Star Roller Substitute?

[Guest PyroManiac1]

As you can buy a rock tumbler for a ball mill can you buy anything that will work as a star roller? Something preferably small. Not for big industrial batches of stars more like 100g or less.

[davidh]

A stainless steel mixing bowl will work. It's more work, but it works fine for small batches, and the price is right.

[rellim]

Stainless steel is too slick so the stars tend to slide rather than tumble. I have recently switched to 2 qt. PE mixing buckets and now I can roll glitter without forming raspberries. Another advantage is that you can vigorously swirl the stars around with one hand. I use two buckets and wet in one and sprinkle in the other. This works well with mustard seeds. A disadvantage is that the polyethylene grows a scum layer fairly quickly.

[Arthur]

I'm cautious about stainless bowls because they can focus sunlight enough to start a fire.

[davidh]

Jesus H Christ, you aren't going to roll stars in the sun. Give me a break.

Second, stainless steel isn't too slick. A crap ton of amateur pyros have rolled stars in stainless steel bowls, including myself. It works fine. Raspberries are caused by bad technique.

[robbo]

davidh is right. Look at all the old (and new) videos of Japanese guys making stars in bowls. All my SS bowls are still shiny after 25 years.

 

If I was making 100g of stars, I'd just cut them. But, if you want to do it the hard way...

 

Nice heavy cores (e.g., steel shot, porcelain polishing balls, etc.) and a starting lot of them at once may help a lot too. For me there seems to be a critical mass of core mass/#/volume that is required to get them going well . This heavy mass also will remove the "scum" if it's large enough. If there's enough star mass pressing on it, the scum will stick to your stars, not the bowl. Your star mass needs to be heavy enough to wipe the bowl clean with its weight. But you end up with a lot of cores...

 

Alternativesly, if you're determined to do tiny batches, perhaps starting with a volume of cut stars (say 1/8", use a rolling pin and 1/8" spacers to control the pancake thickness) would get you closer to the critical mass for easier rolling, so the comp sticks where you want it.

 

Another possibility, if you're near any Asian stores, is to get a Thai tea pot. It looks like a spittoon, made of aluminum, about 1 foot high, maybe 10 inches at its widest. Costs maybe ten bucks or so. The constricted neck allows you to swirl really aggressively when you're working with a small batch. The aggressive rolling makes up for the lack of mass in a small batch. I love these for priming small (= light, non-critical mass) test batches. Mine was a bit rough on the inside when new so I took some wet very fine emery cloth to it so it cleans better.

 

Somebody needs to mount and motorize one of these! And whoever does, let me know when you get the engineering and RPMs right.

[dagabu]

Ice cream buckets, 5 gallon buckets, even cool-whip containers will roll stars.

 

Sorry DavidH but we have had a few reports of focused sun energy lighting off stars here and several injuries due to stainless steel bowls being used for comp or star rolling due to the parabolic shape of such bowls. No Kidding!

[ExplosiveCoek]

Agree on the argument stated above that stainless steel is too slick for an automated starroller. You'll get more of a sliding motion than a rolling/tumbling motion that you would get with plastic buckets etc. For hand rolling it does work fine though

I always start with a plastic 10 L bucket, which is clamped in my automated stainless bowls. If my stars become too big for that bucket (4-6 kg of stars), I'll switch to my stainless roller. Only then it has enough grip or 'critical mass' as elaborated above.

I've tried sanding, grinding etc all type of things to improve the stainless steel. I just doesn't work. Probably the only thing that'll give it the proper roughness is grit blasting it, but then care has to be taken to not just blow right through it.

 

Coating MCRH does work wonderfully though, but then you have a big mass of very wet/sticky hulls, that is obviously a completely different scenario from stars.

[davidh]

I have never once rolled stars in the sun. Here in Florida you would die. Besides, chlorate comps would be problematic in the sun no matter what you rolled them in. To me this seems like a red herring.

[snapper]

if your stainless is too slick sand it with some 200 then 400 and this will give some bite but typically pre spritzing the bowl then dusting with comp will add the layer of grip needed to roll. pumping 3/16's stars to use as cores is the best method so far to give large enough cores to just "go to town" instead of using crutches like lead shot and mustard seed.

[dagabu]

I have never once rolled stars in the sun. Here in Florida you would die. Besides, chlorate comps would be problematic in the sun no matter what you rolled them in. To me this seems like a red herring.

 

Nope, I personally know two people that have had the sun move as the day progressed when building under a canopy and the comp lit off. One got burnt, the other was not immediately present.

[FrankRizzo]

The sun in combo with shiny metal bowls thing is very real. I had a bowl of comp go up on picnic table many years ago. Luckily I had stepped away for a bit to wash my hands or grab a screen, and wasn't nearby when it whumped. I was very confused for a while as to what caused it.

 

I also saw the same issue with a well-known PGI member who taught a class on making whistle mix. He and his grandkid were on a golf cart, riding from the mixing/drying area at the convention, his grandchild holding the stainless bowl. The sun came out from the clouds, and a few tiny whisps of smoke started in the bowl of whistle mix. He was able to quickly pluck out the cooking bits and get the bowl dumped into the dirt before anything serious happened. Had that bowl ignited, it would have been a very very sad day. He no longer teaches that whistle mix class because the experience was so emotionally scarring.

 

Here's a YouTube video demoing the phenomenon with a bowl of Doritos:

https://www.youtube.com/watch?v=VKqDlqOaL5k