Canopy lining on F-4s

v thin coloured decal or good masking

Probably the easiest way:

Get some clear decal film. Spray some of it yellow, and other parts of it the colors of the aircraft around the canopy. Lay down the yellow film so that the "yellow-sealed" areas, are now "yellow". Then lay down the other color(s), leaving only a thin line of the yellow. Sure, this is "decaling over decals", but it is common practice among airliner modelers, for cleaning up trim, patching over-spray, etc. It works.

:o)

To answer this question requires some understanding of the source of these lines on the real aircraft.

These lines are not really on the exterior of the canopy. They are actually a view of the underside of the interior canopy framing. The interior canopy frames often use a sealant, putty, or gasket that is yellowish, off-white, or red. This shows through the canopy transparency and appears as a thin line around the exterior canopy framing (The red putty is actually more of a brown-red color and is primarily used on F-15s although I've seen it on other aircraft like F-111s).

So what you are really seeing from the canopy exterior, is the underside of the internal canopy framing through the canopy transparency.

A way to reproduce this on a model (that I have yet to try) is to mask the canopy framing on the inside of the canopy, apply the yellow, off-white, or red color, apply the canopy interior color over this (in most cases a flat or semi-gloss black), and mask and paint the exterior canopy frames. The thickness of the canopy plastic may have an effect on the width of the frame line but this method would accurately reflect how the canopy frame lines get there in the first place on the real aircraft.

Martin