to various degrees.. they just can't be counted on.

Just wrapping the original silicon ones in the tape is best... no issues on all fronts.

[MtRainier]

Maybe ones like this would help? They're not very expensive.

https://www.stainlesssteelexpress.com/p ... asket.html" onclick="window.open(this.href);return false;" rel="nofollow

I agree that the rigid PTFE ones are too hard for me to get a good seal on. I've never been able to make them not leak.

For the kettle seal others have had good luck with a product here called "expanded PTFE valve stem packing" or "joint sealant" which is available from various places including amazon. It's like teflon foam.

[Expat]

That was my experience as well. Those rigid PTFE gaskets suck ass, even if wrapped in PTFE tape to give them at least a bit of squishiness. When I reported this here literally everyone replied that they had no issues with theirs. Take that as you will... I also tried grinding them down to various degrees.. they just can't be counted on.

Just wrapping the original silicon ones in the tape is best... no issues on all fronts.

They reply that way because it's the truth, most people have absolutely no issues with them. Personally I've done multiple builds/designs and dozens of runs and I've never had an issue with a PTFE gasket leaking.

If you're having issues it's more likely design and implementation than the gasket itself. If a ferrule isn't flat, square and clear of debris it's not going to form a good seal. Similarly if a heavy unsupported component is causing a torque issue, the design should be amended to properly manage the offset weight.

[Subsonic Instability]

Maybe ones like this would help? They're not very expensive.

https://www.stainlesssteelexpress.com/p ... asket.html" onclick="window.open(this.href);return false;" rel="nofollow

I agree that the rigid PTFE ones are too hard for me to get a good seal on. I've never been able to make them not leak.

For the kettle seal others have had good luck with a product here called "expanded PTFE valve stem packing" or "joint sealant" which is available from various places including amazon. It's like teflon foam.

These are working well for me so far.

[Windswept]

Maybe ones like this would help? They're not very expensive.

https://www.stainlesssteelexpress.com/p ... asket.html" onclick="window.open(this.href);return false;" rel="nofollow

I agree that the rigid PTFE ones are too hard for me to get a good seal on. I've never been able to make them not leak.

For the kettle seal others have had good luck with a product here called "expanded PTFE valve stem packing" or "joint sealant" which is available from various places including amazon. It's like teflon foam.

It's kind of odd that still makers haven't switched over to these.

[still_stirrin]

It's kind of odd that still makers haven't switched over to these.

Well, not everyone in the world has subscribed to our creed of “no plastics or rubber” in the hot vapor path....yet!
ss

[MtRainier]

That was my experience as well. Those rigid PTFE gaskets suck ass, even if wrapped in PTFE tape to give them at least a bit of squishiness. When I reported this here literally everyone replied that they had no issues with theirs. Take that as you will... I also tried grinding them down to various degrees.. they just can't be counted on.

Just wrapping the original silicon ones in the tape is best... no issues on all fronts.

They reply that way because it's the truth, most people have absolutely no issues with them. Personally I've done multiple builds/designs and dozens of runs and I've never had an issue with a PTFE gasket leaking.

If you're having issues it's more likely design and implementation than the gasket itself. If a ferrule isn't flat, square and clear of debris it's not going to form a good seal. Similarly if a heavy unsupported component is causing a torque issue, the design should be amended to properly manage the offset weight.

I think my issue is what Expat is saying. There is likely just enough bowing on one of my flanges to prevent them from getting a good seal.

Anyway, the Teflon covered ones I posted fixed it. I ran with silicone for a while and always noticed them getting stinky. If stuff can leach in, surely it can leach out too. I figured why risk it.

[spiff]

Yeah, now I'm wondering if its the difference between a SS still vs a copper one.. seems most people here roll with copper. Copper parts might be helping to conform to the gasket itself.

[Expat]

Yeah, now I'm wondering if its the difference between a SS still vs a copper one.. seems most people here roll with copper. Copper parts might be helping to conform to the gasket itself.

Possibly. I'm using stainless ferrules soldered to copper tube, if that's of any interest. So all stainless.

