GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: kevinbrian on December 08, 2012, 02:06:05 PM
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I have home tuned plenty of HW guns. I just buy them new and then 'have at it'. It's my hobby. It's waht I like to do. I have always had those inclinations. And probably always will. I have always used ARH Moly paste.....just a smear behind the seal...none on the face. I am presently playing with an HW95K in 20 cal. The spring wire is .128. It is 29 coils. It is spaced on the rear guide about two nickels width. I am using a ARH hornet seal. I am getting 810 fps average wth 11.6 grain FTT's. Not bad.
But I wonder one thing. Does anyone use anything else as a piston seal lube??? Something...say.....a bit slicker. My piston is buttoned so there is no metal to metal during the cocking and firing stroke.
This question always seems to tempt several to ask: "WHY CHANGE??? If it' working why change???" Answer: Why not? Why can't i try new technique to see if I can optimize things a bit more?
And to the nice airgunners out there who have entertained the same question......I appreciate you kind responses. I am just in the mood to try new stuff. I have a new can of ARH moly if I mess up. I have acetone and other volatiles available to clean out the tube and all components. I just feel like experimenting today and am hoping that if anyone has, and with success, they'll share a hint or two with me. I appreciate all responses.
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not that im aware of yet
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Ed Canoles over on the Yellow is trying straight moly powder. No other lube inside.
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It makes sense to me that, with the piston buttoned properly and no metal on metal, there are probably a lot of options available to use as lube. I hope that Gene will chime in on this one, about the superlube with ptfe. I don't know enough about it to recommend it, all I've ever lubed a gun with is moly or plain white lithium grease, and ARH moly is my favorite thing.
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This my understanding of what I have read. A spring piston cylinder should be cross hatched with a 400 grit and not high polished. For the reason that the Superlube with PTF as Bryan had mentioned will adhere better in the cylinder. So when applying the Superlube it should be dry wiped off as much possible. And the ARH moly paste on the piston seal is the only moly paste recommended.
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Kailua let me ask, because I have not tried a light film of superlube then wiping it off on the piston seal then covering it with moly, makes no sense to me but I've got to ask! my experience with SL is it migrates past the piston seal, I understand your theory but have you tried this experiment with and with out the superlube and noticed any real difference in performance? :P
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Sorry if I was not clear. My understanding the superlube was to prime the cylinder not applied to the piston or piston seal.
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This might make more sense being this is from Charlie's tuning guide.
Super-Lube
SuperLube w/PTFE can be a good lubricant. Great for piston into tube assembly and it has a silicone base with PTFE to help fill imperfections in compression chambers in synthetic sealed guns and tubes. Must be used sparingly as it will cause detonation. Wipe out all excess before installing piston. Carried by many parts stores and I think Wal-Mart.
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OK that answers my question from where you got the info! but IMO molly is all that's needed and their are different grades of molly out there that are better than ARH molly, the superlube is kinda used as an assembly lube I believe from that info source, molly does the same thing and it will burnish itself into the metal so that's why I questioned the usage of the superlube in this applycation? I do use superlube buy I mix it 50/50 with molly and only use it on external parts like trigger sears and barrel forks or block areas, JMO :P
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I appreciate all of the replies. Ya know, I am having difficulty wondering why a "metal to metal" lube is SO recommended for a synthetic seal, and delrin buttons on the piston. There is no metal to metal until the piston hook engages the trigger lock (if that's the right term for the part of the Rekord trigger that engages the piston rod hook)
In times past, I would put some moly paste on certain parts of the trigger. (I don't do that now). I would tear into the gun a couple months later and see that the moly paste had dried out.
I am certianly not trying to start a war here. I have used good old ARH moly for a quite a while. And as long as I keep playing with airguns, I will always keep some (as long as it's available). It's not that I dislike ARH moly....actually I love the stuff. But I was just hoping that someone who home tunes alot might have stumbled upon a recipe of something slicker, that might be better for a "delrin to metal" or a "synthetic material to metal" application that is very slick and will STAY slick.
I have tried spraying silicon spray into the firing area of the chamber, and letting dry. And then using Eurolube as piston seal lube. Velocity gains were had.....but I didn't put but about 150 shots down the tube before I opened the gun up again to try a new spring. Anyway....I certainly appreciate all who have taken the time to respond. Merry Christmas.
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Kevinbrian,
You might try some of the Vortek lube. I recently installed kits in two R7s and the kits came with some lube that looked a lot like the moly paste from ARH, but thinner. Instead of using the Maccari stuff like I usually do, I tried out the stuff Vortek sent on all of the inside parts like piston seal and piston itself. One one R7 it was a relube since it was slow at about 575 fps after the tune. I also resized the seal, and now its a bit over 600 fps. I don't know if it was the lube or seal sizing and breaking in, but there was improvement. It might be worth a shot trying to order some of this lube and seeing if it makes a difference.
