Wonderfest 2002 "How-To Demos"
Introduction to Assembling Models
(along some helpful hints for filling in seams)
(Page Two)
Different types of gap fillers
Found below are some of the different substances that can
be used to fill in a model’s seams, along with some useful tools that can be
used to assist this process.
Some of the fillers are manufactured exclusively to be used on
a model, while others have more general uses, (like in automotive body repair
work).
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Testors white contour putty
Squadron green glazing putty
Squadron white glazing putty
Tamiya Putty
Bondo Glazing & Spot Putty (Automotive)
Acryl-Blue Glazing Putty (Automotive)
Tamiya Epoxy Putty
Milliput (two-part epoxy putty)
Aves Apoxie Putty (also a two-part epoxy putty)
JB Weld a two-part epoxy resin (glue)
Cyanoacylate (CA or super) glue – (like Zap-a-Gap)
Elmer's White Glue
Stretched Sprue
Although I've never used it, I've read about and heard of
the product White-Out being used to fill in small seams. It is supposed to go on
thin, dries pretty quickly and sands down smoothly. You (naturally) should
experiment with it first on an old, unwanted kit before using it on a good
model.
Useful tools
Listed below are some tools and supplies that can help with
the application of you filler(s):
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Lacquer Thinner
Toothpicks, straight pins and sewing needles
Aluminum Foil
Masking Tape
A Plastic Syringe (that has a plastic tip)
Sandpaper/Emery Boards/Metal files
#10 X-acto knife (curved)
Q-tips
Primer paint
A cyanoacylate accelerator (like Kicker)
Liquid cement
Problems with filling in a model’s gaps
There are two common problems that one runs into when
filling in seams on a model. The first is when too much filler is applied, which
causes a lot of time and effort to be put into removing the excess. The second
problem is the inadvertent removal of surface detail when sanding the putty
down.
There are some very straightforward, simple ways to prevent
both from occurring. In addition, there are a couple of ways to fix the second
problem if it occurs.
Filling techniques and some sanding short cuts
Filling
When filling in a model’s seams, a plastic syringe that has
a plastic tip can be used to more precisely apply putty from a tube that may
have a large opening. These plastic syringes can be purchased at drug stores.
(They are generally used to give babies medicine).
The idea here is that if you apply a small amount of putty
directly into your model’s gap areas, there will be less clean up required once
the putty has cured. In addition, the likelihood of damaging surrounding surface
detail will be minimized.
With some of the plastic syringes, the tips may still be
too large. This can be rectified easily, though. If you pick up some of those
plastic tips that Testors sells for their tube glue and super-glue a tip onto
your syringe, you will have a tool that will allow you to more precisely apply
putty to your seam.
A second useful technique that can be used is to sandwich
your surrounding gap area with two pieces of masking tape. This will help keep
putty only in the gap, cutting down the amount of excess that needs to be
removed. Be sure to remove the tape after applying the putty but before it
hardens, to prevent it from flaking off with the removal of the tape.
Another pretty ingenious technique for filling in a model's
gaps is as follows. Stretch some of your sprue from your kit (using a candle),
so you're left with long, thin sections of this plastic. Cut sections of your
stretched sprue off so they are the same length as your gap area(s). Then, go
back and reapply your thin liquid cement into the gap. Saturate the area so it
remains wet long enough to allow you to insert sections of your stretched sprue
into the seam.
Apply enough sprue to fill the gap in (with this liquefied
plastic). When the glue cures and plastic hardens, sand as needed.
You can use the side of a toothpick or sewing needle to
apply a putty that has been thinned down with lacquer thinner directly into your
gaps. (More on thinning the putty down a bit later).
In addition, a sewing needle or straight pin can be used to
apply super glue to your gap. (Use a section of sheet glass or a small piece of
aluminum foil or wax paper to hold the super glue that you are applying).
If your super glue is thin enough, all you may have to do
is dip the side of your needle or pin into your pool of super glue and touch it
into your seam, letting capillary action draw the glue into the gap. An
accelerator like Kicker can be used to speed up the chemical bonding
process.
Baking Soda as an accelerator?
I know of folks who have used regular ole' baking soda to
speed up the curing process of the CA glue. This technique involves the use of a
thin type of the glue. The glue is applied to the seam, followed by sprinkling
baking soda over it.
