Foam Kit Bashing 101 Ep5 — How to Add Realistic Panel Lines and Weathering

Whether or not to weather or not…?

Last time we covered how to paint camouflage and talked about application of markings.  In this episode, we’re talking about panel lines and weathering!  I get questions quite often about my weathering techniques, so the following tips are some of my simple secrets. 😉

Panel lines and weathering are something that can really make or break a scale model.  When we started this Kfir kit bash, I knew that I wanted to use it as a canvas to show some simple weathering and panel lining techniques.  Very often we can get too heavy with either and so my hope here is to give some pointers for adding some realistic and effective looking panel lines and weathering that’s easy to do.  These are some techniques that are pretty simple to employ and that I actually use on my competition models also.

There are so many different techniques we can turn to for this stuff, so these are just a few that I regularly use.  Ultimately the best techniques are the ones you like and give you the results you’re looking for so experiment and try different techniques.  The only way we develop these skills is through practice and use.

As we talk about panel lines and weathering, my recommendation is less is more.  What I mean is that if you feel that a panel line is too dark, or the weathering is too heavy, then it probably is.  Also, it’s highly recommended doing all of this final finish work inside under artificial light.  The sun washes out much of what we apply and so the results are much less subtle once we bring the airplane inside since we’ll continue to darken until we can see a result.  So, just a couple things to keep in mind as we go through this (it’ll be stated again too 😉 ).


To apply panel lines to the surface, we are simply applying all of them using a mechanical pencil.  This works excellent in this case because the pencil lines when applied, are darker than all of the colors on the airplane.  So, as a result, you can get a really fine and convincing looking panel line on the surface.  Any color scheme where the drawn panel line is darker than the color on the aircraft is a good candidate for pencil panel lines.  I’m using a mechanical pencil with a 0.5mm diameter lead.  This is so that we get consistent width lines that aren’t too wide.  Also, a harder lead is preferred so as to avoid smears as you handle the airplane and avoid applying panel lines too heavily.

One thing to note is that this technique really only works when applying lines onto a hardened surface.  The polycrylic hardens up the airframe well and so provides a surface that is conducive for this.  This is not something you’d realistically be able to apply to a painted bare foam surface.  Also, as you lay the panel lines down, press lightly while drawing, otherwise you run the risk of puncturing through the finish.

Applying the Panel Lines

In applying the panel lines themselves, I simply used a 3-view drawing and transferred the essence of what’s on the drawing to the model.  What I mean is that I didn’t measure and scale things exactly from the drawing, I simply went with a looks about right approach based on the drawing.  My goal is to simulate the full size, not replicate it…especially since this is a modified Mirage 2000, it wouldn’t scale quite right anyhow.  If this were a competition project, then I’d spend much more time scaling to match drawings and pictures of the full sized airplane.

To draw some of the smaller detail shapes like access panels and the vents that are all around the aircraft, I used a template with squares and circles which made those items easy to make.  They weren’t the exact size for scale, but were certainly close enough.  For long continuous lines, I used a long ruler where I could, or I used 3m fine line tape that was applied to the surface.  The tape is thick enough to create an edge that you can draw against (masking tape doesn’t have enough thickness).  I also used the fine line tape for any of the radial lines too around the nose and fuselage which really simplifies drawing those line.  I typically have various widths of fine line tape on hand as it’s really good stuff.  Also, as needed, I used a flexible ruler to draw small lines around contours.  Lastly, for the larger width lines on the rudder, I simply just applied the lines darker and wider.  Basically drawing lines about 1/16″ apart and filling in in between with the pencil.

A Quick Clear to Seal it Up

To seal it all up once the panel lines were down, I applied a light clear coat over the airplane to protect the work we’ve done for the weathering process.  Without a clear coat, the panel lines will smear and/or rub completely off during the weathering process.  I use a non-yellowing lacquer clear coat which is the same I use on my larger competition birds too.  Any clear coat should work, but I recommend a non-yellowing one to avoid the color yellowing over time from sun exposure.

I want to point out that if this were a competition model, then I would have done much the same process as outlined above, but once the panel lines were drawn out, used a double ended scribe to actually scribe the panel lines into the paint.  This then creates a fine groove in the paint vs just a drawn line and adds more realism to the model.  It helps create those realistic shadows you would get in the sun that you don’t get from the pencil lines and also helps the panel lines take washes really well too.

For small access panels and things like that, I like to make raised panels out of vinyl and/or aluminum tape.  For a camouflage scheme like this, I would have applied those before paint.  In some cases however, I like to spray the panels separately and apply them after paint as the tone of the separately painted panels vary slightly to the tone of the model and gives it a more uneven look which adds to the realism since airplanes rarely ever weather perfectly uniform and frequently accessed panels are typically touched up more regularly.



With all of our panel lines down, the final step in the finishing process is to weather the airplane and make it look like a beautifully used warfighter.  As mentioned previously, especially as we talk about weathering, less is definitely more.  If you step away looking at the airplane thinking it’s too dirty, then it probably is too dirty.  There’s a fine line between too much and not enough but ultimately it’s all about simulating a full sized airplane.  So do some research and see how dirty the full sized airplanes were.

