Too Much Lube In Motor

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Delta-IV

Delta-IV

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At the NEFAR Bunnell Blast this past weekend, I suffered my first "operator error" reload flight. :eek: :cry:

After lubing the o-rings and inside of the casing including the forward enclosure and placing the delay element in the enclosure I noticed squeeze-out of the vasoline in the port for the black powder.

I cleaned out the excess and went on my merry way....see below:

Hi-Tech&


With the advice of Brian Coyle of what might be the problem, was in fact found to be correct; After the recover and autopsy I discovered that the paper cap was intact and the delay element had burned completely but all of the black powder came sprinkling out the aft as I unscrewed the enclosure. A blob of vasoline was not visible but the lining was still slick.

Conclusion; be conservative in lubing the casing etc. and when squeeze out is noticed STOP and start over again.

My tribute video:

https://www.delta-iv-rockets.com/joomla/Videos-Website/Hi-Tech 45 Final Flight - lo res.wmv
 
Only supposed to lube them to the point where they're shiney. You should see no grease/lube on them at all after they've been lubed. Never get any lube on either end of the delay grain as that will prevent it from burning.

-Aaron
 
Yep. The idea behind the lube is so the o-rings will slide into place and not pinch during assembly. It also makes it easier to unscrew the closures.
 
JDcluster said:
Vaseline is not a good lube for motors.



JD
Click to expand...

Aerotech thinks it is.

From the instruction manual "NOTE: When all the
grease that comes with the motor has been consumed,
use petroleum jelly or similar grease."
 
Indiana said:
Aerotech thinks it is.

From the instruction manual "NOTE: When all the
grease that comes with the motor has been consumed,
use petroleum jelly or similar grease."
Click to expand...

Right, but Aerotech's rings are intended to be single use, which is why vaseline is perfectly fine.

Someone smarter than me can correct me if I'm wrong, but it's my understanding that petroleum jelly will deteriorate o-rings over the longer term, which is why something like super lube is the preferred grease for o-rings.
 
SpartaChris said:
Right, but Aerotech's rings are intended to be single use, which is why vaseline is perfectly fine.

Someone smarter than me can correct me if I'm wrong, but it's my understanding that petroleum jelly will deteriorate o-rings over the longer term, which is why something like super lube is the preferred grease for o-rings.
Click to expand...

I don't remember who, but when I was just getting into reloads, good ole vasoline was recommended and since I build up my motors just prior to launch I haven't had any issues.....until Saturday of course.

I have built up som 24mm reloads and didn't use it that day and once stored it for two months in a sealed zip-lock bag. No issues from those launches.

Thanks for the insights....and just wanted to post this thread in the hopes of other novices wouldn't repeat my error.
 
The grease doesn't seal the motors, the o-rings do. So, Vaseline is probably just fine if you plan to throw them out after use. However, for anything larger than 38mm I would suggest a better grease. Anything with a graphite nozzle, I suggest a better grease. At those sizes and those nozzle temperatures, something with a little heat resistance is good to help out the o-rings some.
 
You should not grease the delay at all. Put a tiny, tiny amount on the walls only of the forward closure delay well. I grease my motor liners before inserting, not the inside of the casing. If some oozes out, I wipe it off immediately. Getting grease on the delay element is one of the most common reasons for failed ejection charges. Get grease on the rear of the delay element and the delay may never burn. Get grease on the forward end and the delay element will burn almost all the way until that last tiny bit that got the grease soaked in, then it fizzles out and never ignities the BP. Lawn darted a favorite rocket because unknowingly got grease on the forward end of a delay grain when assembling an AMW 38mm motor. Delay burned, but never lit the BP.

I don't fly a lot of rockets using motor ejection anymore. I prefer using altimeters now, when I can.
 
MarkM said:
You should not grease the delay at all. Put a tiny, tiny amount on the walls only of the forward closure delay well.
Click to expand...
Yeah Carl. You gotta stop watching Robb when he's sloppin' the
Dow 111 on those M liners! :D



Anyway, I'm glad you figured out what happend...
 
May my LOC Expediter RIP because of a similar failure. J350 lawndart with my AltAcc in the payload bay for recording purposes.

I learned two things on that flight: Never fly a high power rocket on motor ejection only, and if an altimeter is going up, hook it up to a charge so that it has a chance to save itself.
 
rub the side of your nose , thats how much it takes to make the o-ring slick.
if you can physically see the lube on the ring ...it's way more than necessary
 
Dow 111 has ceased to be part of my range box. After fighting for an hour on several occasions trying to get liners out of 7600 ns AMW caseings,I was advised on slick 50. I used it this past weekend on a 2500 case,liner came out with nozzle with just hand pressure. That 111 will glue your liner to the case,but of course YMMV.
 
jimzcatz said:
Dow 111 has ceased to be part of my range box. After fighting for an hour on several occasions trying to get liners out of 7600 ns AMW caseings,I was advised on slick 50. I used it this past weekend on a 2500 case,liner came out with nozzle with just hand pressure. That 111 will glue your liner to the case,but of course YMMV.
Click to expand...

So far I have use nothing but Vaseline up to a 76/8000 case and on that motor I was able to almost shake it straight out of the case!!

Ben
 
silicon based greases turn to silicon dioxide with the heat and pressure of the motor (dow corning silicon) this is responsible for making liners stuck and cases hard/harder to clean, I believe Teflon based grease is superior
 
I haven't flown many Aerotech motors, but I did lawn dart a tlp Anubis with a recording altimeter in it. I think I got Vaseline on the delay.

