15 replies to this topic

[Caramanos2000]

Made some D1 with Dextrin and constarch spray. yesterday they were almsot dry, just checked them and they are like I just cut them. WTF? Ahhhhh what happened? Can I add some red gum and alcohol and see if they will dry then?

[portfire]

Made some D1 with Dextrin and constarch spray. yesterday they were almsot dry, just checked them and they are like I just cut them. WTF? Ahhhhh what happened? Can I add some red gum and alcohol and see if they will dry then?

You only need to use water for D1 as dextrin is water soluble,not sure if cornstarch spray would work??.I'd leave your stars for about a week,as D1 is slightly hygroscopic due to the NaHCO3 content and can take a while to dry,over here anyway

dean

[King-b]

Yes, D1 dry realy long, i'd dry them on the central heating but they stil take 7 days to dry. I guess it take so long becouse almost al the chems disolve in water. Charcoal based stars dry much faster becouse only the kno3 will disolve.

King-b

[BrightStar]

D1 should usually be pumped, not cut. Adding more than 3 - 4% water (just enough that it starts to clump together) reduces the glitter effect - you need to use a minimum of moisture. 25% IPA in water will work fine and helps speed up the drying. The use of boric acid is a bit of a contentious issue.

I've made great batches of D1 for 3" ball shells with a simple improvised pump - just an old marker pen case cut with a hack saw (about 12 - 14mm ID) and a wooden dowel rammer. This consolidates the D1 into solid pellets about 12mm long. Drop them into a BP prime while still damp then set them on foil to dry. When mixing the comp, keep a third of the charcoal back and screen it in as 60-mesh along with the Al (mill everything else together beforehand) for a bright, dense tail.

It really is a stunning composition when it works

Edited by BrightStar, 16 December 2007 - 12:51 AM.

[Caramanos2000]

It really smelled of Hydrogen Sulphide, my guess is some reaction took place overnight.

[cooperman435]

also dextrin will dry in water.....

if your artificially dryin them then th outer shell wil dry completely sealing in the damp inside. When allowed to stand for a while at ambient temperature the inner moisture will soak into the dry shell and start to leach out again.

Dry slowly is the answer for a week or two at least

youll know there dry because they will be truly hard and not crushable between your fingers.

[Jerronimo]

I suggest using a star plate to make water sensitive glitter stars, rolling or cutting can reduce the glitter effect.
For really rock hard stars I use a 4% gum arabic in water.
I dampen the comp with 7 % of this solution, and when force dried they are literally dry within 12 hours!

For a gold glitter you really can't beat D1, it uses no expensive chems, is easy to prepare and puts on a great show.
For a silver/white glitter I suggest Win39, u can substitute the chinese needle antimony with dark pyro.

[seymour]

I agree with Jerronemo, Gum Arabic is great. It makes exceptionally strong stars and dries fast. According to FAST it dried faster than dextrin, sgrs, wheat paste and several other water soluble binders. It is fairly expensive (compared to dextrin) but very much worth it.

[pudi.dk]

Only thing is that it can't be directly added into the composition and then sprayed with water, since gum arabic dissolves rather poorly, so don't try this.
Instead do as Jerronimo suggested and dissolve it, then add it.

[MDH]

Hmmm... Come to think of it, would a heat lamp and a small fan help dry these sorts of stars in a few hours?

[Arthur Brown]

If this compound really has got wetter with time as you suggest then probably your area humidity is high and maybe this compound is too hygroscopic for use in your area.

Take one star, weigh it. Then dry it for a while and weigh it again, repeatedly.

IF the star actually gains weight it is gaining water and you should reconsider it's place in your formulary.

The star COULD be drying on the outside faster than the inside so a hard outer layer could be softened by moisture continuing to escape. In this case there will be a continual loss of weight as water goes away, but the hardness may vary before it settles.

Really only weighing will settle the issue and it may be well into the milligram range before you see weights change.

[Caramanos2000]

Added some red gum and acetone and they are much better. My tigertails, CuO blue and a weird red comp is drying. What do you guys recommend for a white star with a nice tail?

[MDH]

Well the solution is simple for just about any large tail, and that's large pieces of any material that will burn .

EDIT: You could use simple nitrate flash replaced with spherical AL. That makes nice, bright stars with gentle white tails.

Edited by MDH, 18 December 2007 - 07:00 AM.

[Caramanos2000]

I just got some Titanium, what could I do with that?

[pudi.dk]

Try making a charcoal streamer like Tigertail or Chrysanthemum 8 and mix in 7-10% Titanium.
I have not tried this, but it should make very nice white streamers.
Leosedf here has tried it though: