Spindle sticking constantly

[OldMarine]

Drat. Can't get a single rocket off the 3lb spindle. I've polished, waxed,tefloned, cursed, prayed and begged but they won't come off. I tried going as low as 2500 on the comp and NOPE. What the hell am I doing wrong?

 

I don't know of anything I've changed since my first few that came right off the spindle. I chucked my spindle up in the drill press to check for any bending or whatnot and it's spinning true.

 

My garden is getting a good fertilization with water soaked rocket juice.

[Oinikis]

So, I assume you are using rcandy, right? And I assume your spindle is metal. That's the problem right there. Metal is a great thermal conductor, thus, rcandy sticks to it, cools, and hardens.

 

I use wooden tools, and have my spindle tapered a little. Actually, my spindle isn't even machined and has imperfections, but due to it being a thermal insulator, Rcandy remains soft and moldable. I spin the grain around the spindle and get it off.

 

Another point, do not beg nor pray, you need to intimidate the rcandy, make it listen to you, make it your slave. You also might want to use different swearwords, preferably, Russian ones.

 

Dammit Kūrwa, just realized you are probably talking about pressed rockets. I suggest having your spindle taper, and at first trying to spin it around the spindle, to get it off.

Edited March 21, 2016 by Oinikis

[Mike]

OldMarine. Try to press a nozzle and test if you can get the engine of the spindle. Thata the area where a Problem is most likely. If not, set it back onto the spindle and press a couple increments. Maybe this way yoh can determine where the proble occurs,

Also check the spindle taper, if it has a small bend in it.

[stix]

Are you talking about bp, r-candy or powdered sugar & KNO3?

Edited March 21, 2016 by stix

[Sparx88]

I second that the clay, if that's what your using for a nozzle, is the more difficult non-cooperator. What I have been doing before each motor is rub a little crisco on the spindle where the clay makes contact. Not a lot just coat it a little. You don't want it to touch the fuel. The largest rockets I do are 1# or less so it's a maybe on 3#. More surface area etc etc.

[stix]

I second that the clay, if that's what your using for a nozzle, is the more difficult non-cooperator. What I have been doing before each motor is rub a little crisco on the spindle where the clay makes contact. Not a lot just coat it a little. You don't want it to touch the fuel. The largest rockets I do are 1# or less so it's a maybe on 3#. More surface area etc etc.

 

Yep, I use silicon spray on a rag then wipe over the spindle.

 

We still don't know what type of rocket motor/fuel/nozzle you are making Marine. I did have a look on your profile page/topics to see if any earlier topics you posted were relevant but there wasn't much there! (the last 4 posts - I think there is a forum software limitation? or it's just me.

 

If you're using a nozzle for these, that could be an issue as suggested but that would depend on what type and/or nozzle mix formula.

 

Cheers.

Edited March 21, 2016 by stix

[Col]

The nozzle mix can have a big effect, a mixture of coarse and fine clay plus wax has always worked well for me. The method of removing the motor from the spindle is another thing, ie' a spindle puller versus locking it in a vice/mole grips and twisting it off.

[OldMarine]

Sorry for the lack of detail.I'm making BP nozzled rockets using kitty litter with graphite added for the nozzle. The spindle has a good even taper and has no deformities.

I haven't changed methods or materials so I'm baffled as to why this just started happening. I'll try twisting just a nozzle loose and see if that's the sticking point.

Edited March 21, 2016 by OldMarine

[stix]

If it's got a good taper then that would suggest it's not a fuel issue but the nozzle.

 

Like Col said, if you can put it in a vice, a "quick snap" should release it. If the spindle base is round, then it might be useful in future to file down two opposing surfaces so you can vice it or use multi-grip pliers.

 

Maybe some courser material got mixed up in your nozzle mix?

 

Cheers.

[schroedinger]

Ok report back if you can get the nozzle of or not.

[lloyd]

Patrick,

Although you say it "has a good taper", it sure sounds as if there is a section that is not tapered, or where the taper is not cleanly monotonic.

 

These are little rockets you're pressing, and getting the spindle out just shouldn't be that hard.

 

Please remind me of these things:

1) where'd you get that tooling? (Caleb? If so, it should be OK, concerning the taper)

2) what size tubes, again? (I know, 3lb... but ACTUAL i.d. and length of the spindle would help for review)

3) Pressure -- psi on the comp or psi on the cylinder?

4) contents of your comp

5) contents of your nozzle material

 

Something really basic is at fault here. Nobody else is having this trouble (at least not after they solve a few minor issues)

 

Lloyd

Edited March 21, 2016 by lloyd

[OldMarine]

Lloyd,I wasn't having trouble until a few days ago. Now I'm having trouble with both the NEPT tubes and Phil's spiral wound as well.

I'm going to try some 111 silicone lube on the nozzle area of the spindle and also try pressing one without a nozzle.

Could ball milling my clay help?

Edited March 21, 2016 by OldMarine

[lloyd]

I don't see anything obvious unless your spindle is 'micro-scratched', and that's somehow binding it.