In addition to speeding up the curing process, the baking
soda also adds some "meat" to the glue.
I'd highly recommend that you NOT use this technique! This is because it is possible
for some sort of green or black stuff to start "growing" out from seams that
have been treated in this fashion. This can occur months or even a year or more
after a model has been built.
I have several modeling buds who used this technique, only
to discover much later after their models were completed that dark "growths"
started appearing in the areas where the seams had been treated in this
manner.
I'm not sure what type of interaction goes on to cause this
type of occurrence. However, due to the possibility of your prized model
becoming ruined in this fashion, it would be better to just use a thicker type
of CA glue, along with an accelerator (again like Kicker).
Filling in the gaps on my Starfury's wing assembly
I used three types of fillers on the gaps found on the
inside wing inserts of a Starfury I was working on. The "blue stuff" found on
the right rear portion of the Starfury's wing is the Acryl-Blue Glazing
(Automotive) Putty. The "red stuff" found on the front right portion of the wing
is Bondo (Automotive) Glazing & Spot Putty. Finally, the barely detectable
filler (with the white residue) found on the front and back portions of the left
wing is Zap-a-Gap CA (super) glue.
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You'll notice that both the red and blue putties have been smeared onto the gap areas, in a somewhat sloppy fashion. (This is nothing like the careful application into the seams that I've been preaching about).
The putties were applied in this rushed manner because I needed to use this assembly in my W.F. seminar, and ended up waiting until the last moment - (the night before) to work on these parts. (Nothing like good old-fashion procrastination).
Sanding
If a large amount of putty or super glue has been applied,
metal files can be used to remove much of the excess, before moving over to
sandpaper. (Be careful to only remove the hardened glue, leaving the plastic
untouched).
In addition, a sharp curved #10 X-acto blade can be used to
remove excessive amounts of contour or glazing putty, before going over to the
sandpaper. This can only be done once the putty has hardened. Excess putty is
very carefully chiseled away.
Transition over to a coarse piece of sandpaper next. (I
usually start with a 320 or 400 grit paper, working down to finer grades of
sandpaper, like 600 or 720 grit).
An emery board, cut to shape, can be used to sand down
“hard to get to” spots.
You can use water to wet-sand the area down. This prevents
the sanded putty particles from building up in the sandpaper, which reduces its
effectiveness. In addition, the water acts as a lubricant, giving you a smoother
sand. Also, this has an added benefit of cutting down on dust that may result
from the sanding process. This is especially helpful with putties that can be
harmful if their dust is breathed in, (which is probably all of them).
Not all sandpapers are designed to be used with water. So,
check its type before adding water to it.
Masking tape can also be used during the sanding process,
to protect the surface detail surrounding a gap. Sandwich the gap with two
pieces of tape. Then, sand as normal, removing the tape when finished.
Priming
This very important step is often overlooked during a model
kit’s construction. What’s involved here is the painting of a light color of
paint (usually white or gray), concentrating on the newly puttied and sanded
areas. This procedure will help uncover problem areas that still exist, allowing
you to refill and re-sand where needed, before you apply your base coat(s) of
paint. It may be necessary to repeat this priming step a number of times until a
smooth surface results.
The use of lacquer thinners?
Previously I mentioned mixing a lacquer thinner in with a
modeling putty. I’ve mixed a lacquer thinner in with both Testors contour putty
along with Squadron's green glazing putty, with some pretty good results. The
mixture of thinner with glazing putty worked better than the contour putty.
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The idea behind this is that it is easier to apply a liquid
filler than a thick, paste one. You can paint a liquid thinner on with a fine
paintbrush, applying your concoction more directly to your gap areas.
Although this substance will go on thinner, it tends to
evaporate quicker than the straight putty, and can be built up for full
coverage.
I know of modeler’s who have cut Squadron green glazing
putty with Testors liquid cement, coming up with a similar substance.
Fixing lost surface detail
There is a chance that despite your care in assembling your
model and cleaning up its seams, you still have inadvertently removed some of
your kit's surface detail. Although cumbersome and/or difficult, there are
several ways to repair detail that may have been lost.
The options to use depend on the type of panel lines that
exist on your model. If the panel lines are of the recessed type, then your task
is pretty easy and straightforward. Purchase a "scriber" and carefully re-scribe
your lost detail back in.
