Agglomerating nano-particles

A method of agglomerating nanoparticles to form larger agglomerates is shown. The nanoparticles are mixed with a resin to form a first mixture 803 of agglomerates, having sizes over a range that includes agglomerates considered to be too large, suspended in the resin. A bead milling cylinder 802 produces a second mixture 808 with fewer large agglomerates. A filter removes the remaining large agglomerates. The resulting mill-base may be cut with a solvent before deployment. The nano-particles may have a size less than 100nm and may be substantially spherical or acicular. The nanoparticles may be antimony-doped tin-oxide and the resin may be un-diluted lacquer. Agglomerates having a size greater than 10 micrometres may be considered too large. The mixing step may be performed by a speed mixer operating at a rotational speed of up to 1600 revolutions per minute. Bead milling may reduce the size of agglomerates to below 5 micrometres. The filtering step may deploy a filter with openings having a size of 10 micrometres.