 

I've pressed many thousands of gerbs (mostly 1lb size), where the spindle isn't even twisted to get it loose... just "pulled out". It was _never_ a problem, over a decade of running that press. And I used just straight bentonite clay -- no additives.

 

I'm sure you have a good-quality straightedge you could lay along the spindle to check for a monotonic taper.

 

At this point, unless you have damp ingredients that are somehow 'gluing' themselves to the spindle, I haven't seen anything yet that is a clue.

 

Lloyd

[OldMarine]

My 3lb gerb tooling has a different bevel for the nozzle and presents no problems when removing the finished device. It also has the anodized finish which may help it let go of the clay.

I'll try some extra fine rouge and a felt pad on my Dremel polishing in the longitudinal direction so any scratches are running in the direction I'll be pulling.

I know it's probably something stupidly simple I'm doing wrong and I appreciate all of your patience and assistance.

[Col]

Try blitzing the litter and collecting what passes a 30 mesh screen. Add 8.5g of wax per 100g of blitzed litter, heat it until the wax melts and then run it through a kitchen sieve a few times while its still hot to distribute the wax.

Pressed nozzle should look something like this

I crank the spindle straight out of the motor using a spindle puller, no vice or twisting involved

Edited March 21, 2016 by Col

[OldMarine]

I think I'll try the wax Col. I tried pressing just a nozzle and it stuck like glue. I pressed a 7½" tube with just crushed bbq charcoal and it twisted right off. I don't have a spindle puller for my 3lb tooling but SLD included one in my ¾" set.

[mikeee]

Patrick,

 

A spindle puller is the way to go, it pulls the motor straight off the spindle, any scratches added

to the spindles run a very short distance on the spindle since the motor releases quickly.

When twisting the motor from the spindle you are adding scratches onto the spindle the entire

length around the circumference of the spindle. This creates a great deal of friction while trying

to remove the motor from the spindle the more scratches that get applied.

That is why a brand new spindle releases quickly and as more motors are pressed it gets more

difficult to remove each successive motor. It helps to chuck the spindle into a drill press or lathe

and use a metal polish to clean and polish your spindles once or twice a year depending on how

many motors you press. Some fuels and nozzle mixes are hard on rocket tool spindles.

[OldMarine]

I've used Dura-Glit on the spindle while chucked in the drill press.

I did a bit more paying around with pressures and found this is the max I can go and still get it off the spindle:

 

 

[schroedinger]

3000 psi is not much.

Get some never dull or similar. Polish the spindle and wax it good before every run. Then get a spindle puller too and use that.

[OldMarine]

Well, boophenix brought me some Dr Elsey's kitty litter and a PtoF gauge. We pressed up a rocket and it did spin off the spindle. The only thing I can think of is that maybe my litter has several clays and the bottom was some bad stuff. I haven't been shaking it to mix it but jostling it just enough to cause settling of heavier parts.

I'll try a couple more tomorrow after my graphite arrives.

Edited March 23, 2016 by OldMarine

[Xtreme Pyro]

If it's got a good taper then that would suggest it's not a fuel issue but the nozzle.

 

Like Col said, if you can put it in a vice, a "quick snap" should release it. If the spindle base is round, then it might be useful in future to file down two opposing surfaces so you can vice it or use multi-grip pliers.

 

Maybe some courser material got mixed up in your nozzle mix?

 

Cheers.

 

No offence, but I HIGHLY suggest against using a vice or vice grips to remove a stuck motor from a spindle. I was witness to a premature BP motor ignition just a few weeks ago because an individual did just that.. Ended up going off in his lap, luckily no one was hurt.. could have been ALOT worse. Instead I suggest using a straight spindle puller, so very limited friction is present... Stay safe.

 

- XP

Edited March 23, 2016 by Xtreme Pyro

[ExplosiveCoek]

Hmm, I always 'unlock' all of my rockets like this. But my spindle is stuck to its base, so there really is not much of an other option here I'm afraid. What do you suggest?

 

Last thing I want is whistle rocket going BOOM in my hands.

[MadMat]

If you ever need to polish the spindle, red iron oxide makes a great super fine final polishing agent. In telescope mirror makers circles it's known as polishing rouge. A little bit, wetted down with water (a very thin paste) on a soft cloth, or a piece of suede leather will give you a mirror finish. Add a liberal amount of water as it thickens during the polishing.

[lloyd]

Yep... in telescope mirror makers' use, "washed rouge"... where one suspends 'raw' rouge in a very mild detergent solution, then carefully decants only that portion that has not settled to the bottom in a certain time.

 

I've spent many an hour "walking around a barrel" making big Pyrex mirrors! (It was fun then, back when I had leisure time! <G>)

 

Lloyd

[Mumbles]

Hopefully you can figure out a workable route. In my experience, it's often the nozzle that is the stickiest point. Sometimes just "breaking" the bite will help you when you're trying to remove the rocket. Give the tube a small turn to break the bond between the clay and the tooling before pressing any composition. Press the rest of the rocket afterwards. This can help sometimes.

 

As an alternative, have you considered giving nozzleless rockets a try and see if they're any easier to remove? It may at least help you to pinpoint your problem.