Canadian Airgun Forum

The #1 Community for Airguns in Canada!
It is currently Tue Nov 19, 2019 10:46 am

All times are UTC - 5 hours


The Canadian Airgun Forums are a place for people to discuss and learn about airguns and the airgunning sport in Canada. There are lots of discussions about airguns, airgun accessories, reviews, modification and repair information, airgun events, field target and free classifieds!

 

You need to register before you can post: click the register link to proceed. Before you register, please read the forum rules. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own pictures, and access many other special features. Registration is fast, simple, and absolutely free! To start viewing messages, select the forum that you want to visit from the selection below.








Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: lubricants
PostPosted: Mon Jun 13, 2016 10:23 am 
Offline
User avatar

Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8977
Location: Coalmont BC
Joe, I have melted a Delrin piston in a pumper, so don't fool yourself into thinking they don't get very hot.... If you are going from 15 psi to 1500 psi in one stroke, that 100:1 compression ratio will easily heat the air beyond the flash point of a petroleum based lube.... Just sayin'....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Mon Jun 13, 2016 4:38 pm 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
Jeeze Bob, I hope not. Anyway, I'll be using synthetic lube, so no worries.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Mon Jun 13, 2016 7:25 pm 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
I have an air pump, more or less, at work that makes ~150psi and the output air is either >600F or >800F, I forget which. Point is 70F air at 14.7psi is only going to ~150psi (basically 10-1 compression) and it gets that hot, so 3k (200-1 CR) is no doubt seriously hot.
Now what happens when you compress it with dino grease and it ignites I can't say, but I doubt much of anything and I'd imagine you might not even notice it. My guess is it would burn off slowly as pumping pressure/heat increased while filling the gun so you'd never get a good light off like with a springer. If you freshly oiled it and pumped into a fully charged gun then I'd imagine it would simply vent the extra pressure/volume into the gun so no biggie. Who knows, you might feel some force pushing back on the handle but I really think it would be small. I could be wrong and there are a lot of factors involved that would change that, but that's my thoughts on it...
If dino oil was a serious issue then I'd imagine there would be a serious warning with the pump, and chatter about it online.
I don't know how your pump is setup inside but I kinda doubt there are any metal to metal parts that really need lube. My guess is the guide for the pump shaft at the top is the only metal to metal point and that doesn't "need" lube, but a little dino grease there won't hurt. I'd think the guide would be bronze but that costs $ so they likely skimped. I'd assume all the other parts inside are separated by O-rings, so O-ring to metal would be the only real lube concern and silicone should be the thing to get. Or fancy silicone like that Super Lube or whatever.
So the compressed air will make heat, or more accurately you're concentrating all the heat into a smaller space. Kinda like a magnifying glass concentrates the suns heat it into a tiny spot, and the tinier the spot the hotter it gets. In a springer the duration of heat is extremely short and the gun has tons of time to cool between shots so it usually doesn't bother the seal. In the pump the heat is likely greater, lasts much much longer, and far less time to cool between rounds, so the metal parts get hot and thus the O-ring cooks in that part(s). My guess is once the O-ring starts leaking a teeny weeny bit from being dry/cooked or whatever, then that spot will have both the brutal ambient heat and have it blasting past the spot like a torch, so I think once it leaks at all the party's over. At least that's what I believe happens.
So basically I'd be concerned about the temp where the seals live. Hopefully the pumps hot parts are alum and have cooling fins? The piston face probably has no good way to dissipate heat, and that's probably where the main O-ring(s) are sitting. If so then I suppose I'd coat the end of the piston with ceramic or something to reflect heat and/or be an insulator so the piston doesn't absorb so much.
That or be very easy to swap out O-rings and have a stash of spares.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Mon Jun 13, 2016 7:49 pm 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
Chevota wrote:
I have an air pump, more or less, at work that makes ~150psi and the output air is either >600F or >800F, I forget which. Point is 70F air at 14.7psi is only going to ~150psi (basically 10-1 compression) and it gets that hot, so 3k (200-1 CR) is no doubt seriously hot.
Now what happens when you compress it with dino grease and it ignites I can't say, but I doubt much of anything and I'd imagine you might not even notice it. My guess is it would burn off slowly as pumping pressure/heat increased while filling the gun so you'd never get a good light off like with a springer. If you freshly oiled it and pumped into a fully charged gun then I'd imagine it would simply vent the extra pressure/volume into the gun so no biggie. Who knows, you might feel some force pushing back on the handle but I really think it would be small. I could be wrong and there are a lot of factors involved that would change that, but that's my thoughts on it...
If dino oil was a serious issue then I'd imagine there would be a serious warning with the pump, and chatter about it online.
I don't know how your pump is setup inside but I kinda doubt there are any metal to metal parts that really need lube. My guess is the guide for the pump shaft at the top is the only metal to metal point and that doesn't "need" lube, but a little dino grease there won't hurt. I'd think the guide would be bronze but that costs $ so they likely skimped. I'd assume all the other parts inside are separated by O-rings, so O-ring to metal would be the only real lube concern and silicone should be the thing to get. Or fancy silicone like that Super Lube or whatever.
So the compressed air will make heat, or more accurately you're concentrating all the heat into a smaller space. Kinda like a magnifying glass concentrates the suns heat it into a tiny spot, and the tinier the spot the hotter it gets. In a springer the duration of heat is extremely short and the gun has tons of time to cool between shots so it usually doesn't bother the seal. In the pump the heat is likely greater, lasts much much longer, and far less time to cool between rounds, so the metal parts get hot and thus the O-ring cooks in that part(s). My guess is once the O-ring starts leaking a teeny weeny bit from being dry/cooked or whatever, then that spot will have both the brutal ambient heat and have it blasting past the spot like a torch, so I think once it leaks at all the party's over. At least that's what I believe happens.
So basically I'd be concerned about the temp where the seals live. Hopefully the pumps hot parts are alum and have cooling fins? The piston face probably has no good way to dissipate heat, and that's probably where the main O-ring(s) are sitting. If so then I suppose I'd coat the end of the piston with ceramic or something to reflect heat and/or be an insulator so the piston doesn't absorb so much.
That or be very easy to swap out O-rings and have a stash of spares.

