Magnalium dust is harmful and a dust mask should be worn when handling fine dust. Mixtures containing nitrates or ammonium perchlorate and magnalium sometimes heat up and may ignite spontaneously, especially when moist. Coating magnalium with linseed oil will prevent reaction with nitrates, but this treatment does not protect the magnalium from ammonium perchlorate. Only treating the magnalium with potassium dichromate will prevent this reaction. This is done by boiling the magnalium in a 5% potassium dichromate solution. Adding fine potassium dichromate powder to such compositions may also help.
Magnalium MG/AL -200+325 mesh
Magnalium is a very brittle alloy of magnesium and aluminum. Some common uses are in for spark effects, in strobing compositions and in crackling stars. Lancaster gives some typical mesh sizes for different uses: Magnalium used for strobe stars, for spark effects or to enhance other stars has to be finer than 120 mesh, while for use in crackling microstars it has to be something between 30 and 50 mesh. The coarser type is generally harder to find commercially. Magnalium can also be substituted into most mixtures that aluminium finds use in. These include; thermite and flash powder.