Welcome to a special episode of sprue
world, where today I will introduce the vast and interesting world of painting
plastic model kits. This series should answer the following paint, preparation,
and finishing questions:
Why do I need to primer?
Why do I need to primer?
Why do I need to sand parts before
painting?
Why is a file or a rasp advantageous
over a knife?
How do I properly mask off areas I don’t
want to paint?
How do I prevent paint seepage?
How many different ways are there to
apply paint to a model, and which is the best?
What types of paints are there?
How do I mix my paint?
How far away should I be before
spraying?
How long should I wait for the paint
to dry?
Do I need to thin my paint?
What is the difference between gloss
and flat coat, and why do I need to use it?
We’ll start with painting. Painting a
model is adding color to the plastic parts in order for it to look better. You
don’t have to paint a model, but paint will make a model look fantastic.
What types of paints are there?
There are three types of paint that
can be used on plastic models: acrylics, enamels, and laquers. Acrylics are
water based, Enamels are oil based, and Laquers are also oil based. I don’t use
laquers since they are used for painting interiors and cars. I do use acrylics
and enamels, however. These two types of paints both have their advantages, and
one isn’t necessarily better than the other despite some modelers swearing by
one or the other.
Acrylics are water based paints that
carry a plastic solution suspended in water. They are easy to apply with an
airbrush, but they dry much, much faster than enamels. This can be helpful or
it can be a problem- if the paints are not thinned properly when using an
airbrush, buildup and orange peel can occur. Those terms are for a later video
with more advanced topics. They thin with water and are easy to clean up. This
is why acrylics are very popular. Popular brands include Testors, Tamiya, and
Humbrol in Europe. Another harder to find paint brand, which is out of
production is Pollyscale, which is for model railroading.
Enamels are oil based paints that
carry their pigment in a petroleum based solution. Enamels can look tackier,
can be used to apply texture if desired, and can have more vibrant colors than
acrylics. The downside to using enamels is that they need to be cleaned up with
a toxic thinner and they take longer to dry. Proper disposal must be taken into
consideration when dealing with enamel paints.
How
many different ways are there to apply paint to a model, and which is the best?
There are many ways to apply paint to
a model, but these are the primary ways: via brush, via spray can, and by
airbrush.
Painting via a physical paint brush is
a good way to detail smaller parts. Paints must still be thinned to a proper
consistency, though I like thinning hand brushed paints a little thicker than
airbrush thinning. The disadvantage to hand brushing is that it can leave brush
marks and the medium is not a good way to paint parts with larger surface
areas. If not thinned properly, paints can be thinny or blobby.
Spray cans are another medium of
applying paint. You can get better coating on a part than what you would get
with brush painting. There are some downsides to this convenience, however.
First, you need more ventilation with spraying mediums such as cans or an
airbrush. Second, it is incredibly easy to apply too much paint with spray cans.
If you are too close you will not get an even finish, but if you are too far
away, you won’t apply enough. A good distance to paint at is about 7 inches,
but no closer. Spray side to side, and depress or press the trigger off of the
part for best results. Spray cans apply way more paint, in my opinion than is
necessary. I don’t have an accurate number, but the layer thickness has to be
at least ten times that of airbrushed paints. On a final note, spray cans are
more expensive in the long run than investing in an airbrush.
Airbrushing is the final medium to
apply paint, and combined with hand brushing it is my #1 method of choice. Airbrushing provides the best finish and
coating opportunities for your models, and more advanced air brushers can
create amazing works of art with their kits. Airbrushing adds a very fine and
even layer of paint on your part, allowing you to save bottled paints and cash
versus using spray cans. If you thought that the difficulty of using one would
be a negative, I disagree. Airbrushes are easy to use, they just need to be
maintained meticulously. The tradeoff is the best possible finish by process of
paint atomization. Some cons of airbrushing include fixing spray problems, a
learning curve for paint thinning, and a high startup cost.
There is no best way to apply paint to
your model- it is entirely subjective, and different painters will tell you
different things. I will always advocate airbrushing over spray cans, and I
give this story as a good reason. I spent over $30 USD painting my RX-78-G05 in
spray cans, but I spent about $14USD painting my MG Deathscythe Hell, which had
more parts!
How
do I mix my paint?
