At a guess, I\'d say he\'s probably using a lot of, if not all, of the same techniques as on the NMM and SENMM he does. Most of the best metallics seems to. The painter does a base coat in a mid or slightly lighter metallic, then uses controlled glazes of matte paint (ink for some people, but looking at the Huntsman I think paint was used here) to build up the shadow areas. Then layers of brighter metallic paints to build up the highlights. All using the same principles of where to put the shadows and highlights and of what intensities as NMM does.
I\'ve had the opportunity to see bragon (Jeremie Bonamant Teboul) paint some metallics, and will try to recall what he did that might seem a bit different.
The difference I found most notable is that he thinned the metallic paint down a fair amount to establish the basecoat, which I think made a big difference to avoiding the \'thick\' or lumpy look metallics can get.
Not sure if I wrote this down right, but he uses metII Humbrol enamels for the brightest highlights and hotspots. These are paints that require white spirit thinner and do not mix with regular acrylic paint. Another painter I took a tutorial with used Vallejo alcohol metallics for the hotspots. Sounds like regular acrylics just can\'t get as bright as more annoying types of paint.
He used glazes and colour to do a lot more than just set the shadow areas, which I think he and a lot of the European painters do. So he might add touches of the main colours of the mini to the metallics to capture the feeling of some reflections from the clothes and gear, as well as to increase colour harmony throughout the piece. The demo piece he did for the class, after doing the shadowing he went in with a blue glaze on the deepest shadow areas, a yellow glaze (very thin) on the intermediary areas, and then a glaze of Tamiya clear smoke over the whole thing. Those kinds of colour choices are going to impact a lot on the \'clean\' look you\'d like to try - using blues and/or blacks for the shadows rather than the red tones Arjay used on his piece.