42 replies to this topic

[pyrotechnist]

MDH, on Oct 23 2008, 11:31 PM, said:

Then the trick is to find a solvent which will effectively dissolve the boric acid but not the bicarbonate.

Any suggestions? when the boric acid is added to 75/25 water/alcohol mix it will supposedly turn it acidic and when added to the mix react with the bicarbonate rendering it useless and also rendering the boric acid useless in the mix. I have seen a few people who have made D1 without boric acid and all seems to go well but I don't want my 200g mix of it going up in smoke :>

[Mortartube]

I just add the boric acid as a powder in with the rest of the mix, it has never caused any problems.

Edited by Mortartube, 24 October 2008 - 08:31 AM.

[portfire]

I've made D1 with and without boric acid (100g batches) and haven't noticed any change in the glitter effect. Having said that I always use it now, as maxman said, it's just added insurance.

pyrotechnist- If your worried, just split the mix into 100g batches.

[maxman]

As portfire says, I have not noticed any difference with or without boric acid. I think with very fine aluminium in some comps with a nitrate it is quite possibly essential! But D1 is most likely best with about 200 mesh.

Here is a clip of a 3" plastic shell with D1 Glitter that was fillmed for me at 1/4" mile away.

[pyrotechnist]

How much boric acid is needed for a 200g mix?

[pyromaniac303]

I usually add 1% by weight and dissolve it in the water, before mixing into the dry comp. So in this case 2g, though I doubt the amount is too critical. I have also made 100g batches before I had boric acid and not noticed a heating effect.

[Jerronimo]

Has anyone ever successfully made cut D1 glitter?

Cut stars need a high percentage of water typically 15+ % and I'm afraid this will ruin the delay effect of the bicarb.?

[Night Owl]

maxman, on Oct 24 2008, 11:25 AM, said:

As portfire says, I have not noticed any difference with or without boric acid. I think with very fine aluminium in some comps with a nitrate it is quite possibly essential! But D1 is most likely best with about 200 mesh.

Here is a clip of a 3" plastic shell with D1 Glitter that was fillmed for me at 1/4" mile away.

Really nice Maxman:) ive made a 3" shell with D1, the al is 325 mesh, when one star is burned in test it burns a strong yellow and has white sparks, I cant notice a glitter effect like in your vid but do you think they will look like your D1 shell?

Edited by shell shooter man, 07 December 2008 - 03:39 AM.

[Fred]

Jerronimo, on Dec 6 2008, 06:07 PM, said:

Has anyone ever successfully made cut D1 glitter?
Cut stars need a high percentage of water typically 15+ % and I'm afraid this will ruin the delay effect of the bicarb.?

(excuse my english, it´s not my language)
To avoid the D1 beeing decomposed by too much water use Mowital B (=Polyvinyl butyral) as binder.
„Mowital B“ is produced by www.kuraray-kse.com.
Polyvinyl butyral is highly soluble in alcohol and 3% will be enough to bind D1 cut stars successfully.
Polyvinyl butyral doesn´t have any bad influence on the glitter effect.

With Mowital you can easily make D1 cut stars without boric acid.
Add 3% Mowital to the priming composition and use alcohol for priming, too.
D1 don´t need much prime.

[Jerronimo]

Sounds interesting Fred, how did you discover this compound? is it used in mass production?
Would like to test it but don't fancy buying bulk, any small quantity source of the stuff?

I actually succesfully cut D1 glitter, here's my procedure:

The Al was standard alec tiranty(uk)aluminium filler powder 250 mesh to dust.
Charcoal was lump hardwood bbq charcoal which burns very slowly in bp like compositions.
Sodium bicarbonate is food grade, KNO3 is greenhouse grade, sulpher is 99% pure technical grade powder.

Everything exept the charcoal and aluminium are ballmilled together for 20 minutes, and the aluminium and charcoal are screened in.
This is then wetted with a 4% gum arabic solution in water at about 25% by weight of the mixed composition.
The wetted composition is formed into a loaf, cut and diced and primed with standard bp green mix.
The finished stars are placed on drying screens and put in the drying chamber for 72 hours, first 24 hours without heat, next 24 with heat, final 24 without heat, the stars come out rock hard and bone dry.

http://www.pyrobin.c.....0inch low.mov low break:(

Edited by Jerronimo, 17 December 2008 - 09:51 PM.

[Fred]

Hi Jerronimo

Jerronimo, on Dec 17 2008, 10:50 PM, said:

Sounds interesting Fred, how did you discover this compound?

Mowital known and used as a very good binder among german speaking hobby pyrotechnicians.

Jerronimo, on Dec 17 2008, 10:50 PM, said:

is it used in mass production?

I dont know whether the pyrotechnic industry uses it.
Or did you ask about other use in industry? Yes, it is. Google for
„Mowital 30B“ or visit www.kuraray-kse.com.

Jerronimo, on Dec 17 2008, 10:50 PM, said:

any small quantity source of the stuff?

Yes. For UK, you can buy it at
AP Fitzpatrick Fine Art Materials
142 Cambridge Heath Road, London E1 5QJ
Tel 0044 207 790 0884
http://www.apfitzpat...er_pigments.pdf
100g £ 2.60

Edit: I did not see that you are from the netherlands.
Ask
G de Ru, Verf-Glas-Behang-Autolakken
Van Woustraat 145, 1074 AJ Amsterdam - Z.
Phone 0031 206760631

Test it, you will be satisfied:
High soluble, easy to work with, not expensive - a perfect binder.

Edited by Fred, 18 December 2008 - 06:26 PM.

[pyrotrev]

Or you can order online direct from www.Kremer-pigmente.de/en . They have an ENORMOUS variety of binders, I'd love to have the time (and cash ) to evaluate their usefulness for pyro purposes. BTW, how hard does Mowital 30B dry?

Edited by pyrotrev, 20 December 2008 - 11:16 AM.

[AdmiralDonSnider]

I once read through Oglesby and summed up the most relevant findings about wetting glitters here: http://www.pyroguide...=Glitter_Theory

"Oglesby denominates the two most important factors in metal corrosion in wet mixes as pH and temperature. Boric acid is often added to balance the pH of alkali glitter mixes and to prevent the aluminum from being corroded."

"The excessive use of water during consolidation can ruin a glitter effect. All present materials form saturated, often basic solutions with water and damage the metal fuels. The longer the composition is wet, the more likely the metal fuels are to be damaged. Thus we must use the minimum amount of water practically employable."

Against this background the water itself does not seem to be the problem. It´s the fact that it forms solutions in contact with chemicals; in case of D1 a basic solution of sodium bicarbonate. While boric acid restores a neutral pH in the wet comp, it does not effect the properties of sodium bicarbonate as a delay agent (thus you can´t say the use of boric acid renders the carbonate "useless").
The second issue is temperature: that means glitters have to be dried as fast as possible, but without using heat (heaters, sunlight etc.). We should dry them in cool, shadowy locations.

If I´m right, the D1 glitter will not be damaged even when using the necessary amount of water for cutting (about 15-20%), if we do two things: a) add boric acid to our solvent, and b.) dry the mix correctly.

Any experiences with cut glitters (using water as solvent)? Is there a decrease in performance?

Edited by AdmiralDonSnider, 23 February 2009 - 04:38 PM.