Use these natural hair brushes (non-heated) with molten wax. Sizes in the pack are 2mm / 4mm / 8mm / 12mm & 20mm .
The Painting Iron (Ref #5301.00) can be set up as a small Hot Plate / heated palette where waxes can be mixed, etc. Also consider using a Heated Plate Warmer / food warming tray (domestic appliance) as an excellent heat source for keeping waxes molten. Use a multi-dished muffin tin to contain your wax colours.