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2" Screw On Sight Glass Seals

edited December 2017 in Accessories

I bought some 2" sight glass they look the same as the ones you fellas sell. Was wondering if you know where to get seals for them. The seller I bought mine from is not answering questions and I don't know what my seals are made of. One is obviously silicon the other is a fairly firm blue material. I have had both seals sitting in 65% for a week or so and they seem fine but still a bit iffy about using them..any ideas


  • They are the ones with the screw on front

  • Why would you purposely ruin your seals?

    A week submerged in alcohol is easily equivalent to 1-2 years of hobby use.

  • If it breaks down in spirit in a week I wont be using it..

  • edited December 2017

    I'm more like I am now than I was before.

  • It sounds like you are using a bulls eye sight glass, if its a screw on. If its Blue, the material is NBR.

  • Awesome thanks will look that up

  • They look identical to the ones sd sell btw

  • Post some pictures of yoursight glass. ....better still of the gasket as well

  • edited December 2017

    Ok here they are




    389 x 800 - 51K
    389 x 800 - 65K
    389 x 800 - 50K
  • edited December 2017

    I see StillDragon America sells them will see what I can do..

  • Yes this is a male, nut and gasket to DIN11851. Never seen a such a royal blue gasket like that before. Try search under suppliers Kieselmann, Sudmo (Pentair), GEA tuchenhagen etc. Try get a union gasket... EPDM lip seal. Best solution.

  • edited December 2017

    Nothing to do with bluc, but I'm in the mood for a rant.

    I know this whole "stick it in alcohol for a week and see" thing is common in the hobby community, but honestly, it's nonsense and would be better if it was completely forgotten about. Maybe this was useful 15 years ago, when building a still was all jury-rig, and we made do with whatever we could find. But today?

    The testing methodology is worthless, because unless you are dealing with a completely unknown material, and one that is completely incompatible with ethanol, the test will tell you nothing (unless you have a HPLC to analyze the alcohol for contaminants). There are plenty of contaminants you would never be able to smell, taste, or see. Or, if you can, they can easily exist at levels that we can't easily detect with eyes, tongue, and nose.

    Even worse, it now gives the tester a completely false sense of security. Exposure to high proof alcohol for a full week, over 100% of the gasket material? This doesn't even approximate real-world use. In the real world, probably 1/20th of that gasket has any exposure to alcohol, and for a short period of time. So lets say, 1 full week, that's 168 hours. Given a typical distillation run is 5 hours (column time), you are talking about 33 distillations. Now, given you've exposed 100% of the gasket, and not the typical 5%, you are talking about the equivalent of 660 distillations worth of exposure. Yeah yeah, I'm sure you could argue that the temperature differences would mean this is an overstatement, but it's for effect/understanding and not an actual calculation.

    After a week we've now subjected the gasket to an entirely unrealistic level of exposure. So, what to do now? It looks good, so we're now going to put it into service? No no no, throw the gaskets in the trash bin. Your test certainly negatively impacted the integrity and potential purity of the gasket material. The gasket has surely absorbed ethanol through the entire body of the material. Even teflon would swell under these conditions. This test should be considered destructive.

    So what to do? Treat it like a 5 year old beat up gasket now, toss them out, and replace them with new gaskets. Even though they look good, that tells you absolutely nothing about the actual gasket material integrity after the exposure. It's not something you can assess by looking at it, unless you are dealing with something entirely incompatible that fell apart.

    I know that this is rooted in good intentions, but really, can we forget about this already? Let's raise a glass to modern PTFE/Teflon and chemically inert gasketing and forget about the old days.

  • edited December 2017

    Reminds me of a thread on one of the other boards that gave serious consideration to leather as an appropriate material for gasketing.

    Leather? Leather!?!?

    You mean completely porous animal hide that is subjected to an incredible amount of nasty chemical processing and coloring, much of it still remaining in the porous leather?

    Somehow, this is better than a nearly inert plastic. Probably because it's "natural". This is the kind of nonsensical misinformation that drives me insane. It just won't go away.

  • edited December 2017

    Agree with the comments. I personally have a pet hate for NBR materials having seen such gaskets having broken down after "some" lengthly period of use. Broken down because of chemical or heat non compatability.

