Yankie's KP Purple
Posted 07 June 2014 - 04:36 PM
Posted 09 June 2014 - 08:53 PM
I tried the formula Yankie's kp purple.
Wet with acetone and cut.
I like this color.
What was the star size?
Edited by LambentPyro, 09 June 2014 - 08:53 PM.
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Posted 19 May 2020 - 06:31 AM
So, I'm reviving a 6-years-since last post thread, but nice purples are always worth revisiting. I'd tried Yankie's KP Purple without and then with minor modification:
50 Potassium Perchlorate
9 Strontium Carbonate
8 Red Gum
5 MgAl (325 mesh)
Powder was burning nicely on a ground burn but not so deep purple as I'd wanted--leaning towards a violet and the metal desaturation effect was clearly showing. So I screened in +10 Copper Oxychloride and powder burned closer to purple but now was leaning towards a hint of reddish fuschia undertones and still appeared a little washed out by the metal. Acetone bound (20% by weight, which was perfect) and screen-cut (4-mesh) and rolled damp while step-priming with a screen-mixed hot perc prime (71% Perc/14% airfloat--half ERC, half generic hardwood/9% red gum, and 6% MgAl -200 mesh + 3% silicon 200 mesh) followed by a screen-mixed BP prime (67% KNO3/14% same charcoal mix/9% sulfur/5% MgAl -200 mesh, and 5% red gum + 5% silicon, using 91% IPA as dampening solvent. Ended up with 4-5 mm balls after first minutes of gentle hand rolling to round edges before drying. Primed heavily with pure hot perc prime, then a mixture of hot and cold BP prime, and finished with BP prime dusting. Most stars were approximately 1/4" diameter (6-7 mm), with a few in the 5 mm range (just over 3/16"). Dried 4 hrs and static ground burnc test showed a reasonable and pleasing purple-fuchsia color, still a little lighter than I'd have preferred.
Shown is a clip of a 1" mini-mine hard-launching 16g stars (1/4") with 2.4 g 10-mesh hot willow lift, with 2 grams of star-screened composition/prime fines containing 20% titanium added loosely among the stars for a little extra splash out the barrel. The heavy priming likely wasn't necessary and the first frames show a 20-foot blast of yellow burnoff that quickly changed to some really deep purple--approaching royal blue--fireballs that peaked at 40-50 feet apogee. Had 100% ignition with reasonable initial lift velocity, so overall was pretty pleased. What still needs improvement, perhaps, is enhancing saturation. Maybe by reducing the metal or by slowing the burn with a fraction or replacement with cooler fuels like hexamine or lactose? Although it wasn't very noticeable by eye during several similar launches, you can see the camera apparently caught multiple brief yellow-orangish glowing remnants at the end of the burn. This too, I'd like to eliminate, and wonder if it isn't possibly glowing slag from the parlon or gum remnants. Though primed heavily with charcoal-containing mixtures, I can't envision that any BP components are still burning at apex when the purple is finishing it's max effect--seems more of a low-level orangey glow...
Suggestions and hypotheses are always welcome.
Posted 20 May 2020 - 01:08 PM
Posted 20 May 2020 - 04:16 PM
It's a good color but needs some tuning, parlon is too much it's a good chlorine donor so 8 will works, CuO is far too much and the same for strontium carbonate, the orange tint come in my opinion from an excess of copper and an excess of oh group from the oxichloride, so 6 of CuO and 6 of carbonate will works better, variation on percentage ad blue or red on choise. I think that remove the mgal and subs with pure mg could be a major value. Another way is eliminate the metal and use only red gum, may be 10 a good point, in case a bit of pvc to act as combustible if there is too much oxigen from perchlorate, a oxigen deficiency will go for a cooler stars that reinforce the blue emission. Well let me known if you find usefull some of my hints. Thanks for share composition.
Appreciate the keen insights, King! Agree it needs tuning. My chems are top-quality, so I was questioning if the previous posters really got that deep purple from Yankie's unmodified formulation--I certainly got closer to poorly-saturated dark violet w/o the copper oxychloride... Could be different chems. Could be different cameras. Could be different visual perceptions. In my mix, I'd think the strontium would be more potent than the copper oxychloride's OH- anion in imparting an orangish hue. This really wasn't an issue until star burn-out. where i noted an orangey tint to the extinguishing embers, but perhaps your suggestion to reduce the parlon (and my guess that parlon slag is tinting orange at burn-out) would fix this. Ah, I see you also suggest a reduction in strontium carbonate, which might help. I'd expect reducing MgAl would help with the saturation issue, but substituting with straight Mg is probably not going to be my first fix for 2 reasons: 1) I only have -100 mesh pure Mg at the moment, and 2) though not working with nitrates in this comp, Mg's increased general reactivity may become an issue in future changes to the comp.
I appreciate your thoughtful dissection of my comp vs issues very much, and will make changes along those lines on the next batch, for sure. And will report on effects of those changes.
Thanks again, amigo!!!
p.s. To give credit where credit is due, the original comp was listed at the start of this old thread--by Yankie. My only modification was the addition of Copper Oxychloride to try to enhance the purple, which I was not able to reproduce (to my liking) from the base formulation...
Edited by SharkWhisperer, 20 May 2020 - 04:18 PM.
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