Question about a wash: it's clear as mud to me

I'd rather not use enamel on top of acrylic. But I suppose if you do apply a coat (of Future or the like) first it should be OK.

Washes will stick like permenent ink to a matte surface. I learned this the hard way! I ruined a red-white-n-blue YF-16 this way. Aaaarrgghhhh!

About 9 parts thinner to one part paint.
To test the mixture, take an old model section or if you don't have any around, the top for a condiment container that holds Chinese mustard or salad dressing from a take out restaurant.. When you place a drop of the mixture at one of the right angles and it extends long the angle without spreading out on the flat surface, you have the correct mixture.
Better to err on the side of too thin, than too thick, since you can easily add more wash but you'll have to repaint the whole thing if it's too heavy.

I have one question about washes, what is the right amount of paint to thinner ratio to get the proper result. I've tried differant ammounts and it alays comes out too thick or too thin. Can some one enlighten me please

a long long time ago I tried model acrylic paint as a wash and Al is right, it just didn't look "right" to me and took a lot to keep from haveing too dark of areas around the detail....

from different peoples comments here as well as personal experience, Future the model.. then you can use anything on it including:

oils, water or turpentine/linseed oil soluable
artist acrylics in the tube
watercolors
enamels
(some people use this not me) india ink for panel lines
etc...

you can put almost anything over the paint (in my experience) as long as it is sealed with Future as thehannaman said. Try it on a test model or on extra pieces or sprue you have left over... I've used oils, artist acrylics and water colors over future with no thought of what kind of paint is underneath. As long as you dont use an ammonia based solvent in thinning the wash you are ok!!! (ammonia cuts through the future)

First, most acrylic paints don't work well as a wash, the pigment is too big and the surface tension of water is such that it won't flow as well as thinner.
Second, you should be applying your wash wher you want a shadow, such as in panel lines and NOT risking your entire paint job by covering the model in a wash and hoping to be able to wipe off the excess. By doing this, you can use any type of apint over any other type of paint without a mess.

Aplying Future before washing works very good. Because of the gloss surface, the wash runs easely.
I always use a oilbased wash, it has no effect on the coat of Future. I can't comment on using an acrilic wash.

I use either artist's acrylic or artist's water color washes over acrylic paint all the time with no problems. But then I'm normally only washing panel lines on aircraft to.

I would imagine that the Future would take the guess-work out of it. Give it a try on some scrap to see if you get the results you desire. I'm almost positive you should be okay.