Actually the whole tube is 1/8" wall aluminum, and the valve is aluminum, so is should absorb the heat between shots. The metal to metal, is the pump shaft and guide as you said. Not much oil needed there. Its steel on steel. All other grease or oil points are exterior. However I have read that super lube synthetic is great on all applications.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Mon Jun 13, 2016 8:21 pm 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
I mean the parts that actually see the heat. I can picture the fixed part at the base dissipating into the tube, to a degree, but I'm really wondering about the piston itself. It doesn't get as much heat as the rest, but almost no way to dissipate the heat and my guess is the piston/shaft is solid steel so the heat moves very slow. But maybe they made it in such a way that it cools well enough? When you take it apart please post pix so I/we can check it out.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Tue Jun 14, 2016 5:19 am 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
Chevota wrote:
I mean the parts that actually see the heat. I can picture the fixed part at the base dissipating into the tube, to a degree, but I'm really wondering about the piston itself. It doesn't get as much heat as the rest, but almost no way to dissipate the heat and my guess is the piston/shaft is solid steel so the heat moves very slow. But maybe they made it in such a way that it cools well enough? When you take it apart please post pix so I/we can check it out.

This is a home made single stroke pneumatic pump. Any heat will be produced the last inch or so of the pump stroke, between the pump face and valve face. O rings are Viton, which are a higher heat range than Buna.
In case anyone is curious aboul the building of this SSP. It,s been a year in the making, and looks like at least a couple of months before the reveal. The first prototype showed no signs of heat problems, only linkage wear, so we're beefing up the pivot points. We only get to work on it one day a month on avg. So its slow going.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Tue Jun 14, 2016 5:39 am 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
rsterne wrote:
Joe, I have melted a Delrin piston in a pumper, so don't fool yourself into thinking they don't get very hot.... If you are going from 15 psi to 1500 psi in one stroke, that 100:1 compression ratio will easily heat the air beyond the flash point of a petroleum based lube.... Just sayin'....

Bob

Bob. The melting point of delrin is 175 to 250 degrees F. The autoignition temp. of gasoline is 536 F, whereas grease is around 1000 degrees.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Tue Jun 14, 2016 10:10 am 
Offline
User avatar

Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8977
Location: Coalmont BC
That's Celcius, not Fahrenheit, Joe.... Delrin melts at 350-482*F.... I can assure you Delrin won't melt in boiling water (212*F).... It got hot enough to not only melt, but it was charred.... The auto-ignition point of gasoline is 475-536*F.... Interestingly, Diesel fuel is only 410*F....