You may need to use something to guide your scriber, in
order to keep the lines that you're reapplying straight. The best thing to use
as a guide is label tape. It is very tacky on one side, which is great for
helping it stick in place on your model (and not move) while you use it as a
guide. This is especially helpful if you are working on curved surfaces.
When using your scribing tool, apply no pressure on your
first couple of passes. Let gravity do the work.
This process is something that really needs to be
practiced, to ensure that the lines you are rescribing are of the correct (and
same) depth.
Ok, what if your model has panel lines that are raised.
Well, my friend, your task just got a lot harder. You basically have two options
here. The first is to carefully try to rebuild the removed raised panel lines by
using stretched sprue. This can be very difficult, cumbersome and time
consuming, since you not only have to try to apply stretched sprue of the
correct thickness back onto the surface of your kit, you also have to glue it in
place (using thin super glue), blending the new sections in with the old, so
they form a seamless, continued line.
Your second option can be equally time consuming. It
involves sanding down ALL THE EXISTING RAISED PANEL
LINES, AND RESCRIBING THEM IN!!
I know of a guy (Jay Chladek - J) who just decided to remove the remainder of the panel
lines whose sections had been removed with the cleaning up of intersecting gaps.
He was (also) working on that infamous Starfury, and this trick of his worked
out pretty good, since the same panel lines were removed from all four of his
ship's engine pod areas.
I stumble upon a really kewl trick myself when working on
my Starfuries. This involved using a weathering technique, in which a section of
tape or an index card is placed directly adjacent to a panel line. (The tape or
index card is positioned so that it angles away from the panel line).
A color slightly darker than your basecoat is lightly
airbrushed onto the card or tape. If done correctly, the overspray will
highlight the section of the panel line on the other side of your tape or card,
with the color gradually decreasing in intensity.
I used this technique to add weathering to panel lines that
were also located on my Starfuries' engine pods.
This is how the engine pods looked while the seams were still
being cleaned up:
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This is how they looked after the model had been built completely, painted up and the engines weathered with
the airbrushing technique:
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When this weathering was continued across the sections of
panel lines that had been removed, it created an illusion that these sections
still remained and the lines were continuous, (since the darker weathering color
in effect recreated them).
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Filler characteristics
Found below are characteristics of most of the fillers that
are listed above. There are a number of them that have been left out.
Specifically these are Tamiya’s two types of putties, Aves Apoxie Putty and the
Acryl-Blue Glazing Putty. Since I have never used them (although I do own them),
I really can’t comment on their characteristics. However, I still wanted to list
them, since they are options currently available for use.
Each of the fillers found below has advantages and
disadvantages. Certain ones are better in certain situations than others. In
order to determine the one (or ones) that will work the best for you, you should
purchase several and try them out.
1. Testors Contour
Putty
Advantages:
It is easy to apply. (With narrow tube opening, can be
applied nicely directly to gap).
Not very “messy.”
Disadvantages:
Unlike the “glazing” putty, does not stick well onto
surface; (it must be “pushed” into the seam).
Does not cure quickly.
Does not sand down as “uniformly” as “glazing”
putty.
According to the warnings listed, breathing in the vapors
of this stuff can cause a person problems.
2. Testors Contour Putty/Lacquer
Thinner mixture
Advantages:
Depending on the mixture of putty to lacquer thinner,
anything from a watery wash to a thick liquid paste can be created.
It’s easy to apply. A toothpick or small paintbrush can be
used.
Because it is lacquer based, lacquer thinner can be used to
clean the brush.
Even though it is a “messy” liquid, it can be applied very
accurately to very small areas.
It dries very rapidly.
Even though it shrinks a bit when dry, multiple layers can
be applied relatively quickly, filling in the gap completely.
Since it dries to a thin layer, much less sanding is
required afterwards, starting out with a much finer grade of sanding
paper.
Disadvantages:
The fact that it is mixed with lacquer thinner means that
by using it, you will be breathing in the thinner vapors, which makes using it
not good to one’s health.
Sometime “bubbles” form while it cures.
3. Squadron green and white
(glazing) putty
Advantages:
It is easy to apply.
Due to it’s “sticky” nature, applies better to surfaces
than contour putty.