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the Molly is more than just metal to metal lube...it is also a fuel.
Giving a slight increase in performance by wicking the Molly in through the hone lines.
Have tried everything myself, from eddies slick 50 treatment to my own creations.
I will stick with what the pros recommend, as it has worked very well and my guns perform the best this way.
Goodluck.
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The Kid is onto it. The crosshatching retains grease, the hydrocarbon part of Moly added grease and feds a small amount into the compression chamber with each shot so that it diesels and gives more power. This is well documented by Cardew. OK if that is what you want but I always want a bit less power in the higher power rifles.
Here in Wellington some of us use Di-electric grease on piston seals. It is a silicon grease used for lubicating electical things where a spark might cause a bang. Also used in the marine industry for lubricating salt water pump impellors. A very small amount on the lip of the seal on assembly is all you need. It is recommended for synthetic to steel lubrication but not for steel to steel because it does not had have good load carrying capacity. It does resist high temperatures where hydrorcarbon grease, which all or most moly are based on, will ignite.
Your fellow countryman Dr. Beeman recommends a drip or two of oil through the transfer port every 500 pellets.
The same recommendation appears in the older Weihrauch instruction manuals. This was obviously necessary with leather piston seals but probably no so with the synthetic ones.
Sometimes a synthetic seal can become dry and squeak. Rightly or wrongly I put two drops of silicon oil down the transfer port sometimes. I am not particular enough to count or estimate pellet numbers. So far no adverse effects and silicon oil does not ignite. It supplements the silicon grease I use on reassembly. Possibly a smear gets ejected into the barrel and lubricates that.
Take care of it in your workshop becaue it is tenacious stuff and can transfer from bench to timber and then your gluing job or your painting job will be a problem.
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When I reread the above I cringe at the typos. Ah well I will get over it soon.
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theirs is a spell check LOL!!!!!! :P
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I got some of the white lube. And the purple. And the moly colored. All from Vortek. I get a different color with each kit. Saved 'em all. I'll start my experimenting tomorrow. Thanks...kevin
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I've been using DuPont Krytox (http://www2.dupont.com/Lubricants/en_US/index.html) in my springers for over 15 years. IME/O this lube is superior to anything I have read about others using and yes, I started as most do, with James Maccari's excellent lubes. I know that's going to fly in the face of the establishment but check it out if you're looking for something that works great for synthetic polymer seals AND O-rings. Krytox is THE lubricant for O-rings. Nothing else comes close. Please research it before flaming me! I've been modding and working on air rifles since the 80's. Just a tinker, toiling away in obscurity.
Reasons for use:
It is completely free of any hydrocarbons and chemically inert.
It can NOT support combustion, even in a pure oxygen environment, so "dieseling" is out of the question. Coefficient of friction is very LOW i.e. very slippery. There's NO silicone in it so it safe to use with silicone O-rings, seals and hoses. Has a wide temperature range, so it doesn't increase viscosity at low temps and that makes it great for cold weather hunting. ALL of F-1, Indy Car and NASCAR use it for nearly all applications requiring "grease". All they care about is the high temp rating and the low coefficient of friction but they swear by it.
In another life, I was a diver and started using this stuff on my rebreathers and regulator O-rings.
DuPont had to invent this product for the space program, so it should go without saying, O-rings and lubrication are huge issues in outer space. The downsides to this are the availability and the PRICE. As you can imagine, it's not cheap. BUT, a little goes a long way. If you're a tightwad and think that Maccari's lubes are too high, then don't even bother looking this stuff up!
..also, there's basically only two viscosities commonly available. I have both and blend the two to get something in the middle. Not necessary, I'm just sick like that! Get the thin stuff if you want things simple.
*NOTE* IF you smoke, do NOT get Krytox on your fingers! Even if you don't smoke, wear nitrile gloves while handling Krytox.
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No flaming from me Quigley!!! I appreciate your post. And for your candidness. I am going to see who has Krytox in my area. I am always open to new stuff. A home tuner can ALWAYS backtrack to the good ol standard. And I mean absolutely no disrespect to the ARG kube users. I am one of them. I have placed MANY AN ORDER with ARH and I;m not even a pro-tuner. I'm a self tuner. And I wear that label with pride. Again...I mean no disrespect to the pro tuners. I have shot many of the rifles they tuned and I am always amazed at the wonderful shot cycle. It's just that... I've got time to try doing it myself. And there are likely more than just a few of use who do it like that. It's our nature.
So, Quigley...I thoroughly appreciate the 'heads up' on a product that I will try.
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Good info Quig thanks for sharing! :P
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Dang. I was just looking at some prices for the krytox, you ain't lying about the price! Which one is the lower viscosity version?
