[jack404]

lotsa a ways of laying a colour on alu just most are either ionic transfer or a dye

get yourself the matching grade of alu ( manufacturer should specify the type of alu generally 6061 T6 grade is used

then select some Black and either navy blue or mahogony RIT r fabric dye ad 1 part black to 4 parts colour and test and adjust , do 3 coats to test leave for 15 mins and wipe clean and reapply and see if that will get the colour to your likeing \

the compound dye used by rit is a bastard staining dye on alu and will stain alu bowls forever if used to dye stuff in but its never a real deep stain and its hard to get even unless you spray gun the whole thing to get a even coverage on fast

some places use a varnish type stuff on alu parts this will block any stain finish etc test with a small dab of amour all if it goes white ish after a few its coated if not the metal will disperse the amour all (then ya gotta degrease ya gun , oh well )

if not then ionic transfer

normally used is anodizing but theres a few others , mild acid can transfer various colours from metalic bases and attraction and deposit is provide via a current passing from one annode to the other ( the alu being the neg so the metal deposits on it )

most anodized finishes are rather shiny but there are matt compounds on the darker shades t5o at the better shops ..