How to work with resin Kits

Introduction

When building models and dioramas one cannot do without resin cast accessories these days. The market is well-supplied with resin kits or kit conversions with a quality level ranging from very poor to very good. Where the major kit manufacturing companies had to call off, the so-called 'Cottage Industries' took up. Some of these have even grown to the extent of becoming one of the leading forces on the model market. Producing relatively small diorama accessories would call for a new, very labour-intensive production facility. The best results are still obtained using people instead of machines, so production costs are bound to be high when one has to produce sufficient stock to supply the world market. The versatility of these kinds of accessories is another problem one has to deal with. Different packing boxes of all sizes, instruction sheets and full colour labels are a few items which call for a well organised, highly productive way of working. In this kind of business 'flexibility' is the key-word. Then there is the master. A good quality resin kit or accessory can only be obtained using a first class master on a 1:1 scale. Resin is very forgiving where undercuts are concerned but it very accurately reproduces every fault on the master as well. The best moulding technique can only be established after a lot of expensive , trial and error' jobs. These are a few of the problems encountered when starting resin kit production. For the modeller, resin is easy to work with. It can be cut, drilled, milled and scraped like plastic. It has only one slight disadvantage. You need cyanoacrylate glue to bond the parts together. On the other hand, detail is much sharper than on plastic injection moulded kits. Undercuts for which plastic parts have to be divided into separate components can be cast in one piece. This of course saves the modeller a lot of time in adjusting, fitting and gluing. However, we don't think of resin as the replacement for plastic injected moulded kits, rather as detailing and enhancing additions to the Tamiya, ltaleri and Hasegawa kits both in existence and yet to come.

WORKING WITH RESIN

All resin cast kits come with a carrier which has to be removed before the parts can fit together. The best way to remove this carrier is to use a very sharp X-acto razor saw (fig.l) .

The sawing movements should be well-controlled. Be very careful or you might damage the part itself with sawing marks which are difficult to remove. There is no need for spending a half hour on filling a saw cut because you wanted to save 10 seconds on the sawing job.

 After removal of the sprue the part itself needs a little sanding. It is advised to use a piece of waterproof sanding paper which is taped to a flat piece of waterproof plywood (fig.2). 

On most of the VP resin cast accessories the side to where the sprue is positioned is the area which will be obscured after gluing the parts together. This however is not always possible so a scratch-free surface is needed. Wet sanding guarantees such a surface. For the best possible result we suggest using water with the sandpaper (emery cloth), to prevent clogging the grain of the paper. Sanding in circular movements, both clockwise and counterclockwise, will ensure a flat, square surface (fig.3). 

The side may need a brief scraping with a sharp knife to smooth the edges (fig.4). 

Test-fitting before gluing is of ultimate importance. By not doing so you will find yourself filling gaps and sanding ill-positioned parts on your model. When you're satisfied with the fit of the parts, preposition them with white glue. Just a few drops will do to keep the part in place long enough until the cyanoacrylate secures it all (fig 5). 

Applying the cyanoacrylate should never be done in the way shown in figure 6.

Use a rounded knife to apply the glue. A straight edged knife will prevent the cyanoacrylate from leaving the blade. Squeeze a drop of glue on a non-absorbing surface. Dip the knife in it so a small amount of it adheres to the blade. Position the knife on the parts to be glued and let the glue flow into the seams. Repeat this action until the parts are firmly bonded. Be careful, you don't need large amounts of cyanoacrylate because it flows like water. And you don't need to glue your fingers to your kit either

Figure 7 illustrates the way to prevent this. Eventual gaps and air-bubbled surfaces can be cured using putty. Let it dry for at least 24 hours before sanding. As previously mentioned, drilling and milling pose no problems, the material can stand it all.