My first thought would be that you are not mixing the paint enough before you are watering it down.
Clear matt finishes, even though looking clear and mixed, still consist of the same constituents as any other paint, i.e. a carrier containing suspended pigments and solids. Obviously clear does not have the pigments included but to get the matt effect you must mix the coating very very thoroughly to ensure the solids are evenly held in suspension.
There could also be a tendancy to loose the matt effect if you mix the clear with too much water or thinners as, of course you are spreading the solids too thinly on the surface to generate the correct matt effect.
The fasct that you say 'sometimes' fully gloss would indicate an inconsistency somewhere which I would think quite likely to be the mix of the clear in the first place.
I would start by very thoroughly mixing up the clear and doing a test with a brush on a sample. If that dries matt successfully then you know the paint is OK and you can progress from there.
Keep us informed as to how it goes. |