You may have heard of Future floor polish. It is widely used by modelers as a gloss finish. It is sometimes referred to as a wax. This is incorrect, as there is no wax in it. You can see it's ingredients here. It is an acrylic coating that dries hard and has the nice feature that it can be re-desolved by a solution of ammonia. It is 80% water and can be thinned with anything water soluble. Some people use water, some use alcohol, and some use Windex which contains ammonia and also reduces surface tension. A good place to read about it is Swanny's Models.
Its main uses are as a coating for clear parts such as canopies, and as a coating before and after applying decals. It does wonders for canopies, making them crystal clear. And, it also acts as a barrier against cyanoacrylate adhesive fumes which can fog bare plastic. Some people have still seen fogging, but I think it depends upon amount of exposure.
Since I work mainly in 1:72 scale, I keep a small amount in an old paint bottle to dip my canopies. I thin it about 50% with water and it seems to have less tendency to pool.
Many people can airbrush Future and get nice smooth finishes. I have to admit that I am not one of them. I've tried all the variables and still get a pebbly finish. I just don't have the right touch. So I brush it on like a lot of others do with a wide flat sable brush. It brushes very nicely without leaving stroke marks, so this is no problem. Just don't put it on too heavy and don't overbrush. Experiment on some scrap plastic first. To clean the brush, I use Windex first and then wash with dish detergent and running water.
If your paint is smooth, one coat of Future is enough before applying decals and one more coat will seal them. I use it even on aluminum foil finishes as it protects the foil from corrosion and seals the edges. For a dull finish, I overcoat Future with Testors Dullcote lacquer, and have had no problems. But I always let it dry until I can't smell it, and this can take several days.
Here is a 1966 Mustang by AMT that I painted with Rust-Oleum Paint for Plastic that I decanted from the spray can and airbrushed. This was then rubbed out with plastic polish and then covered with a brushed-on coat of Future. There is no wax on it. The windshield and rear window were also coated with Future.
I got an E-mail from Flo Austin. Flo tells me that Future is now sold as Pledge Multi-Surface Floor Finish, and the manufacturer says the formula is the same. It has also been marketed as Pledge Tile & Vinyl Floor Finish with Future Shine.
Does Future protect against corrosion?
The one on the right was hand brushed with Future after polishing. The one on the left was not. This is how they look after sitting in my hobby room for almost a year. When freshly polished, the Future coated duck was not quite as shiny as the plain one. But, as you can see, it has retained its shine much better.
According to Swanny's Models, which in my opinion is the ultimate source for information on Future, it is now labeled as Pledge Floor Care Multi-Surface Finish in the U.S. For equivalents in other countries, visit Swanny's.