What Are Gunpla Conversion Kits? Conversion and Resin Kits 101

Every year, Bandai Hobby creates a set number of Gundam model kits in its factories. But what do you do when you want to build a different model kit that might not be available? Enter conversion kits and resin kits. 

While Gundam model kits are made in Bandai Hobby’s Shizuoka factory out of polystyrene, conversion kits and resin kits are, as you might have guessed, made from resin—a bonding agent that can be poured into a mold. These resin parts can be combined with an existing Gundam kit to completely transform its look.

We asked our contributor Nanochi to answer some frequently asked questions about Gundam conversion kits for Gunpla 101 readers. Check them out below!

Q: What are Gundam conversion kits?

A: Gundam conversion kits are upgrade parts that you use to add extra details to an existing Gundam model kit or convert it to an entirely different kit. They are usually very detailed, with much more panel lining,  internal details, or even new-looking parts entirely. 

Q: What is the difference between a resin kit and a conversion kit?

A: A resin kit, also known as a garage kit or GK for short, is a full kit with all the required parts included in order to build a single kit. A conversion kit is similar to a garage kit but must be combined with a specific Gunpla model in order to be used. Conversion kits will tell you which model(s) you will need in order to make the kit. 

Another difference is that conversion kits usually retain the articulation of the original kit while most GK kits have no articulation. (Some do but it is very rare and usually more expensive.)

Q: What do conversion kits offer that regular Gundamn kits don’t?

A: With a conversion kit, you can add extra details or even make an entirely different character out of conversion kits. You can even make a kit that isn’t available from Bandai Hobby if you find the right conversion kit! Also, it can be a lot of fun to work with resin pieces, which feel different than polystyrene, and try something new.

Q: Is buying and selling Gundam conversion kits legal? Does Bandai Hobby frown on it?

A: In fact, Bandai Hobby used to make its own resin kits back in the day known as B-Club. You can still find some from 2012 and earlier. The reason conversion kits are not a big problem for Bandai is because they are not mass-produced like Gundam kits are. They are made sparingly because hobbyists can only use a mold so many times before it becomes unusable. While it’s not illegal to make and sell resin kits, the process takes a long time. 

Resin kits are essentially fan-made kits that began as passionate projects to help builders make what they want to make. They are custom-made and have a lot of care put into them. 

Q: How do you attach conversion kits to a Gundam model?

A: It depends on the kit’s creator. Each kit is a bit different. Most, but not all, kits will have instructions on what to do, so some research may be necessary depending on the kit you see. However, applying super glue to the resin to plastic is more than enough to secure the parts. Please follow any instructions that come with your conversion kit, as some will require you to cut and remove plastic parts from a kit to attach them. 

Q: Do you have to paint Gundam conversion kits?

A: Yes! They will arrive unpainted, in a brown, orange, or yellow-ish resin color. You should also wash them before you paint to remove any mold-releasing agent that can still be on the parts because they will make it more difficult for the paint to stick. Also, make sure you prime resin parts before you start painting! And of course, for safety precautions, make sure that whenever you sand or file any resin, you wear a dust mask. 

Q: Is there a resin or conversion kit for every Gundam model?

A: It is quite possible that the kit you are looking for may have a resin copy if there isn’t an official Bandai Hobby Gundam kit. However, some of the more obscure Gundam models may not exist, as most kits add more detail or change to a slightly different model of the same kit. There are also some known as “upgrade parts” which offer much more details to a kit that already exists. We’ve even published an example of this on Gunpla 101 already: Emily’s PG 00 diorama.

Q: Where do I get conversion kits?

A: If you live in Japan, you can attend Wonderfest, the annual figure festival where you can score lots of custom 1-time only conversion and GK kits. However, be aware these are only made for the fest and will be gone afterward. If you’re lucky, you may be able to find some of these on eBay from various sellers. 

SH Studio is a bigger studio that makes many resin and metal upgrade parts. 

Gk Gundam is one of the biggest companies for getting Gundam resin kits and conversion kits. 

Gk-M is another shop to get unique resin kits from Gundam, and other anime and sells some conversion kits.

Newtype will sometimes sell some conversion kits but they tend to be much more expensive.

Q: Which Gundam Garage kits are good for beginners?

A: This…Is a very loaded and difficult question to answer. Since there are SO many out there to choose from, and with each one having different kinds of quality and such. It is very hard to recommend any particular ones. 

There are Gundam resin weapon packs that some hobby stores sell and are usually very simple to build. They come in a tiny box with no instructions but few enough pieces to figure out. 

If you want to start working with resin, however, I do recommend you start with simple Etching (or Photo-Etched) upgrade parts. These simple metal detail parts are easy enough to figure out and will give you a basic understanding of how to change up parts of a Gundam. Unlike others which will require you to cut out cavities, these you simply glue on. Replacing your verniers with a metal set is cheap and very easy, and makes a great first project. You will just need to cut out the nub that would normally hold the verniers and superglue them in. 

Working with resin is similar to learning how to airbrush, as you will need good ventilation, lots of sanding, and plenty of time and patience. I personally recommend you start with some basic resin character kits from shows you like. For example, these from GK-M—some of which are from Gundam shows! These are usually no more than 20 pieces and will teach you the basics of how to sand, fit, and paint kits. Once you have done a few and are very happy with them, only then do I recommend you try a resin conversion kit. 

Nanochi got interested in Gunpla after building the MG Infinite Justice. Today, she is an award-winning modeler who builds Gunpla for commission. You can learn more about her work on Twitter and Instagram.