Tuning Artemis P15 Woes

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loganlexow

loganlexow

Member
Dec 5, 2018
24
1
WA, United States
Good morning everyone. I am a stupid gorilla and ruined my .25 poppet and poppet spring yesterday when trying to install the Xtreme XL plenum. I am hoping to find someone in the states that has spare parts or can make a new poppet valve for me. The only place I've found with available parts is in Greece and they want 50 euros to ship for $5 worth of parts. You can see in the pic how dumb I am. Please don't make me feel worse lol. I have searched all over for spares, and asked on FB and other groups with no success. Help me Obi Wan Kenobi; you're my only hope. 



**I am cross posting this on GTA to get maximum help**

20201202_141032.1607007649.jpg

 
I don’t want to give you a hard time about it but I would love to know how that happened.

Regarding OEM replacements, at one time you could get them direct from SPA but my understanding is the Diana partnership put an end to that (or the timing was a coincidence).

These guys in the UK show the poppet available.
https://spares.bagnallandkirkwood.co.uk/smk/smk-artemis-p15-air-rifle-spare-parts/
It says no stock on the valve spring but you can probably improvise one from a spring assortment, or worst case order one from McMaster.
 
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I will look in an hour and see if I have a poppet. you can get the spring at a local Ace hardware store. nick
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I haven't been to an Ace yet. My concern is that it is a conical spring approximately 2in X 1/2in bottom O.D. X 1/4in upper I.D. and is very heavily tensioned. McMaster-Carr has nothing like this that I have found. My search for a generic replacement spring hasn't ended yet. However, I am building this out to be a slug gun with good power. Would a lighter spring help in this situation? 
 
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I don’t want to give you a hard time about it but I would love to know how that happened.

Regarding OEM replacements, at one time you could get them direct from SPA but my understanding is the Diana partnership put an end to that (or the timing was a coincidence).

These guys in the UK show the poppet available.
https://spares.bagnallandkirkwood.co.uk/smk/smk-artemis-p15-air-rifle-spare-parts/
It says no stock on the valve spring but you can probably improvise one from a spring assortment, or worst case order one from McMaster.
Click to expand...

Well, the plenum was assembled when I received it. There is a piece on the new plenum that looks JUST LIKE the stock plenum (circled in red). Where the spring sits, the new plenum had a smaller I.D. I simply thought that I was battling heavy spring tension and forced it to go together. Like I said, I am dumb lol. 

P15_Plenum.1607012778.png




I did email the guys in the UK. They want 20GBP for the poppet and 24GBP for shipping, and they do not have the spring in stock. I did think about trying to make a poppet from PEEK using my dremel and sandpaper. However, I have never done something like that, and seeing my track record here, think it could be a risk lol.
 
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In a regulated system, you can get by with a weaker valve spring. It won’t make a significant difference in how hard it is to knock open the valve (how much hammer spring tension is needed) but it does affect valve dwell....the weaker spring allowing more dwell which could be a good thing for shooting slugs. However most OEM PCPs will easily deliver too much dwell so by no means is it a must-do.

The valve spring plays a much more important role in an unregulated PCP. Using a weak valve spring will give a narrow bell curve.
 
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Dunno if he's still open buy Mrodair might have what you need or try Air Venturi Pyramid Air or Airgunproshop or AOA.

OH! Try these guys! Bear in mind due to Canada power restrictions the spring may be weaker best to ask but they might have other parts. You can make your own spring with piano wire or fishing leader steel line if piano wire is too expensive. Springs are easy to make yourself.

https://airgunarcheryfun.ca/pcp-rifles/
 
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Yeah I don’t advise tackling a PEEK poppet with caveman tools unless you are very patient and supremely confident in your skills. It can be a humbling material...the slightest imperfection and it will leak. It’s quite possible with hand tools if you can fashion a lapping jig to help shape the sealing face, and then do a final lapping run in the valve to bring the surfaces into a perfect mate. For the first-timer, a simple cylindrical poppet is a better place to cut your teeth. A tapered poppet will prove more challenging. 
 
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Dunno if he's still open buy Mrodair might have what you need or try Air Venturi Pyramid Air or Airgunproshop or AOA.

OH! Try these guys! Bear in mind due to Canada power restrictions the spring may be weaker best to ask but they might have other parts. You can make your own spring with piano wire or fishing leader steel line if piano wire is too expensive. Springs are easy to make yourself.

https://airgunarcheryfun.ca/pcp-rifles/
Click to expand...

I didn't even think about making a spring. Great idea if I can't find one, thank you!
 
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In a regulated system, you can get by with a weaker valve spring. It won’t make a significant difference in how hard it is to knock open the valve (how much hammer spring tension is needed) but it does affect valve dwell....the weaker spring allowing more dwell which could be a good thing for shooting slugs. However most OEM PCPs will easily deliver too much dwell so by no means is it a must-do.

