stars

[eb11]

anyone try this formula for crackling stars

 

Red Gum Crackling Stars

Bismuth Trioxide 37.5g

CuO 37.5g

MGAL 25g

KCL04 +7g (Decided upon KClO4 because it's got less incompatibilities/sensitivity than nitrate or chlorate.)

Red Gum +6g - Binder (Alcohol)

 

Silicon Prime

Black Powder Meal 100g

Dextrin or SGRS +6g - Binder (Water)

Silicon +8g

[Seymour]

USA pyro certainly has I believe, since it's his modification of David Trimmel's original formula.

 

37.5% Bismuth trioxide

37.5% Copper (II) Oxide

25% MgAl

Bound with NC (I believe it was specified in parts of laqure, though I just used 4% NC by dry weight to bind).

 

The original formula is very good, and while I have not tried USA pyros RG and KP modified variant, from the videos he posted it seems very good.

 

I can confirm that you can simply replace the NC in the original formula with Dextrin, and don't see any reason why not to use almost any binder you want, and if it's a good binder, you can just use a normal amount without worrying about the extra fuel. USAPyro can confirm or deny this, but I expect that the KP is there to compensate for the rather large RG content, which I expect is a result of RG having less favorable binding qualities than all of the normal binders.

 

As far as I can tell, and I would love to know if there are reactions that water can cause in Bismuth trioxide/MgAl/CuO that I have not experienced, NC is used in dragon eggs out of habit more than anything, with a fair bit of people doing it because it is traditional.

 

A few others will use NC for the features such as fast drying and the fact that they will not soften and mix with water bound matrix mixes. Both of these features however, can come with a host of other volitile solvent bound binders, and I expect Resinox or similar resins to be common binders for dragon eggs in a lot of Chinese product.

 

As I said, I have not tried USAPyro's variation, so canot with full confidence comment on it, but my experience with david Trimmels original and my own binder substitutions should rougly correspond to what you get. With coarse MgAl (I found 60-100 mesh great) these explode in a single bang like a classic dragon egg, even up to sizes three or four milimeters cubed. With finer MgAl I get multiple pops from a single grain. Each 'Dragon egg' will sizzle in a brief cloud of crackling, throwing off a rather impressive display for such a sized grain. In my opinion, both effects are very nice in their own right.

 

I got the miltipop effect sinply by using -100 mesh MgAl, though I know other people have had singe pop effects with much finer stuff than I... obviously MgAl size is not the only tunable feature.

 

Again, this may differ with the modifications USAPyro made, but I have found the original formula and my varients rather easy to ignite. Simply mixed with Tigertail as a Matrix, they perform perfectly. If you are going to use them in a matrix or as the core of a star, I doubt they'll need any priming at all, and if you do want to ad a prime for a delay, opr if you want to use them as stand alone dragon eggs in devices, The Silicon in the prime is a nice feature, but complete overkill. Greenmix with a little binder should suffice if you don't have Si, or want to save it for when it is required.

Edited October 27, 2012 by Seymour

[rveline]

I have not experienced any serious (heating up) reactions in the presence of water, although if left soaking in water for a couple of days the stars will no longer crackle. Also when coating or priming this kind of star, potassium nitrate containing comps applied with water as the solvent will let the nitrate migrate into the core and ruin the crackle effect.

[eb11]

in the above formula that i posted what is the binder can i use dextrin or parlon