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Krytox is a cryogenic product used for pure oxygen environs. It is totally hydrocarbon free for use in oxygen clean applications. I used to work in the field, it is good stuff and very expensive....
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I have home tuned plenty of HW guns. I just buy them new and then 'have at it'. It's my hobby. It's waht I like to do. I have always had those inclinations. And probably always will. I have always used ARH Moly paste.....just a smear behind the seal...none on the face. I am presently playing with an HW95K in 20 cal. The spring wire is .128. It is 29 coils. It is spaced on the rear guide about two nickels width. I am using a ARH hornet seal. I am getting 810 fps average wth 11.6 grain FTT's. Not bad.
But I wonder one thing. Does anyone use anything else as a piston seal lube??? Something...say.....a bit slicker. My piston is buttoned so there is no metal to metal during the cocking and firing stroke.
This question always seems to tempt several to ask: "WHY CHANGE??? If it' working why change???" Answer: Why not? Why can't i try new technique to see if I can optimize things a bit more?
And to the nice airgunners out there who have entertained the same question......I appreciate you kind responses. I am just in the mood to try new stuff. I have a new can of ARH moly if I mess up. I have acetone and other volatiles available to clean out the tube and all components. I just feel like experimenting today and am hoping that if anyone has, and with success, they'll share a hint or two with me. I appreciate all responses.
Well.......I've been messing with the stripping of all "grease" from my HW pistons and lubing with only dry graphite powder. I do lose a few fps (maybe 10) since there is little/no combustion in the shot cycle, however I get very consistent velocities that aren't affected very much by temperature induced lube thickening/thinning. So far my brother has been running dry graphite lube for a year with great success in the squirrel woods and field target course shooting his R9 in the hunter class.
A bit of a warning though......the first time I used dry graphite I puffed some dry graphite through the transfer port without thoroughly degreasing the piston. Well.....the graphite powder mixed with the existing molly paste and formed a sort of "gloopy stuff" that made it even hard to extract the piston. After that I disassembled the R9, degreased the piston and receiver, then applied the dry graphite powder........worked a treat!
I'm not saying that YOU should do the same.......only answering your question pertaining to "alternate piston seal lubes". By the way, I'm running home turned oring sealed piston caps in my HW springers (my brother also) and here is a pic of a couple orings. The one on the left is unused and the one on the right was used with graphite powder for quite a few shots, then removed for inspection. Notice that the oring on the right looks like it's been "pewter plated" by the embedded graphite..........
(http://img.photobucket.com/albums/v734/wved/Airgun%20Mods/Piston%20Cap/GraphiteCoveredOring.jpg)
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Ed Canoles over on the Yellow is trying straight moly powder. No other lube inside.
After using 6 micron molly powder for a while I do believe that graphite powder worked better. LOL.....been thinking of a 50/50 mix of molly and graphite but haven't tried it yet.
By the way, the molly powder (pretty expensive stuff) did work well for a few thousand shots, but then I started getting a SLIGHT grating noise when cocking. Disassembled the R9 and there was no evidence of galling, however I didn't relube with the molly powder.
I also tried a 50/50 mixture of 100% silicone grease and molly powder thinking that the silicone would be good for the oring and the molly would be good for the metal. Well.....not so good since the R9 started having the "light grating sounds" quicker than molly powder alone.
Anywhoo..........IMHO the general user would be better served by just using Maccari molly paste!
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No flaming from me Quigley!!! I appreciate your post. And for your candidness. I am going to see who has Krytox in my area. I am always open to new stuff. A home tuner can ALWAYS backtrack to the good ol standard. And I mean absolutely no disrespect to the ARG kube users. I am one of them. I have placed MANY AN ORDER with ARH and I;m not even a pro-tuner. I'm a self tuner. And I wear that label with pride. Again...I mean no disrespect to the pro tuners. I have shot many of the rifles they tuned and I am always amazed at the wonderful shot cycle. It's just that... I've got time to try doing it myself. And there are likely more than just a few of use who do it like that. It's our nature.
So, Quigley...I thoroughly appreciate the 'heads up' on a product that I will try.
You're more than welcome Kevin!
..when I read your opening post, what you said really resonated with me because it sounds like we're a lot alike. If people never experiment or think outside the box, where would civilization be??? Hope it helps everyone out. ..especially the folks using O-rings. Even though I don't have any guns set up with O-ring seals, I can't help but to think that this lube is what they're looking for! I'm actually very interested in the O-ring piston seal idea but don't have the time right now for machining any adapters and/or doing a conversion along with the experimentation that would go along with that endeavor. It's on my "to do" list for sure. Good luck to all.
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Dang. I was just looking at some prices for the krytox, you ain't lying about the price! Which one is the lower viscosity version?
