Ejector pins are used as part of the process of Injection moulding. Used to release the parts from the mould the can leave a small mark in the cooling plastic that can be quite noticeable on the plastic. Most modern kit manufacturers are fairly sensible where these marks show and try to avoid highly visible areas of the kit for them to be applied. Some kits however do end up showing these marks in prominent areas through lack of design forethought or simply because in some instances they are impossible to avoid on some parts no matter how much ingenuity the kit manufacturer applies. In the photos below I have applied a small wash to the ejector marks to make them more visible for the purposes of photography.
Unfortunately when they are in visible areas they can leave a visible defect during the painting and weathering process that is highly visible and reduce the quality of the finished model. In these instances it is important to deal with them before the painting and construction begins.
My personal preference for dealing with these recessed marks is to use a liquid putty. In this instance I am using Mr. Dissolved Putty from choice although there are other putties and filling products available that are equally suitable. Using a wooden toothpick I mix the putty in the jar before leaving a small amount on the toothpick which is then used to apply to the ejector mark. As it is fairly thin it will flood the hole and fill up to the edges. I always apply a little more than is necessary so it creates a raised level on the hole to ensure I haven’t used just a little too much. Once applied leave to dry, I usually wait 24 hours before starting the next stage.
Sanding and levelling.
After 24 hours and the putty has dried its time to remove any excess and achieve that unblemished look you are seeking to achieve. On interior surfaces that are curved I would usually use a small sanding sponge that I can cut into smaller pieces for particularly tight spaces. Usually a grade 600 – 800 is ideal and slowly work on the area gradually sanding back any raised areas where the putty has dried. It is important to remember to not press too hard with the sponge or it can actually sand the putty out below the surface edge of where you have filled, so take your time and go lightly. As a useful guide to work out when you have sanded enough you should be left with a perfect circle of putty that shows clearly against the plastic. All that is left then is to apply a primer to make sure you haven’t left any excess or sanded too deep. If you have simply repeat the process and prime again.