Diana Chaser CO2 seal

My beloved Chaser has started to leak down over time. It appears to be the cartridge seal. I recently performed this same repair on my Plinkster, but for the life of me, I can't find where I sourced the seal. It's more of a neck seal than your standard Crosman compression face seal.

I have seen Youtube DIY videos that convert to a face seal made of some toilet gasket material, and I may go that route if I can't find what I'm looking for.

Any help appreciated.

@jim_in_pgh 

Have you tried these:

https://www.ebay.com/itm/294978819482  

??

I left CO2 many years ago, so I am not really conversant with what is current. Sorry I cannot be of greater assistance.

Keep us posted!

HM

Thanks for the reply Hector. That kit does not contain the critical cartridge seal. I've found them in bulk, but I would have to buy 10 packs of 3, and pay overseas shipping. My quest continues.

As stated earlier, there is a DIY conversion to a simple compression face seal, which is looking more and more attractive.

I love these SPA modular guns, but the lack of maintenance parts is frustrating. Perhaps Diana should know about this?

@jim_in_pgh 

Hi Jim. You might give these guys a try and see if they have what you need. They do show the CO2 seal as in stock.

https://spares.bagnallandkirkwood.co.uk/diana/diana-chaser-2/

Not sure what the shipping cost would be like but it might get your Chaser back up and running again. You might even be able to pick up some other bits to help make the shipping seem better.

EDIT: Or maybe since they still sell it, you might see if Pyramid can get you a seal or two.

Good Luck!

i saw and than tested with some Buna 70 dura Oring size 009 and they work fine 

they should be urethane but the buna seems to be 

working and have worked for months 

x2 on the -009 O-ring.

https://www.gatewaytoairguns.org/GTA/index.php?topic=144028

@marflow 

Is this what I want?

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_1321_1323&products_id=27483

Thanks. I appreciate your knowledge of these guns.

so, i think i have another option 

the Gamo R-77 have a flat urethane seal that is about 1mm thick but you will see in the picture they would work also OD is 9mm and they are a cart nose seal 

Pistol CO2 O Ring for Gamo CO2 pistols - Replacement Part

All is well. A few drops of ATF stop-leak and a day of sitting muzzle up, and it is holding gas again. No parts purchased, and no tear-down.

Very nice!  I hope it lasts.  I did something similar when my SPA CR600W started leaking but it only postponed the repair for a few CO2 cartridges.

The good news is the replacement in polyurethane has held up great. 

@jim_in_pgh 

Building on NT's experience and knowledge, I would suggest these:

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_2205_829_830&products_id=35088  

Quad seals need less pressure to seal and the Fluorocarbon compound will last a long time when exposed to CO2.

Alternatively, I can send you a couple of 009 Buna in Sh 90 A for the cost of shipping. Harder compound will resist better the adsorption of CO2 into the material which is what degrades the seal over time.

AND you could also try a M2X5 Oring, they are bit "fatter" than the 009, but so close in OD that they should fit into the CO2 cartridge receiving recess.

Let me know if I can be of further assistance.

HM

@hector_j_medina_g 

Thanks Hector. Would you recommend the quad seal over these? (Minimum purchase is an issue.)

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=367_1321_1323&products_id=27483

I appreciate your knowledge and feedback.

@jim_in_pgh 

While I have not used Polyurethane (PU) in CO2 guns, I use it in my ORing piston seals for cases where the power is moderate to low (mainly old Match rifles).

In higher power applications I use H-NBR because it has better resistance to "setting".

Now, this table:

https://www.apachepipe.com/assets/chemical-resistance-table.pdf  

Says that PU has excellent resistance to Carbon Dioxide, experiencing "little to no effect" from exposure to CO2.

Now, my experience with Pistols, (the SSP's like the V-10 and the FAS 6004) tells me that Quad rings are better suited to the low pressures in those systems.

So, I would buy the PU Orings if a few dollars made the difference, whatever you decide shipping is almost going to cost more than the Orings themselves.

Now, for the price of a first class stamp, I can send you two 009 Sh 90 A Orings and two M2X5 Sh 70 A Orings. 

😉

Why don't we do this:

You buy the PU Orings and I will send you the Sh 90 A and the Sh 70 A, you can then test all.

The only requirement is that you keep track of the endurance of them and post to this forum when you have some experience.

Huh?

What say Ye?

Keep well and shoot straight!

HM

@hector_j_medina_g 

I just ordered minimum qty of 16 009 70D PU o-rings. Given that I have only 2 SPA CO2 guns to maintain, if they work, I'll be willing to disburse the rest of them to the community.

Thanks for your offer.

you can make this type of seal with and the right size leather punch and some material 

material for CO2 

back in the day when, The 850 Forum was alive and well they told us Urethane always and nothing else and in the perfect world that is what we should do as it will not absorb CO2

people will tell that buna will be all swollen up and will off gas the CO2 

sheet urethane goods are not cheap and hard to find the Chaser would take 1.5mm, the Gamo R-77 is 1mm, a stem seal for a S&W 78-79g pistol is 3mm or 1/8 

finding the right punch is easy on Ebay but the centering of the seal is the hard part 

i take a wood dowel and that will slip inside the punch and the wood dowel has a pin centered in it, punch the small hole slide and then the wood dowel with pin in the small hole and punch out the seal

 now are Urethane Oring need always maybe not but the rule was if they came in contacted with CO2 the answer was YES can they always be found and that answer is NO 

i have been chasing Orings and seal for 15+ years 

if you look for sheet goods you do not want rubber urethane 

Hello and best wishes to all. This is great information. Thank you.