When I wrote that reply, it was all from memory so I had to check...
Product Guide (http://www2.dupont.com/Lubricants/en_US/uses_apps/Product_Guide.html)
..the thin one is a 68 and the thicker one is 220, but looking at that chart it seems more is available than I remember. ? The thick stuff is similar in viscosity to commonly available wheel bearing grease. A little too thick for our application IMO.
Anyone interested in this product should peruse the link that I gave to DuPont's website. Tons of great info on this product! Also, because there are so many "formulas" available, it would probably be a good idea to contact a dealer rep that really knows the product. I procured my stash (many years ago!) from a friend that works in the aerospace industry. ..still in the original plastic butter tubs marked A and B. Ha!
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hey-Hey!!!,
Seems the tuners are in competition with Catholic priesthood in who can be the most stubbornly conservative. Have they said they were wrong to go after Copernicus and Gallileo yet?
Krytox can also be had with boron nitride. That stuff is sublime. By itself it is a bit sensitive to water, but in a grease...top notch.
cheers,
Douglas
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Great post Quigley !
I was not aware of the DuPont lube. Definitely something to think about for the next tune. Excellent information.
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This is a grease we use on Turbo Chargers, high temp hydrocarbon free....
http://productsearch.nyelubricants.com/pdf%5CTDS_English_UNIFLOR%208512R.pdf (http://productsearch.nyelubricants.com/pdf%5CTDS_English_UNIFLOR%208512R.pdf)
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WOW.......
http://www.newgateonline.com/application/industrial/ball-and-lead-screw-lubricants/uniflor-8512-50gram-tube.html (http://www.newgateonline.com/application/industrial/ball-and-lead-screw-lubricants/uniflor-8512-50gram-tube.html)
Over $100 for 50 grams (about 1 3/4 oz). It SHOULD be good stuff!!!
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I think that is very close to Krytox "Krytox oils and Greases are based on perfluoropolyether oils. These synthetic fluorinated lubricants
are used in extreme conditions such as continuous high temperatures up to 300° C (572° F) and higher
temperatures for shorter periods, depending on product grade limits. They are non flammable and are
safe for use in oxygen service. They are chemically inert and are used safely around hazardous
chemicals. They do not damage plastics or elastomers or cause corrosion to metals. They are
commonly used as lubricants in aerospace, automotive, industrial and semiconductor applications as
well as solving many other routine lubrication problems.
The 2Cx series grease contains an oil soluble additive that is effective at preventing corrosion and
reducing wear. It also contains a micro powder boron nitride extreme pressure additive. Typical
applications include those in potentially corrosive atmospheres, where vibrational or shock loading may
be significant and where an element will spend more time experiencing mixed film or boundary
lubrication versus the desired full film or hydrodynamic lubrication"
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WOW.......
http://www.newgateonline.com/application/industrial/ball-and-lead-screw-lubricants/uniflor-8512-50gram-tube.html (http://www.newgateonline.com/application/industrial/ball-and-lead-screw-lubricants/uniflor-8512-50gram-tube.html)
Over $100 for 50 grams (about 1 3/4 oz). It SHOULD be good stuff!!!
Yeah, and the stuff on my tool box is a 600 gram tube.....
We buy in bulk and the tubes cost about $250.00 each...
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That is the second warning I have read about Krytox in the last few days. "Use gloves and no smoking."
How toxic is it and what happens if you get some transfered to the person?
Does any of it ever end up getting discharged out the muzzle as a mist?
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I just relubed my HW95K 20 cal with my tube of Krytox 205 Grease (17 bux from Macmasters carr) I am now getting 827 fps from FTT pellets with zero dieseling. I used a thin film around seal, and put a dab on all six buttons. I also put a little on a qtip and wiped a film behind the piston once the piston was inserted, and before the spring/guides went in. So far....this is the stuff I have been looking for!!!!! Thanks Quig!!!!!!!I just bought a .5 oz tube. But it doesn't take much. I could lube tune several more springers with it. Heck, it might even work great as a hammer lube on my 410 bolt action Xtra Fac as I am running it dry right now with excellent results. This stuff is not supposed to gum up and evaporate. It's white. It's slick. It's............KRYTOX!!!! Maybe I'll get a kickback from Dupont for that mini commercial.
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I can guarantee anyone using Krytox will love it.
Results like Kevin posted will speak for themselves.
And like he said, if you think it's c r a p / not worth it, then go back to the status quo!
