Gunpla Community Blog


by Studio G on Oct 16, 2020


As a sequel for the running of the Build Divers: Re:Rise series that I am currently doing for the channel on Youtube, I am customizing the HG Gundam Seltsam this time around. 

To experience the full custom experience, I would totally recommend you guys to watch the video I made for him here. 

Read time: 5 - 10 minutes

First let us look at some of the stuff that I’ve done for the Gundam Seltsam. 

  1. Added LED
  2. Added custom thrusters
  3. Added Panel Lines
  4. Custom details like grills and such
  5. Fixing the V-Fins
  6. Fixing the hollow fingers of the right arm
  7. Custom color scheme
  8. Painting
  9. Masking
  10. Panel Lining
  11. Water Decals

Now that everything that I’ve done is laid out let’s dwell into the details that I want to highlight. :)


The design behind this build is Alus’s Possession. As we all know in the anime series, Seltsam was actually possessed and taken over by Alus and I really want to translate that into this custom build itself. For this purpose, the eyes and also the torso are lit up using red leds, the colors are mainly purple and also white was also used to make his right arm look bone-ish. Kinda like a messenger from hell that sort of thing.  

Custom Build HG Gundam Seltsam


What you’ll be needing: 

  1. LEDs
  2. 1.55v CR621 Batteries
  3. Battery Casings
  4. SPDT Switches 

Parts I’ve added LEDs are the eyes, the chest, the backpack, and the two thrusters at the back of the legs. 

Custom Build HG Gundam Seltsam

Adding Leds on a HG is not a joke and it’s what most people would stay away from due to the size of the kit itself. But for me personally, I like the challenge and I did my first ever HG LED on the Custom Earthree Core Gundam which you can check out the video right here. 

For this build itself I am exploring mainly on switches and the switches that I’ve got are the 3 pin SPDT switches because of their size. It’s only 4mm long if I’m not mistaken. It took me 6 hours to figure out the correct way to wire them to be honest and it’s just so simple to do it after you have figured them out. Basically out of the 3 pins, you just have to wire 2 out of the pins and you get yourself a working switch for your LED lights.

Here’s a diagram that I’ve drawn using my ipad if you want to understand a bit further. 

SPDT Switch LED Wiring Diagram for Gunpla


So now that I’ve got the concept of having switches figured out it's time to move forward with the build itself. First thing is to have an access point for the toggle of the switch so I can just switch on and off without disassembling the kit. With that in mind, I went ahead and got started with the first part which is the thrusters located at the back of the legs of the gunpla. The original thrusters were too small for the LED to fit in so I’ve decided to use some custom ones from CJ Hobby. It’s pretty self explanatory on what’s going on here, all you have to do is to somehow figure out a way to fit the LED, the batteries + casing and also the switch in a simple thruster flap and here’s what I did here. 

For the toggle, I’ve carved out a slot at the top with the 1.4mm scriber that I’ve got, it fits perfectly. And, for the battery casing it’s just some 1mm pla plates cut to the exact measurement of the 2 batteries stacked up together with two holes on each side of the casing to allow wires to make the connection. Once you’ve figured all that out, it’s pretty simple moving forward from there to finish up the rest of the LEDs in this build. 


The eyes of a HG kit is basically just a piece of plastic with some embossed shape of an eye and for that you’d have to carve out the light path for the leds to shine through. For this, I’ve used my thinnest scriber which is 0.1mm to start scribing out the outline of the eye and then move forward with the carving process. Then, it's just a matter of figuring out where to place your LED for optimum shine.

Last but not least, drill through the back of the eye and also the neck so you can have the wires run into the torso which will be the main place where you house the batteries and also the switch. 


The torso is the biggest part of the gunpla by itself with the most cavity space and frankly speaking, I can fit 2 switches, 2 LEDs and 4 batteries inside it with a bunch of wires running around with no problem. Every gunpla is designed differently so you just have to figure out which peg to remove to fit all these parts inside while still keeping the integrity of the torso. Meaning, they don't fall apart.

I’ve decided to light up the torso part as well to further accentuate the build’s design and it really adds to the whole evil look itself. So I’ve carved out the holes at the back of the grill to let the light shine through and boy did that come out good! As for the switch, they are both located at the side of the position where the backpack would go, left for the eyes, and right for the chest. Nuff said, here’s a picture of the torso. ;)


The original design of the backpack has 3 tiny thrusters and I simply can’t fit 3 LEDs in them cause the maximum output of the 2 batteries just isn't enough to support them. As I explore more, I find out that with the batteries that I’ve got, I can, only light up two LEDs properly.

