Tuesday, January 11, 2011

The CORE Method Groin Fix

This was an answer to a PM question at MAC forum, but I'll put it as a tutorial somewhat.

Breaking/broken parts are inevitable. Even simple handling and/or assembly can break a part that's structurally weak or has inherent molding flaws, like bubbles in the molded part, or in my recent blog post, directionality of the molded plastic. The latter is not so much of a problem until it comes to sanding; each time you complain about having a nub mark at an odd position which makes progressive sanding an entire part necessary, you can attribute it to directionality.

In my case, I break a lot of parts especially during test fits and modifications. Sometimes, a part is just too darn weak, or, I'm just too darn impatient. When I break a part though, I no longer fret because I've learned a few trick on how to fix them.

So here's one, strangely enough, not by me, but, something I can relate to nonetheless because it's all too familiar.

DarkWorkx sent me these two pictures:

I assumed this is a groin part from an HG/HGUC kit (I was later told it was an FG kit). My experience with most HGUC kits I have is that they do break often at the groin. Sometimes, they make the connecting pegs/balls so weak, it breaks easily after a few fittings. This same thing happened to the Ice Queen AFTER she's been painted and propped for a shoot. As such, the "easiest" way to fix this and make the part stronger than before is to employ the CORE method.

Referencing the picture above, drill a lateral hole on the base of the peg/ball joint and on the hip ideally the connective parts that broke so you can align them easily later on. Make sure that the hole is just big enough to fit a piece of runner or round beam SNUGLY (it should hardly move even without cementing them together). Next apply enough cement to the holes, plug the core in, and align the parts together using the other side as a guide. If you also have extra thin cement, use that to saturate the surface of the join. Let cure for AT LEAST 24 hours or more preferably. Work on something else if you're impatient.

I guarantee, this method works since I have employed it a few times on broken MG groins, joints and pegs extension modifications as well (where I had to combine ABS with PS plastics). If done correctly, the repaired part should be stronger in normal handling situations than it was factory made.

Here are a few examples.

Hi-Nu groin peg fix:

Angelus Leg Extension and Wrist Joint fix:

Angelus Neck Extenision:

Chimera Neck Extension:


  1. Why do you have 96 views from the UAE?!!!! For a long while now I thought I'm the only Gundam hobbyist here, it looks like I'm wrong apparently. hehehe. Gotta find these guys.

    Just dropping by bro! ;) and oh, thanks for offering to help on the detailing of the resin project. hehe.

  2. Those 96 views might just have come from one person over a period of 6 months.

    Anyways, since it's THE Gundam Wing, I'd be more than happy to help with its design.

  3. question: how do you make the pla plates go "Wrapping" around the circular neck piece?

  4. Plaplates are bendable to a certain extent and can keep that form, and they do have grain or directionality. All I did is cut the right shape and size, bent it gently, and cemented it over the neck piece.

    I've made a tutorial post/reply of heatless plaplate bending at ZeroG, and have been asked a few times, so I'll make it into a tutorial entry.

  5. Thanks you very much, it's really helpful, now I can start experimenting on the Plaplates and use them for good


And These Came in the Mail

Rather, I had these sent to my school since I was on an off-site training.  Bosny Philippines has once again graciously sent me free...