Making Cut Stars

[jrin0630]

I made my first batch of cut stars (been pumping them until now) and everything looks ok except the stars seem less compact than the pumped ones. I used the 3/8" star frame from Wolther, filled it to the top of the frame with comp, then compressed it using a piece of plastic cutting board (cut to fit inside the star frame) with a decent amount of downward pressure. However as I was cutting them I noticed they were fairly brittle. Is this normal? Is there a better or different way to compress the comp before cutting?

 

Any thoughts?

 

Thanks

[rogeryermaw]

several thoughts. most of them are questions though. what comp are you working with? if it's a charcoal comp, they generally require more water for cutting than rolling. did you make that adjustment? you will have to give more details to get good help.

[jrin0630]

I was using C8 comp. I used slightly more water that I do with pumping but I was thinking I didn't make enough of an adjustment. When I pump I get the comp wet to where it almost looks dry but will hold its shape when squeezed in your fist. How wet should I make charcoal based comps when cutting?

[Andres1511]

If you remove the frame and the comp just holds its shape, it is perfectly wetted.

When just cut it is normal they look brittle, but when dry they're as hard as pumped stars.

[jrin0630]

Ok, then maybe there's nothing wrong because it did hold shape with the frame removed and they looked brittle after cutting. However after 2 days of drying (so far) they seem to have gotten hard. I'll wait a few more days and test them.

 

thanks.

[GMetcalf]

I was using C8 comp. I used slightly more water that I do with pumping but I was thinking I didn't make enough of an adjustment. When I pump I get the comp wet to where it almost looks dry but will hold its shape when squeezed in your fist. How wet should I make charcoal based comps when cutting?

 

 

I tend to make my cut star compositions wet enough to hold together in a ball like play-doh. Slightly glistening on the surface. Admittedly I don't use a frame to cut my stars so I need to rely on more moisture to hold the mix together.

[LiamPyro]

Not to de-rail the topic, but I had a problem with cut stars as well. I have successfully made them with charcoal compositions in the past, and I decided to try Buell Red. When wetted, the composition became extremely soft and barely held together, and when cut was porous and almost "foamy", like a puff-pastry or something. The stars were very delicate, I'll have to see how they are when fully dry.

What did I do wrong? I don't think I over wet it, as it wasn't slimy at all. I may have under wet it though...

[Mumbles]

Charcoal compositions get wetter the longer they sit. Colored compositions are less apt to do this. They do to an extent, but not nearly as dramatically. Do you think you might have just expected them to get wetter like C8, when it wasn't really prone to do this?

[nater]

LiamPyro, how are you compacting the dampened composition in the frame? I have noticed comps with high charcoal being difficult to compact in a slab or patty and ending up porous like you mention.

 

For me, this is one benefit of using a loaf type box. You can use a board with a mallet to really consolidate the comp. Then slices of the loaf are cut off the thickness you desire and those are cubed.

[GMetcalf]

Not to de-rail the topic, but I had a problem with cut stars as well. I have successfully made them with charcoal compositions in the past, and I decided to try Buell Red. When wetted, the composition became extremely soft and barely held together, and when cut was porous and almost "foamy", like a puff-pastry or something. The stars were very delicate, I'll have to see how they are when fully dry.

What did I do wrong? I don't think I over wet it, as it wasn't slimy at all. I may have under wet it though...

I don't like the idea of a 'foamy' mix. It sounds like something might be reacting to produce gas although with the Buell Red composition I can't think what it might be. Ammonium Perchlorate contamination of your Potassium Perchlorate maybe? The only other thing that occurs to me is that maybe your Dextrin isn't activating properly and that's what's giving you the problem.

[frederick]

I experienced a similar 'proofing' (for lack of a better word as it resembled the effect yeast has on dough.. not foam) type reaction with Buell red while creating falling leaves. The extra water needed to create a spreadable paste, which is required for the effect, caused what appeared to be fluffing/foaming of the comp. It was very gradual, not violent or effervescent. No increase in temp was felt and they dried fine and performed perfectly. Same chemicals, same formula normal moisture, gave no such reaction and perfect cut stars. The only difference was the increase in water. Perhaps a reaction with the Mag/Al and the lower tension of the thinned comp?

