Hatsan Flash-R QE question

[Rat Sniper (AKA: PaulT58)]

Well, the fix wasn't long lived!  After shooting several magazines through the Flash-R yesterday, I cleaned the barrel, aired it up to 250 BAR and let it sit.  This morning it's one again empty!  I have not tried to refill it yet, so I don't know if the air is once again leaking out of the fill valve or from somewhere else!  I guess I will be tearing it apart again today to see what's going on... 

[Back_Roads]

 Dang I was all ready to watch a rat get flashed

[Rat Sniper (AKA: PaulT58)]

Dang I was all ready to watch a rat get flashed

Well, I have no idea of the exact dimensions or durability rating of that o-ring and just put one in that fit!  I probably need a harder durability rating, like a BUNA-N 90 for this application and the one I used is most likely a BUNA-N 70.  I have reached back out to Hatsan and asked them to provide the specs for that o-ring, but no telling when or if I'll get a reply.  I may have to dig through my stash of o-ring and see if I have any denser o-rings in a size close enough to see if I can get it working again...  But first, I need to air it back up and see if that's where it's leaking from, or if I have another leak!

[mikeyb]

Dang I was all ready to watch a rat get flashed

Well, I have no idea of the exact dimensions or durability rating of that o-ring and just put one in that fit!  I probably need a harder durability rating, like a BUNA-N 90 for this application and the one I used is most likely a BUNA-N 70.  I have reached back out to Hatsan and asked them to provide the specs for that o-ring, but no telling when or if I'll get a reply.  I may have to dig through my stash of o-ring and see if I have any denser o-rings in a size close enough to see if I can get it working again...  But first, I need to air it back up and see if that's where it's leaking from, or if I have another leak!

O-ring and groove size matching is critical especially at high pressure. If dimensions of BOTH are correct then a 70A hardness Buna o-ring "could" work just fine. For loose tolerances seen in budget PCPs I've found that the 90A hardness Buna o-rings can be a more reliable choice.

I see a lot of o-ring ERRORS daily. People STRETCHING o-rings like rubber-bands to fit something WAY TOO large, o-rings too fat for their grooves which get SLICED during assembly, and wrong material used (Buna,Viton,EPDM,Silicone,etc.) for the temperature and/or chemicals contained.

Proper fit & space to "squash", material type, and material hardness and all critical. Your o-ring failing so quickly could be improper sizing as well as improper hardness.

Buna is FINE for airgun use. No need for any of the other materials which would fare better than Buna in a brewery environment.

More than you ever wanted to know about o-rings ;-)
https://www.parker.com/content/dam/Parker-com/Literature/O-Ring-Division-Literature/ORD-5700.pdf

[Rat Sniper (AKA: PaulT58)]

I just refilled it to 250 BAR. It is still leaking from the fill valve, so it could very well be a combo of both wrong size and wrong durability. It’s a slow leak now, but still a leak!  I can put my finger and thumb over both sides of the fill port and feel the pressure building!  If I knew the correct o-ring size, I probably have one on hand.

And one know the correct size o-ring for the Flash Fill Valve?  Thanks.

[mikeyb]

Sorry I don't have the "R" version to help.

I have to replace o-rings at work on a daily basis. Ordering an o-ring from the original manufacturer is usually painfull. THEY get them cheap and add a huge markup. Usually something silly like >$10 per o-ring, +$10 S&H, and a couple week lead time.

I can choose best material and hardness because I already know the operatiing conditions (like pumping HOT Caustic cleaning solution under moderate pressure).
From there I take a couple measurements of the GROOVES (not the old o-ring which is damaged and will provide the WRONG dimensions) with some dial calipers and find the closest size using the McMaster-Carr online catalog. I then check if Amazon has better pricing for THAT particular o-ring. Bags of 50 o-rings are usually in the $10 range. Whichever source is faster/cheap gets my part order and a lifetime supply of that o-ring usually arrives in 1-2 days.

It gets easy if you have to do it every day for work ;-)

[billygee]

I just refilled it to 250 BAR. It is still leaking from the fill valve, so it could very well be a combo of both wrong size and wrong durability. It’s a slow leak now, but still a leak!  I can put my finger and thumb over both sides of the fill port and feel the pressure building!  If I knew the correct o-ring size, I probably have one on hand.

And one know the correct size o-ring for the Flash Fill Valve?  Thanks.

Paul

thought I was in the Same Boat as you, but fortunately mine was only the fill probe o-rings getting clipped,
So all aired up now awaiting tomorrow seeing if things hold together,
only downfall was a missing molded piece plug where the Flash manometer would go,
Hatsan, stated they would send one out, so we'll see.

Some Auto parts stores do have a wide o-ring individual selection, As sounds like your on the right track,
Hope you can zero in on the right one

Bill

[Rat Sniper (AKA: PaulT58)]

I replaced the o-ring again!  The one I removed was shredded just like the last.  I tried a different size this time.  So far it's holding air, but the last one did too until I shot it and refilled it several times, then it leaked out overnight.  It was a much slower leak this time, but it still leaked.  I'm hoping this one hold up better.

I did detune it a bit, it was shooting the 10.5 CPDs at over a 1000 FPS, it's shooting them at an average of 920 FPS now.  It's also much quieter now also!  Still have not heard a word from Hatsan about the correct size o-ring for the fill valve!  Got to love their customer service!

[Rat Sniper (AKA: PaulT58)]

Sorry I don't have the "R" version to help.

I have to replace o-rings at work on a daily basis. Ordering an o-ring from the original manufacturer is usually painfull. THEY get them cheap and add a huge markup. Usually something silly like >$10 per o-ring, +$10 S&H, and a couple week lead time.

I can choose best material and hardness because I already know the operatiing conditions (like pumping HOT Caustic cleaning solution under moderate pressure).
From there I take a couple measurements of the GROOVES (not the old o-ring which is damaged and will provide the WRONG dimensions) with some dial calipers and find the closest size using the McMaster-Carr online catalog. I then check if Amazon has better pricing for THAT particular o-ring. Bags of 50 o-rings are usually in the $10 range. Whichever source is faster/cheap gets my part order and a lifetime supply of that o-ring usually arrives in 1-2 days.

It gets easy if you have to do it every day for work ;-)

I'm betting the o-ring in the fill valve is the same because the fill valve is probably the same.  Hatsan doesn't have a parts breakdown for the Flash R, just the regular Flash, but I'm betting they share a lot of the same parts!