Rolling - Issues

[enanthate]

Getting better, this is really exciting. And fun!

 

Used a batch of sesame seeds (i know, but it was all i had at the time). They are now eggshaped. I know this can also happen when using round cores, but i have no clue on how to fix it.

Will keep reading on PF.

[schroedinger]

The egg maybe comes from a to slow roller or a to fast rolling

[Dean411]

I havent read all responses but you have a few things going on here

1. Charcoal comps are the worst to start learning with.

start with colored cores they are easier to roll and will give you a sense of accomplishment.

 

2. From the picture of your roller drum there is way to much water being used even an atomizing sprayer

will be putting alot of water in there with that small a # of stars.

 

3. Heavy cores will help till you get the feel for rolling.

 

4. TORO is not a largely published method however there are a couple videos on you tube one by a user with the name

of LADIS

 

if you want to roll stars you need to roll a larger quantity of stars the more stars in the drum the easier the process

will be

[Dean411]

Practice makes perfect.

 

keep at it and you will succeed, I taught myself how to roll stars with a shitty little roller and if I can do it you can.

 

Dean

[enanthate]

I have started over, Dean.

 

1. Its a color strobe

 

2. My roller is still dry after a batch, got the hand of that now (thanks to you guys).

 

3. Tried lead shots, but found a millet-like seed to work very well. I rolled another batch last night using these that got perfectly uniform (so far).

Looking for a fix to save the egg shaped batch.

 

4. Looking forward to try Toro! This weekend, perhaps.

 

That's a nicely rolled star you got there.

 

Schroedinger, I might have rolled a bit too fast. Will slow it down a notch.

[Dean411]

I learned TORO by trial and error and if I can find time I will film the process at some point.

 

just dont roll to much at one time limit size increases to an 1/8 inch between drying it will save lots of trouble

in the long run

 

there are a pair of 12 inch shells in the shell competition section the second shell in that video uses the star

pictured above

 

Dean

[enanthate]

That would be very helpful, Dean.

Have rolled ~5mm stars today, so far they are perfectly uniform with a smooth surface. That was until the 0.5mm layer bp prime, which messed up the uniform sizes. Charcoal really is difficult to roll. Spray and sprinkle less and more often on these?

 

Also, got a question for the experienced that would really be helpful.

I've read that you will roll more effectively eventually, and still uniform etc.

When you've reached this level, do you find yourself adding more water and comp with longer delay between increments than before? Perhaps the opposite, less water and comp but more often?

 

Trying to figure this out, as my rolling today took 4,5 hours.. about 2000 5mm stars. Would love to make it a bit quicker.

[MrB]

Trying to figure this out, as my rolling today took 4,5 hours.. about 2000 5mm stars. Would love to make it a bit quicker.

Then you need a larger roller... Or, a change of tactics.

 

One should be able to make a star making machine that works on the same principle as a glass marble making machine. Without the glass melting heat, of course.

Extrude a cylinder of composition, cut it in to star-blanks, and make them round by spinning two parallel corkscrewsforcing the star to take the right shape, and travel down the screws.

http://i793.photobucket.com/albums/yy217/SantaRich/Virgo%20Run/_MG_2249.jpg

Getting the star-blanks to have the right consistency would be crucial. Not to dry, flammable / explosive, or just to crumbly, not to wet, or it wont hold it's shape once it's down the screw... Also, it means you cant make layered stars, and so on. If your not intent on making round stars, there is an easier way, for the same result. A rotary pill press. Don't EVER run one indoors. Sooner or later one will burst in to flames. Make damn sure nothing of value is anywhere close by. Load it with a pound at the time, run it for 5 mins, and load the next pound when the hopper starts to get empty. Oh, and, btw. These are quite expensive, and you'll need to make your own dies, since you want your pills to be square, or cylindrical and about as high as wide.

If you wanna build your own, here is the idea behind how they work:

http://upload.wikimedia.org/wikipedia/commons/5/5a/Tablet_press_animation.gif

There isn't much to read about it, but i stole the image here.

The upside to these are that you can pretty much make unlimited amounts of stars, you just need to make the machine large enough to process the composition fast enough. But especially in the case of a automated press... Don't build it, and "test it" in a basement somewhere.

 

Oh, and under ideal conditions, a press like that would work with dry powder, much like pressing a rocket engine. Which means "ready to use" stars.

Personally i stick to rolling stars. Less chance of getting killed.

B!