[GCB3]

Yeah, I think Expat is correct in my case. I have a torque issue I need to resolve to take some load off the joints. Ran in potmode today with no issues,

Thanks for the link, MtRainer. The description says the “Viton” is completely enclosed but the photo makes it look like its maybe laminated? How does the actual product appear? How long have you been using them?
Thanks again.

[SaltyStaves]

Thanks for the link, MtRainer. The description says the “Viton” is completely enclosed but the photo makes it look like its maybe laminated

The outside edge is open so that the gasket can compress. The inside edge (vapour side) is enclosed. An 'Envelope'.

[GCB3]

Thanks Salty. I’m going add these to my “to do” list. Damn, that thing keeps a growing! (Where’s that “That’s What She Said” thread when you need it?! )
Thanks for the info.

[corene1]

Something I have noticed when building a column with 4 inch ferrules,is fit before welding. If it is a nice tight fit to the tube the flange stays very flat if the fit is poor meaning a gap in one section of the weld between the ferrule and the tube. I have noticed that the flange will pull a tiny bit causing a bit of a problem with the hard ptfe gaskets. I have switched to using a long flange ferrule. These have a 1 inch straight section instead of the regular 1/2 inch section above the flange . This seems to help keep the flange nice and flat particularly on the larger ferrules. If I have to use a short ferule I will clamp a blind flange and aluminum spacer ring to it while making the weld and let it cool that way. The aluminum won't damage the face of the ferrule but will keep everything tight and flat. Just something to think about.

[MtRainier]

Yeah, I think Expat is correct in my case. I have a torque issue I need to resolve to take some load off the joints. Ran in potmode today with no issues,

Thanks for the link, MtRainer. The description says the “Viton” is completely enclosed but the photo makes it look like its maybe laminated? How does the actual product appear? How long have you been using them?
Thanks again.

Yep, they're kind of covered on 3 sides including the inside. I haven't used them for long, only 3 runs, but they seem to hold up OK so far and don't smell like the product. AT $7 per gasket they were a bit expensive for the 4" ones. It takes 6 of them to go on all of the 4" flanges in my flute (4 sight glass sections plus the dephleg), so that plus the 2" flanges would add around $50 to the cost of a flute from a place like Mile Hi. Seems like they could offer it as an upgrade, maybe.

[spiff]

Thanks for that link.. just ordered a set. Its the first I have seen about these envelope type gaskets.. seems like a perfect solution.

BTW. my 6 T MileHi 4in rig doesn't have any flange deformities at all. If these T's are made by hand its hard to tell because they're all perfectly identical. Stack them together without gaskets and you can't get a feeler gauge between them. So for now I guess its a mystery why some times those rigid PTFE gaskets work fine and other times they don't.

The first time I used those rigid ones, it was a 100% failure rate.. my column looked like a garden fountain. After that I went back to the wrapped silicon but would test just one PTFE gasket change at a time at the top of the column so I could quickly swap it out. I tried grinding down the ridge bump on one side, then both, wrapped with PTFE tape or not.. those were also 100% failures.

[GCB3]

If you go to SS Express to order, their pull down size menu doesn’t have a 3” available. I spoke to a guy there who confirmed that they do have 3”. It’s just that their webpage isn’t up to date. He didn’t offer to take my order, but, did offer to call me “when the webpage is updated so that you can place an order”.

SS has a good point about plastic concerns. If the makers change the fri-clamp seals, then what about the boiler seal, then what about the silicone product tube, the thermo bung plug and yada, yada, yada...... I don’t agree with their approach but I see how it happens. Chemically “resistant” tubing and silicone seals are obviously good enough for the majority of their customers. It was for me too until I started diving deeper here. So, now I guess all my off tastes are my own fault!

It’s another good argument for building your own, if you can.
Thanks for the feedback.

[MtRainier]

Thanks for that link.. just ordered a set. Its the first I have seen about these envelope type gaskets.. seems like a perfect solution.

BTW. my 6 T MileHi 4in rig doesn't have any flange deformities at all. If these T's are made by hand its hard to tell because they're all perfectly identical. Stack them together without gaskets and you can't get a feeler gauge between them. So for now I guess its a mystery why some times those rigid PTFE gaskets work fine and other times they don't.

