Description: Iron powder is used for spark effects, mainly in fountains and sparklers. It produces golden yellow branching sparks. Not every iron alloy will work equally well. Iron alloys with a high carbon content generally work best. Stainless steel will produce hardly any sparks.
Hazards: Iron particulates of micron-submicron size are pyrophoric (may spontaneously ignite on contact with air). Care should be exercised with this particularly reactive form of iron. Iron needs to be protected before use in pyrotechnic compositions. Otherwise it will corrode and render the composition useless or even dangerous. Iron containing compositions are generally best kept dry and not bound with water soluble binders. Iron can be coated with linseed or tung oil. The latter was used in ancient China (and may still be used today). Linseed is very convenient to use and easy to obtain. Blackpowder-like compositions (ie Charcoal/sulfur/saltpeter based) with added metal, such as they are often used in fountains, are more sensitive than the composition without added metal. Extra caution, especially when pressing or ramming, should be excersised.
Sources: Iron turnings can often be had for free from places were iron is used for construction. Drilling, sawing etc produces a powder with wide range of particles. This powder is treated with mineral oil to remove oil and grease, sieved, and then coated with linseed oil.