Can I use common floor/Furniture gloss laquer (white spirit thinned) as final gloss cote on my Tamiya Mercedes 300 SL kit?
Future is not a lacquer and lacquers are also not thinned with White Spirit/Mineral Spirit. I'm not exactly sure what you are asking about.
It also has not been called Future for a while. What you would want, at least in the USA, is Pledge Multi Surface Finish. Do not get the one for wood floors. It used to say Pledge, with Future Shine, but they stopped labeling that way a few years back.
Generally Pledge/Future does not need to be thinned. You can airbrush it straight. Myself, I do not like to airbrush it, and just dip smaller parts, or apply it with a large, soft, CLEAN paint brush for larger parts. Wick off any excess that builds up around the bottom or edges of parts. Let dry THOROUGHLY.
As an alternative you could get some Alclad II Aqua Gloss clear finish. It's basically Alclad's answer to Future for those who can't find Future or who don't like messing with it. I find it sprays a lot better.
I expressed me wrong. What I ment was how about using a common clear/glossy mineral spirit laquer as gloss cote on a model car -(with furniture I did not mean the stuff Future Clear, but furniture/floor laquer. It is much cheaper than special model laquer ... has somebody tried it?