Wednesday, June 6, 2012

Project HGUC Sinanju Start to Finish: Modifications

Welcome to part 3!

While I'm building a model, I'm always on the lookout for things that could be improved. The Sinanju is a really good design, but there are still a few things we can do to make it look that much better.

Independent skirts

We're going to separate the right and left sides of the front and back skirts. This is one of the most basic mods, and usually one of the first attempted by most modelers. To separate them I'm going to use a X-acto plastic saw to cut through the material connectiong the two halves. If you don't have a plastic saw, use your nippers for even your x-acto knife.


Just sand down each end once you're done cutting, and you'll have independently moving skirts.

The rear skirts don't need to be as mobile as the front, I don't necessarily recommend doing this step.

Panel line scribing

I don't panel line often, I'm not very good at it so my lines look a bit rough. In general I think most kits have a decent amount of lining on them to begin with.

We’re going to add some panel line scribing to a few parts. Generally try to keep to straight lines until you become comfortable with this step.

Once I'm happy with the pattern, I'll take a piece of this heavy duty adhesive caution tape and lay it down against the line. You can use dymo label tape for this step, I just have a roll of this caution tape lying around, and it seems to do a pretty good job.

Once you're happy with the tape placement grab your scribing tool. I'm using a sewing needle secured in a pin vise. Now lightly run the scriber along the path, I'll usually do 2-3 passes to get the right depth.

Once you're happy remove the tape and lightly polish the surface with high grit 1000+ sandpaper to smooth out the edges. You don't want to remove too much material at this point to retain the panel lines.

After sanding your part should look something like this.

Drilling Details

The pin vice mentioned in the steap above is a tool that can hold and secure small drill bits. I use this tool to drill out small details and indents on kits with head vulcans or recesses.

The right side has been drilled in this picture while the left has not. Notice the difference?

Similarly we can add more depth to the divots in the helmet.

This didn't come out quite as well as I had hoped. But I prefer the added dimension over the stock.

Modifying part geometry (sharpening)

While still working on the head, I decided to remove some material from the head.

For lack of a better name the "cheek armor" was a bit too thick for me. I removed both sides of the helmet then gently sanded away some of the plastic on both sides. It allows more of the 'face' to show through.

Bandai leaves some of the 'pointy' parts on their models rounded and dull to keep younger modelers from hurting themselves. While that's noble goal, those parts generally look pretty crappy. We're going to use some sand paper to sharpen them up.


I'm going to start with the commander’s horn on the helmet. There is a slight indent on the plastic left over from the molding process. I don't recommend using your nippers for this part. I tried that method, but only succeeded in stressing and subsequently breaking the part off. Instead use a piece of sand paper and gradually sand away at the indent until it has been completely removed.

Surprisingly the MG's antenna is much slimmer than the HG. You can fix this my alternating sanding on both the left and right sides of the antenna.

Again I don't recommend this method, try to use your sand paper or X-acto knife to gradually shave the plastic until you're left with a point.

You can just make out the stress mark at the point there the body of the antenna transitions to the point.

If you happen to break the end piece off like I have, you can glue a small piece of plastic plating (pla plate) to the end of the antenna. Once the glue has dried, gently sand the pla plate to match the antenna. This can be a frustrating step, so I hope you don't have to do it!

Here's what my antenna looked like after the repair.

Vents and waist

These lower leg vents have an additional piece of plastic on the indented side. We're going to use a piece of coarse sand paper to remove it.

Angle your sand paper to follow the natural line of the part.

Then use a finer grade to polish the area. You should be left with you piece looking like this.

The side hip armor has a similar piece of plastic. We're going to use the same technique to go from this.

To this.

You can also use a fine grit sand paper to sharpen the point of this piece from this.

To this.

Shoulder Spikes

To sharpen the horns that adorn most zeon mobile suits we need to use a different technique. We need to a special tool for this step. I took a piece of one of my sanding sticks and made a slit on one side to create a V shape. You can make a similar tool by gluing a length of sand paper to a popsicle stick and then slitting one side to create a fold.

Whenever you sharpen a horn, your sharpening tool needs to be at least as long as the horn, otherwise the horn won't be sharpened from the base, and it will leave an odd looking shape.

The one closer to the camera has been sharpened, the back is still stock

The one on the right has been sharpened, the one of the left hasn't.


I'm going to use some poly putty on the backs of these skirts to fill in some of the blank spots. Any type of modeling putty will do for this step, but I will be using a tub of Plamo UK's poly putty. Be careful using Tamiya's offering, it can make the surronding plastic brittle.

On HG and AG kits Bandai will leave blank spaces like these holes on the rifle.

I'm not entirely sure why Bandai does this, it could be part of the molding process or just a way to save plastic. We're going to fill in these spaces along with spaces on the following pieces.

You want to fill in the space completely, but don't go overboard; putty isn't very easy to remove. I usually keep a few sheets of toilet paper around to clean the part up before the putty sets.
Once the putty has set for several hours (or longer depending on the brand you're using). take you knife and remove the excess. You can sand down the remainder until it's flush with the surface.


Now that I'm done modifying my kit, it's time to start prepping our kit for the next step, painting. To do that we need to get all of the plastic residue left over from sanding the kit off. We also need to remove the molding release agent off.
The best way to do this is to fill up a large bucket with warm (not too hot) soapy water. I prefer to use a soap with some degreasing agent like dawn. It will breakdown and mold release on the kit fairly quickly.

Break your kit down to the large component parts, legs, arms, shoulders, etc. and let them soak in the soapy water for a few minutes. Most of the sanding material should come off during the soak, but to be sure that we get everything off you will need to use a toothbrush (or some other small brush) to clean out the crevices and panel lines.

Once the parts have been clean, lay them out on a absorbent cloth for a few hours. Before you start to paint make sure the parts are completely dry.

In general you want your parts to be as clean as possible before you paint them. Sometimes that means cleaning parts more than once, if you leave them for an extended period.

Wrap up

If you have completed all of the steps listed above, your Sinanju should be looking meaner and cooler than ever. Some modelers will go much further with their modifications, they'll battle damage kits, or use photo etched parts, metal option parts scratch build or kitbash pieces from different kits. It's all up to you to decide which modifications are for you.

When I build kits, I try to stay true to the source material, and I will only make small tweaks to a kit. Just remember there's no right or wrong way to detail your kits.

Go back to part 2
Go to part 4


  1. Thanks for another well photographed and detailed post. This sort of article has the kind of advice that I like to come back to when I'm building my own kits.

    Quick question though, even after sharpening your shoulder spikes seem to be significantly more rounded than some of the other bits that you sharpened. Did you just not want them to be sharper or was there some other reason to not sharpen them to a finer point?

    1. Hi Michael, sorry I didn't respond sooner. But your message got bumped over to spam and it took a bit to dig up!

      Unfortunately there's only so much you can do with the shoulder spikes on the HG Sinanju. It’s a bit difficult to judge scale from the photos, but those spikes are really close together, only around 1-1.5cm tip to tip and they’re not removable on the HG kit. It’s pretty difficult to get a tool in there, but on larger kits, and kits with removable spikes you get them very pointy. The photos aren’t super either, the plastic looks very ‘rough’ in the photos, they very smooth irl.

  2. Great update, thanks for sharing! Seems there are a few things I'm gonna need to go re-visit on mine. Awesome progress shots too, really helpful and concise.

    1. Thanks E! I think you're going to be surprised with the next start to finish project. I'm hoping to announce it this weekend while I'm waiting for my shipment of paint.