All I can tell you is that compressed air gets hot.... Obvioulsly diesel engines, with a compression ratio of only about 15 or 16:1 reach over 410*F to ignite Diesel fuel.... I agree, your SuperLube should be fine for your application, however....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Tue Jun 14, 2016 6:14 pm 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
If it's home made then I really want to see pix! I love that stuff. Even the prototype...
I've contemplated making an electric pump with a Crosman nitro spring as the piston, but the whole heat thing is what's really put a wrench in the idea since it has a rubber seal inside. I was also considering using compressed air to drive the little high pressure ram rather than an elect motor. I have one at work that goes past 10k? but it seems kinda slow to me. It's uncomfortable to pressure test new untested things at that pressure, as you can imagine. One guy died, instantly...


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Tue Jun 14, 2016 9:18 pm 
Offline
User avatar

Joined: Thu Feb 02, 2006 11:35 pm
Posts: 3099
Location: Alberta Canada
Chevota are you talking a Haskel pump? And I have to ask why wasnt a containment cell being used for a PT. If buddy was killed?

_________________
May the cry of the pack be with you upon your hunt

Whitewolf


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Wed Jun 15, 2016 4:57 am 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
Chevota wrote:
If it's home made then I really want to see pix! I love that stuff. Even the prototype...
I've contemplated making an electric pump with a Crosman nitro spring as the piston, but the whole heat thing is what's really put a wrench in the idea since it has a rubber seal inside. I was also considering using compressed air to drive the little high pressure ram rather than an elect motor. I have one at work that goes past 10k? but it seems kinda slow to me. It's uncomfortable to pressure test new untested things at that pressure, as you can imagine. One guy died, instantly...

When the gun is finished and tested with 1000 shots, and all is well, I plan to make a video. Until then its a secret. Even the first prototype, because the valve is our own invention, it has gone through a few modifications sinc the original idea, and now works perfect, possibly patentable. However we need to finish the gun and do the endurance test first.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Wed Jun 15, 2016 8:50 pm 
Offline

Joined: Sat Jan 25, 2014 9:16 pm
Posts: 1271
Location: United States
Roger on the secret squirrel pump, but now I'm even more curious...

The 150psi pump I mentioned is actually whatever turbine engine I happen to be testing and you can feed air off the compressor section if you want. I was playing with that last week actually, it makes some serious volume! I was thinking about the dream air compressor it would be for shop use, but kinda spendy, extremely loud and and a major gas hog so I guess not very good at all... The low volume high pressure pump is a Haskel type, but no clue on the brand. We use a 9kpsi N2 tank (dream pcp tank) for testing a maze of tubing from 1/4"ID to 1" with a zillion fittings, but then if needed you can fire up the boost pump to break 10k on up to whatever its limit is. No safety, except safety glasses. Fill the lines, then crawl around in them with a spray bottle w/ dish soap. They never blow but I suppose one day...

Where the guy died was a different test and a single container that weighs like 20+klbs and has ~20cf of volume that we fill to ~3kpsi? I don't know the details, they don't like to talk about it. The containment cell was the building reinforced with wood and I guess steel, which still didn't contain it. It has a huge cover plate which was basically the size of a manhole but way thicker. The cover was leaking so he was out there tightening the bolts while under pressure. Threads let loose and that cover launched while he was in front of it. I'm totally baffled it could've happened normally, but rumor mill says he only installed every other bolt and used a huge stack of washers under each bolt to save time threading them in. My guess is over torquing a bolt barely threaded in and the threads let loose, which cascaded to the others in a micro second. Witnesses said the cover took off half his torso on up, and what the cover hit splatted him everywhere which had to be mopped up, but it was everywhere and in everything so they never actually cleaned him up, especially the ceiling, and could smell it for a long time. Now if you get caught fixing leaks while under pressure they throw a fit, but it's still done on smaller but still deadly things since doing it by the book would take too long.


Top
 Profile  
 
 Post subject: Re: lubricants
PostPosted: Thu Jun 16, 2016 5:53 am 
Offline
User avatar

Joined: Sun Jan 09, 2011 8:07 am
Posts: 3320
Location: Central West River Nova Scotia
Seems theres always one person who thinks shortcutting to save time or money is OK. More often than not, it bites you in the buttock, later. I have made that mistake during this gun build, but was lucky to have been out of the line of fire. Its too easy to become complacent with high pressure when dealing with such a relatively small volume, but, even a small volume, when you introduce a projectile, a pin or bolt,etc... can be deadly. Cascade failure is all to common in high pressure aplications. Like the 2240. If the valve screw fails, the other screws down stream, like the breach and trigger screws, dont seem to even slow down the valve as it exits.

_________________
If I had only one wish, it would be to be able to "unsay" things.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group

phpBB SEO