Resin modelling hints
By: Joe
Poutre
One thing to remember at ALL times - resin dust is carcinogenic. Wear a dust
mask, and sand either outdoors, or if you're inside, wet sand to keep the
dust down.
Which glues work best for resin parts?
- Fresh super glues with an accelerator. Use the super glue and accelerator
to "tack" parts together, then use more super glue and allow to
cure for 30 minutes or so.
- Epoxy. I use the slow set type, but that is my choice.
- Try 5 Minute epoxy.
- Superglue of various types.
Which fillers work best for resin parts?
- Auto body fillers for gross filling. I have heard that Gunze Sangyo "Mr.
Surfacer" 1000 is excellent for filling pinholes in the surface. It is
probably a good idea to gouge the area to be filled to insure the filler gets
a good "grip" on the surface, and doesn't come loose later.
- Squadron White works for me!
- I like auto body filler and Humbrols red filler. Plastic filler as Revells
Plasto don't stick.
Which paints should be used for primer?
- I prefer Floquil grey primer myself. Easily applied, coats well, shows up
last minute flaws as well.
- I'm happy w/ the spray primer made by The Armory. I've airbrushed on thinned
white acrylics too. (I build horror and SF figures, so I do most of my work
in acrylics.)
- I wash the parts in water and detergent and spray a thin coat of Humbrol
matt white. I believe any primer work as well.
How should Silver/Aluminium finishes be applied?
- "Carefully". It depends on what paint you are using. Lacquers
seem much more resistant to masking problems than many acrylics.
- A net pen-pal built a 1:1 scale Terminator skull, and finished it w/Testor's
Metalizer. He mentioned in passing that a smooth finish was essential, as
the metalizer tended to "show" all the surface blemishes. He didn't
mention if any special priming prep. was needed.
What makes a good/bad resin model kit?
- Look for pronounced or offset mould lines in a bad kit.
- Air bubbles are also a sign of poor production quality. Some small pinholes
are to be expected, but BAD kits can have 1/8" (or larger) bubbles in
them. When buying ANY garage/resin kit, I'd recommend inspecting the pieces,
or at least reading a review from a reputable source.
- I hate pinholes and air bubbles, bad sculpturing, and warped parts.
Are there any recommended books or periodicals
with methods?
- There doesn't seem to be too much readily available on resins. If you are
looking for basic techniques, there are several publications from Kalmbach
on AFVs and planes. Likely model car magazines carry books for automotive
modellers.
- Well, my sources deal specifically w/ figure modelling, so if you're into
cars or planes steer clear of these: Model and Toy Collector and Kit builders
magazines, and any of Terry Webb's "Garage Kit That Ate My Wallet"
books.
Resin Modelling Primer
- Take off flash with sharp hobby knifes. Putty/fill the seam lines, then
sand away until smooth. Use progressively finer sand paper. Final sanding
should be ~400-600 grit. Contrary to popular advice, files can be used, but
gently. They do leave teeth marks in the soft resin. If you're careful, you
can sand these off after you're done with the bulk of the filing.
- Files need to be used gently, don't press down hard when you use them. They
can be a great help. You should also sand very carefully, as the resin is
very easily sanded down (I've actually sanded parts down to a flat surface
that used to be curved :) oops!)
- Wash thoroughly in detergent. Use a toothbrush to scrub at the crevices.
This is to remove the gunk the manufacturer uses to ensure the model is released
from the mould (or what is commonly known as mould release compound).
- You can also use rubbing alcohol which evaporates faster than water.
- You can glue the different parts using two part epoxy if the parts don't
fit well (and most garage kits don't) or superglue.
- Dry-fit the parts together, and then..depending on how heavy the pieces
are, you might have to drill holes in them and use metal rod to help support
the pieces when they're glued together. For most parts, Superglue is sufficient,
but for parts that would be exposed to a lot of stress, I would recommend
an epoxy (which usually stinks).
- Let the glue harden, then scrape away the glue that's oozed out. Now fill
the gaps using a variety of fillers.
- Just from my own experience, the best putty I've used has been Tamiya's.
It doesn't shrink, and it is easily sanded. As for epoxy putty, Tamiya makes
a good one of those as well...and there's always milliput.
- Gaps can also be filled with superglue, depending on your own preference.
- Wash again to remove your greasy hand prints. This is not an insult, but
a fact of life. After this wash, handle very carefully so as not to grease
up the kit again.
- You can either prime or not prime depending on your mood, style, effect
you want to achieve. Acrylic paints can go directly on resin kits.
- I would recommend the Gunze Sangyo Mr. Surfacer primer, it's available in
both spray can and bottle (it's very expensive and hard to find, but it's
worth it). Since this is a resin kit, you can use either acrylic or enamel
paints (generally vinyl kits should be painted with only acrylics, as enamels
might melt them).
- Airbrush is highly recommended, but not required.
I've never built a resin kit, but why wouldn't
flush cutters (with maybe a bit of sanding) or a razor-blade knife work?
- Resin is a much softer - yet more brittle - material than styrene. It is
FAR more susceptible to easy breakage, warping, etc. Flush cutters CAN be
used in some situations that are noncritical. but most times when I have tried
cutting resin sprues with a Xuron cutter, for example, there has always been
some amount of small damage to the part itself. Resin seems to "catch"
a cut far easier than any other material.
- Actually, I do use flush cutters and cut a couple of mm away from the part.
Then I sand it down. Also, I use a grinder which is the most expedient way.
However, a note of caution: make sure the bits are not dull and the torque
is sufficiently high on your grinder (probably Dremel), otherwise, the bit
will catch on the part and will "run" across your part leaving these
disconcerting tracks.
- Sawing through resin sprues and resultant trimming is the most reliable
method. I use an X-ACTO micro saw blade in a #1 knife most of the time to
do this. To trim resin flash, DON'T use a #11 blade - it can "hook"
into the resin and irreparably damage the part in question. Use a ladies'
emery board or a hobby sanding stick instead. A Flex-i-File works particularly
well for small, tight corners.
- I learned the hard way - by my #11 and Xuron cutter destroying a couple
of over-$50 resin items . Experience is the best teacher, but that was a VERY
expensive lesson.
- In these cases, make sure you have Gunze Sangyo's Mr. Surfacer handy. It
will fill in these microscopic marks. An example of how well this works, I
use 400 grit sandpaper to do the rough sanding. Then I graduate to 600-800
grit for the final polishing. However, the 400 grit will leave some rather
deep scratch marks. Not to fear. With Mr. Surface, I just liberally glop it
on the area, let it dry, and then sand lightly with 600 grit. The result is
a bunch of deep grey lines where the scratches used to be and the whole thing
is really smooth. (Depending on how deep the scratch is, you might need a
couple of applications).