Vaseline....it's all I've ever used, never had a problem. As has been said, it's so the rings and the liners can be inserted before and removed easily after use.
NAR L2 #84021
Member SCRA #430
Dow 111 is what I use for Research motors. Only because that is what my research mentors told me to use. I do not grease liners (or not yet). I can see where it could be troublesome there.
I never grease the liners either. Rule of thumb: clean out the casing right away after use, no grease needed for the liner. That's what I do, again, never had a problem.
NAR L2 #84021
Member SCRA #430
Uh oh, you said the N-word (never)... and during Mercury Retrograde too!
I find myself wondering how this stuff would work:
http://www.petrolgel.com/
Its melting point is 195, so it is significantly higher than Vaseline. Since I work in a dairy, we have this stuff all around and use it for most everything that doesn't need a lubricating spray. I may swipe a dollop or two to try next time I fly my reloads.
Greg Poehlein
Member of Launch Crue - http://launchcrue.org/
Hint #1: Do not use magician's flash paper for recovery wadding!
Hint #2: Clean your shoes after flyin' in that cow pasture - that ain't no dirt clod on the sole!
My bet is it would work well. But it's also likely a bit on the expensive side, since it looks like it's for use in areas that will come in contact with food.
Remember, the point of the lube is just that -- as a lubricant to allow the ring to slide into place without hanging up and tearing. Anything that doesn't attack the rings or other motor components should work just fine.
-Kevin
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Dow 111, Super Lube, etc. are silicone greases, there are only a few
companies that make silicone grease the rest of them are just repackaging
and marketing their brand.
Go to any Hardware or Auto Parts store and ask for dielectric grease.
That will do you just fine.
All depends on what the O-ring is made of.
Ron Lemke
When The People fear their government there is tyranny.
When The Government fears The People there is Liberty.
Thomas Jefferson
www.shopfloortalk.com
Total Ns flown last year: 270.6
(I gotta fix that problem...)
Total Ns flown this year: 67.0
I've used a wide range of their products. I've used 33, 44, and 111 on everything from my pistol to O-rings in an RMS. Most was applied with a toothpick or Q-tip, and then wiped off (most people put too much on). You do not want to get 111 on your fingers, it has to wear off. A very little bit goes a long way. Expensive? I've never paid for any. They give free samples away if you call and ask nicely.
MolyKote 44 does a really good job of preventing galling on the slide/frame surfaces of an auto pistol.
[Insert clever, witty signature here]
I did the same thing as you - never greased a liner - until my cert flight a week ago.
I've flown 29/40-120 hobbyline RMS loads for years, dozen's of "F" and "G" flights without a problem. Ever. Liners slid right in, and came right out after the flight. I always assembled the motors the night before a planned launch day in my air conditioned kitchen.
My cert flight was my first assembly of a 38mm motor. Not sure if 38mm normally has a tighter liner, or it was just a very humid day, but the ungreased liner locked up in the case about 3/4 of an inch short of going all the way in. We tried everything to convince it to get in there, but no luck. It finally came out with a ton of effort using a set of needle nose plyers. By this time it was a bit mangled, and even after greasing it got stuck again. I ended up having to buy another reload kit for my cert flight. Expensive lesson.
The following day I still had rocket fever so I launched two G64-4W at my local field. The motors both assembled fine, I didn't grease the liners either. When I got them home, both liners were solidly stuck and it took alot of time and mess getting them out.
Moral of the story - I'll be greasing liners from here on out!
Jeff
___________________________
TRA #13709
Flight stats for 2013: H=4, I=5, J=6, K=3
Total Impulse Burned: 14494
Current Projects:
4" Mad Cow Frenzy5.5" BSD Horizon Clone ("Artificial Horizon" - my L3 certification rocket)
Hate to break it to you, but greasing liners doesn't guarantee they'll come out easily. I've fought to extract greased liners.
It's a matter of when the liner burns through a bit and chars, sticking to the case in the process. Grease does you absolutely no good when that happens, and I can tell you from experience that it doesn't do anything to prevent it, either.
It does, however, consume a lot more grease, and make your hands slimey.
-Kevin
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For me, phenolic liners are more likely to seize in a case, no matter what lube I use on it.
I've found the same to be true. I suspect that motors that use phenolic liners run hotter, and are thus more likely to char, which is what causes them to stick in the first place.
Purely a theory -- I know enough about making motors to be dangerous enough to be at risk of getting a hangnail, and not much more than that.
-Kevin
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There is a dry graphite lubricant I use on a number of my peices of ag
equipment. I wonder if a dry graphite film would work better on liner issues.
I will post some more on this product later.
I launch some Aerotech RMS F and G motors and have not had any liner
issues yet.
Ron Lemke
When The People fear their government there is tyranny.
When The Government fears The People there is Liberty.
Thomas Jefferson
www.shopfloortalk.com
Total Ns flown last year: 270.6
(I gotta fix that problem...)
Total Ns flown this year: 67.0
thanks for saving me from typing that ... it has nothing to do with heat or pressurization... it's simply for making the o-ring slick so it doesn't pinch during assembly. the o ring provides the seal.
it takes a very tiny amount
this is a far as o rings are concerned .. greasing liners ..I don't know whats best
Last edited by Stymye; 27th March 2012 at 10:55 PM.
Andy
RIP Justyn Palmer, Erik Gates,Paul Robinson and Frank Kosdon
You all will be deeply missed
Ns of 2011: 5395 Ns (35% M)
Ns of 2012 : 5373.9Ns Ns (34.9% M)
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I haven't typically greased liners, but I do on the Aerotech G138, per the instructions: "6. Apply a liberal amount of grease to the outside surface of the propellant grain". There is no paper liner for this grain, just a thin synthetic liner of some sort bonded to the grain.
Last edited by dpower; 28th March 2012 at 04:19 PM.
Paul
NAR #87246 L1 - Section #558 - www.wooshrocketry.org
"If we weren't all crazy, we would go insane" - Jimmy Buffett
I do use grease on the outside as per the instructions, though I've never had burn-through on a G138 before. I take off the forward closure, everything pops out of it nice and cleanly under pressure from the o-ring (unlike the high-power 29mm's: I HATE those forward closures), take out the aft closure, and then use the nozzle to push everything out of the case. No scrubbing necessary.
2013 impulse burned: 5205.1 Ns
2013 impulse lined up to burn: ~56,445 Ns
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You mean that the grease prevents the edge of the liner from getting flame behind it?
In any case (or rather, in only the 29/40-120 case ahaha) the G138 is awesome because it's so fast to load and easy to clean and has such amazing performance for the size. Though that was off-topic.
2013 impulse burned: 5205.1 Ns
2013 impulse lined up to burn: ~56,445 Ns
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