Gerb - Fe & Al


Name: Fe & Al
Source: Alan Yates


percent parts component
53.13% 17 Potassium Nitrate
18.75% 6 Iron (-100 mesh)
12.50% 4 Charcoal (airfloat)
9.38% 3 Sulfur
6.25% 2 Aluminium (-100 mesh, flitters)

Required Mass


Screen together well using a 60 mesh screen.

Coat Iron if the composition is not to be used immediately.


Interesting effect.

Additional coarse Charcoal may be added to moderate burn rate if required. Using extra Charcoal also seems to alter the Aluminium effect, improving its hang-time and creating a "transformation" style effect. I do not understand the mechanism for this but it is quite repeatable - Aluminium Carbide perhaps?

Tends to slag the nozzle a bit, use a good convergence cone to get a nice plume. Lots of magnetic fall-out and dross, less Iron increases burn rate and improves clearance but reduces the effect.

Finer Iron yields an almost exclusively glitter effect with bright silver flashes occurring some height above the case in the plume. I suspect Iron Sulfide production may be acting as a delay agent - Winokur mentions that very fine Iron can substitute Antimony Trisulfide in glitter compositions for an inferior but usable effect. Using fine atomised Aluminium and less but extremely fine (-325 mesh, granular) Iron may improve the effect and produce a usable glitter gerb that does not suffer from the typical severe slagging problems.

Further experimentation in this area would be interesting.