(The dangers
of) Pre-shading with permanent markers
Modelers are always
looking for materials and techniques which can speed up each step of
model building, and that is good as we don't have time to spare as we
used to. Sometimes, however, someone drops by with an interesting tip,
something that seems a great finding at first. You decide to use it
only to discover, weeks or months later, that that particular trick
ruined your latest masterpiece. This article is just about one of such
things: pre-shading with permanent markers (or sharpies). And allow me
to start by my personal advise on using them to pre-shade your models: don't do it!
Years ago I was building a Spitfire and used a permanent marker to
circle spots that needed further sanding. I corrected the signed spots,
but I didn't bothered removing the circles because another layer of
primer would be necessary. I applied the second layer of primer and,
after a few weeks, I noted that the circles were showing through. Not
wanting to run any risk, I sanded those areas until all traces of
permanent markers were removed. That episode remained in my mind until
another model, when I didn't removed the marks. And to my horror, they
showed on the top of the camouflage weeks later. It wasn't too late to
repair the model, but I decided to study the subject and recalled my
college classes of mass diffusion.
This
is a process where mass particles migrate from a more concentrated
medium to the the less concentrated, subjacent one. This is similar to
the salt water and drinking water experiment, where both solutions are
separated by a membrane. With time, the salt will progressively migrate
to the drinking water until the concentration is about the same on both
sides of the membrane.
Back to our modeling life, during the last years many modelers have
been reporting fast pre-shading on their models using sharpies and
similars.
It seemed a good idea: quick and cheap - you don't have to crank
your airbrush up and mess with painting, cleaning and all. This is an
example I found on the internet:
The (big) problem is that the permanent marker ink will migrate through
all layers of paint until it is visible... No, I don't mean faintly
visible, it will look like a punk graffiti. It is the Physics in action:
More recently, many modelers have been reporting sharpie pre-shading bleeding through, and you can find
several cases on discussion boards (like here,
here,
or
here).
I've
been waiting a long time for a chance to record the effects of
using permanent markers for pre-shading. Unfortunately, it happened to
a friend of mine, despite my several warnings not to do it.
This is Academy's F-89 in 1/72 scale built by Volmir Batista. I watched
him working on this model during months. After my warns, he tried to
remove the pre-shading but "successful
cases" on using the method convinced him to run the risk. Well,
here is the model:
You don't find anything wrong with it? Look closer:
It looks like
the sharpie was used after the painting, doesn't it? I'm sorry for
Volmir, but glad I recoreded it.
For the
records, he used automotive primer, Testor Model Master enamel paints
and Future as a gloss coat. As you see, no fancy Devil brand products.
In fact, this is a quite common recipe among modelers. Volmir called it
transmigration, and the name
stuck among our club members. Here is another shot of the "The
transmigrated", as he refer to it now:
Please, note
that the migration will happen provided the marker pigment is small
enough. I mean much smaller than the paint pigments. There are many
paint brands out there, many clear coats, and I won't claim the problem
will happen to all of them. But if it does, it takes some time to
happen, maybe weeks or months before it becomes visible, and I will
tell from my own experience it is not a good thing to see a black mark
on your model surfacing more and more visible day after day.
I also have been reading and listening comments in favor of this
technique. Well, the photos are here, it is your model. Permanent
markers do are useful tools in modeling, and someone can find another
interesting use for it.
Just remember that in this case the old saying "Test it in a piece of scrap before using
on your model..." should be appended by "...and wait a few months just to be sure".
Not
exactly my recipe to speed up model building safely.