Takes a shorter period to cure than the contour putty;
(roughly 30 minutes)
Sands down more “uniformly” than contour putty.
Disadvantages:
Due to its “sticky” nature, more care must be taken in
applying it to make sure it goes only where it’s supposed to.
Can be difficult to apply due to large tube opening. (A
toothpick or plastic syringe can be used for a more precise application).
According to the Warnings, breathing in the vapor of this
stuff or having it come in contact with one’s skin or eyes is not a “very good
thing.”
4. Squadron’s Glazing Putty/Lacquer
Thinner mixture
Advantages: (Pretty much identical to those of the contour
putty/lacquer thinner mixture)
Depending on the mixture of putty to lacquer thinner,
anything from a watery wash to a thick liquid paste can be created.
It is easy to apply. A toothpick or small paintbrush can be
used. Because it is lacquer based, lacquer thinner can be used to clean the
brush.
Even though it is a “messy” liquid, it can be applied very
accurately to very small areas.
It dries very rapidly.
Even though it shrinks a bit when dry, multiple layers can
be applied relatively quickly, filling in the gap completely.
Since it dries to a thin layer, much less sanding is
required afterwards, using a much finer grade of sanding paper.
Disadvantages:
The fact that it is mixed with lacquer thinner means that
by using it, you will be breathing in the thinner vapors, which makes using it
not good to one’s health.
5. Bondo Glazing & Spot Putty
and Acryl-Blue Glazing Putty (Automotive)
Advantages:
It’s easy to apply. Due to its “sticky” nature, applies better to
surfaces than contour putty.
Also, since it is not quite as “sticky” as Squadron’s, its
application is not as messy.
Goes on more uniformly than Testors contour or Squadron
glazing putty.
Sands down very smoothly and uniformly.
Cures fast.
Disadvantages:
Also it is difficult to apply, due to large tube opening.
(A toothpick or plastic syringe can also be used for a more precise
application).
According to it's warning, can cause a person MORE problems
than the Testors and Squadron putties. (Its vapors may affect the brain or
nervous system, etc., along with it causing kidney and liver damage if absorbed
through the skin).
Related to the previous characteristic, quite a bit of dust
is created while sanding, unless “wet-sanding.
6. Cyanoacylate (Super) glue –
(Zap-a-Gap)
Advantages:
It is easy to apply, (by putting some on a sheet of glass
or a piece of aluminum foil, and using either a needle, straight pin, or
toothpick to apply directly to gap area).
If applied carefully, is not “messy.”
In addition to filling, also bonds.
When used with an accelerator, bonds in seconds.
Disadvantages:
Be careful when applying. Due to its nature, it’s quite
easy to glue things together that shouldn’t be, (like fingers, hands,
etc.).
Since the cured area becomes harder than the softer
surrounding plastic areas, care must be taken when sanding down.
The vapors given off can cause eye irritation.
7. Elmer’s White Glue
Advantages:
It’s easy to apply, (with a toothpick).
It’s also easy to correct mistakes. With it being water
based, a wet Q-tip or paper towel will remove any excess.
In addition to filling, it also bonds.
Since it will not craze clear plastic, it is great for
attaching clear parts, (like aircraft canopies and windscreens).
Also, it can sometimes be applied to a gap having a large
amount of surrounding surface detail, (which might otherwise be destroyed by
sanding).
Disadvantages:
It’s not a very good gap filler: it shrinks a lot when it
dries, and it does not fill a gap uniformly, (i.e., there will be higher and
lower areas with the filled gap). With this, repeat applications may be
necessary.
Conclusion
Model building is an enjoyable hobby. (At least it is for
me, along with most of us I suspect).
However, the process of trying to make your model look as
good as it can possibly look may not be a fun activity.
In model building, the initial boring, burdensome steps are
often overlooked, with emphasis being placed on hurrying up to get to the more
enjoyable painting phase.
By investing just a bit more time into the initial stages of dry-fitting and assembly, along with investing a little more work into cleaning up any existing seams that remain and "sprucing up" panel lines that may have been damaged in the process, you can come up with a really, REALLY Great looking model!
(Back to the Tips n Techniques Page)
Copyright © 2007 Anthony I. Wootson. No material may be
reproduced without permission of Anthony I. Wootson. Unauthorized duplication is
prohibited.