The first time I used those rigid ones, it was a 100% failure rate.. my column looked like a garden fountain. After that I went back to the wrapped silicon but would test just one PTFE gasket change at a time at the top of the column so I could quickly swap it out. I tried grinding down the ridge bump on one side, then both, wrapped with PTFE tape or not.. those were also 100% failures.

I have the 4 plate MileHi 4" flute. I agree that my flanges seem very flat and straight, but I assume that when using the rigid PTFE ones the bubble plates enter into it and confound the seal somewhat. I got it to seal pretty well using a "cheater" on the tri-clamps of a screw driver doing the last couple turns, but never felt good about that and often still had small drips I didn't like.

I believe that they get silicone gaskets that are narrowed on the inner diameter to allow their plates to fit entirely inside. I tried carving up the insides of my rigid PTFE gaskets to get the same effect, but they were heck to cut cleanly. I don't know if it ended up helping or not. So I ended up with the envelope ones and they seem to work pretty well.

[GCB3]

Just heard back from SS Express and they have their website updated. The 3” seals are available at $4 ea.

[spiff]

Thanks for that link.. just ordered a set. Its the first I have seen about these envelope type gaskets.. seems like a perfect solution.

BTW. my 6 T MileHi 4in rig doesn't have any flange deformities at all. If these T's are made by hand its hard to tell because they're all perfectly identical. Stack them together without gaskets and you can't get a feeler gauge between them. So for now I guess its a mystery why some times those rigid PTFE gaskets work fine and other times they don't.

The first time I used those rigid ones, it was a 100% failure rate.. my column looked like a garden fountain. After that I went back to the wrapped silicon but would test just one PTFE gasket change at a time at the top of the column so I could quickly swap it out. I tried grinding down the ridge bump on one side, then both, wrapped with PTFE tape or not.. those were also 100% failures.

I have the 4 plate MileHi 4" flute. I agree that my flanges seem very flat and straight, but I assume that when using the rigid PTFE ones the bubble plates enter into it and confound the seal somewhat. I got it to seal pretty well using a "cheater" on the tri-clamps of a screw driver doing the last couple turns, but never felt good about that and often still had small drips I didn't like.

I believe that they get silicone gaskets that are narrowed on the inner diameter to allow their plates to fit entirely inside. I tried carving up the insides of my rigid PTFE gaskets to get the same effect, but they were heck to cut cleanly. I don't know if it ended up helping or not. So I ended up with the envelope ones and they seem to work pretty well.

Thanks for bringing that up. I suspected the plates might be part of the issue as well. I did exactly that too; trimmed the gasket down to the bump on both sides, allowing the plate to fit inside. I used a Dremel, it was pretty easy if a bit time consuming. They still didn't seal right. I went on to eventually grind down the bump ridge on one side and then the other too, plus the tape wrap but that never helped either. So it ended up not being the plates. Even on flanges with no plates they leaked. That's what I meant about 100% failure.. every single one leaked, both sides of the RC, my foot extender, ect.

They're just not worth it. Two things I refuse to do; over crank clamps to compensate for a shitty gasket, or put myself in a roll of the dice situation where after spending 1.5 hours to bring 20 gallons to a boil to find out whether I have leaks or not. The wrapped silicon was a cheap solution and never had issues with them. The upgrade to the envelope ones will be nice to never have to rewrap or worry about leaching getting past or thru the tape. I just hope they're everything as advertised. I won't know until next fall.. I do all my running in the cold seasons, then its ran once or twice every weekend until spring as I replenish stock. Hopefully someone else can give another review before then and hopefully they'll all be positive like yours.

[Expat]

Thanks for bringing that up. I suspected the plates might be part of the issue as well. I did exactly that too; trimmed the gasket down to the bump on both sides, allowing the plate to fit inside. I used a Dremel, it was pretty easy if a bit time consuming. They still didn't seal right. I went on to eventually grind down the bump ridge on one side and then the other too, plus the tape wrap but that never helped either. So it ended up not being the plates. Even on flanges with no plates they leaked. That's what I meant about 100% failure.. every single one leaked, both sides of the RC, my foot extender, ect.

