Okay, I’m sure this has been answered a million times but I’ve missed it.
From the FSM articles and a lot of the online build info I’m seeing, there are a lot of people doing 90+% of their painting with an airbrush, I can’t see how this is done without a huge amount of masking. I’m back at modeling after a 20 year lay-off. Did the industry reformulate paints so you can glue a painted surface now? I’m doing about 45% of my painting with my airbrush & 55% by hand brush because I can often hand paint faster than taking the time to mask, paint, dry & unmask. Example - armor road wheels. After spraying the wheel assembly, I can brush paint free hand the rubber tires faster than masking each wheel & spraying the black rubber. Or is there a technique I don’t know about? (there seem to be sooooo many.)
As for surfaces to be glued, do you still have to either mask or scrape off paint? Or it this no longer necessary with acrylic paints. (I’m just learning acrylics after 40 years of using enamels-old habits are hard to break.)
Apart from areas that can’t be painted after build, like the cockpit or certain intakes, I mainly build the larger parts like wings, fuselage & tail up before airbrushing them. Say its a 2 colour camo job, I will then do an overall coat in the lighter colour, before masking for & painting the darker colour.
The smaller items like landing gear, gear doors, probes & such are usually a mixture of airbrushing (if It justifies it or I am using the paint in the first step) & brush painting. So far for 1/72 aircraft wheels I will airbrush the whole lot black & then brush paint the centres in the wheel coulour.
As for removing paint before glueing, acrylic paint is no different to any other - the paint still has to be removed to allow the glue to weld / adhere the plastic.
Armor road wheels; one technique is to use a mask template, which is quick and easy, (such as Royal Model, tank wheels template), mount the wheels up on matchsticks (using some white glue) then paint the entire wheel black (I like to use the Tamiya Nato black XF-69), then using the masking template spray the camo colour. (the road wheel is only held beneath the mask, not adhered to it).
If the wheel has a lip at the edge of the rubber, you can roll out blue tack, and push it down and use the lip to tear off the excess blue tack.
I have never scraped paint off surfaces to be glued (unless the part is chromed, or it requires CA glue), the (liquid styrene) glue should melt the paint as well as the plastic beneath it
I will scrape some opaint of of certain things where I do not want a color run, but otherwise I use a styrene weld glue and that stuff is the cat’s meow!! I think it makes stronger joints than CA glues.
I use a drafting template with circles in it for my wheel maks, works like a charm. Put the right size hole to the wheel and air brush.
Im more versed in scifi kits then armor but I can help you out. First find what pieces fit on where, what ones are accessors for what, and build the sub assemblies, build the body of the tank, build the road wheels, build the turret, build the internals, anything that can be attached later and isnt required for the main thing. Paint each of these seperatly, keep the sub assemblies as small as you can so there is less and less masking.
Another way that I see often, is ABing parts en-mass on the trees then touching up what is needed after you snip them out.
The plastic model glue will disolve the paint the same as it softens the plastic (but it gets a litte l messier).
CA: Whenever I have gotten lazy and glued a part with superglue without scratching off a little paint first, I have regretted it. The glue bonds to the paint much more strongly than the paint bonds to he plastic, so eventually the part gets knocked off and leaves behind a perfectly paint-free spot on the plastic that is the exact shape of the CA drop.