Best way to paint the underside with different color?

I’m tackling my first airplane kit (Tamiya 1/48 Me-262). I’ve been an armor guy.

The underside of both the wings and the fuselage needs to be painted in light blue. Other parts will be painted in dark grey with some camo patterns. As for the wings, do you mask the upper parts and paint the exposed parts in light blue and reverse the process to paint other parts in dark grey? For the fuselage, the demarcation line between light blue and dark grey is irregular on many photos of the Me-262. So I don’t think masking will work here. Should I use something like silly putty? Any tips will be appreciated!

Thats exactly what i do. Paint the blue first, then mask and do the top camo. Silly putty works great for irregular demarcation. Put the masked canopy on too and paint it in one go. Tack it on with small dap of white glue if you plan on displaying it open later.

Yes spray the rlm 76 first, then the topside camo. These types of patterns are best done freehand to replicate the real thing. Masking just doesn’t really work that well. With a little practice, you’d be suprised how easy it is to airbrush freehand and get it to look realistic. Being an armor guy, you’re used to feehand camo anyway?

One of my favorite masking mediums for hard edges (demarcation lines) is a post it note, very light tack, straight line, stays in place nicely.

I usually do not mask the upper part of the aircraft when I spray the lower part blue with an airbrush. I find I usually have enough control to keep the blue predominately on the lower parts of the plane. Yeah, a little blue may get on the top, but not enough to worry about. I DO mask the blue then when I paint the top color. If there is any blue on top I may have to airbrush a little heavier in that region to keep the color uniform, but that is easy enough to do.

I do exactly what Don said, and it works fine.

Yeah, I’ll just freehand the fuselage & top camo. I guess I am too nervous because it’s my 1st airplane build.

I’m finishing up Hobby Boss’ excellent Me 262A-1a/U4 at the moment, and I painted it freehand. With the very triangular profile of the fuselage, it’s actually very easy. The engine pods are a bit trickier to work around, and when I was in the vicinity of them I used a scrap of cardboard to block overspray while I worked. For the actual upper/lower demarkations, I just took care to keep the airbrush pointed “out” from the RLM 76.

Ditto. This is what I do as well.

Sorry, meant to say I do what Don in MN does.