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Small star rolling machine


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#1 Sparky

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Posted 09 April 2014 - 08:33 PM

Hi all

 

I have a very limited space e.g. not a workshop but a cabin about 10 by 7 feet.

 

I would like to do some rolling of small stars and not huge batches. Given the likely and current guidance there is little point in large machines capable of rolling a kilo at a time lol.

 

I also have a small rock tumbler which I modified slightly to get the rpm just right for BP. Has anyone tried this small for small rolled stars before? I'm thinking of looking for a small tyre from a model or garden equipment or anything I can find that fits this tumbler.

 

The reason I want to do this is I find cut stars just don't break nicely, the slightly erratic shape can spoil a nice clean break on a shell. I just want to get a more uniform size and shape.

 

Or do you think I probably just need to spend more time on my cutting equipment and skills lol.



#2 phildunford

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Posted 09 April 2014 - 08:43 PM

Getting a good rolled star needs a bit of practice, but they are probably the best for shells etc. Pumped stars are best for candles & a star pump is easy to make out of a piece of copper tube or similar.

 

Rolling does not scale down all that well, but I've had some success with a medium sized plastic flower pot mounted on a variable speed motor...


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#3 helix

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Posted 09 April 2014 - 09:04 PM

I think it would be quite challenging to roll stars with a tyre that would fit in a rock tumbler.  Making sure you didn't over wet the cores etc would be difficult also if you start with very few cores then its hard to get them rolling.  You might be able to use parlon screen pressed stars as cores and roll over the top of these.  You can also roll the stars in a mixing bowl by hand if you have plenty of time.

 

I have a small roller that I made out of an old expansion vessel from a hot water cylinder that I cut an opening in the end of it and filled/ adapted the other end to mount it to a variable speed motor - it works quite well, the vessel is about 350mm diameter.


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#4 Arthur Brown

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Posted 09 April 2014 - 09:21 PM

Star pumps are the obvious answer. All the usual suspects sell them in several sizes, or in a limited range of sizes you could make your own from tubing and wood. Should you intend to use comps with much hard metal content (eg Ti flake) try to look for disposible plastic syringes -Ti in particular scores pumps badly so using a cheap and disposible one saves the expensive ones "for best".


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#5 Arthur Brown

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Posted 09 April 2014 - 09:30 PM

I did once hear of someone using a wok to roll small batches of stars.


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#6 pyromaniac303

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Posted 09 April 2014 - 09:58 PM

I built a star roller from a toy potters wheel with a voltage selection switch to adjust the speed and a large bowl bonded onto it, but never really got good results.

 

I had far more success rolling stars by hand with a 300mm mixing bowl, and managed to process batches as small as 20g. I'll try and give a brief description but a video may be in order soon:

 

It is easy but not so environmentally friendly to use lead shot as a core material, and I also found success with tapioca pearls. By far the best I found though were the contents of some desiccant packs - I have no idea what the material is but it looks like clay, and it is very consistent in size, with a rough surface that picks up composition easily.

 

You'll want to start out with a small (finger actuated) spray bottle, of the type sold to dispense perfumes. A couple of sprays of water/alcohol solution on the core material is usually enough to get them started. As the stars get larger (and your fingers get tired!) you may feel the need to migrate to a larger spray with a trigger, of the type used for antibacterial kitchen spray.

 

I would also advise you to place a couple of teaspoons of composition in a pepper shaker or similar, to minimise clumping during the early stages of rolling. Then as the stars become reasonable sized you can move to 1/8 teaspoon for a few minutes, then 1/4 teaspoon. As you become familiar with the technique you will find out how much the stars are capable of absorbing between powder/wetting cycles.

 

Another thing that seems to minimise loss of composition by sticking to the side, is to have separate sides of the bowl for wetting and powder dispensing. It is inevitable that you'll get some stuck to the bowl when dealing with such small amounts, as they don't have the weight to pick it all up.

 

Keep them moving at all times to prevent sticking, especially during the early stages. If you over-wet you can usually rescue them by dumping an extra increment of powder into the bowl then prize them apart, rolling them without adding any further powder for a couple of minutes afterwards to smooth off any bumps.

 

You'll discover different motions work for different stars, and some compositions lend themselves to the technique better than others. Metal fuelled and barium nitrate based I find are much easier due to their additional weight, with light and fluffy charcoal based compositions being a real pain to get started.

 

I have seen videos of people sliding woks around on a carpeted floor, which looks easier on the arms, but you can't get the full range of motions needed, and besides my workshop is not carpeted!

 

Have fun, and if nothing else it is good exercise standing there waving a bowl around for 30 minutes.


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#7 David G

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Posted 09 April 2014 - 10:20 PM

Pyro Gear sells a small star roller. http://pyro-gear.co.uk/Shop2.html



#8 maxman

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Posted 10 April 2014 - 02:57 PM

I made a small star roller last year but have not tried it yet P1020902.JPG

 

The base is a plasma TV stand and is quite heavy giving it a sturdy platform

P1020907.JPG

 

It is driven by an old windscreen wiper motor

 

P1020905.JPG

 

I added a power switch and a variable speed control which I got from ebay and mounted it all in the little plastic box you see here and thenput a knob on the potentiometer.

 

 

 

 

 

AlP1020904.JPGl All the wiring is buried under the plastic of the stand and between the metal seen in a picture above

 

P1020903.JPG

 

and finally a video in use with some no10 lead shot as cores. Sorry about the big pictures.

 

http://www.pyrobin.c...ar Roller_2.wmv Not sure how to make this embedded

 

Rod



#9 Sparky

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Posted 10 April 2014 - 07:29 PM

This is a Pyro-Gear star roller Fixed speed

 

That actually looks pretty good and would save me the effort of building one lol.



#10 Sparky

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Posted 10 April 2014 - 07:31 PM

Rod - You win the award for cleanest pyro workshop I have ever seen! I will hang my head in shame. How do you keep it that clean with charcoal dust and other metal powders? Even if I scrub mine it gets right into the surfaces and wood grain lol.

 

You should try that out and share. Or sell it to me :-)



#11 Sparky

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Posted 10 April 2014 - 07:33 PM

Pyromaniac, I've done a fair amount of hand rolling, especially when adding primes but to be honest it has pretty variable results. I'm really looking to up my game a bit with some nice accurate stars.



#12 David G

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Posted 10 April 2014 - 08:02 PM

The one from Kenneth works like a charm for me.



#13 maxman

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Posted 10 April 2014 - 08:06 PM

Thanks sparky, I try my best to clean up as much as I can, but it may be due to limited experimentation time! I hope that will change soon :)

 

Rod



#14 starseeker

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Posted 10 April 2014 - 08:08 PM

I roll my stars with a stainless steel bowl,

 

As they grow in size i use a 5mm screen first to get the cores equal, and then a 3/8 screen as they grow.

 

When i tried this method for the first time i very quickly picked up the technique and you can buy a bowl for about £2.

 

I use no 8 lead shot which i first roll some bentonite clay onto to help the comp to stick in the initial stage of rolling.

 

If i was you i would not start with a charcoal base comp as these are a total pain to roll,glitters etc are really easy to roll.



#15 maxman

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Posted 10 April 2014 - 08:26 PM

Starseeker did you make or buy your screens? have you got any pictures? I made some from plastic tubs but they weren't very good as the drilling process produced rough edges and they were damaging the stars or they were getting stuck.

 

Rod






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