As I stated in my first post, Krytox is superior to anything I have seen/heard of other tuners using and I have ~15 years experience using it in air guns. I'm getting 850 fps w/ an 18.1gr. JSB out of my Trail NP XL, but I have no idea how much, if any, performance can be attributed to the lube because that rifle was such a POS when I got it I had to tear it down numerous times to fix/replace/mod parts before I'd even consider shooting it. I admit that I am a nobody here / in the air gun world, because I’ve never bothered to become active online until recently. I have many hobbies besides BB guns so I don’t know how much longer I will stick around. One of my other hobbies is custom flashlights, dive lights, lasers and weapon lights that I either mod or build from scratch. I do this by referral only and primarily cater to active military/LEO. I often use Titanium and other exotic metals, and anyone who works with Ti knows it can be a bear to work with from a home machinist’s standpoint. The reason I mention this is because Krytox is my lube of choice for the threads and the O-rings on all my lights. Ti is notorious for galling and Krytox prevents this, which speaks volumes to its lubrication properties. As PakProtector/Douglas mentioned, you can get this lube with many various additives and bases to cover just about any scenario a mad scientist could envision. (http://i28.tinypic.com/ou9ord.jpg)
Good luck and have fun!
Oh, and about the “warnings”.
I put that in quotes intentionally because IMO, this stuff is very safe but there’s always caveats.
Here’s a MSDS (http://www.vacuumoil.com/msdspdfs/GPL22XMSDS.pdf).
And here’s the skinny in layman’s terms...
Because Krytox is such a very unique product you have to look at all this in perspective.
It is not a carcinogen, but you don’t want the stuff in your body either!
The only reported health concern was caused by smokers that got it on their cigarettes and then vaporized/inhaled it into their lungs, causing respiratory problems. Big surprise, duh! Krytox can only be dissolved/removed by a very special solvent. This is both good and bad. The good is that it PERMANENTLY bonds to metals that are properly cleaned/conditioned. The bad news is, you don’t want to get it on anything you care about subjecting that solvent to. And btw, if you thought Krytox was expensive, wait till you get a gander at the solvent! No pain, no gain! hahaaa
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no more toxic than a teflon pan that was overheated and burned.....ya don't want breathe the results if its burned. The amounts we use in an air rifle are extemely small Don't lube ya smokes with it LOL...its for the rifle piston and seal
SECTION 2. HAZARDS IDENTIFICATION
Emergency Overview
Repeated or prolonged skin contact may cause allergic reactions with susceptible persons. The thermal
decomposition vapours of fluorinated polymers may cause polymer fume fever with flu-like symptoms in
humans, especially when smoking contaminated tobacco. Repeated episodes of polymer fume fever may
result in persistent lung effects.
Potential Health Effects
Skin : May cause allergic skin reaction. Itching, Rash, Swelling.
Eyes : May cause eye irritation. Discomfort, tearing, Blurred vision.
Carcinogenicity
None of the components present in this material at concentrations equal to or greater than 0.1% are listed by
IARC, NTP, or OSHA, as a carcinogen.
Print
AUT 2C5 Krytox has a great additive package...I know somebody who has a huge tub of it.
Perfluoropolyether 70 - 80 %
PTFE 10 - 20 %
Boron nitride 10043-11-5 5 - 10 %
Proprietary Additive 2 - 3 %
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Thank you Tom, good stuff apart from the price.
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Sounds like great stuff. Makes sense that it would work best on a polished cylinder, vs. a honed one. What do you guys think?
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From what I understand, the spring tar provides the fuel. Although thick, it gets flung off and then works into the crosshatching. Ed maintains there is no contribution from hydrocarbon fuel or fumes but I will.stick with the Cardews on this one.
As to experimenting with different materials, by all means try them. JM's products are time tested and great for those simply wanting to lube their gun, etc.
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I understand crosshatching with moly. It's the krytox that i am asking about. As for the tar, i though that was for dampening spring vibration...
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Sounds like great stuff. Makes sense that it would work best on a polished cylinder, vs. a honed one. What do you guys think?
The Krytox is just like any other lubricant it will fill in the groves and provide lubrication there...
The PTFE is a really slippery substance so it has to be in between the seal and the cylinder wall...
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Bryan,
I always hone.
To get the best results from Krytox, you need to thoroughly remove any traces of your old lubricant. Hydrocarbon residue adversely effects the molecular bonding of Krytox, a very desirable quality we are paying for.
Here's what I do:
I like to blast everything clean w/ 3M's HP Brake Cleaner followed by scrubbing with hot soapy water(Dawn), rinsing and then wet hone with 600 grit silicone carbide. The honing is primarily to ensure that you are down to "bare metal" but the cross hatch does helps to retain the lube during break-in. I then use compressed air to blast dry my parts. You need CLEAN, DRY compressed air. I do custom paint jobs (another hobby!) and have a refrigerated dryer with Motor Guard desiccant traps at all points of use drops in my shop. If you don't know what any of that means, don't use compressed air for "drying" your uber cleaned parts. Prior to assembly, I then wipe with DuPont Krytox HC Plus cleaner and then lather everything up lovingly with Krytox. (http://i28.tinypic.com/ou9ord.jpg)
There's very little "break-in".