Mixing paint is all about the way you
are applying it. If you open a paint jar and it is “goopy” at the bottom, you
want to stir it and add some thinner. For acrylics you can use isopropyl
alcohol or water. For enamels, you can use any oil based thinner, including
laquer thinner. As a warning- do not use acrylic thinner on enamels, or enamel
thinners on acrylics!
For airbrushing you want a milky, non-clumpy
consistency. This should be enough to get the paint through the brush, but if
it is not, add thinner sparingly. For spray cans, the paint is already thinned
for you. For hand brush painting, I like to have a slightly coarser mix than
air brushing- not too runny, but not clumpy, either. The exact ratio of paint
thinning is difficult to determine because of the type of paint and the batch.
The only way to truly get good at paint thinning is to practice and gain experience.
Some paints, such as Tamiya paints,
say that you can recoat and touch your parts after as little as an hour or two.
I strongly discourage this practice, as you should give all paints, primers and
finishers 24 hours to dry. I have come back after 6-12 hours of painting,
however and I could gently handle the parts and repaint them without a problem.
For enamels though, I wait the full 24 hours because they dry slower than
acrylics. Give finishes at least 18-24 hours before touching them.
Why
do I need to sand parts before painting?
Painting is only as good as the
preparation given beforehand. Some model builders will argue with me that
preparation is not necessary in a model, and they are correct. HOWEVER, their
finish will not compare to a well-crafted, well prepared model.
Sanding parts is critical in achieving
the best possible finish. Sanding removes defects in the plastic, evens out
burrs and gates, and also provides a better adhesion surface for primer and
paint. This will also allow the paint to finish smoother. The results speak for
themselves.
Why
is a file or a rasp advantageous over a knife?
Although I use a hobby knife for
cutting off gates and excess plastic, I also like to use a small file. This
removes gates quicker, but can deform the part if you are not careful. This is
another reason why I use sandpaper to smooth out the surface; to repair any
deformations caused by the file. I typically use 600 to 1000 grit sandpaper,
electing to use 600 to clean up rough areas, and 1000 prior to primer and
paint. You should always sand primer, if you have to, with 1000 grit or finer.
Your finger pad is 2000 grit.
Why
do I need to primer?
Primer is an undercoating that goes
onto the model before the paint. Again, amateurs argue that there is no need
for primer, when in fact there is for the best possible finish. Primer does a
couple of things. It fills in micro scratches from sanding or filing, it sets a
base color for your paint, depending on the shade of primer, and it provides
the best adhesion surface for your paint. Paint can be used as a primer, and I
recommend using a primer that is a light gray or a white. These are neutral
colors that will not distort your colors. YES, if you paint green on top of a
molded black without primer, the green will be darker than the bottle color.
Primer also allows you to see mistakes easier so that you can correct them
before painting.
How
do I mask off areas to paint?
They call it masking tape for a
reason- it allows you to mask off areas you do not want to paint. I personally
use scotch 3M automotive tape as it provides good adhesion and minimizes paint
seepage. If you just painted a layer, I highly recommend putting gloss or flat
coat over it before masking it off for another job. If you do not wait a day
for the paint to dry and then you apply masking tape, you risk ripping paint
off that hasn’t dried yet. If you are really paranoid about it, wait a maximum
of two days after the finish coat. Sometimes, to get around complex corners you
will need to cut pieces of tape into slivers or pieces. This is fine, and take
your time doing it. You can also use a liquid mask, but that is an advanced
topic for another video. Paint seepage is caused by three factors: how far you
are spraying from the part, the angle you are spraying at, and the volume of
paint coming at the part. Too much paint is the prime suspect for seepage. It
is coming in so fast and in such large amounts that it will leak below the
tape. You should also paint as parallel as you can to the surface of the tape
to prevent seepage. Also, don’t spray right up against the part; find a
comfortable range.
What
is the difference between gloss and flat coat, and why do I need to use it?
A finish coat protects the paint.
There are three types of finish, but I primarily use two: flat coat, matte coat
(which is essentially the same as flat coat) and gloss coat. Flat coat makes
the paint appear flat, and gloss coat makes it appear shiny. To apply decals
correctly you must use a gloss coat. After application, you can use gloss as a
final finish or go to flat. Finishes come in spray cans and bottles, and like
airbrushing, I am going to recommend the bottles over the spray cans. Apply too
much and the finish will ruin the model.
That should be it in regards to simple
questions about finishing, preparation and painting. Ask any questions below- I
would be happy to answer them.
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