stars - cut, rolled, or pumped. pros vs cons

[giod]

So made my first batch of rolled stars today, hand rolled in a bucket. Not that hard, a little time consuming. Should I purchase a star pump? Which stars perform better?

Also is a comet really just a giant star in a cylindrical shape?

What's the best method of priming stars, just 3 coats BP?

[mikeee]

Do you have a hydraulic press? Yes, you can buy s star plate and press quite a few at a time.

If you want different sizes, you will need to but different sized plates.

Cut stars do not require any other equipment.

Cut stars you can make variable sizes.

A star roller is nice if you have the time and money to build one, they are versatile.

[hindsight]

Mikee, your answer was helpful and perhaps you will expound. What about performance of cut vs rolled vs pumped/pressed stars aesthetically? How about ease of priming and assembly? I assume pressing is not difficult from looking at the pix and vids.The notion of an efficient "industrial" method of doing things, in general, appeals to me, so pressing stars with a star plate rather than a manually intensive method may be preferable if everything else is equal. I'm not interested in perfection at this point. Hope you don't mind providing a novice pyro an education on this. (Silly question, this last one, as everyone has been more than gracious on this forum). Edited September 28, 2013 by hindsight

[dynomike1]

Star rollers are cheap. I don't have anything in mine. The only thing when you get to colored stars, you dam show have to prime them. I hate to prime cylindrical stars. Edited September 28, 2013 by dynomike1

[Shadowcat1969]

I have spent about $15 to build my star roller, $12 of that was to buy a wiper motor at a junk yard.

 

If you are doing stars with only one effect (one color or glitter, etc) then there won't really be much esthetic difference. The esthetics come in when you start trying to do color changes and such. Since there are corners on either pumped or cut stars, that portion of an outer color will burn off first and some of the outer color will still be burning when the corners of the inner color starts causing some "color contamination". Otherwise cut stars are often a lot faster to make, and pumped can be too, especially if you have a star plate.

 

I like using my roller as I can put some cores going, apply a little solvent and a little composition and then I go and do something else for 10 minutes, then go back and do the next application of solvent and comp. If I get into whatever else I am doing, it doesn't hurt the rolling stars to just keep rolling for half an hour, or even more, if I just temporarily forget. That way I'm not actually working with the stars/roller for more than a minute or two at a time, yet still get a good batch of nice round stars given plenty of time. Always remember, when rolling stars go slow, and doing it this way helps keep me from getting impatient and loading up too much solvent or comp at any one time, since I'm doing something else too.

[jaysgoh]

Circle Star for me are the best , it can be easily arranges well in the shells .

if cut star and pump star they wont arranges nicely ..

[nater]

Circle Star for me are the best , it can be easily arranges well in the shells .

if cut star and pump star they wont arranges nicely ..

 

Pumped comets stack quite nicely in a cylinder shell and done properly are an important part of the structure of the shell. Cut stars also lock together with polverone to create a nice solid shell.

 

All the different ways of making stars have pros and cons.

[hindsight]

Thanks guys, your info has been useful in deciding which method to use. Since canisters are planned, pumping will probably be the way I go.

[nater]

Pumped stars in cylinder shells are normally stacked tightly around the inside perimeter of the casing like bricks. This makes the shell nice and strong. Priming them can be a challenge. A layer of prime prevents the uniform comets to stack nicely. Some stack the comets unprimed and then brush them with a slurry prime. Others carefully prime the ends and ensure each comet stays the same size with a nice flat end. Others make comets that don't need prime. I am sure there are other techniques I didn't mention, those are just the ways I have been shown.

[mikeee]

Nater,

 

On a pumped star could you lay them on their side and and brush a light layer of slurry and dust prime on one or two sides?

This would still allow you to stack them and not increase the diameter all the way around the star.

[nater]

Mikee, that might work too. That is essentially what I was shown by brushing prime on after they are stacked. The shell I am working on now for Christmas, I am planning on using unprimed D1 comets with cut color stars as a double ring. So far I have had good luck with D1 lighting without a prime. I have not yet tried color comets or slowe burning BP type stars stacked in a cylinder shell. Prime is more essential so another method might need to be used.

[mathiasxx94]

Mind if I ask a question when we tallks about stars. I have a star plate from René from pyro-stuff.com when he was still running. I think it is 11mm and 20-30 stars, will a 2000kg press be good for this, or too much. I feel that 2 tons is a bit much for this plate? It's made of a composite like material and not metal. Thanks in advance.

[Mumbles]

If there are 30 holes, then 2000kg is actually about right, to perhaps on the light side. It's of course going to depend on the composition. 30 holes would deliver about 975psi on the composition. I generally see recommendations between 700 and 1500psi, with most landing around 1000 for stars and 1500 or higher for comets. For 20 holes, you'll deliver 1466psi, which is on the higher side, but you don't have to give it the full force of the press either.

 

I don't know how the material holds up to this kind of pressure. The recommendations I have are based on metal star plates. I've used the ones you described before. Well, Rene claimed his were of a high quality construction and not the same as the cheap ones available directly from China or as imports here in the US. They sure looked basically identical, down to the number of holes and manufacturer marks for alignment though. I was able to apply sufficient force to properly make stars with them using a 10,000lb arbor press. I'm sure I wasn't delivering quite that much force, but probably as much as I described above without any issues.

[WonderBoy]

Giod,

 

Will you be making ball shells or cylinder shells?

 

Nater,

 

Have you experienced a lot of deformation of your pumped stars when priming? Whenever I have primed pumped stars, they have stayed essentially the same shape, just a bit larger and with more rounded edges.

 

 

WB

[nater]

Yes, I have had a lot of deformation when priming pumped stars. The prime tends to build up on the edges faster than the sizes resulting in stars that will not stack. Even with stars that have a good even layer of prime, the rounded edged make it hard to stack too. Edited October 2, 2013 by nater

[WonderBoy]

Yes, I have had a lot of deformation when priming pumped stars. The prime tends to build up on the edges faster than the sizes resulting in stars that will not stack. Even with stars that have a good even layer of prime, the rounded edged make it hard to stack too.

 

Nater, that is interesting. I have not had that experience, here is a photo of a 2" insert shell with primed 1/2" pumped stars:

 

 

 

WB

[giod]

Giod,

 

Will you be making ball shells or cylinder shells?

 

Nater,

 

Have you experienced a lot of deformation of your pumped stars when priming? Whenever I have primed pumped stars, they have stayed essentially the same shape, just a bit larger and with more rounded edges.

 

 

WB

 

Working with cylinders for now..

[Mumbles]

The amount of buildup on pumped stars is going to be dependent upon how they're primed. I've seen everything from borderline eggs and dumbbells to what look like perfectly pumped stars covered with sand paper. I've had decent luck slurry priming comets and pumped stars. You have to be careful about wetting them. You need to get them evenly wet all around to get a nice even layer. The sort of trick being that you need to let them stir or tumble for a while to get the slurry evenly spread around. After that, adding in the powder allows for relatively even coatings and flat edges and sides. The corners are the sharpest edges, and typically have the most impacts. Trying to do a spray and dust type of priming promotes uneven build up in my experience. I mostly work with larger pumped stars and comets, probably 3/4" and larger. This might be easier to avoid uneven buildup than something smaller.

[nater]

I have 1/2" and 3/4" pumped comets drying, I'll have to try priming some of them and see what I come up with. Maybe it will be easier to get an even layer of prime on the larger ones. I usually spray them with water and dust the prime on in small increments. I have not tried an atomizer sprayer to get the water droplets even finer.