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Posted

I'm just going to throw this in here, because I've been making yellows for decades, and have some 'definite opinions'.

 

One: I just hate sodium yellows. They look "sodium vapor amber" to me, no matter how well-executed.

Two: I very much like tunable "optical" yellows that are made by blending red and green fires to get exactly the yellow shade you want.

Three: The red/green blends tend to be much less hygroscopic, if you use good-quality strontium compounds for the reds.

 

FWIW, four: Our clients really (REALLY) like the optical yellows better than sodium yellows, four-to-one.

 

Lloyd

Posted (edited)

I get that, Lloyd. I've never had the pleasure of playing around with the possibilities, and liked the effect on video. I've never (to my knowledge) seen sodium stars in person, so really have no basis for comparison. The yellows that I've made have tended to the lemon and in this case the amber tone of this star is part of the appeal.

 

What sealed the deal is that my spouse saw video of these stars and said "Oooh. You have to make that." ;)

 

Kevin

Edited by Nessalco
Posted

No matter HOW much you personally like or dislike an effect, the net result comes when you please the 'client' -- even if it's your wife! <G>

 

Lloyd

Posted

My goodness these stars are bright! I lit a couple on the ground (too dry for star gun), and the spots in front of my eyes took forever to go away...

 

I tried two different grades of MgAl - #-325 burns steadily, #80-200 gives a strobe-like effect, more pronounced as the size of the star increases - which may be an effect of the stars not being fully dry. I have no idea if the effect will persist when the stars are in motion.

 

Kevin

  • Like 1
Posted (edited)

My goodness these stars are bright! I lit a couple on the ground (too dry for star gun), and the spots in front of my eyes took forever to go away...

 

Yep... This is exactly why I want THIS stars! still the hyrdoscopic part is annoying as sh*t...

Edited by Stef727
  • Like 1
Posted

I'm lucky to be working on these now because the humidity is so low - so far I've had no problems with moisture. My dry box uses a dehumidifier for both a heat source and water removal, right now holding 38C and 28% relative humidity. More concerns about static at these values, of course. In my work area the RH is about 45%, so there's a little less problem.

 

I want to build these into shells that I can store and not have the stars turn to a pile of goo. I'm thinking that if I apply a coat of polyurethane to the inside of the shell casing it would act as a pretty good moisture barrier.

 

Kevin

Posted

When you finish them just put them in zip bag, until you put them in mortar.

  • Like 1
Posted

Could also place them (stars or the shell) in a sealed container with dessicant packs.

Posted
I find zip lock type bags don't keep moisture out very well. I've had dried ammonium nitrate in 5 and 6 bag inside of bag and it still turns into a wet mess in about 6 months and only a couple days in one bag.
  • Like 1
Posted

Yeah... LDPE bags breathe a lot more than one might think.

 

LLoyd

Posted

I do use bags and desiccant crystals for storage, but as has been said, the bags allow a fair chunk of moisture through. I tend to be a 'belt-and-suspenders' kind of guy, so want something simple and reasonably foolproof. I coated the inside of some shell cases with polyurethane a few minutes ago. Seems a super-simple precaution - use enough to coat, not enough to soak through and affect the pasting. I used a paper towel to apply the varnish.

 

Kevin

Posted

Yeah... LDPE bags breathe a lot more than one might think.

 

LLoyd

Didn't know that!

Posted

Okay - don't use polyurethane on the inside of ball shell cases. When dry the cases were severely distorted (egg shaped) and difficult to get the edges to mate and properly form into a sphere.

 

Kevin

Posted

What would be the matter with coating them after they're pasted and dry?

L

Posted

Doh!

 

Yeah, that should work. :blush:

 

Kevin

  • Like 1
Posted

 

Name of composition: Sunrise yellow

Composition Type: Color metallic

Creator: Pirotex

Color/Effect: Bright yellow

Precedure/Preparation: Pump with water or 25% alcohol in water.

NaNO3 - 55%

Magnalium - 25%

S -10%

Charcoal (airfloat) - 5%

Dextrin - 5%

VIDEO: https://www.youtube.com/watch?v=QIY3sfNq7R0

VIDEO2: https://www.youtube.com/watch?v=BP_YMSAnI24

 

I never really understood how to pump MgAl-based compositions with water.

How safe is that, and do you need Potassium Dichromate?

  • Like 1
Posted

Sodium nitrate doesn't tend to react vigorously with magnalium, even in the presence of water. That differs from how KNO3 will react with metals.

 

 

Lloyd

  • Like 2
  • 3 weeks later...
Posted

They can be cut using that 50% alcohol at dollar tree. Use hot prime.

  • Like 1
Posted
That was awesome Stef, the yellow was bright enough the titanium didn't overpower it.
Posted (edited)

That was awesome Stef, the yellow was bright enough the titanium didn't overpower it.

Thanks :)

 

btw I actually added just 35g of Titanium to 400g of sunrise yellow comp, no idea why the tails were so thick, maybe because the stars didn't fly very fast, because of no such a strong break.

Edited by Stef727
  • 1 month later...
Posted

Thanks :)

 

btw I actually added just 35g of Titanium to 400g of sunrise yellow comp, no idea why the tails were so thick, maybe because the stars didn't fly very fast, because of no such a strong break.

 

No problem there. I think it broke nice. I see so many other shells that are over way to fast. And a lot of those have to be broke so hard to get any decent size it's like a splash of whatever and gone. There are a type of shell called dahlias post-18732-0-43609700-1454742476_thumb.jpeg larger longer lasting multi effect or color stars. Not so dense as a peony but more interesting and more capable. Some sunrise yellow for the inner petal and brightened up ruby red outer should make that pic. P.s. I like sunrise yellow :)

  • 2 years later...
Posted

I have put sunrise yellow in a 4" shell and it was really bright.

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