TargetTalk

Filling cartridges for an LP 10 Problem. Do you normally fill below 200 bar or just above or right on? It seems I'm blowing o rings if I fill too high slightly above 200 bar. The cartridge o ring blows out. I've now testing how high I can fill before another o ring goes. Its holding at 160 bar so far. These are older Pilkgun o rings and I think they may be tooo old. Thanks Ron

Ron;

I use a bicycle pump style and go to 200 bar and add two more pumps so when I remove the cylinder with the quick loss of air they are right at 200 bar.

Have two cylinders and they both will hold at 200 bar for as long as it takes for me to use them again on my next session which could be a few days to more than a month.

To be clear, are you saying that the cylinder end seals are leaking(either at the gauge end or the spanner nut end ?

Hope someone can help you out.

Clarence

If you are asking about the O-rings on the filling adaptor and the cylinder mount on the gun then the answer is simple, get some new O-rings.

Compared to the other costs of shooting they cost the square root of nothing.

One thing I forgot to mention is a very small film of lubricant grease on the o-rings.
I use Super Lube applied and when I say small, i mean small, a little goes a long way.
It keeps the o-ring from rolling and produces a sort of hydraulic seal.

Clarence

Thanks all! It doesn't leak it blow a tare in the side of the o ring and all comes out in about 5 seconds as its tank is screwed on. I guess these rings are too old. Thanks Ron

Take one of your rings and see what you can find at your local Ace Hardware. You may be surprised. Anything will be better than what you're using.

According to the Steyr parts list, the O-ring is 4 x 1.5 mm. Metric O-rings are measured by inside diameter and then thickness.

McMaster Carr has 9 different flavors in this size (use the search feature on the left)

http://www.mcmaster.com/#o-rings/=ytjx48

I think I would probably go with Viton. It's a bit harder than the typical Buna-N rings, which will hold up better to the high pressure. Viton is also more chemical resistant, which might mean they would deteriorate less in storage. They may not be as good as the official green ones, but for $3.33 for 25, they are certainly cheap enough to experiment with if you can't get the real thing quickly:

http://www.mcmaster.com/#9263k289/=ytk1xg

Depending on how close you are to an industrial area, you may be able to find the right size locally, but they will probably be Buna N, and they will want to sell you a bag of 100 for more money.

You definitely want a tiny bit of grease on them. Just enough to put a thin film on the surface. This will help avoid abrasion (which leads to tearing), and improves the sealing. Any extra tends to attract dirt. If you order from McMaster, this will work:

http://www.mcmaster.com/#1418k29/=ytk3wo

Most hardware & automotive places will carry silicone grease that will work as well.

Thanks all! I tried American hardware. They had some the right size in black but they blew out like a bad balloon. I have a call it to Pilkgun but I'll also contact Mcmaster and see. You say the best to get is the Viton. Are you saying Viton is the original? I just pumped a cartridge up the 175 bars and will get to try this week. Maybe the old ring will hold at this pressure. I will place an order anyway.They are holding at 160 bar so at least I can shoot. Thanks Ron

Gwhite wrote:According to the Steyr parts list, the O-ring is 4 x 1.5 mm. Metric O-rings are measured by inside diameter and then thickness.

McMaster Carr has 9 different flavors in this size (use the search feature on the left)

http://www.mcmaster.com/#o-rings/=ytjx48

I think I would probably go with Viton. It's a bit harder than the typical Buna-N rings, which will hold up better to the high pressure. Viton is also more chemical resistant, which might mean they would deteriorate less in storage. They may not be as good as the official green ones, but for $3.33 for 25, they are certainly cheap enough to experiment with if you can't get the real thing quickly:

http://www.mcmaster.com/#9263k289/=ytk1xg

Depending on how close you are to an industrial area, you may be able to find the right size locally, but they will probably be Buna N, and they will want to sell you a bag of 100 for more money.

You definitely want a tiny bit of grease on them. Just enough to put a thin film on the surface. This will help avoid abrasion (which leads to tearing), and improves the sealing. Any extra tends to attract dirt. If you order from McMaster, this will work:

http://www.mcmaster.com/#1418k29/=ytk3wo

Most hardware & automotive places will carry silicone grease that will work as well.