Depending on how heavy handed you were w/ application and your technique, you will get a very slight discharge from the transfer port into the barrel. This is a BONUS(!) because if you have a properly cleaned barrel, you will then get the "Krytox effect" in your rifling! (http://i28.tinypic.com/ou9ord.jpg) After the first half tin/tin of pellets, you can run some patches through the barrel to clean it up, check on the results. YMWV with this. I do this after the first couple tins and then don't bother with the barrel anymore unless I develop a problem. After the first tin of pellets, you should start to notice some very nice, CONSISTENT shot strings. I don't get more than 10 fps extreme spread (ten shot string) in a healthy/Quigley tuned gun. Have a few guns that are very consistently 5-6 fps es. Anything more is a bad pellet. Best of luck!
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KevinBrian,
Don't let my post above worry you or make you feel that you need to re-do things.
I didn't go through all that on my first couple guns and still had very good results!
See how your job holds up and then tweak things as you go along.
..that's what led to what I wrote above.
Also, I'm just a wee bit touched in the head! (http://i28.tinypic.com/ou9ord.jpg)
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I have read that with an O-ring seal, you want a polished cylinder unlike the regular piston seals we use. I figured that the way this stuff bonds with the metal, in conjunction with the fact that it is not a source of fuel for combustion, it would work best with a polished cylinder- or that perhaps it wouldn't make a difference either way. I have read that the honing of the cylinder serves 2 purposes- provides a better surface for the moly lubricant to "stick" to in order to create an evenly lubricated surface, and also to provide a tiny amount of fresh moly for fuel on every shot. That's why I had to ask...
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Bryan,
I forgot about the O-ring scenario!
If you clean like I described, bonding is a non-issue, so don't bother honing if you already have the correct surface finish/roughness. And speaking of that, "polish" is a vague term. What you really need to find out is what the correct RMS/micron rating is supposed to be and compare it to what you have. There are micron rated abrasives (3M) available that can be used to "clean up" the compression tube. May or may not be necessary, just throwing it out there. Most of my experience with machining O-rings is for their use in a static condition as opposed to a truly dynamic one such as this.
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Here's what I do:
Thanks for the detailed procedure! Yesterday I ordered "Dupont Krytox Standard Gpl 205 Grease, 0.5-ounce Tube" from McMaster Carr and I'm hoping that this stuff will be what I've been searching for. I've been running oring sealed piston caps in my HW springers with great success for over a decade. The issue however has been the propensity of molly paste to diesel and eventually "wear away" at the point of sliding metal parts like the high pressure point of the top skirt of the piston against the receiver tube during cocking.
I'll give my oring sealed R9 the "scrub and Krytox" treatment as do some testing, especially as it pertains to temperature induced poi shifts. I've felt that one of the issues with hydrocarbon based grease like molly paste (basically molly powder in mineral oil) is that the molly paste "out gasses" more at higher atmospheric temperatures than lower so there is a tendency for the poi to shift. Years ago both my brother and I had a poi shift of 1" at 20 yards during an early spring field target match where the sight-in was done during snow flurries, yet the afternoon temps rose to the 60s. The search was on for more stable early/late season squirrel hunts and I found that MINIMAL lubing along with oring sealed piston caps mitigated the poi shifts to a great degree. Our (my brother and I) latest lubing scheme has been to use only dry powdered graphite for piston/oring lubing and it does work great (very little temp induced poi shifts), however I have found that I occasionally need to "puff" a bit of extra graphite into the compression tube through the transfer port to keep things sliding free.
I'm hoping that the "$17 for 1/2 oz stuff" would give a good lubricated oring/piston lube without temperature induced poi shifts. Along with the Krytox I also ordered a package of 90 durometer Nitrile orings to try instead of the 70 durometer rings I normally use. In the past I've tried the harder stuff with molly paste lube and found that the softer rings worked better for sealing the varying nature of a R9 compression tube.
For a dynamic oring seal the recommended surface finish of the bottom of the groove and cylinder surface is 32 microinch (smooth honing), and the recommended finish of the sides of the groove is 63 microinch. Here is a chart of recommended dynamic oring sealing specs......
http://www.allorings.com/gland_dynamic_reciprocating.htm (http://www.allorings.com/gland_dynamic_reciprocating.htm)
Here is a chart giving the surface finishes achieved with various cutting methods.......
http://engineershandbook.com/Tables/surfaceroughness.htm (http://engineershandbook.com/Tables/surfaceroughness.htm)
Keep in mind that the high pressure spike of the springer shot cycle is very short (cylinders operate under full pressure for the full length of the stroke) and the mainspring "duty cycle" isn't very long (most springs don't last for 10,000-20,000 shots), the peak pressure isn't really high (perhaps 3000 psi) so I've found that the well fitted oring usually lasts longer than the spring. I can get a 100 count bag of Nitrile orings for less than $5 plus shipping so I usually replace my orings yearly (have occasionally skipped a year without incident) when I do my winter "dustin & cleanin".
