iv been to the sites and they have 5 micron 10 micron and 30 micron What dose it all mean!?
Aluminum and propylene glycol.
The number of microns refers to the average size of the aluminum powder particlesA 5 micron Al powder has particles that are (on average) 5 microns in diameterAnother way to measure the size of particles is by mesh number; a larger mesh number means a finer powderThe other answerer is correct - smaller particle sizes mean faster reactionsWith thermite, it is very difficult to ignite mixes made with coarse aluminum, and relatively easy to ignite ones with finer aluminumThat said, it can go too quickly to make a good stream of molten ironThe only aluminum powder I have is 1 micron, which goes too quickly (shower of sparks instead of a slow burn)Aluminum powder size is also given in mesh numbers (conversion table below)I think a good size of aluminum to use is between 100 and 300 mesh (~40-150 microns), but the size isn't super criticalShape is also important - spherical particles burn more slowly than high surface area shapes like flakesSmall flakes should not be used in thermite; they burn too quickly and are more expensive than other types of aluminum powder anyways.