Great info! Do you have an LP10 or LP1? Do you use these rings and are they working good for you?
Sounds like your a big fan of those Viton rings you sent the page on. Are the original rings Buna-N rings or Viton or what? It sounds like the original rings are not in this country only pilkgun. Thanks again Ron

I don't know what the original rings are, and I haven't tried the Viton ones. I think Steyr used the same green rings on their CO2 pistols, in which case they are probably polyurethane, which resists absorbing high pressure CO2. Unfortunately, polyurethane rings are pretty scarce, which might explain the high cost. They are also available in green, but so are other materials.

I recommended Viton for two reasons:

1) The ones McMaster has are slightly stiffer (durometer 75 instead of 70) than the typical Buna N ones. This would make them hold up better under the high pressures involved.

2) Viton is more resistant to chemical attack, which means they probably won't deteriorate in storage as quickly.

Polyurethane O-rings can be had in a durometer rating of 90, which is a good bit stiffer than the hardware store stuff. I wouldn't be surprised if that is what Steyr uses.

McMaster does have durometer 90 Buna N O-rings:

http://www.mcmaster.com/#1247n132/=ytmoe0

for another $3.11, you could try both.

I did a quick search on-line, and I didn't find anyone that had urethane O-rings in the right size in stock.

darticus wrote:They had some the right size in black but they blew out like a bad balloon.

Did you mentioned that their application would be compressed air?
You probably bought o rings for water. They are not suited for this.

Don't waste time, just get in touch with Pilkguns and i'm pretty sure they will have them in stock.

Hope this helps

darticus wrote:They had some the right size in black but they blew out like a bad balloon.

This is why I suspect you need a harder (higher durometer rating) than typical hardware store O-rings (which are undoubtedly Buna-N material, and probably durometer of 70 or less).

For compressed air, durometer 90 O-rings should work much better. For CO2, the pressures are lower, and the Viton (durometer 75) might hold up better because it doesn't absorb CO2 as much as Buna N.

Don't change direction when attaching or removing the cylinder. Screw it all the way on or all the way off. Reversing direction pinches the o ring and will cause it to fail. At the point where you hear the valve open when attaching there is ~120^ further rotation before it is fully engaged. Also as others have said the lightest smear of grease on the o ring is helpful.

It sounds like the store-bought O-rings are too soft, allowing them to extrude out the gaps in the joint. If that is the case, lube will make it worse. They aren't working anyway, so the fix is to get better O-rings.

There are some Buna-N O-rings that are very soft (durometer rating of 50). They would be easy to install, and fine for domestic water pressure (~125 psi max). I suspect that's what the hardware store sold him.

I've used standard durometer 70 Buna-N O-rings up to ~ 120 bar for oceanographic work, but the tolerances on the joints must be fairly precise. They are also fine for CO2 pressures (only ~ 55 bar) except for the gas absorption problem. I did some poking around, and all the scuba shops recommend durometer 90 O-rings for full tank pressure, so I think that is the issue. The general consensus in the scuba world seems to be that Buna-N is OK, Viton is better, and polyurethane is best. The big selling point for polyurethane is that it's abrasion resistant, which would be good for the pistol cylinder connection.

The team I help coach now has about a half dozen Steyrs. I think I'll toss in a bag of the durometer 90 Buna-N O-rings from McMaster the next time I place an order. I haven't found any place that sells Viton or polyurethane O-rings in the right size, much less with a durometer of 90.

I'm very happy that I got an invoice for 5 o rings for my guns LP1 and LP10 from Pilkgun. I had no idea that 5 o rings would cost anywhere close to $24.30. I gonna have to hold until I make some money as I'm out of work and just making it and too old to mow lawns. I may have to sell my LP10 AND LP1 next months to pay bills. I still have some O rings I bought from Pilkgun 5 years ago and they are holding 160 bar at present. They may only last through 3 cycles but will see. Could be worse could have a Daisy. I do have a daisy HUMMMM. I may have to try some o rings that you guys suggested. Thanks All Ron