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Thread: Original Diana 35 - elastomer piston seal ? Better?

  1. #1
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    Original Diana 35 - elastomer piston seal ? Better?

    I am close to buy an original Diana model 35 and (maybe) an original model 50.

    These rifles most probably will need new piston seals. There is a website in Germany that has many replacement parts (I do not know if I am allowed to write their address/link here...I am sure many of you know who they are).

    They have the original seals, three parts, all (I believe) made of leather. They also have an elastomer piston seal, only one piece that replaces the three leather parts.

    Should I buy the "modern" elastomer seal? Better than the originals -why?

    Thanks
    Ignacio

  2. #2
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    I know of these seals and someone on here has actually tried them out, try a search using different terms maybe it will come up? IIRC it was for a 35, too.

    Having said that whatever the outcome don't expect any major power or you may be disappointed. But perfectly usable guns.
    **WANTED**: WEBLEY PATRIOT MUZZLE END; Any Diana/Original mod.50 parts, especially OPEN SIGHTS

  3. #3
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    Quote Originally Posted by ignacio49 View Post
    I am close to buy an original Diana model 35 and (maybe) an original model 50.

    These rifles most probably will need new piston seals. There is a website in Germany that has many replacement parts (I do not know if I am allowed to write their address/link here...I am sure many of you know who they are).

    They have the original seals, three parts, all (I believe) made of leather. They also have an elastomer piston seal, only one piece that replaces the three leather parts.

    Should I buy the "modern" elastomer seal? Better than the originals -why?

    Thanks
    Ignacio
    Polyurethane elastomer seals are by far the best. Having "memory" resilience they can take a pounding and keep their shape. I make my own on a lathe and seen old rifles improve after fitting replacements. Having a thin lip parachute design gives the best results. Most manufacturers today use polyurethane.

    Baz
    BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD

  4. #4
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    Ignacio,

    My 1974 Diana (Original) 35 still has the original leather piston washer, and is still going strong

    Perhaps you could 'save' the washer in the 35 & 50 you are buying ?

    Have fun & a good Sunday

    Best regards

    Russ

  5. #5
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    Quote Originally Posted by PhatMan View Post
    Ignacio,

    My 1974 Diana (Original) 35 still has the original leather piston washer, and is still going strong

    Perhaps you could 'save' the washer in the 35 & 50 you are buying ?

    Have fun & a good Sunday

    Best regards

    Russ

    Russ, I also have an original 35, 1970, which I bought new and, as yours, still working fine. Seldon used, and seal kept wet, that's why I guess.

    But the 35/50 I am considering have been treated careless as far as I can see (some oxide and dirt), and hence my suspicion that they may need a seal change. Hope they won't.

  6. #6
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    Something else....

    Somewhere I read that the modern seals are shorter, and the piston will/may hit the cocking arm and may cause serious damage.

    Have you heard about this? Comments?

    This is the "modern seal" I am looking at. It replaces the original three parts seal:

    http://www.waffencenter-gotha.de/sho...a57a5be3272786
    Last edited by ignacio49; 27-06-2017 at 12:55 AM.

  7. #7
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    Anybody?

    http://www.waffencenter-gotha.de/sho...a57a5be3272786

    Anybody here that has installed this seal, and could confirm if working fine or not?

    Thanks

  8. #8
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    Quote Originally Posted by ignacio49 View Post
    http://www.waffencenter-gotha.de/sho...a57a5be3272786

    Anybody here that has installed this seal, and could confirm if working fine or not?

    Thanks
    Really sorry I cant help mate as all conversions over to synthetic I have had done over the years has been to ptfe. Whilst I haven't had a moments trouble.I would suggest that the seal you show here would be equal if not superior to ptfe by virtue.of it being an.OEM part. Diana seals are.particularly good as far as factory ones go and I don't think you will go wrong with one..Plus from what I can see of things if the worst happens and performance goes backwards you have the option with this one to revert back to leather. I suspect you won't need to though. I think modern synthetic seals are superior to leather and keeping leather is good for originality but not if more consistent and higher power are the goal.
    Dave

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    [QUOTE=jonnyone;7290152....all conversions over to synthetic I have had done over the years has been to ptfe. Whilst I haven't had a moments trouble........
    Dave[/QUOTE]

    Thanks Dave.