With that in mind, I’ve swapped out the original thrusters again with a single custom thrusters that has the same design with the ones on the back of the legs and again, it’s all about figuring out where you want the switch to go with easy access to the switch toggle, the batteries and also the LEDs. I’ve removed a lot of materials and pegs in the backpack itself but keeping the main ones intact so it doesn’t fall apart. 

As you can see, once you have figured out the fundamentals of the LEDs, it's up to you entirely on how you want to incorporate them into your gunplas. And it’s basically really hard to do a full fledged tutorial on this cause every gunpla’s design is different. But with that said, I am currently developing my own custom LEDs with ribbons and battery casings to be available soon in the future for you guys. The goal is to minimize the hassle and also no soldering :) Stay tuned for that ;)


Nothing shouts details more than having custom panel lines designed by you! The HGs are known to have little to no detail on the kit and if you are looking at this as a bad thing, boy you are very wrong. I used to be the guy that borderline dislikes HGs but after working with them I simply just love them so much because they LACK DETAILS! Which means, I can now scribe like crazy and be super creative on how I want my gunpla to look! I have collected a lot of scribers in the 10 months of my journey in customizing gunplas and I’ve gotta say, you just can’t cheap out on getting yourself a good scriber cause they make all of the difference. I’ll list out what I can find on amazon below but generally I would go for MadWorks, DSPIAE, SUGIBORITO.

Custom Build HG Gundam Seltsam

You can get the scriber (Grida) from Gunprimer as well and they work just as well but one thing I don’t like about it is that there are no size options. To me, personally when I scribe, I do all sizes like 0.125, 0.2mm, 0.3mm, 0.5m, and also 1mm to further elevate the design of the custom panel lines. As promised, check out the scribers below:


I struggle a lot when it comes to the colors for this build. This is because of the fact that I’ve done so many kits already in this 10 months alone and I don’t want another black and red build so this time, I went with purple. Okay, I know that the Seltsam came with purple but this time I used a different shade of purple, alongside with 2 shades of grey (not 50) and also a salmon red to create some sort of contrast in them.

Custom Build HG Gundam Seltsam

All of the colors used in this build is from my very own brand of model paint GPaint, you guys can check them out here :)  Here are the color shades as well as the formula that goes with them. 

Color #1: Dark Purple
Ratio: 3ML Purple + 7ML Dark Iron

Dark purple is mainly used to replace the dark purple armour.

Color #2: Medium Purple
Ratio: 10ML Purple + 3ML Dark Iron

Medium purple is used mainly to replace the purple armour and also color separation on the dark purple armour. 

Color #3: Light Purple / Metallic Purple
Ratio: 3ML Purple + 5ML Silver

Light purple is used mainly for the custom pla plates armour on the armour.

Color #4: Light Grey
Ratio: 10ML White + 1ML Dark Iron

Light grey is used mainly on the right arm and also on the weapons of the kit.

Color #5: Medium Grey
Ratio: 10ML White + 3ML Dark Iron

Medium grey is used for color separation on the right arm and also on the weapon of the kit.

Color #6: Salmon Red
Ratio: 10ML White + 1ML Red

Salmon red is used for the little tabs that I’ve added throughout the kit to throw some contrast in. 

Color #7: Gun Metal

Gun metal is used for the inner frames of the gunpla. 

Custom Build HG Gundam Seltsam 

Mixing colors is fun and you can do that with only a number of selections of colors so you don’t actually need a whole library of colors to be honest. This saved me a lot of money in the long run and this is also why GPaint was developed to have only 8 colors. You can literally mix any colors you want and have a lot of fun in the process. Well, fun and also learn something at the same time XD

Overall, this build took me around 126 hours to complete from start to finish. Honestly, this kit isn’t perfect, the articulation is a joke and the design is hard to like. The custom job I did on this kit isn’t perfect as well but like I’ve always said, it’s not perfection that we strive for but instead, it’s improvement. 

I hope you guys like this custom cause that would mean so much to me personally, and if you have any questions, feel free to ask around the growing community that we have on the subreddit which you can check it out here

For all of the tools that you need you can see them all here. :)

Again, I’m Justin from StudioG, you can check out my Youtube Channel here and Instagram here for more of my work. Until next time. ;) #NeverStopBuilding

1 comment

  • Richard Hart
    Apr 10, 2021 at 03:04

    I missed your Halloween colors, what formula would say makes the best purple from the original G paint colors?


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