If you're modifying the gasket that much just to make it fit, it's likely that the source of the problem. No changes should be required for the gasket to work.



Perhaps include a picture of the ferule

[spiff]

Thanks for bringing that up. I suspected the plates might be part of the issue as well. I did exactly that too; trimmed the gasket down to the bump on both sides, allowing the plate to fit inside. I used a Dremel, it was pretty easy if a bit time consuming. They still didn't seal right. I went on to eventually grind down the bump ridge on one side and then the other too, plus the tape wrap but that never helped either. So it ended up not being the plates. Even on flanges with no plates they leaked. That's what I meant about 100% failure.. every single one leaked, both sides of the RC, my foot extender, ect.

If you're modifying the gasket that much just to make it fit, it's likely that the source of the problem. No changes should be required for the gasket to work.



Perhaps include a picture of the ferule

They "Fit" as well as any other gasket... just being useless hard plastic instead of something gasket like that can conform. My plates overlap on my silicon gaskets too, but are a non-issue since the silicon will give way and conform to both the plate edge and the ferrule.

But yeah, I certainly agree " No changes should be required for the gasket to work.".. a testament to how shitty they are when even grinding them down to perfect match to mated surfaces they still can't seal right. I wonder if we're even talking about the same gasket material sometimes.....

[spiff]

I consider this common sense.. I have dealt with gaskets my whole life in multitudes of applications and never ran into a rigid gasket. It was completely no surprise when I got them that they didn't work. My ferrules are fine.

Show me a picture of your gasket.. its probably not what we're talking about. I wonder about anyone advocating their use in any capacity.

[Expat]

3" ferule and gasket, standard item.

[spiff]

Yep, that's it. (thanks) I'm amazed that you're able to get them to work. The recessed ring on your ferrule looks wider and deeper.. that's probably the difference. On my Mile Hi T's, that ridge/bump doesn't even start to enter the recess.. it just kind of sits on top. Not sure if its the T's fault though because this ridge is wider on these PTFE gaskets than they are on all my other ones. Curious what the actual standard is now, if there is one concerning that bump/recess.

Not exactly mine, but just grabbed an equivalent URL off Milehi's site... you can see the difference I think. The whole ferrule is probably thinner than yours, the recess being both narrower and thinner.

https://milehidistilling.com/wp-content ... window.jpg" onclick="window.open(this.href);return false;" rel="nofollow

I still think its the gaskets fault. Gaskets are inherently supposed to have give to provide seal.. those don't. Even with something like metal head gaskets (which are the worst types you can use unless they're copper) they compensate by layering the metal up so its basically a stack of 5-6 layers of metal gasket that together presumably provides give.

[GCB3]

Spiff,
I think we are looking at different manufactures. My 3” ferrets look exactly like Expat’s and the standard gaskets from US Plastics are a perfect fit. I am now 99% convinced my leak came from a self induced torque on my column. I’ve never had a leak before and didn’t have one the other day running in pot mode. My solution will be to try the envelop type gaskets at the higher moment connections and probably still use the std TFE for the column cap and in pot mode.

I think you may be right that we’re not comparing apples to apples.
Take care.

[MtRainier]

Here are some more details so folks can decide if the envelope gaskets will work for them. Also in case anyone comes on this thread in the future when looking for alternatives to their silicone ones.

The PTFE part consists of the top and bottom with the bead molded into it plus the inside that connects them together. The viton part is not attached to the teflon inner surfaces. It's just in there to provide structure and some flex once you tighten down the clamp. It's thicker than the silicone ones so the clamp will be a bit wider than with silicone because the majority of it doesn't really squish. The PTFE envelope is 0.04 inches thick and the entire gasket is 0.1 inches thick.

They do seal my column, but I do have to put more torque on the screws than with silicone because they're still not as pliant as the silicone ones.

Here are some photos. If you want any more measurements or photos from a different angle, let me know.

envelope thickness

gasket thickness

gasket on flange

flanges clamped together