Do you grease delay O-Rings?

[eggplant]

Do you?

 

[trippkid]

I do.
Matt

 

[New Ocean]

Vaseline just enough to shine... but I never keep a motor that doesn't fly after it is built.

 

[Aksrockets]

Yes. I do. DONT GREASE THE DELAY!

 

[Rocketman248]

Yes. It says to do so in the instructions.

 

[Bazookadale]

Why would one not?

 

[eggplant]

I don't know, I just remember hearing someone who recommended not doing it to make delays more accurate.

 

[New Ocean]

Also grease the insulation around the delay and the grains so they come out after.

 

[Bazookadale]

I don't know, I just remember hearing someone who recommended not doing it to make delays more accurate.

Ah - getting grease on the delay itself would do that - just put a light coat on the o ring and you will be OK

 

[Rocketman248]

Also grease the insulation around the delay and the grains so they come out after.

You mean the liner, right? Greasing the outside of the grains themselves can cause a problem.

 

[n3tjm]

I never grease the delay o-ring. It only takes a little amount of grease to ruin the powder; especially on a warm day and the motor is aloud to warm up and the grease gets nice and fluid. With the hobby loads, simply drop in the o-ring. With RMS+ lightly grease the outside wall of the delay well so its easier to insert the delay assembly.

 

[New Ocean]

You mean the liner, right? Greasing the outside of the grains themselves can cause a problem.

Also grease the insulation around the delay and the grains so they come out after.

 

[Zephhyr]

With a good quality grease, it's going to take much higher temps than is seen on the pad, to cause the grease on the o-ring to free flow, we should only be putting enough grease on the o-ring to cause it to shine = very little chance of the grease free flowing, causing contamination of the ejection powder/delay.

That being said, I do grease the delay o-ring, per the instructions.

I never grease the delay o-ring. It only takes a little amount of grease to ruin the powder; especially on a warm day and the motor is aloud to warm up and the grease gets nice and fluid. With the hobby loads, simply drop in the o-ring. With RMS+ lightly grease the outside wall of the delay well so its easier to insert the delay assembly.

 

[scsager]

For Aerotech RMS hobby and High Power reloads I follow the instructions exactly to the letter. I have never had a problem.

The O ring is greased, and on HP, "Apply a light film of grease to the
inner circumference of the delay cavity" -exactly like the instructions state.

 

[MarkII]

Yes, if the instructions call for it. But "greasing them" calls for an explanation. I put a tiny dab (not much bigger than a pinhead) of grease on my fingertip, rub my other fingertips (on both hands) in it, and then wipe it all off with a dry paper towel so that there is no more grease visible. Then I pick up the O ring and twirl it between my fingertips to transfer the scant trace of remaining grease onto it, literally just to give it a shiny appearance. That's it. I have never had a problem with delays. On one occasion, I just touched my forehead and used some of my skin oil to grease the rings.

 

[chadrog]

Yes, if the instructions call for it. But "greasing them" calls for an explanation. I put a tiny dab (not much bigger than a pinhead) of grease on my fingertip, rub my other fingertips (on both hands) in it, and then wipe it all off with a dry paper towel so that there is no more grease visible. Then I pick up the O ring and twirl it between my fingertips to transfer the scant trace of remaining grease onto it, literally just to give it a shiny appearance. That's it. I have never had a problem with delays. On one occasion, I just touched my forehead and used some of my skin oil to grease the rings.

When assembling motors at the field, I usually use the forehead method. Never had a problem, helps that I'm Italian...

 

[MarkII]

When assembling motors at the field, I usually use the forehead method. Never had a problem, helps that I'm Italian...

I'm a blue-eyed, fair-skinned northern European mutt and I have more than enough oil on my face to do the job.

 

[chadrog]

I'm a blue-eyed, fair-skinned northern European mutt and I have more than enough oil on my face to do the job.

Proof positive that you don't need much!

 

[New Ocean]

No wonder women flock to rocketry launches... : )

 

[Barracuda]

Yes per instructions.

 

[Eat, sleep, and Fly]

yep... follow the instructions 100%

 

[gdjsky01]

Yes. Petroleum Jelly or Synthetic lube. Both work. IMO, it helps them move a little if need be to seal. Plus the instructions say so.

 

[JDcluster]

Just about the worst thing you could use, as Vaseline has paraffin in it.
https://en.wikipedia.org/wiki/Petroleum_jelly#Uses

It will turn into liquid and it has a really low melting point.

