March 29, 2010

Gundam Building 101: Nub Management

Guide to Gundam Making: Nub Management

I'm calling this nub management because that's really what I'm going to be showing you how to do this entire time. I'll have pics here, and a brief description of what is going on underneath it. Make sure to pay attention to the lessons learned sections (bolded for convenience).

Materials you will need:

- Gundam model ($$$ whatever you decide)
- Model pliers (flat on one side) ($5-7)
- Exacto Knife ($2.50)
- Sandpaper (I recommend fine, and extra fine grits, usually 600 and 800-1000 grit) ($2 a stick, get 2-3 of different grits)
- Sandwich/snack bags & Sharpie (should already be in your house)

Materials I recommend in addition:

- Gloves: these can really help out preventing oil from getting on the pieces and from slipping in general ($5/box)
- Tweezers: they just make things easier on occasion ($5-7)
- Plastic cleaner: for releasing the mold agent and getting it ready to be painted (not necessary if not painting) ($7.50)
- Airbrush without paint: for use similar to an aircan to blow the sand/plastic off of pieces. ($$$)
- IF no airbrush, get a big dry paintbrush or toothbrush to wipe it away ($0.25)
- Daylight spectrum lamp with magnifying area: sometimes can make it easy to see, and the light is easy on the eyes. I personally recommend 2 lamps. ($20-25 a lamp)

Introduction to terms and overall ideals:


This is what's called a Runner. It is the plastic framework that the model pieces are molded into.


The part that connects the actual piece to the runner is what is called a gateway.

When you first open the plastic glory of your Gundam, it is near overwhelming how many runners can be in the box. This guide is for a relative newbie, someone who's made maybe 1-2 gundams, or someone who needs a refresher or different perspective.

The Steps:

1. Read the directions. 3 times. Each frame. No joke. It's not as fun the second and third time, but you see how the parts fit together and what goes where so that when you ARE cutting out pieces, you won't screw up and understand kind of what it is for.

2. Put on your gloves, and get your materials ready for cutting out 1 runner.

3. Cut out your first piece. Make sure you cut AWAY (not adjacent) from the piece and more on the gateway by about a couple millimeters (as shown). I like to minimize work, but if you don't have a steady hand you can just cut off in the middle of the entire gateway. Do not try to cut as close as possible to the piece, this precision work is for the exacto knife later on. Proceed to cut off the entire Runner in the same fashion, and pile them on one side of your workspace.

4. If you elected to cut the middle of the gateway, cut the nubs down so that they're only sticking out about a few millimeters. Lesson learned: do NOT let the leftover nub sticking out exceed more than a few millimeters (in fact, in this picture, looking back, I think the nubs are almost too long haha). If it is long, it can cause the nub to snap off, which will give a bad result. I will talk more about this later.

5. I press the blade against the piece, and slowly shave down by pressing on the top of the blade with the hand not holding the knife's handle. Lesson learned: Shave SLOWLY!! If you press hard like a cave man to cut off the nub, it will *pop* off by force, and cause stress marks (white/lightened colored plastic) where it essentially snapped off. Here is a diagram of what I use as my rule of thumb for the larger nubs:

6. As you get down to the bottom of the nub, have your knife run parallel to the surface the nub is on and carefully shave in light strokes across the surface of the nub. If you press too hard, you will begin shaving outside of the area the nub is on.

7. Using your airbrush/toothbrush, brush away the excess shaved plastic to get an idea of what the piece looks like without the dust all over it.

8. If your nub has snapped, which you will have occasionally, you'll get a result like this: plastic that appears warped and lightened because of the stress on the plastic. If not, it will be ready to go, like this!

9. Sanding: I use sanding only if I am painting as a rule of thumb. If you aren't, sanding is a better option for white parts only in my experience, but with the right amount of care, you can sand anything and make it look pretty good. Using a rougher grit (my sandpaper says "Fine", but its around 4-600 grit), carefully sand parallel to the surface your leftover nub is on. Your objective here is to get rid of all rough edges, or evidence of warped plastic. Be careful not to bleed over into other areas of the piece, as you'll have to go over it again with the lighter sandpaper. A note about warped plastic: if you are painting, and where your nub was is perfectly flat, but with evidence of warping, leave it. The paint will cover that up! Don't bother sanding if it's not rough.

10. With your finer grit sandpaper (800 and higher recommended), sand over the areas to smooth out your scratch marks with the previous sandpaper. I personally recommend the nail file type ones because it is easier to handle.

11. If you want to buff the scratches (if you're not painting), you can use buffing compound and a terry cloth/painters towel. I didn't do it here because I'm painting this model, but it will get rid of some of the scratches, or alternatively you can use a super high grit sandpaper (1500 and higher).

12. You are done! All that care just for 1 piece.

13. Once you have finished all pieces, label a sandwich bag with a sharpie and put the pieces in there. I put 2-3 runners in a bag to save bags, and - this is where reading the guide comes in handy - put them in according to the sections they belong to. An entire runner should take 30-45 minutes (depending on the size).

To streamline this, I recommend an assembly line approach:

- Cut all pieces off runner
- Trim Nubs with pliers
- Exacto nubs
- Sandpaper what's left of the nub
- Put into sandwich bag

It's important to have a repository for all of your pieces once they've completed a phase so it is easier to manage; i.e. if you have finished exacto-ing a piece, put it in a tupperware/shoebox lid/whatever or even a separate area on your working surface, and when you are all done with that phase, dump the pieces back out.

Please refer to my guide that is going to be coming out - Tips for Painting - Exercising Fitting Holes and Proper Cleaning. This is for people who will be painting their model using my techniques.


  1. Nice tutorial - I see you like to keep things neat :)
    Good tip with the gloves - although I'd be a bit cautious about the powder they use to keep the gloves from sticking each other (and to your hands) - has that ever been an issue?
    Looking forward to your painting tutorial - maybe I'll learn something new there too ;)

  2. I love this guide.

    I've been trying to get into gunpla recently and some tutorials said to use sandpaper to get a decent finish. You're the only one I've seen so far to explain why/how you use it so you don't screw up whole pieces XD

    Thanks a lot!

  3. Glad you liked it! I've watched most all the seasons of the professional modeling/hobby show in Japan, and I've learned a lot from the masters across the sea. They know entirely too much about making things look awesome, but its to all of our benefit!

  4. So how do you differentiate pieces that are similar but not identical? Do you just remember them from reading?

  5. hey just wondering when u use sandpaper to sand down the stub/nub mark, wouldn't the sandpaper cause many unwanted scratches on the plastic itself? How would you avoid it? Thanks

  6. Thanks Major for this wonderful guide. Im a newbie in gunpla, one of those "someone who's made maybe 1-2 gundams" heheh. anyway this guide is very helpful..iv been in a lot of tutorials online, but i preferred reading yours..thanks again for this guide..

  7. Thanks for the post! Helped me tons! NO MORE CRATER NUBMARKS FOR ME!!!

  8. Would this be the same process for resin pieces?

  9. I'm interested in finding online videos of the Japanese hobby show you mentioned, do you know where I can find them?

  10. Is there a reason why you prefer sanding white surfaces? Does sanding surfaces other than the colour white distort it?

  11. hi there are certain oarts i dont manage to use in other gundam. what do i do with them

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