Loki motors?

[mbeels]

I noticed that Loki doesn't offer the polished graphite nozzles anymore, what is involved in cleaning the non-polished nozzles?

 

[heada]

I don't "clean" my nozzles unless there's some slag built up. Then I pop it out with a flatblade screw driver. If it doesn't immediately come out, it will the next time it's fired.

 

[tim cubbedge]

I noticed that Loki doesn't offer the polished graphite nozzles anymore, what is involved in cleaning the non-polished nozzles?

I talked to Scott about that. It’s a lot of work to polish a nozzle and they’re all done by hand and time consuming. I’ve also bought both polished and unpolished and right now I can’t tell the difference after several flights. And like heada, I don’t bother cleaning anymore unless there’s a lot of slag.

 

[Banzai88]

I noticed that Loki doesn't offer the polished graphite nozzles anymore, what is involved in cleaning the non-polished nozzles?

Yeah, for the time spent polishing a nozzle, for what you paid as an upgrade, it was basically like he was throwing in labor for free.

As others have said, after a few firings you won't know the difference anyway, especially after a sparky or two. Most of the larger parts of slag will fall right off when you touch it, the firmer bits may take a pick or two with a screwdriver, and the rest will blast off the next time you use it.
And yes, you're eventually going to scratch it.....just be careful in general, and remember that nozzles are consumables in the grand scheme of things with snap ring motors. Long term use, surely, but consumables none the less.

In any case, no matter what you do, no liquids! Carbon nozzles soak up anything like a sponge, especially water, and will crack on the next firing if they've been soaked. Store it clean and dry, like you would store a reload.

 

[3stoogesrocketry]

Ohh man,
How nostalgic is that..
Raceway Park expanded and built track after track..
All my life growing up it was a dragstrip next to the Englishtown airport..
Then they started expanding..
I kind of think one of the things that played big role in them closing their doors was
a driver loosing his life at a national event there..
They were open for a few years after that but then eventually closed their doors..
That place was simply a part of life in central New Jersey..

Teddy

I remember when Kenny Bernstein went 300.3 there . First driver to hit 300 in a competition run.

 

[Onebadhawk]

Ha,
Another central Jerseyite..

I like your sig line..

Teddy

 

[Theory]

In any case, no matter what you do, no liquids! Carbon nozzles soak up anything like a sponge, especially water, and will crack on the next firing if they've been soaked. Store it clean and dry, like you would store a reload.

i was not aware of this

i have sprayed mine with a little simple green on a few occasions

guess i should stop doing that

 

[Banzai88]

i was not aware of this

i have sprayed mine with a little simple green on a few occasions

guess i should stop doing that

Yes. Stop doing that. Liquids of any kind, ESPECIALLY water, are a no no with graphite nozzles. If it's been a long time since in a relatively low humidity storage location, probably OK in the short term, but certainly bad practice.

 

[heada]

Liquid and graphite lead to steam explosions. Its a big no-no. If you somehow do get your graphite nozzles wet, let air dry for a few days and then bake at the absolute lowest temp possible, below 212 F if possible. I have a toaster oven that gets down to 160 F

 

[mtnmanak]

Yes. Stop doing that. Liquids of any kind, ESPECIALLY water, are a no no with graphite nozzles. If it's been a long time since in a relatively low humidity storage location, probably OK in the short term, but certainly bad practice.

What about wiping the nozzle with quickly evaporating solvents like alcohol or acetone? Not saturating the nozzle, but merely wiping it down with a rag that has some solvent on it? If the risk is that the graphite absorbs water and then cracks/explodes later because the of the steam produced by the high heat, it would seem like solvents pose little risk as they evaporate very quickly.

Having said that, I understand the preferred method to clean the nozzles is dry scraping with a blade or screwdriver, just asking more as an academic question of the risk of using a solvent with graphite nozzles.

 

[jimzcatz]

not doubting Banzai88 , but I have alwas cleaned my noozles in the sink with dawn and a scotchbrite. No issues so far but they do go sometimes years between uses.

 

[Banzai88]

What about wiping the nozzle with quickly evaporating solvents like alcohol or acetone? Not saturating the nozzle, but merely wiping it down with a rag that has some solvent on it? If the risk is that the graphite absorbs water and then cracks/explodes later because the of the steam produced by the high heat, it would seem like solvents pose little risk as they evaporate very quickly.

Having said that, I understand the preferred method to clean the nozzles is dry scraping with a blade or screwdriver, just asking more as an academic question of the risk of using a solvent with graphite nozzles.

Probably fine for a simple surface wipe, as long as it doesn't have an residual oils to penetrate, all solvents have well flashed off before storage, and that it's not fired again 'wet' with any residue from anything that you use.

In any case, unless it's a sparky with a lot of metal in it, the slag usually wipes off. Even most sparky residue from the Loki loads, since that's what we're discussing here, will come off relatively cleanly with some picking.

not doubting Banzai88 , but I have alwas cleaned my noozles in the sink with dawn and a scotchbrite. No issues so far but they do go sometimes years between uses.

No one that I've ever talked to that makes or uses carbon nozzles has ever suggested anything OTHER than staying away from saturating them with water, pretty much at all costs. More than a few folks have ruined a nozzle with water as it flash heated, cracked it, and sometimes done some nasty things to the burn!

In fact, that very point was called out in the field this weekend. A guy's EX powered launch landed in a wet drainage ditch.....and all the EXers made sure to mention to him to make sure that his nozzle was well dried in a slow bake oven or desiccant before trying to fire it again......and to at least get the mud out of it, too!

"......sometimes years between uses" has probably been your primary saving grace, as it's surely had time to normalize as much as possible without being baked dry.

