Rob- I think Matthew posted the optimum time to use them. However, some of the products (streaking grime for example) I have applied at various stages (always after letting any oil stages dry thoroughly) as some weathering products can lessen the impact of products applied beforehand. For instance I applied some streaks that got slightly muted by pigments, so to make the grime appear fresh I applied some more afterward.

Hope this helps.

-Karl187-

Do I first shoot a gloss coat, then do a wash, etc, before using them?
I know this should be pretty obvious but I can't seem to make the mental leap that would allow me to properly sequence the overall finishing process when using these products.

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That's one of the things that I really like about the AK products. You can layer them with other products and mediums and re-apply them for old and fresher stains and streaks. It's easy to get a lot of depth and reality to the finish. I am really loving the fuel stains and oil stains, they look so great I really have to restrain myself from overdoing them!

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and how long did you have to wait for each layer to cure?

and the colors didn't mix?
I only tried their filters once, and waited overnight, there was still mixing when another color was applied after the wait. IMO 8 hour isn't sufficient for enamel to form a in-re-hydrable (making up word, but you get what I meant) layer regardless of the solvent vehicle. In automotive painting, when real enamel was still used, they baked the paint to accelerate its cure and that was done over longer periods of time than 8 hours. Although, they also painted much thicker coats, more layers of applications...

The reason I asked. If the colors mixed, then the result wasn't "filters" (plural)...............Brian,The term you are looking for is "reversible".Back in the day(35 years ago)most of your auto finishes where either laquer or enamel and where reversible,meaning that you could take a solvent ,laq. thinner or enamel reducer,and with a little work you could wipe the paint right off the car!With the advent of acrylic enamels came the 2 part piant systems,i.e.paint plus a catalyst.The addition of the catalyst to the paint caused a chemical reaction that cross linked the paint and made it "non-reversable",in other words the paint did not dry (evaporation) it cured(chemical reaction)and was not effected by solvents .Now a days almost all cars and trucks are finished at the factory with base coat clear coat system.The clear is a urathane and requires a catylist.The vecs. are baked as that speeds the cure.So anyway,most of the paints we use on models are reversable and will soften or dissolve with the right solvent.I would caution any one not to use a 2 part paint system as the chemicals used are HIGHLY TOXIC!Pick your solvent carefully. Thats my lecture for today boys and girls,there will be a quiz on Tuesday.LOL

and the colors didn't mix?
I only tried their filters once, and waited overnight, there was still mixing when another color was applied after the wait. IMO 8 hour isn't sufficient for enamel to form a in-re-hydrable (making up word, but you get what I meant) layer regardless of the solvent vehicle. In automotive painting, when real enamel was still used, they baked the paint to accelerate its cure and that was done over longer periods of time than 8 hours. Although, they also painted much thicker coats, more layers of applications...

The reason I asked. If the colors mixed, then the result wasn't "filters" (plural).

I was under the impression that urethane is the only one that requires a chemical process to cure. Enamel and acrylic enamel can use hardeners, but they don't necessarily accelerate the curing, and the curing is essentially drying of the oil or water in the mixture. In the case of enamel, it never really dries (like an oil paint).
Anyway, I think curing and drying meant the same thing to enamel and acrylic.

In acrylic enamel, the acrylic molecules form a hard bond when the vehicle dries. This bond protects the enamel content within. The paint has a complicated base but could be understood as oil based, and I've heard that acrylic enamel required 1-3 days between each thin coat in automotive painting.

Acrylic paints (in modeling) are pigments suspended in pure acrylic materials. Because there's no need for oil based filler or binder, water was chosen for it evaporate faster. It's expansive (like twice the price of acrylic enamel), and the finish, although durable, isn't as durable and scratch resistant as urethane, so auto industries use urethane.

Baking was only necessary for oil based paints, enamel and acrylic enamel. Acrylic paints dry fast, and urethane paints don't benefit from the heat as it's hardened from chemical reaction.

The base coat - top coat system you mentioned was only to obtain the gloss finish. In fact, since the clear coat could act as a filter and alter the perceived color, one stage application is arguably better.

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Whenever I use filters I seal it with varnish/future etc to stop it mixing with later stage weathering.

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this is why I prefer acrylic paints. a lot of clear coats will knock down small details.