Hi, I want to know the differences between this two paints.
1) can I apply both of them only by airbrush or you can use brush?
2) can Alclad for Lexan damage the plastic of our models, like a 1/35 Mercedes?
3) any tips?

TIA
Alvaro

1) Alclad is for airbrush only, and does not brush on well if at all.
2) Alclad for Lexan is exactly that, it's made to be more flexible and scuff resistant for use in R/C and slot car applications, it's probably not a good idea to use it on polystyrene since it's a hotter formulation designed for "slippery" plastics.
3) Alclad chrome paints are excellent for simulating chrome or highly polished metal, but they are best applied over a glossy black finish. I highly recommend Alclad Black Microprimer and Pore Filler, but other gloss paints work well-- Tamiya and Gunze Mr. Hobby work very well.
Hope this helps,
VR, Russ

Thanks Russ.