Anywhoo......again, thanks for the "how to" info and I'm hoping that the 'spensive Krytox stuff works well enough to nix both the molly paste and the graphite powder.
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I home-honed ( I made a home made........mandrel?) and lightly honed it with 320 grit leaving it very smooth but crosshatched at what appears to be a 60 degree angle, though there is no way of my measuring. I just know that I only ran the hone in and out at a fast speed with drill turning at slower speed. I only made a few passes in and out with transmission fluid as my cutting oil. I then cleaned up everything and checked my work. Like alot like the inside of a TX200 compression tube.
I weighed my FTT;'s. They are 11.8 grains. At 830 fps. Over 18 fpe. No dieseling. No smell of smoke.
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I never liked the idea of using a brake cylinder hone in my airguns- and I've never invested near as much as some of you into one. I made a "flapper" for my honing purposes with a wooden dowel and a piece cut from a plastic package that a centerpoint scope came in. Put a piece of 400 grit in there and honed tge cylinder evenly even across the cocking slot and etc. so that the whole tube had a proper cross-hatch for the thin layer of moly to stick to. Made more sense to me than honing the compression area only, as all the metal on metal contact occurs behind it, after all, and the use of moly for fuel seems like a secondary purpose compared to providing a lubricant between two pieces of steel.
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I've been using DuPont Krytox (http://www2.dupont.com/Lubricants/en_US/index.html) in my springers for over 15 years.
I wish to personally thank y'ALL for this thread that mentions springer lubing and the Krytox lubes! I have ordered a $17 half oz tube of the "205 stuff" from McMaster Carr and I'm hoping that it will "live up to the billing".
Over the years I've relied on molly paste for my internal lubing, however I have learned from experience that the carrier in the molly paste I've been buying from a couple airgun sources will evaporate over time leaving a kinda gummy substance. LOL....I have a "screw top container" of molly paste bought years ago and over the years the paste became so thick that I ended up thinning it a bit with mineral oil to restore the original thickness. I don't know what the carrier was originally, and the mineral oil did seem to work, however the mix will detonate if it gets in front of the piston seal.
A couple years ago I started messing with dry graphite powder as a piston seal lube so there would be no "age related thickening" and it has worked well for the oring sealed piston cap, however it also seemed to need an occasional "puff" of powder through the transfer port to maintain a "piston to receiver contact" lube. Then I experimented with 6 micron molly powder in place of the graphite and it also seemed to work well, however after a while I would start noticing a SLIGHT "grating action" when cocking. Regular molly paste on the piston skirt would solve the "grating action", but I learned that if the molly paste migrated to the dry graphite lubed oring sealing surface it wasn't so good. I learned that when graphite powder mixed with migrated molly paste, the resulting "sticky gum" would kinda "glue" the piston to the receiver which affected the velocity.
Anywhoo.......IF the Krytox performs as claimed for my applications, then perhaps I've found an all around springer internal grease that will lube everything without excess dieseling (I'm hoping NONE)!
Again, thanks to all contributors to this very interesting thread! My Krytox is on the way and I'm looking foreward to trying it!!
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Ed maintains there is no contribution from hydrocarbon fuel or fumes but I will.stick with the Cardews on this one.
LOL....Ed doesn't CLAIM that there is NO contribution.........just that the velocity difference between lubing the piston/receiver of his .177 R9 and .177 HW77 with dry graphite was only 10fps less than when lubing with Maccari molly paste, and the graphite lubed velocity was very consistent. My brother also had about the same velocity drop when he switched to dry graphite. Anywhoo........I don't get NEARLY the velocity increase using molly paste instead of dry graphite as Cardew got with his experiments.
Perhaps this is because Cardew was doing most of his tests with leather sealed HW35 class springers and they REQUIRED the oiling of the seal. I personally don't think that tests of an 8fpe leather sealed springer are NECESSARILY applicable to a synthetic sealed 15fpe springer.