[schroedinger]

B! Look for these

[MrB]

Thats something along the lines of the shaping of marbles i suppose, only it doesn't travel down the length of a spiral, so they don't get as smooth & round. Seams to be fairly available, which means you don't have to build it your self, which is an advantage. Get the "BoilieRoller 18 mm MAXI" And you should be golden...

 

Actually, if he made something similar making 5mm balls, i could really see that as a viable way of making cores. but at a grand and counting + shipping, in Euro, it's not a cheap way to make 18mm cores :- )

Cool, but not quite viable.

B!

[rogeryermaw]

Couldn't you press stars in the same die as one casts batches of lead media?

[MrB]

Not in a very effective way. Since it's half the shape on ether side of the mold, you would end up pressing the composition in the flat parts of the mold rather then the hollow shapes.

Honestly, for round stars, rolling is the way to go. There are a few ways you could create them, but most of them have drawbacks such as not consolidating the composition as well, and having stars crush when the shell breaks just means you wasted them... For faster mass-production pressing other shapes then round is a viable alternative, but to really make things move along, slice and dice is the way to go.

 

That said, i'm rolling all my stars. I'm pressing rockets, fountains, a few special effects, and comets.

B!

[calebkessinger]

There is some people that have done it I believe, Some issues to overcome. getting the right amount of comp. getting them to eject, keeping them from snapping down the center.

I don't believe it's a common practice by any though. It's much easier to cut small cores and start your rolled stars off of them. After the core is over 1/4 in. it's a cakewalk to get them rolled with a little practice.

I don't believe I have time to get into it before christmas but hopefully the new year will bring some free time.

[dagabu]

Couldn't you press stars in the same die as one casts batches of lead media?

 

In a pill press, yes. No, you cant use a clam shell, you have to use a tube and two 1/2 hemisphere rams (dies) to shape the star (pill).

[enanthate]

The huge advantage of rolling over pressing is that you can roll in layers.

I'll stick to rolling them, but still looking for advice to roll more effectively. That means decent stars in a little less time.

 

 

Rolling Dragon eggs, any1? Preferably with water/alc binder.

[Mumbles]

I've worked in a commercial setting where rotary presses were in use. You still need to wet the composition somewhat. The stars are dry overnight though under most circumstances. Just load up trays during the day, and store them the next morning. However for a variety of factors, they're not very amenable for home production or use. They sure would be convenient though.

[MrB]

I've worked in a commercial setting where rotary presses were in use. You still need to wet the composition somewhat. The stars are dry overnight though under most circumstances. Just load up trays during the day, and store them the next morning. However for a variety of factors, they're not very amenable for home production or use. They sure would be convenient though.

Weird. Whatever can be dry-pressed / rammed should be possible to press in to "pill-sized" stars also dry. The difference between theory and practice in action i suppose.

You have any idea why? Could it be the stroke of the pill-press that is to short so the stuff has to be somewhat compacted from the start to achieve the goal, a solid "pill" ?

 

B!

[Mumbles]

It's just the way it was done, so I don't know explicitly. If I had to guess, it was related to binders. It may have just been a hardness thing. Pills are pressed with a wax binder mostly. That may not be amendable for pyro stars. I have been told that certain resins like shellac, phenolic, or red gum can be pressed to a high enough density that they begin to flow under pressure and act as their own binder. These presses may not quite get there.

[schroedinger]

There is one more big factor that is a problem, most of the comps we use are to be considered more or less coarse. Normally only bp is milled to a fine eneough grade.

And it is a fact that coarse particles need much more pressure/temperature to permqnently stick together compared to fine powders.

[MrB]

It's just the way it was done, so I don't know explicitly. If I had to guess, it was related to binders.

Oh, your just no fun. Jump on a time machine, go back, and find out more. Just kidding of course, thank you for sharing.

 

There is one more big factor that is a problem, most of the comps we use are to be considered more or less coarse. Normally only bp is milled to a fine eneough grade.

And it is a fact that coarse particles need much more pressure/temperature to permqnently stick together compared to fine powders.

That might be a part as well. I mean, we can press the stuff, as seen in comets, and rocket delays. I feel a lot more comfy pressing then ramming, but when we are using dedicated presses the relative stroke might be a lot longer then what these machines can achieve.

 

Dunno. But i like the idea of having a fully automated rotary press making cores that i could roll on. If all that is preventing it from happening is the stroke length, then it "should" be possible to fix. However, the logistics of filling the star comp in to the cavity before pressing might take some tricks... Anyway, since i'm not skilled in the sort of abilities needed to pull of a build like this, it ain't happening over here. I'll quit wasting screen space, and be on my merry way. I'll keep thinking about it in amusing ways, but nothing will ever come of it ;- )

B!

