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Written by Jim Hiller
RC Jets
Feature
As seen in the May 2019 issue of Model Aviation.

this is a simple technique
01: This is a simple technique to weather your scale jet. It works well on a model with flat paint. For stage one, use pencil lead to darken the recesses such as access doors, panel lines, and even some rivets. This gets the initial dirt (pencil lead) in the right places.

stage two is to clean
02: Stage two is to clean up the mess using a lightly wetted rag with 91% isopropyl alcohol. Wipe off the pencil lead and wipe in the proper direction to control the direction of the streaking. Concentrate on cleaning the flat sections while leaving the pencil lead in the recesses to highlight the details. At this point, the model can be left as is or, if desired, clear coat can be used to seal the weathering.

IT’S TIME FOR some creative fun! The first 20 flights on my Der Jet Grumman EA6b Prowler went well, so now it is time to dirty it up. Warning: the technique I will describe only works well with satin or flat paint. It does not work well on glossy paint.

The Prowler has all of the panel lines and rivets molded in, along with the access doors, hinges, and other surface details. They do not stand out, however, so all of that wonderful detail is lost to the human eye.

First things first. If you plan to do some extensive weathering detail, you should search for how-to videos from Phillip Noel’s Pinnacle Aviation on YouTube. Phillip has done some wonderful videos on detailing and weathering. His techniques are well developed and beyond the scope of what I am looking for on this model, but they are relevant. My detailing is toned down.

A quick comment on weathering: The panel lines and access doors are places where two or more pieces of aluminum typically come together on the Prowler, so the gaps tend to fill with deep, dark black dirt and aluminum rubbings. My goal is to duplicate that color and only highlight the surface details to attract the eye—not overwhelm.

The full-scale aircraft that my Prowler is modeled after has a light gray special show paint and the pictures show it is kept pretty darn clean for an in-service military aircraft. My goal is subtle weathering—only enough to highlight the details.

Before starting, you need to do one important check. Rub the paint with some 91% isopropyl alcohol to confirm that it will not affect the paint. The aggressive use of this alcohol is required with the following process.

First, let’s start with the surface recess areas such as the access doors, latches, hinges, panel lines, and rivets. You need to fill the recesses with some dark color to make them stand out. I prefer to use regular, soft pencil lead such as H or 2H. This color darkens the recesses nicely in a manner that is similar to aluminum rubbings. It is not a deep black because that would be the wrong color.

Run your pencil around all panel lines, doors, hatches, and latches. This will look ugly and that’s fine. Intricate, clean detail work is not important. Getting the lead into the recesses is the objective at this stage.

After applying the lead, remove it from the surface using 91% isopropyl alcohol. Lightly wet a small area of a paper towel with the alcohol and use it to clean off the pencil lead. You will see that the lead tends to stay in the recessed areas, making them stand out nicely. This is an opportunity to determine how much of the lead to clean off because it controls the deepness of the color and how aggressively or subtly you want the detail to stand out. In this case, I went for slightly darker around the hinges and doors and lighter in the actual panel lines.

It’s important to wipe in the direction of airflow or gravity, depending on the direction of the flow lines coming out of hatches and doors. Study some photographs to get the feel for the direction of the streaks for these details.

Now onto the rivets—and this is solely a subjective thing. I prefer to only highlight small groupings of rivets to point out that there are rivets on the model, but not every rivet, because rivet gaps are small to nonexistent. They really don’t fill with dirt.

I use pencil lead around five or six rivets, skip six or eight, then highlight another small grouping, cleaning up the lead with the same wiping technique and cleaning out the rivets more aggressively. Remember that the goal is to only highlight them enough to subtly draw the eye to them, not overwhelm as is the case with the access doors and hatches.

If you don’t like the look, simply wipe it off with additional alcohol and a rag. With heavy cleaning, you can completely remove the pencil lead and start over again with little risk.

At this point, the weathering is not permanent, but it will hold up well to normal handling on flat paint. Under typical handling, you should get a few years out of this effort.

Stage two is adding surface color to represent the staining of the aircraft paint from liquids, hot exhaust, or other sources. The Prowler’s tailpipe exhausts are at the trailing edge of the wing. They tend to discolor the lower section of the fuselage, moving aft and down from this point.

On my model, I chose to use a brown oil paint that was aggressively thinned with linseed oil to duplicate this effect, again using an apply-and-wipe-off technique. An oil-based paint such as this tends to be a more permanent technique, so practice before applying it to your aircraft.

Carefully apply the excessively thinned oil-based brown paint, wiping only in the pattern of the look you want. Follow this with a wipe of a rag and linseed oil to clean it. Care is required to only allow the brown stain in the area in the pattern that you are trying to achieve. It’s similar to what I did with the pencil lead.

The stain can be lightened more then followed with a wiping of 91% isopropyl alcohol, but it cannot be completely removed, so make sure to only apply paint and wipe in the area and the pattern you are trying to achieve. In the case of the exhaust stains, I went with the alcohol wipe only on the edges to soften them.

How’s that for a simple way to dirty up your jet and make the surface details stand out? Not much time is required.

At this point, it’s time to decide whether to seal in the weathering with clear coat or leave it alone. I did my Der Jet Vampire this way many years ago and I have never touched it up. It still looks good today. The surface details are highlighted but not overwhelming.

With that stated, last winter I used this same technique on my Grumman Cougar then sealed it with clear coat. This was a special case, though. The Cougar came with flat paint, but I wanted a shiny paint, so I used a small amount of pencil lead to highlight some details then applied clear coat.

I took the easy route with the Cougar’s clear coat and did not bring out the spray gun. Instead, I used spray cans of 2K clear coat for the finish. It’s a simple and effective process. The modern 2K spray cans are of better quality than what is commonly found in a hardware department. I was amazed at the quality of the spray nozzle, which is similar to the performance of a good spray gun. It allowed me to put on a single pass of clear coat with minimal orange peel effect. I did not sand or buff the Cougar, so it is still in the as-sprayed finish.

A good automotive supplier carries 2K clear coat. Approximately three cans were required for the Der Jet Cougar, so buy plenty if you plan to go this route. Eastwood carries this product, but a quick Google search reveals more suppliers. It’s a wonderful product for quick and easy clear coat application.

SOURCES:

Phillip Noel’s Pinnicle Aviation RC

"How To" tutorials

https://bit.ly/2SR3Crs

Eastwood

(800) 343-9353

www.eastwood.com

Jet Pilots Organization (JPO)

www.jetpilots.org

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