Disassembly
The Kotobukiya SD Alteisen Riese was a kit I build very long time ago. As such, it was covered in dust and needed some cleaning. So I started with disassembly.
When it comes to parts that are hard to pull apart, I used a sharp model knife to press it gently against a seam line.
If the blade was dull or if I applied too much pressure, I ran the risk of cutting through the plastic as well.
Once the pieces part across the seamlines, it was just a matter of twisting the blade very lightly to pull them apart.
After pulling all the pieces apart, I washed them with water and dish washing soap.
Once it was laid out for drying, it was quite a lot of pieces... Why does a SD kit have so many pieces?
This was also a nice opportunity to go over all the pieces and review which pieces needed to be painted in what order and which pieces required extra sanding before I can start the painting.
Seam Line Removal
First thing I wanted to tackle was removing seam lines. This meant I had to re-assemble a few pieces.
But before I started re-assembling, I decided to make some fixes to the pieces to make them fit more loosely. This process is very helpful for two reasons. First, it makes disassembly much easier (which is probably not going to be necessary anymore going forward). Second, it makes applying force to the contact surface between two pieces easier, making the seam line removal process much smoother.
The most obvious way to do this is making the inner holes bigger. I used a pointy file or a round file to cut the holes slightly wider so that the male pieces can fit through without any resistance.
I had to be very careful with this process to not accidentally make the holes too big or even destroy the plastic surrounding the holes.
The other way is to reduce the size of the male pieces. I usually achieve this by cutting the pointy nubs diagonally. This reduces the amount of contact surface against the hole significantly, making it much easier to press in the pieces together or pull them apart with little to no effort.
Like the other method, I had to be careful here. If I accidentally cut off the entire nub, it would cause problems with alignment when I reassemble.
Actual seam line removal process was same as before. I dropped a drop of extra thin cement glue between a slightly cracked open seam line (this process feels a lot like panel lining) and then used something like a paper clip to apply pressure.
After a few minutes, melted plastic oozing through the seam lines hardened and was ready for sanding.
I started sanding with 320 or 400 grit to make the surface flat. I then used 500 or 600 grit to make the flat surface smooth again.
I've heard some people prefer to further sand at this point with 800 to 2000 grit to make it even smoother but I chose to just move on.
Scribing
I didn't plan on adding any new panel lines but I noticed some of the existing panel lines were very shallow. I learned from the last kit that these shallow grooves are going to be hard to work with later so I took a few scribing tools and started cutting them deeper.
I didn't have any scribing guide tape so I tried cutting by just following the existing grooves. This turned out to be a mistake as I ended up making lot of scratches and cuts outside the existing panel lines. Normally I want to fix this with super glues or putty but I didn't have any of those on hand either. I ended up just sanding the surface and hoped it would be enough to hide the scratches. Note that the sanding process was also necessary for making sure the plastic that was cut out by the scribing tool did not jut out, making a rough surface.
Sanding
For candy coating, I want to make sure every surface is uniformly smooth as possible. While this is the rule of thumb for all paint jobs, candy coating requires extra care since flaws can become even more visible than other painting process. This means getting rid of gate marks but also injection mold lines as well.
The photo above is an example of an injection mold line. These are much more subtle than things like seam lines and are often hard to see unless you shine it against bright light. After candy coating, these parts will come out like a slightly dented car surface after someone dinked you at a parking lot. I fixed this by lightly sanding the surface with a 600 grit sanding pad.
Again, this is where lot of people suggest sanding further with 800 to 2000 grit to make it even smoother. And once again, I decided to just move on.
I completed prep work for about 1/3 of the entire kit and decided to start airbrushing.
Airbrushing
Since lot of the prep work involved sanding, I made sure to wash the pieces again in water and dishwashing soap.
This part is important because I want to make sure all the newly created dust from sanding was clean and any grease from my hands were not left on the surface of the plastic.
I dried the pieces overnight and I was ready to prime.
Instead of priming with grey and later painting gloss black paint afterwards, I decided to just prime with a glossy black primer. As always I started by misting on a thin tacky layer first.
The tacky layer helps so that the wet layer does not pool. Again, it's important to remember that any flaws on the surface becomes painfully visible once the candy coating is finished so I have to take extra caution.
Once the tacky layer was evenly applied, I painted the wet layer.
Unfortunately, this is where my lack of diligence with sanding started really showing form. Once the paint started drying, some of the surfaces that were sanded with 600 grit became slightly visible. The primer did help hide a bit of the scratches but there were definitely visible ones that were not getting filled by the primer. I am hoping that the clear coat I will apply later will help with hiding the scratches.
Today I Learned
- Always use guiding tape when scribing (even when cutting existing ones deeper)
- 600 grit sanding isn't enough for perfectly smooth surface after priming
- The standard 2-1-1 thinning ratio for Vallejo paint is not suitable for primers (makes it too thin)
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