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Title: Working With Resin

Vredesbyrd - February 8, 2008 03:50 PM (GMT)
This isn't my work, its just taken fromForgeworld.

Working with Resin Models

There are many books and step-by-step guides telling modellers the best ways of working with metal or plastic kits, however there are very few explaining how to work with resin kits. Unsurprisingly, with Forge World making resin kits, we get lots of questions on how to work with them. This article will run you through the basic techniques and methods involved with resin kit modelling.

If you need extra help. We are always happy to help you with your Forge World models. We can offer advice on assembly techniques or painting enquiries. If you have any queries or problems, don't hesitate to contact us


Most of the following tools are available from your local Games Workshop store or any good modelling store. When using tools please make sure to read and follow the manufacturers guide lines. Many tools can be dangerous and should be used with care.

Craft Knife

Recent governmental legislation in some parts of the world has made it increasingly difficult to obtain good craft knives, but nonetheless you are going to need one. If you only buy one tool, make it a good knife - it will be necessary for cleaning up castings prior to assembly. It is also worth buying a proper cutting mat to use with the knife so that you can avoid cutting directly onto your work surface (or dining room table!).


Clippers are useful for removing pieces of plastic/metal/resin that are too large to safely remove with a knife. They are also faster and easier to use than a saw so make a good middle ground tool.


There are many types of saw. The most useful to you when modelling will be a jeweller's saw and/or a razor saw. A jeweller's saw gives very fine cuts but the blades are quite fragile. A razor saw is more substantial but won't give as fine a cut. Both are far more suitable than a Junior Hacksaw, which I have seen in people's modelling kits.

Drill or Pin Vice

You will need one of these if you want to drill holes in your components. This is usually only necessary if you want to add strength to a join with large and/or heavy components by pinning them with metal rod.

Files & Sand Paper

After a knife, a set of files is the most useful part of your tool kit - used for cleaning and smoothing castings and filing pieces 'to fit' where necessary. Files come in different profiles - flat, round, half-round, etc, and it is a good idea to have a selection. Sand paper or sanding pads are also useful for sanding larger areas.

Variable Speed Rotary Tool (Dremel, Minicraft, etc)

This can be used any time you need to sand, file or cut something and will greatly increase the speed of those tasks. It is however a tool for the experienced modeller and should be used with care.


You do not need any special form of glue to assemble your resin kit. Standard modelling super glue works just fine.

Dust Mask

When filing or sanding resin components please make sure to wear a face mask. Like any fine dust, breathing resin dust is not particularly good for you.

First step

The first thing to do is lay out your resin model and make sure it is all there. It sounds obvious but it is very easy to get carried away and start assembling the model without checking. A missing piece will then stop you from finishing it (which is far more annoying than finding that a piece is missing before you start). In some cases it will be necessary for the kit to be returned and this is much easier to do if the kit hasn't been started.


The next step is to start preparing the model for assembly. This is a multi stage process, which I'll go through as different stages.


This isn't always necessary but I find it's generally better to be safe than sorry. Washing will help with the painting stage later. To get the best results from washing your model components I'd suggest using a mild abrasive cleaner diluted in water. I use a kitchen floor cleaner diluted in water. The models should then be given a scrub with an old toothbrush or something similar. A toothbrush is useful as the bristles are fine enough to fit into small gaps but firm enough to actually do something. I usually leave the components to soak for a little while before using the toothbrush. Then remove the models, rinse thoroughly and allow them to dry.
The reason for doing this is to make sure all traces of mould release fluids are removed. It also gives a very slight abrasion to the surface of the model that with some of the smoother models will help with paint adhesion.

Removing Excess Resin

Just like metal and plastic models there will be excess material that needs removing from the model before assembly. The difference being that with resin models the bits needing removal may be larger and must be removed with more care. These are the result of the casting process and unavoidable but all can be easily dealt with.

Mould Lines

Resin pieces are produced from rubber moulds that usually have a split line. Consequently there will often be a line on the model that shows where the mould joined. Sometimes these are fine enough that they can be ignored. To get the best results however they will need removing so that they don't show up after painting. To remove the lines use either a modelling knife, file or sandpaper and carefully scrape or file away the line. This shouldn't take too long and makes a big difference to the finished model.


