Hi masternater,
If you want to tint nitro cellulose, you will need dyes that are compatable. LMI sell analine dyes that can be used with nitro but you need to dissolve the dye in denatured alcohol,(the water based dyes are not suitable for this). It is best to leave it over night, even then there will be a sediment which needs to be filtered out. A coffee filter paper in a funnel works well. In this form the dye can be stored [FONT="]indefinitely. When you add it to nitro, you need to mix it with equal parts with acetone otherwise it will cause the nitro to break up. It sounds like a hassle but it is okay.
Another tip about finishing that helps is before any stain, sealer or lacquer is applied you should raise the grain. This is done by lightly wetting the timber (use mineral water applied with a rag or a hand spray), this will cause the cells in the wood to swell up. Allow this to dry and sand the surface with 320 grit. Repeat this process, this time the the cells will swell a tiny amount, again sand the wood. by doing this the timber is all swelled out and any further moisture applied to the surface won't have any affect on cells allowing for a smoother finish and less sanding.
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