My new greasing procedure is to rub just a little Vaseline into the palm of my left hand with my right index finger. I rub it in pretty good and then put an o-ring into my palm and rub it around getting both sides and the outer edge shiny. After ten seconds or so they have a nice shine, but there are no globs of Vaseline to cause problems. I then wipe off my finger and assemble the motor.

I like this method as there is only a little Vaseline involved, the rings get the right amount of grease and only one finger is "contaminated" reducing the chance of accidentally getting grease on the delay or motor grain.
 
Chrisn said:
silicon based greases turn to silicon dioxide with the heat and pressure of the motor (dow corning silicon) this is responsible for making liners stuck and cases hard/harder to clean, I believe Teflon based grease is superior
Click to expand...





Chris,I will give it a try,thanks alot. Any recommendations?
 
I've always used good ole' Vaseline for my my O-rings and I never lube up the liner. I always clean my casings right after the flight, even while the casing is still warm, everything slides right out and it cleans right up. This was all the way up to 54mm motors. Baby wipes are good to have handy, especially after pre-greasing everything, the wipes clean all that stuff off and then you can assemble the motor. My .02 cents.
 
jimzcatz said:
Chris,I will give it a try,thanks alot. Any recommendations?
Click to expand...

I use SuperLube which contains PTFE....slicker than Teflon.
Another key to getting the liner, etc out of the casing is not letting the motor cool down too much. That's what can lead to the seizing. I try to disassemble my larger motors when the motor is still warm.
 
Delta-IV said:
After the recover and autopsy I discovered that the paper cap was intact and the delay element had burned completely but all of the black powder came sprinkling out the aft as I unscrewed the enclosure. A blob of vasoline was not visible but the lining was still slick.
Click to expand...

Vaseline is the traditional back-up lubricant. It has been used successfully many, many thousands of times--with no problems. However, if you have access to a high temp lubricant--only use vaseline in an emergency. Vaseline has a melting point of just over 100 degrees. If you have anyone around with a fever--put a tiny dab on their forehead--the vaseline will start to melt and run. The reason that you saw no blob of vaseline when you took the motor apart is because it may have melted. Someting like Slick 50 and Dow 111 have a melting point of 450 degrees. Between the time that you load the motor--and fly it--there is often a chance the temperature surrounding the motor could exceed 100 degrees. Even in a cool climate--throw the motor in the trunk of your car--and you are often well over 100 degrees. After the motor starts to burn--and before ejection--there is usually a delay of 5-10 seconds. During that time, I would think that the extremely hot case could melt something like vaseline--and cause problems. If you do use vaseline--just use it very sparingly. An ultra thin coat of vaseline on O rings should be OK. Someone mentioned that a liner with Dow 111 is hard to remove--I agree. I use Dow 111. It is very hard to insert a phenolic liner with an ample coating of Dow 111. It is even harder to remove it. One of these days, I will have to try Slick 50 or Super Lube. I purchased several tubes of Dow 111, I like it's very thick consistency--so I will probably use up what I have. I probably have a tendency to over-lube. Therefore, using a lube that will not melt at a moderate temperature is a good idea for me.
 
hognutz63 said:
PTFE is Teflon
Click to expand...

Not necessarily. First, Teflon is a name brand of PTFE from Dupont. I think Dupont's patent on Teflon has expired so other manufacturer's can produce PTFE resins, they just can't call them Teflon. Second, there are other compounds that also carry the Teflon name such as PFA and FEP which have similar properties to PTFE, but also some differences as well such as melting point and moldability.
 
I've always used Vaseline, and I haven't had any problems with it. Of course, I haven't done as many reloads as a lot of other people have. I think the main purpose of applying a lubricant is so the O-ring doesn't bind when the closures are screwed on. Once the motor is buttoned up, it is the job of the O-rings to provide a seal. The fact that Vaseline liquefies while the motor is burning shouldn't cause any problems.

Dave
 
On the liners for my reloads including HPR, I use a synthetic grease made by VersaTech. I get it at O'Reilly's. It's a brake and caliper grease which is blue in color. I have had no issues with it. For my o-rings, I use vaseline...
 
stymye said:
rub the side of your nose , thats how much it takes to make the o-ring slick.
if you can physically see the lube on the ring ...it's way more than necessary
Click to expand...
I am SO trying that next time.
 
I had this happen once too - it was on an H180W reload in my 3" BSD Thor. Beautiful up, gut-wrenching landing. Same result as above, same pre-flight observation on motor assembly, same post-mortem conclusions.

Since then, I have gone to only applying a thin film of grease to the sides only on the forward closure, and a very light film of grease on that very thin flat washer that lays flat inside the forward closure. Just enough grease on the flat washer to make it shiny. I do not grease the forward most delay o-ring that sits around the forward end of the delay element.

The greased side walls of the closure facilitate removal of the liner post flight, and the greased forward flat washer makes everything release from that end. Works fine. Everything releases and works great. This is the least amount of grease that I'm comfortable with using and still feel confident that I'm gonna get everything apart later.

Oh, I do grease the threads and everything (as instructed) from there down through to the aft closure and nozzle but I'm very judicious in the forward closure and delay area.

This doesn't apply to the 29/40-120 as there is no flat rubber washer at the front. Just lightly grease that forward most o-ring but not the flat front (or bottom) of the closure itself.

I've also read elsewhere on this forum that some folks don't use any grease at all anywhere in their reload assembly. My understanding is that the sole purpose of the grease is to facilitate disassembly and clean-up, so whatever works for them, I guess.......
 

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