 

[Saint_Tiki]

Food dehydrator would probably do well to remove moisture from it. That's what I use for my 3D printing filaments. Set them on about 120*F for 12-24 hours with forced dry air on them.

 

[Theory]

Very good to know

this was the worst one to date, an I377



the I405s that I have flown have been very clean

 

[heada]

Hit the dirt with a soft brush, the white slag with the screwdriver or the tip of a knife blade and you're done.

I've had some nasty slag from an AMW 75mm sparky that had sat for 2 years. Picked anything loose off and maybe 75% of the rest stayed. The next firing was an AMW 75mm white and after that was done, the nozzle was clean.

 

[Saint_Tiki]

Yay, USPS finally decided to move my package from one state away. Next time I’ll just drive there... Ground shipping right now is the worst, but no Haz!

Quick inspection, it looks very high quality and well packaged. Can’t wait to fly it!

 

[John Kemker]

That’s why I like them. Only downside is they don’t come with starters so you either have to learn to make your own or buy at additional cost.

I was about to say that the 38mm G motors I purchased included them, but now I realize I can't remember if they came with or if I added them on when I ordered the motors?

I like the Loki motors a lot. I just wish they did a 29mm set so I can use Loki in my Cherokee-H!

 

[jbr]

it does not take 2 min to polish the inside, also depends on if you use iso molded graphite

 

[mtnmanak]

it does not take 2 min to polish the inside, also depends on if you use iso molded graphite
View attachment 439608

Are you saying it takes longer or shorter than 2 min to polish the graphite?

Not sure if you are saying "it takes no time at all, you can easily polish the graphite", or if you are saying "wow, no way you can do this in 2 min, it takes forever to polish the graphite, wouldn't do it again!"

2 min already sounded short to me, so wondering if it is the latter?

 

[jbr]

I make a lot of nozzles, easy to polish, takes longer to chuck the nozzle than polish each side

 

[jimzcatz]

in all my years using graphite noozles, this thread is the FIRST time I have ever been warned against using water to clean-up.

 

[Banzai88]

That information comes straight from Loki, and every other supplier/user of graphite nozzles that I've ever talked to (including two senior members of the TMT).

It's even part of their instructions included in every Loki motor reload.
"Clean all motor parts with soap and water except nozzle "
"DO NOT soak the nozzle in any kind of solution."

https://lokiresearch.com/images/Documents/54mm%20White%201200.pdf

https://lokiresearch.com/images/Documents/Loki%20Research%20Nozzle%20Cleaning%20and%20Care.doc

 

[jbr]

I make lots of nozzles and clean them up in vinegar, never had issues but I use iso molded

 

[jimzcatz]

Instructions, just another man's opinion!! Seriously, I appreciate all the advice.

 

[crossfire]

in all my years usung graphite noozles, this thread is the FIRST time I have ever been warned against using water to clean-up.

I myself have never heard of it. I used to soak nozzles in vinegar over night. Never had one crack or break.

 

[Banzai88]

Not mean as a point of contention, simply as illustration of the only source that I've found of cleaning guidance......straight from the guy that sells them.

Are there documented accounts of nozzles cracking due to liquid saturation cleaning, or are they all apocryphal and anecdotal? I have zero idea, but Loki seems to think it's enough of a concern to be quite explicit in their provided literature.

For the average user, which is most of the retail crowd, the only way to ensure that you never have a liquid saturation induced failure of your nozzle ($ invested in a critical part) is to not saturate it in any liquid.

If you have a 'best practice' that works for you, you do you.

The first time Loki user might not be aware of the care/cleaning direction from Loki. I simply noted it for the laymen approaching snap ring configuration motors for the first time, since the more common AT and CTI motors use disposable nozzles, thus, care and cleaning of a carbon nozzle would be new practice for them.

 

[KilroySmith]

>>> Are there documented accounts of nozzles cracking due to liquid saturation cleaning, or are they all apocryphal and anecdotal?

Unfortunately, the two options you've given are one and the same - one person documenting that they soaked their nozzle (that sounds bad) and it failed on the next launch is still just an anecdote, though it is a documented anecdote. Nozzles fail for many reasons; soaking it may simply be coincidental to it failing. Obviously soaking a nozzle, or using water-based liquids (like vinegar), to clean doesn't cause a 100% failure rate, or crossfire, jbr, jimzcatz wouldn't be continuing to do so. So, at worst, using water on the nozzle increases the likelihood of failure by some amount.

Getting a reasonable answer would require running controlled experiments - perhaps one would build up 100 motors, and soak the nozzles of 50 of them in water for an hour, then let them dry for 24 hours. Light all 100 motors, and keep track of how many unsoaked nozzles failed, and how many soaked ones did. Sounds like a lot of work, and a lot of money to me, but if you want to do it I'll help you light them off. I'm guessing that the Military/NASA has done this testing, and the results may be available for Military/NASA sized nozzles comparing with Military/NASA specified failure rates, which may not be yours.

 

[heada]

Ignore this post. I linked to a restricted area so not everyone could see.

 

[0011001100]

I have literally poured water onto a graphite nozzle to help clean it in the field (modified sugar motor with lots of slag) rubbed the slag off, poured more water, then wiped it with a paper towel and loaded it up to be fired again. Never had a nozzle crack. When I am done I just put them in a bag and rinse them in the sink at home. Now with steel nozzles it is even easier to clean because they don't get scratched and dinged like graphite.

 

[jbr]

it all depends on your type of graphite
the cheap kind is coarse grain and does have spaces between the grains
the expensive kind is fine grain iso molded and has no spaces