[LiamPyro]

LiamPyro, how are you compacting the dampened composition in the frame? I have noticed comps with high charcoal being difficult to compact in a slab or patty and ending up porous like you mention.

For me, this is one benefit of using a loaf type box. You can use a board with a mallet to really consolidate the comp. Then slices of the loaf are cut off the thickness you desire and those are cubed.

I didn't use any sort of box, I just rolled out the star dough on a piece of waxed paper and cut it. That may have been what caused the weird texture. BTW the composition I was having trouble with was the Buell Red and not the charcoal stars. The sentence structure in my post was a bit misleading, my bad.

I don't like the idea of a 'foamy' mix. It sounds like something might be reacting to produce gas although with the Buell Red composition I can't think what it might be. Ammonium Perchlorate contamination of your Potassium Perchlorate maybe? The only other thing that occurs to me is that maybe your Dextrin isn't activating properly and that's what's giving you the problem.

I don't have any ammonium perchlorate, so that definently wasn't the problem. And to clarify, by foamy I meant light and very soft, not bubbly or anything. I guess it could have been the dextrin, although it has never failed me in the past.

[nater]

Let me rephrase my comment from earlier:

 

I suspect that poor compaction is the cause of your funny texture. While I have not made or cut Buell Red, I have experienced a similar texture with high charcoal content stars. Using a loaf box and properly compacting the comp rather than trying to roll to the desired thickness solved my texture problem. Perhaps, it would solve yours too.

[DaMounty]

Hi,

 

I don't wan to derail the topic. My question is simple should star compositions (i used turbo pyro recipe) be ball milled?

 

Thanks,

...DaM

[Maserface]

Only when specified

[nater]

The only comps that can be ball milled are those with KNO3, Sulfur and Charcoal. Even then, the desired effect may be better milled or simply screened. It depends on the comp and your taste.

[schroedinger]

If you mill, then only comps containing only bp chems.

Then, from my point yes, 15 min is as good as screening but much less messy.

For longer milling times, it depens on the comp and desired effect. E.g. longer milling time can reduce the size of charcoal dust, and give brighter tails, compared to a screened mix. On the other hand it burn out much faster.

Also the star will burn muxh faster.

 

TT is comp that you should try. Once unmilled only wetted and once milled.

[LiamPyro]

Let me rephrase my comment from earlier:

I suspect that poor compaction is the cause of your funny texture. While I have not made or cut Buell Red, I have experienced a similar texture with high charcoal content stars. Using a loaf box and properly compacting the comp rather than trying to roll to the desired thickness solved my texture problem. Perhaps, it would solve yours too.

Alright. That probably is the issue, now that I think about it. In the past, I've occasionally had cases of this same problem, although to a lesser degree, with some charcoal stars. One other thing, is it normal to see little specks/flakes of parlon in color star mixes? Should these coarser particles be screened out?

[nater]

I do screen Parlon if I am not using acetone as solvent. The acetone dissolves those larger chunks, but water will not.

[Mumbles]

I've found if I don't remove the coarser bits of parlon, it leaves an annoying incandescent tail from the star. A 60 mesh screen usually does the trick for me. It's easier to pass the whole composition through the screen. Parlon on it's own can be somewhat stubborn and tedious.

[GMetcalf]

I've never had that problem with Parlon (my supply is a very fine powder) but I've definitely had problems with PVC powder having lots of larger specs in it and it does affect the star quality. Problem with plastics and rubbers like Parlon, Saran etc. is that they don't mill very well because they effectively get squashed and bounce back instead of breaking up. A total of 10 minutes worth of coffee grinder milling didn't make a squat bit of difference to my PVC powder, still has bits in it. Hence I try to stick to Parlon for my chlorine donor. But I'm waffling now... In answer to the question, get the bigger chunks out or dissolve them using acetone because they will indeed affect the star's performance!

[LiamPyro]

Thanks guys!