The valve spring plays a much more important role in an unregulated PCP. Using a weak valve spring will give a narrow bell curve.
Click to expand...

Yeah I don’t advise tackling a PEEK poppet with caveman tools unless you are very patient and supremely confident in your skills. It can be a humbling material...the slightest imperfection and it will leak. It’s quite possible with hand tools if you can fashion a lapping jig to help shape the sealing face, and then do a final lapping run in the valve to bring the surfaces into a perfect mate. For the first-timer, a simple cylindrical poppet is a better place to cut your teeth. A tapered poppet will prove more challenging.
Click to expand...

Dang, thank you for helping me learn here! I wondered about the taper on this poppet being a pain to shape. I like your "caveman tool" remark. That's exactly what it would have to be at this point lol. Would delrin be easier with my hack tools? I am only asking to learn. 
 
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Yes Delrin or acetal is much more forgiving of slight imperfections. PET-P (e.g. Ertalyte) is another good material for DIY poppets.


Here’s a thought...you could make a simple cylindrical poppet and let it seal along the outside rim against the tapered wall of the valve. That will concentrate the force on a small ring of poppet material so it will compress and help form a seal despite any minor surface imperfections. Note the important part here will be to ensure the poppet OD is made concentric to the stem. If the stem is off-center, the rim of the poppet will not meet with the valve properly. If off by too much, it won’t seal at all. If off by just a smidge, it may seal but the stem will be in a bind.
 
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Yes Delrin or acetal is much more forgiving of slight imperfections. PET-P (e.g. Ertalyte) is another good material for DIY poppets.


Here’s a thought...you could make a simple cylindrical poppet and let it seal along the outside rim against the tapered wall of the valve. That will concentrate the force on a small ring of poppet material so it will compress and help form a seal despite any minor surface imperfections. Note the important part here will be to ensure the poppet OD is made concentric to the stem. If the stem is off-center, the rim of the poppet will not meet with the valve properly. If off by too much, it won’t seal at all. If off by just a smidge, it may seal but the stem will be in a bind.
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I think I will try that. But I'm am really crossing my fingers that @socaloldman can find a poppet and save me a headache. I'd rather experiment when I have the ability to go backwards lol. 

Here's what really gets me. I just ordered a LW barrel to have A.E. Swede swap on to this thing. Bah lol
 
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I have some more sorta bad news for you. I built my P15 for max power in .25. It has some unobtainable parts. Over $1,200 invested not including lathe time building custom hammers. Sadly it’s still an underpowered slug gun. Happily it’s a great 25gr pellet gun. Shoots them right in the sweet spot velocity wise that all the good guns do. Thank god TJ barrels like pellets and slugs. 
 
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I have some more sorta bad news for you. I built my P15 for max power in .25. It has some unobtainable parts. Over $1,200 invested not including lathe time building custom hammers. Sadly it’s still an underpowered slug gun. Happily it’s a great 25gr pellet gun. Shoots them right in the sweet spot velocity wise that all the good guns do.
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I don't look at that as bad news. If it doesn't shoot slugs but will shoot pellets well, I think that's still a win. My gun is just so bad, even at 20yds. But I love this little thing so much. It looks the business and doesn't weigh much at all. I know I'm polishing a turd but, I'm OK with that lol. It's more of an experience and experiment gun anyways. I figure eventually I'll grow into something like a FX, but until then, I'd rather learn on something like this. 
 
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If you decide to try it, you’ll need a pretty beefy torch because the bolt will be wicking away a lot of the heat. For example a pencil torch on a propane bottle won’t cut it. I’m guessing you’d want to get it spinning in a drill so you can heat the whole thing. Not sure, haven’t attempted something like it. 


Winding a spring from music wire isn’t that difficult but I’ve only done common compression and torsion springs. Never tried making a conical. 


As Tony expertly observed, springs are available in all shapes and sizes...except the one you need.

https://www.youtube.com/watch?v=jAawhg6JtyY 


 
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If you decide to try it, you’ll need a pretty beefy torch because the bolt will be wicking away a lot of the heat. For example a pencil torch on a propane bottle won’t cut it. I’m guessing you’d want to get it spinning in a drill so you can heat the whole thing. Not sure, haven’t attempted something like it. 


Winding a spring from music wire isn’t that difficult but I’ve only done common compression and torsion springs. Never tried making a conical. 


As Tony expertly observed, springs are available in all shapes and sizes...except the one you need.



https://www.youtube.com/watch?v=jAawhg6JtyY 



Click to expand...

That was a great video lol. I don't know if I'll be able to pull that off or not. If I had a lathe I'd be able to make my own poppet, among other things. Crap
 
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