My approach to weathering is always to simulate and not replicate because you’ll never be able to replicate the years of sun exposure and operations that these aircraft endure.  Also, ALL weathering should be done inside under artificial light.  If you do any of this outside in the sunlight, it may look good outside, but as soon as you bring it inside, I guarantee that the weathering will be too heavy because the sun washes out the effects of the colors being applied.  On the flip side though, if it looks good inside, it will look just as good outside.  It really does work that way.

Applying Washes for Oil Streaks & Stains

Now, for a fighter jet, the dirtiest part of the airplane is always the underside and these airplanes typically get dirtier as you go further back towards the tail.  So, with this in mind, the first place I like to start is applying oil streaking and stains using an acrylic wash on the underside at the back of the airplane.  I like to use Folk Art acrylics that you can get from Michael’s or Hobby Lobby (or amazon) with my primary go to color being raw umber.  This is a dark redish brown color that simulates oils and hydraulic streaks and stains wonderfully.  The other item I have on hand is Tamiya acrylic thinner.  This is so that if at any time the acrylic wash gets applied in a way I don’t like, I can clean it completely off with the acrylic thinner and try again.  Also, having a paper towel with some thinner on it helps smear the acrylic paint to create some streaking on the surface.

For the application of the acrylic washes, I like to take a flat and kind of wide paint brush and apply the acrylic paint along a panel line or any area I want a stain or a streak on the airframe.  From there, I wipe the acrylic paint off in the direction of the airflow with a paper towel.  Usually it has a little acrylic thinner soaked into it to help smear the paint and create a streaky kind of stain on the surface.  The beauty here is that if at any time, something is applied that we don’t like, it can be completely cleaned up with the acrylic thinner without any risk of lifting up the paint.  Also, there’s a certain amount of thinner soak on the paper towel that is optimal, so it usually takes a couple passes to get the desired look.  Plan to use a number of paper towels in the process since as the paper towel gets dirtier, it won’t provide clean up as well.

Note that this technique works the same for scribed or molded panel lines, but in that case I brush the acrylic paint over all of the panel lines and clean it off wiping perpendicular to the panel lines (and airflow).  This keeps the acrylic in the recess giving the appearance of soot and grime in the panel lines.

The acrylic wash process was continued all around the airframe, but with restraint. Heavy stains and streaking were only applied on the underside fuselage near the back primarily and wiped off in the direction of the airflow.  Some streaking was also applied on the wing undersides in the process too.  On the top side, I only applied a streak here and there from the smaller access panels or from hinges, things like that.  Also, in some cases on the fuselage I wiped the paint off downwards towards the ground since the fuselage typically collects weathering in that direction from sitting in the elements. It’s all about small touches and subtleties on the top side.  I only used the raw umber color as I’ve found this really gives the look I want as a whole, but you can experiment with different colors and see what you like.

Applying Airbrush Shading to Finish it Off

Once all of the washes were down all around the airframe, I finished it all up with some airbrush shading (I used a Grex double action pistol grip airbrush).  To do this, I used some flat black paint thinned to the consistency of dirty thinner.  I keep it this thin because it is easier to add more shading than to take away.  So, if you make a pass and want it a little darker, then simply make more passes until you get the desired look you want.  Using the black, I shaded over all of the panel lines to darken them only slightly.  Also, the small panels were shaded in the centers to darken them a little bit to get an uneven look.  In some cases you can add some streaking too by airbrushing a line in the direction of the flow.

During this process, I used some post-it notes to mask around the vents that were drawn on the fuselage.  From there, I masked one by one each of the individual louvers and darkened one side with the airbrush.  The key is to airbrush the paper close to the masked edge rather than painting the edge itself.  This helps give some control on the amount of shading applied and keeps the edge from getting too dark.  Ultimately, the point here is create the illusion of depth between the louvers since we’re not physically adding vents into the surface.  The same thing was done for the rudder too to give depth around the hinge line.

Once all of the shading was done, stepping back and looking at the airplane, the black shading felt too heavy.  So I took a fine scotch-brite pad and burnished down all of the surfaces on the model to even it all out.

Finishing It off

Once I was happy with it all, I sprayed a final clear coat and she was done!  Stepping back and looking at the finished Kfir, the airplane came out so much better than I expected.  The airplane really looks the part convincingly and comes across looking very scale.  All of the work put in really pays off in the finish and the combination of the washes and the shading really portray a realistic finish.



My hope with this series has been to hopefully show you guys some easy techniques for building and finishing not just foam models, but any kind of model.  These techniques are some that I use on my competition airplanes which include my Jet Hangar A-7 and Mirage IIIRS.  So, I hope that you are inspired to give them a try.  Remember that when it comes to weathering, we’re trying to simulate, and not replicate the full sized aircraft.  Don’t worry about having that perfect oil streak or shaded panel because the full size is far from perfect too.  The more you practice weathering, the better and easier it becomes, so give it a shot!  You’ll love the results and as mentioned, you can try this weathering on any type of aircraft medium.

Next time, in our final episode we’ll discuss flying the airplane and some of the things that were done in getting the airplane ready.  I’ve gone through and swapped out a few things including the radio and the batteries and also added some extra coolness too which you’ll see in the next episode.  So, until next time, go weather your airplanes and I hope to see them at the field!

Photo Credit: Scott Plummer,

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