The gate is the area where the resin is poured into the mould. This is where you will find most of your excess resin. A gate can appear in different forms, depending on the detail and shape of the model. The most common are V shapes that are on the side of a detailed or odd shaped component or a large rectangle going onto a squared component. These will need removing and may take some effort with the larger model kits. With smaller components, a pair of clippers and a file should suffice. With your clippers remove the gate at a point above where it joins the component. Don't use the clippers next to the actual component shape. This is because clippers are quite a savage tool and often damage the areas on either side of where you cut. If you've ever tried to cut a metal figure in half with a pair of clippers you'll know exactly what I mean. After clipping most of it away use a file to remove the last of the gate and to ensure a smooth finish. With larger components, the gate will often be too big to remove with a pair of clippers. In this case it is best to use a saw. Unlike the clippers this can be done as close to the model as you like. It's usually best to do it slightly away from the join though just to make sure that any deviation in your cutting line doesn't affect the model. Again after the gate has been removed, use a file to ensure a smooth finish to your model.


Vents are small holes cut into the mould that allows air to escape when the resin is poured in. These are recognisable as thin pieces of resin leading away from the model. These are removed in the same manner as the Gates above but are usually far easier.


Flash can be formed in two ways. The first is deliberate. Thin gaps in the mould allow resin to flow into other parts in the mould without filling a gap. For example, a cockpit canopy or a window, large gaps are needed between the frame of the windows and to allow that gap the mould only has a very small gap for the resin to flow through. This leaves a thin membrane between the larger parts of the component. The second way flash is formed is when it leaks slightly between the two layers of the mould. This again leaves a thin membrane that usually fans out from the component. In both cases flash is easily removed with a knife and then a quick scrape with a knife or file will remove any last traces of the flash.


Warpage can easily occur with thin components as thin resin components are susceptible to temperature just after casting. To get a warped piece into the right shape (or even to just reshape a piece like a tail or arm.) just immerse it in hot water and gently bend it. With a larger piece it is best to do this in stages. Bend it a little, allow it to settle and repeat until it is in the correct shape. Larger pieces may also require longer immersion to soften. If you don't want to use hot water then a hair dryer should give the same results, just don't let the piece get too hot (or blow away!). Do not heat resin with any kind of flame.


Once the components have been washed and all excess resin has been removed the model should be ready for assembly. If the model has any interior detail, now might be the best time to paint it, as it could be difficult once the model is assembled. Before gluing the components together it is a good idea to dry fit them. This just means placing the parts together to make sure they fit okay. This is useful, as it will point out any potential problems such as uneven joins and slight gaps in the joins. Unfortunately gaps are unavoidable with some joins. If there is an uneven join just quickly take a file to it and make it flat before gluing. If there is a gap this will need filling. Glue the components together straight, don't worry if it leaves a gap (this was why you dry fitted it), once the glue has set, use a small amount of modelling putty to fill the gap. It's best to glue all your components that will need filling at the same time as it will save you time and putty. Once the putty has set it should be sanded flat. Now you can finish putting the kit together and then it's on to painting.


I'd suggest priming your model with something like a spray Car Body Primer (available from most motor stores). Some model primers don't have the required solvent strength to adhere to resin properly. If the primer comes away then anything you have painted over it comes away too, which would be a bad thing!

It's then simply a case of choosing your colour schemes and painting your model!

Iacton - February 8, 2008 03:57 PM (GMT)
Where's the "what to do when that crucial bit of detail breaks off in your hand as you are tidying up the castings and gets lost in the carpet?" section -_-

Vredesbyrd - February 8, 2008 04:07 PM (GMT)
QUOTE (Iacton @ Feb 8 2008, 03:57 PM)
Where's the "what to do when that crucial bit of detail breaks off in your hand as you are tidying up the castings and gets lost in the carpet?" section -_-

GW needs to do one of those too!

The number of conversions that've gone down the drain because I've dropped a bit and can't find it in the carpet and don't have a replacement....

Weiss - February 8, 2008 04:23 PM (GMT)
That's a great help, cheers man. Out of interest, where do you usually get the defects on the red scorpions torsos/heads?

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