POST # 33.
Painting engines.
My 3rd rail NP Z-5 2-8-8-4 came black and I want it to have a grey boiler.
Normally, I disassemble the entire engine to paint them but this one is already painted and it also has all the electronics in it: so best to paint the boiler without any dis- assembly.
First I used some slightly soapy water and a toothbrush to remove any dust and oil and then blew off the water via an air hose.
Next the boiler is masked off.
Initially, 1/16"-3/32" wide masking tape is used to outline the domes, thin widths needed to navigate the compound curves without kinking the tape.
Some larger widths of tape is then used to build up the around the domes.
Masking tape, a straight edge to cut the tape, a piece of glass for cutting the tape on the surface, tweezers and scissors and a toothpick to apply the tape without fear of scratching the existing painted surface.
After all non-painting surfaces are covered, she is ready for painting. Masking paper is from home depot (paint section) as all parts not to be painted needs to be thoroughly covered as spray paint has a nasty habit of finding the smallest hole.
Like all painting, painting is the easy part, the prep takes all the time. It took me about 2 hours to mask off the boiler.
The paint is applied, vertically from back to front and then front to back at about a 45 degree angle, each way to get into all corners. Then the paint was applied horizontally, left to right, right to left for the final coats.
After cleaning up the air brush, the masking tape needs to be removed before the paint thoroughly dries. The paint can often be ripped off surfaces when the tape is left on until the paint is thoroughly dried (especially if you're 'heavy handed' and put on a thick coat of paint). Care has to be taken not to touch the newly painted surface but much better than leaving tape on the model until the paint dries. The pipes, etc still have to be touched up by hand and brush after the grey dries.
I've used a binks for the past 40 (or so) years but I went to harbor freight and picked up an inexpensive airbrush and it works great for painting engines.
Water filters is best used as close to the paint gun as possible.
You don't need a 60 gallon air compressor but a small one with an air tank is nice (an air tank keeps the motor from running constantly).
I'm partial to scalecoat (enamel base) paints. A well ventilated area is needed (same with all spray painting). I normally bake the painted parts at 200 degrees for 2 hours. This allows quick masking and painting other colors on the same day. An accurate thermometer should be used to insure the temperature is 200 degrees as those toaster/oven dials are not always very accurate (don't want to be melting solder joints and making your model into a kit!).
The Z-5, being not disassembled, will have to air dry for 1-2 days or until the odor is no longer noticeable.
Two days later:
I used a 50/50 solution of high gloss and flat gloss of scalecoat paint to get a match to the factories paint finish.