Just My Humble Opinion here! :o
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In reference to Bryan concerning "brake cylinder honing". I fully agree. Oh I have several including a 400 grit one which feels just as abrasive as the 220 grit. There is no numbering on the sides of the rather inexpensive brake hone stones so who knows. But I did one HW95 tube (compression area only using the "supposed" 400 grit 3 way brake hone and it was too aggressive. I could take a dental pick and lightly scratch the area and FEEL the crosshatching. So I went back to using a wooden dowel with a slit cut in the end for a three inch wide strip of wet/dry 320 grit. It actually leaves a LESS aggressive surface feeling and I can crosshatch the entire length of the tube. They look pretty good and they feel very smooth. And yet I can see the crosshatching. It took some practice and messing up some tubes, but I have finally got to where I can make one feel and look about like a TX200 compression tube (if ya happen to get one that is properly done). With the entire compression tube crosshatched, my 6 piston buttons have a very thin film of Krytox to glide on. I am constantly monitoring my velocity. Still getting 831 fps ave with a VERY low Extreme spread using an unsized Hornet seal (it goes in tight if its dry). I use a spring of .128 wire. The coils are opened up pretty good so the only spacing I use is about a millimeter and a half on the rear guide. Plastic tophat in front. The firing cycle is "snick" and that's it. No after shock, after buzz, after nothing. I have it just like I want it. It is 30 yard one hole accurate with FTT's, Exacts, and Barracudas. I think that the Exacts are running at 763 fps average but not sure. I use the FTT's as my standard. Got lots of them. But when I run my dowel in and out a few times using transmission fluid as a cutting oil/lube, my goal is NOT to alter any dimensions. I ONLY want to score the tube with as nice a pattern as possible for lube retention. I forgot to add that I also VERY LIGHTLY chamfer the inside of the transfer port but I leave the transfer port alone. I've got enough spring power to push the air through that .118 inch port without noticeable rebound. I think that I have got it balanced out pretty good for a rookie.
But this set up requires an unsized Hornet seal (with this powerful spring). I tried a Vortek red seal that was sized kinda loose but still sealing, and I lost about 20 fps. Don't really know what's going on there. I figured a looser seal made of harder material would be the ticket. But not with THIS particular set up. The Spring is a Vortek spring from a 2G hw95 kit. The spring wire needs to be the .128 wire. I think some have come with .125 wire. But a good balanced set up could be achieved with that as well. Tight guides. No buzz. Just my rookie opinion. (It's a 20 cal by the way)
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Some of what I've found goes against conventional wisdom so causes issues for some folks. For those who prefer to play it safe, stick with the tried and true methods. They obviously work well judging from their high success rate. If your'e into experimenting, have at it. That said....
I've done a lot of research into the manufacturers of the materials used to make piston and rod seals and what they say regarding their products.
Since interlocking friction is not a significant issue with synthetic seals, the need for a finished surface with strong lubrication retaining properties is reduced. For metallic bores and piston assemblies that utilize synthetic seals, lower RA in the 8-10 range allows better sealing, reduced wear, and lower interlocking friction which results in faster piston assembly response. 320-400 grit depending on the hardness of the metals, will give an 7-10 RA finish. The requirements for wet seal and a self lubricating dry seal are very different, and a lot of what is being applied to airguns seems to be more applicable to wet seal characteristics. High speed pnuematic applications (airguns) are generally dry and rather than wanting to hold any oils, greases or other lubes in the cylinder surface, you want just enough roughness to allow seal material to wear off and adhere. Once that happens, usually after the piston has gone through 100 or so cycles, the roughness in the walls is filled with seal material which acts as lube, and further wearing is greatly reduced. In my opinion, and its only that, any other lube is only a precaution against metal to metal contact, hence the use of moly which is for that purpose and not synthetic to metal contact.
Surface finish depends a lot on the hardness of the metal. A 400 grit stone will not leave the same surface RA on two metals of different hardness.
Also, seal materials impregnated with graphite, teflon seals and other similar extreme low friction materials according to manufacturers can use somewhat smoother finish. This stuff is according to Daemar and Goodyear for those needing reference.
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Please by all means start a thread to follow you Krytox results ;D
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Please by all means start a thread to follow you Krytox results ;D
Be glad to......I'll start one in the "Airgun Gate".
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Thanks ED I am wanting to follow your results. You are good on details. I want to see if you like it as much as I have but I have used a different version with other additives. The one I listed ingredients on
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Thanks ED I am wanting to follow your results. You are good on details. I want to see if you like it as much as I have but I have used a different version with other additives. The one I listed ingredients on
Tom, I did a search on the formula you mentioned and couldn't find it to buy in small quantities, however, so far I'm liking the "205 stuff"!
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I've been using Krytox in my RWS350 since last May when Pak Protector/Douglas recommended it and have been very satisfied.
http://www.gatewaytoairguns.org/GTA/index.php?topic=31299.msg290138#msg290138 (http://www.gatewaytoairguns.org/GTA/index.php?topic=31299.msg290138#msg290138)
It is interesting that it took this long to catch the interest of everyone ...better late than never. Thanks Douglas!
Eric