See the quoted text below:

"Physical properties

Petroleum jelly is a semi-solid mixture of hydrocarbons, having a melting-point usually within a few degrees of human body temperature, which is approximately 37 °C (99 °F).[2] It is flammable only when heated to liquid, then the fumes will light, not the liquid itself, so a wick material like leaves, bark, or small twigs is needed to light petroleum jelly. It is colorless, or of a pale yellow color (when not highly distilled), translucent, and devoid of taste and smell when pure. It does not oxidize on exposure to the air and is not readily acted on by chemical reagents. It is insoluble in water. It is soluble in dichloromethane, chloroform, benzene, diethyl ether, carbon disulfide and oil of turpentine.[3][1]

There is a common misconception that petroleum jelly and glycerol (glycerine) are physically similar, because they feel similar when applied to human skin. While petroleum jelly is a non-polar hydrocarbon hydrophobic (water-repelling) and insoluble in water, glycerol (not a hydrocarbon but an alcohol) is the opposite: it is so strongly hydrophilic (water-attracting) that by continuous absorption of moisture from the air, it produces the feeling of wetness on the skin, similar to the greasiness produced by petroleum jelly.

Depending on the specific application of petroleum jelly, it may be USP, B.P., or Ph. Eur. grade. This pertains to the processing and handling of the petroleum jelly so it is suitable for medicinal and personal care applications."


JD

Vaseline just enough to shine... but I never keep a motor that doesn't fly after it is built.

 

[MarkII]

No wonder women flock to rocketry launches... : )

The step is so subtle that it wouldn't be noticed.

 

[gdjsky01]

Just about the worst thing you could usye, as Vaseline has paraffin in it.
https://en.wikipedia.org/wiki/Petroleum_jelly#Uses

It will turn into liquid and it has a really low melting point.
JD

For the 6 years I have used reloads (1998-2003 and 2011) it is virtually all I have ever used. The idea is to stop the binding and deformation of the o-ring when the closures are tightened, not to be a sealant. I was told this by a manufacturer. Even in the 40C+ degree heat of Lucerne Dry Lake bed in August, liquid as it may be (and was), it does exactly the prescribed task. Stop the binding or bunching of the o-rings when the closures are tighten.

JD I know you've probably forgotten more than I will ever know about rocketry, but I have 6 years of worthless anecdotal evidence that says petroleum jelly works just fine for lubing o-rings on reloads of D thru J impulse.

YMMV, and when in doubt, do what the instructions say.

 

[MarkII]

For the 6 years I have used reloads (1998-2003 and 2011) it is virtually all I have ever used. The idea is to stop the binding and deformation of the o-ring when the closures are tightened, not to be a sealant. I was told this by a manufacturer. Even in the 40C+ degree heat of Lucerne Dry Lake bed in August, liquid as it may be (and was), it does exactly the prescribed task. Stop the binding or bunching of the o-rings when the closures are tighten.

JD I know you've probably forgotten more than I will ever know about rocketry, but I have 6 years of worthless anecdotal evidence that says petroleum jelly works just fine for lubing o-rings on reloads of D thru J impulse.

YMMV, and when in doubt, do what the instructions say.

Considering the scant amount that is used on O-rings (that IS what we're talking about, right?), I can't imagine how a very slight moistening of the ring surface with a trace of petroleum jelly is going to lead to problems. The addition of a trace amount of grease is to lubricate them so that they seat properly as the reload is being assembled. The greasing is not meant to create a seal, because the O-ring doesn't need any augmentation in order to perform that function. Greasing liners, delay cavities, etc. is fodder for another discussion; this one is about O-rings.

 

[troj]

Vaseline works just fine.

The biggest problem? It's probably the messiest thing you can use. Talk to someone who's had the container of it fall over in their range box on a warm day, or while in the car.

Where it fails miserably is if you using lube to fill the snap ring grooves on AMW/Loki/Gorilla/etc hardware, to facilitate getting the o-rings past them without tearing. If the lube isn't relatively thick, it doesn't stay in the grooves, and does you no good for this.

High temp wheel bearing grease is dirt cheap (makes petroleum jelly look expensive), readily available, and it stays "solid" even on a really warm launch day.

-Kevin

 

[JPVegh]

I've used nothing but petroleum jelly since my introduction to high power in 1993. It's never caused a problem. Yes it will liquify on a hot day and no you don't want to keep it in your motor box or range box. You can get a big container of the stuff for a buck and it will last forever.

Oh and yes, ALL O rings get some lube.

 

[gdjsky01]

I only buy the little travel size squeeze tubes of P.J. That way, even if it liquifies, its contained and easy to get a tad out on my finger. One travel size tube lasts a year or more even when lubing the liner for clean up. Again, you are just putting a shine on o-rings and the liner. Anything else is (IMO) waste.

As I said, YMMV and follow the instructions.

:wink::2:

 

[MarkII]

High temp wheel bearing grease is dirt cheap (makes petroleum jelly look expensive), readily available, and it stays "solid" even on a really warm launch day.

-Kevin

Definitely. Good point.