Cutting Pihko Blue #2 Questions

[BlueComet24]

I'm planning on making Pihko Blue #2 soon and am very excited about this. However, I have a few questions to ask first so that I don't waste a batch of stars or hurt myself.

1. What size (before prime) should I make for 1.75" ball shells? I plan to cut them, so these will be cubes. I have previously made my charcoal streamers and glitters 1/4", but this seems like it might be too big for a slower-burning star.

2. What solvent should I use? So far it sounds like I should use acetone to activate the parlon, but I thought I'd check and make sure this will be fine.

3. Could I use a wire to cut the stars? This method is used for cutting soft things like cake and cheese, so I thought it might work for stars. I've always used a blade, but I've heard that parlon-bound stars can be gooey and stick to the blade.

4. If I think this composition needs to be deepened a little, I was thinking I could replace half the red gum with sulfur. If I think it needs brightening, I was thinking that I could replace half (or less) of the red gum with Eckart 5413 Al. I just wanted to check and make sure that these changes would be safe in case I want to try them.

[AzoMittle]

I'm assuming you are referring to the Pihko KP Blue #2, not the AP variant. Shouldn't matter either way though.

 

1. Like you noticed, you have to adjust based on burn rate. I'd recommend starting at 1/8" - 3/16" - 1/4", try it out, adjust. You'll probably want to make some kind of tool in order to cut them to exact size.

 

2. Acetone should be fine, it is parlon and red gum bound. You can always add dextrin/sgrs/preferred binder and use water if you want, starches may yellow it a tiny bit though it shouldn't be enough to be an issue.

 

3. I don't see why not. If you use a blade make sure it is sharp and use a 'cleaving' action, don't try to run the blade through it like an exacto knife. You can also use a lubricant on the blade to help reduce sticking, PTFE in a spray can works great, so does graphite powder.

 

4. Try it as is first, if you can't test it before your next shoot make 3 small batches and see which one you like. If you want it deeper I would suggest the Pihko AP blue, or upping the copper and chlorine. For brighter, try magnalium, aluminum will probably wash it out. However you change it though, small changes make a big difference, try adjusting by 10% of component weight at a time (e.g. if KP is at 63% of total weight, adjust by 6.3%).

[Mumbles]

I don't think I've ever used this exact formula, but I have used very similar ones. Organic blues are known for being kind of slow burning. I'd cut them on the smaller side, possibly 3/16". Bindingwith parlon will often speed up compositions though, so it's hard to really say. When judging the color, I'd suggest doing it in the air. Up close, stars will often look washed out, especially if staring at them. It will also give you some idea if the parlon or parlon binding is contributing an incandescent tail.

[braddsn]

I will second what Mumbles said on stars looking washed out on the ground.. in fact, it was he that suggested to me that when burning a star on the ground, pick something light colored nearby to look at, instead of at the star to get an idea of the color hue. Organics are indeed slow burning, but don't get too caught up on what size to cut. You can be a bit off either way (too small or too large) and they will still work fine, it will just affect your break diameter. You can fire a few shells, then make fine adjustments from there. And remember what we talked about in chat... blue stars (contrary to what some think) ignite easily. However, they also blow out very easily. So make sure and get a nice thick layer of prime so they have time to slow down before they ignite.