    I find that EPDM ticks just about all the blocks especially heat. Silicone is also great BUT I generally find that its "available" hardness generally is not similar and is too soft by comparison.

    Teflon is a bitch especially in steam applications. It leaks until the heat comes up where it expands and seals.

  • edited December 2017

    Teflon gaskets are not forgiving, once deformed or damaged, they will not return to shape.

    However, Teflon should be considered the defecto king of plastics, along with the other two less common fluoropolymers - FEP and PFA. You rarely see FEP and PFA outside of high purity pharmaceutical and semiconductor manufacturing though. These three, you can consider their purity to be higher than that of metals, especially reactive metals like copper.

    Yes, you read that right, the fluoropolymers are purer and more inert than typical 316L stainless.

    Teflon/PTFE is more inert, and typically higher purity than 316L Stainless.

    Anyone questioning a teflon gasket being used to join two sections of 304 stainless is asking the wrong question. Anyone questioning PTFE while simultaneously running a home soldered copper condenser needs to have their head examined.

  • If PTFE is to hard why not use jacketed ( that might not be the correct term ) gaskets the ones with PTFE outside a silicon core? Best of both worlds!

  • For triclamp, those things are the Rolls Royce of gaskets.

  • Does no one make them in flat gaskets like the OP is asking about?

  • Need to pull/supply actual dimensions. There are various sizes that do appear similar upon first glance.

    StillDragon North America - Your StillDragon® Distributor for North America

  • I will put up dimensions later today

  • edited December 2017

    I am no machinist so don't know how accurate my measurements are but heres go grabbed with digital vernier

    Blue one:

    • OD 60 mm
    • ID 50 mm
    • Thickness 5.35 mm

    Lip on blue one

    • ID 49 mm
    • 3 mm thick lip


    • OD 64.58 mm
    • ID 49.5 mm
    • Thickness 2.08 mm
  • edited December 2017

    Teflon envelope gaskets are the business. They are unfortunately too expensive to use on every joint. I used them on my reflux columns as there was only a couple gaskets in a VM, but at $20 each 10 years ago.....

    They have a edpm core wrapped in a skin of teflon with the core exposed on the outside edge. They seal as well as silcone nearly and have the quality of teflon.


    800 x 600 - 61K

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • edited December 2017

    Prety sure these are what I need but as smaug said as long dimensions are right

    2" SGU Repair Kit @ StillDragon North America

  • Ah you're in Oz.

    You'll need to take up with Punkin.

    StillDragon North America - Your StillDragon® Distributor for North America

  • All sorted mate, Dee is looking after him.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • edited December 2017

    @grim said: Yes, you read that right, the fluoropolymers are purer and more inert than typical 316L stainless.

    Certainly more inert than 316L exposed to brackish and/or seawater applications (says the guy having to weld up pinhole leaks in high pressure 316L piping) Stainless and chlorides don't mix...

    I'm more like I am now than I was before.

  • edited December 2017

    I think you can find them cheaper then $20.00. Price goes nuts at 6 inch I would imagine is about supply an a demand. I would definitely buy these from StillDragon if they were available.

  • @Drywall_Dan, @punkin stated the $20 each was 10 years ago. You're right they would be cheaper now - the link you posted supports that.

    Please remember @punkin will have a minimum order quantity to buy so he can offer you a sweet price. The challenge he faces is are there enough people in the Aussie distilling community than want these parts (including you) to make it worth his while to get them in. Maybe, maybe not. I'd think he'd have a pretty good idea by now ;)

    The SD distributors do a great job of standing behind their products and helping out the wider distilling community where they can. However it isn't always possible for them to provide solutions for issues with or support for other parties product. This may be one of those cases.

    Try out the ones SD US supply - hopefully they do the trick for you. Don't forget to post your results here.

    Cheers Crozdog

    PS @grim some very good points mate. well said

  • @crozdog I never asked for a sweet price just said i would buy from SD if available.

  • edited December 2017

    I'd stock them if the demand was there, as Croz said. My problem is that i'd have to stock them in 3/4", 1.5" 2", 3", 4", 5", 6", 8" and then i'd definately have to spend money on mold fees (if it was possible to do) to make the special plate gaskets for 4", 5", 6" and 8". So that's 12 new lines and at least 4 x mold fees (probably 12 x mold fees) that would add into the thousands.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

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