[schroedinger]

B! Just to give you some idea which forces we are taking about, for IR analyses of chemicals in KBr discs 10 mm diameter discs are used. They are made from finely powdered chemicals and pressed in vacuum to about 3 mm thick wafers using 10 metric tons of force for about 1 min. If they drop from 10 cm heigh they are still brittle enough to crack or break up.

But then there is also the problem that charcoal is expanding after you stop applying pressure and i would estimat that just this light swelling would be enought movement to make the stars crack.

But if you want to test it, maybe you got a 6 mm pump and some meal at hand, charge the pump and press to 8 tons or so. Than you will see everythjnb breaking up again.

Also drying cores takes just a couple days, so why go a complicated route, if there is an easy way to do it? If you roll 'em with using ethanol or an other solvent they are ready after one or two hours

[MrB]

I barely have any star-pumps, and none that tiny. But i admit it's just speculations on my part, and the only reason for wanting "ready for use" stars is simply to be able to roll the next layer on them.

Something i pretty much could do by "ricing" damp comp, and go from there.

B!

[Mumbles]

B! Just to give you some idea which forces we are taking about, for IR analyses of chemicals in KBr discs 10 mm diameter discs are used. They are made from finely powdered chemicals and pressed in vacuum to about 3 mm thick wafers using 10 metric tons of force for about 1 min. If they drop from 10 cm heigh they are still brittle enough to crack or break up.

But then there is also the problem that charcoal is expanding after you stop applying pressure and i would estimat that just this light swelling would be enought movement to make the stars crack.

But if you want to test it, maybe you got a 6 mm pump and some meal at hand, charge the pump and press to 8 tons or so. Than you will see everythjnb breaking up again.

Also drying cores takes just a couple days, so why go a complicated route, if there is an easy way to do it? If you roll 'em with using ethanol or an other solvent they are ready after one or two hours

 

Pressing IR pellets has little to do with what we're talking about here. IR pellets are 98+% pure KBr, and we're not vitrifying anything when making stars. 3mm pellets also seems awfully thick to look at most normal IR bands of interest.

[enanthate]

Thought I would post an update here as well, since this is where it started.

Have rolled a batch of TT's, with success.

Also, a buell red on cut cores was rolled and finished today, pictures below.

Thanks for all your help, couldnt have done it without you guys.

The star cut open is obviously the buell red with cut cores. Not so evenly cut. Oh well..

Im very satisfied, as i did not need to screen any of the stars, and every single one is about the same size. Not a perfect shape, but that doesnt bother me yet.

 

Edit: tigertails are done, rolled on strobes (last pic). Not a clean cut on that star, but i'm too cheap to sacrifice another one.

Edited December 1, 2014 by enanthate

[petroleum]

Dear all,

Recently I encountered a problem with the batch of rolled stars consisting of red metallic core covered with C8+Ti flake. The problem is that after drying the surface of the stars is cracked. Red cores: potassium perchl/Sr(NO3)2/MgAl (up to 25%)/parlon/charcoal/phenolic resin (6%). OD of the cores 7mm. Solvent - EtOH (I suppose it was 96%). In order to keep the cores protected, these were covered with hot prime consisting of KP/C/phenolic resin (6%)+additional 5% of potassium dichromate (hand milled and sieved -180 mesh). This comp was rolled using acetone (the idea was that parlon is soluble in it and it will additionally protect the metal particles from undesirable reactions). The comp was rolled to get the final OD of the stars of 8 mm. After drying (48h), C8+Ti was rolled on these cores until OD of the stars reached 11mm. Solvent - 50/50 EtOH/H2O (v/v). However, after drying I saw the cracks on the surface of the stars. Without any doubts, some reactions occurred between the MgAl and other ingredients. Moreover, these cracks were not only in the C8 layer, but on the hot prime layer as well. In the same day another batch of stars with green cores was prepared (the same system, but with Ba nitrate) with the same hot prime and C8 comp and there are no problems with these stars. Some years ago I prepared the same stars (red metallic core - C8) and successfully used them, but with the another batch of Sr(NO3)2. What would you propose to solve the problem? I suppose that the problem came from the gyroscopic properties of Sr(NO3)2. My idea is to try to roll the cores using acetone or EtOAc only - in this case MgAl will be protected better. Who had the same problems with metallic colored cores covered with charcoal based comps using water based solvents? Another option is tho roll the C8 comp using red gum or phenolic resin as binder, although I'm afraid about the deterioration of the charcoal effect.

Regards

petroleum