I am currently working on three 1/48 scale models, an XB-70, a B-52G and a B-52H. I’m new to airbrushing and am not sure how to tackle these “monsters.” The XB-70 is 31" long with a wingspan of 12" and that’s a lot of surface area to cover. All three will have very significant areas of gloss white and I was planning a base coat as well. The B-52s will have dirt, grime, exhaust, oil leakage, etc. which I can use to hide some imperfections, but the XB-70s were always pretty pristine and consequently imperfections are going to be harder to deal with. My main two questions are: 1. Are there airbrushing techniques unique to very large models that would help me do a high quality job? 2. Are there things that I should NOT do that are unique to working with large scale models?
I find that is an interesting question, especially since I am about to start my B-29. I am finishing a 1/48 P-51D which I base sprayed with a rattle can. It worked out good; so I am thinking of using a rattle can on the B-29 for the base coat. Let’s see what the experts say!
Yep,rattle can is the way to go on things like that
The largest build that I have airbrushed was a 1/48 B-17 in OD & Neutral Gray. I just did it in sections and used a wider pattern except in the color demarcation line areas. The B-52 with its camo should be easy enough as each color is a smaller area. But the B-70 will likely requires sectional approach. For white I like to use a flat white for primer/base, then a top coat of satin, semi gloss or gloss for a more “vivid” white.
Go watch folks in a body shop paint full size cars, or in an airport shop paint a full size aircraft. They have the same problem. The coverage of a spray gun does not cover the panels they are doing at one time. They have to move in a pattern.
In general you need more than one coat. By this I mean that you go over the model in one direction and trace overlapping lines. Then you do lines in the other direction. If you always move, in lets say, horizontal lines, you will end up with some visible horizontal shading in your finish. So do a complete surface with horizontal lines and then, not waiting for anything to dry, go back and do another coat in vertical lines. In both cases try your best to overlap evenly, but by doing lines in both directions 90 degrees apart, this will help prevent shaded lines in the final finish.
Thanks, Don! Your comments are very helpful and what a great suggestion about the body shop. I have a close friend from church who owns a body shop and I’m sure would be a great source. I hadn’t consider the horizontal then vertical coverage strategy, but it makes great sense. Thanks much!!!
You need, lots of paint, and an airbrush with a larger needle opening. I would spray can the primer for sure, but there is no substitute for an airbrush, no matter how large the model. Just do it in sections, take breaks, and have patience.
Thanks for the response, Stikpusher! Yep, the camo on the upper surfaces of the B-52s should be much easier, but their undersurfaces are gloss white. I’ll follow you suggestion about using flat white as the basecoat.
Lot’s of paint! How true!! You just made me think about the capacity of my airbrush. It uses a glass bottle attached from the bottom and I had assumed that it would have adequate capacity, but in retrospect I’m not so sure that’s correct. Guess I’ll have to mix up a rather significant batch to keep adding. I’m a bit intimated by spray cans though. In the past, I’ve always gotten runs and/or uneven patterns. Perhaps that’s less of an issue with a basecoat.
For good airbrushing you need to think of an airbrush as a brush that puts down paint without brush marks. It is not a spray gun. Attempting to use an airbrush as a high volume spray gun will lead to bad finishes. I DO often put down a coat or two from a rattle can first, then sand with fine paper and do last coat with airbrush. It is hard to put down a flawless finish with a can, however, hence the need for the last airbrush coat.
You touched a subject that I encountered plenty of times, the large surface area led me away from airbrushing to first rattle cans, then to a small regular spray gun by Binks, called a “detail brush.” Looks like just a smaller version of what you would see in a body shop, you’re shop friend likely has one to show you. I find I can get essentially the same results with a good quality spray can, don’t laugh, I get most of mine from Wal-Mart, the cheap ones around a buck. For a large surface area, single color, it works very well for me, from primer to finish coats. Don S. is right, opposing directions give more uniform coverage, but do remember to overlap each pass a bit, to avoid the rough texture of being too light between passes. Get some shiny, printed cardboard sheets and practice, you’ll soon see how to do it, and remember to have good lighting, THAT is the spray painters best tool. Warming the can in warm water is helpful, it gives a more fluid substance, cold paint is more viscous and doesn’t flow as easily. The ability to easily blend one pass into the next is crucial. Practicing on printed, shiny cardboard will show you how close or far away to be, and I do recommend you give it a thorough try before painting the model, it can save a pricey model and prevent a poor finish. For the camo job, by all means spray can the primer and base color, then airbrush the succeeding color patterns. You’re friend with the body shop can surely give you many pointers, maybe even let you watch a paint job in progress, that would be a great lesson. Hope it helps, best of luck. Patrick
I also have a detail brush but the flow is too big for my airbrush compressor so I do not use it in my workshop, only in my garage where I have a larger compressor. So, here in Minnesota that rules out using it in winter 
Actually, in cold enough weather like we are having at the moment, compressors may not start in garage!
It’s the large jobs where I switch from my double action airbrush to my old tried and true Badger 200 Single action. I use a large bottle, set it to a wide spray and do multiple coats. Rattlecans are probably a better option but I just don’t like to give up the control of an airbrush.