    Probably you converted a Diana 35 or 50. If so, do you remember if the ptfe seals you used were shorter than the originals?

    I ask because the seal I am looking at is shorter, and I was told this will cause trouble.

    Ignacio

  10. #10
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    Quote Originally Posted by ignacio49 View Post
    Thanks Dave.

    Probably you converted a Diana 35 or 50. If so, do you remember if the ptfe seals you used were shorter than the originals?

    I ask because the seal I am looking at is shorter, and I was told this will cause trouble.

    Ignacio
    Morning ignacio. I have fitted ptfe seals to two Diana 45s, one 50, one 50T01, two anschutz 335s, one HW35, and a BSF as I recall.
    I have been fortunate in that despite the seals being thinner height wise than the original leather seal they have still had clearance between the cocking lever rod and the piston body. This can easily be checked after the seal is fitted. A few millimetres clearance is needed when the piston is fully pushed home against the end of the compression tube. Should this not prove to be the case then the new head will need.packing between it and the piston body to create that required gap. I recall some have used large tap washers in the past but as I say it has proved unnecessary for me. I can't say it will be the same for your gun as I have no experience of working on a 35.
    Perhaps an email query to the seller of the synthetic seal may throw some light on things but even then I would still check the clearance as per the above after fitting?
    Wish you luck
    Dave

  11. #11
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    PTFE is a poor material for piston seals as it is malleable and can be squashed out of shape. Polyurethane elastomer is a far better material and the most commonly used today.

    Baz
    BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD

  12. #12
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    Quote Originally Posted by Benelli B76 View Post
    PTFE is a poor material for piston seals as it is malleable and can be squashed out of shape. Polyurethane elastomer is a far better material and the most commonly used today.

    Baz
    Someone had best explain the ptfe failings to my guns. I fitted the first seal to an RWS 45 in the late 80s and its worked perfectly since (as they have all done). I think it's about time they started playing up a bit
    Dave

  13. #13
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    Thumbs up

    You should really have a word with those 50's while you're at it. They don't always realise tap loaders are meant to be old crap...

  14. #14
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    Quote Originally Posted by Drew451 View Post
    You should really have a word with those 50's while you're at it. They don't always realise tap loaders are meant to be old crap...
    Very true.
    Which is going to come as a shock to my .22 Original 50T01 as it's shooting very sweet right now after a mainspring upgrade.
    All jokes aside back in the day there wasn't the choice of piston head materials we have now and ptfe was about the only alternative unless you had access to a lathe and was pretty handy on one. If I could have had someone run me up a few dovetail converters so that the pistons would accept OEM washers I would definitely have gone that route. Diana piston washers are definitely some of the best around giving good sealing qualities combined with reasonably low friction.
    As I've said a few times on here now aside of a HW35 with a tapered cylinder end and a BSF55 with a less than true cylinder all the guns I've swapped to ptfe have worked flawlessly and for quite some time now. Maybe I've just been incredibly lucky with all of these? Or maybe ptfe isn't the demon material some make it out to be? For the time being I'm certainly enjoying benefits from swapping over.
    The good thing is that nowadays we seem to have more choice in the direction we go with upgrading from leather washers. Which can't be a bad thing and long may that continue.
    Dave

  15. #15
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    Quote Originally Posted by jonnyone View Post
    Someone had best explain the ptfe failings to my guns. I fitted the first seal to an RWS 45 in the late 80s and its worked perfectly since (as they have all done). I think it's about time they started playing up a bit
    Dave
    PTFE does not need explaining to the guns but to people. PTFE can be cut with a knife. It is usually white in colour and is malleable that is why it is used for flange seals etc because it adapts to shape. A lot of people look at a synthetic seal in an air rifle and call it PTFE when it is actually polyurethane because they do not know about polymers. You can use it for piston seals but it will not give a good seal eventually, that is why airgun manufacturers do not use it. I repair airguns every day and never see it except on old Webley pistols, and it is used on the capsule seal for the Tanfoglio Witness pistol which is why they need to be changed after squashing out of shape.

    Baz
    BE AN INDEPENDENT THINKER, DON'T FOLLOW THE CROWD

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