Sink Marks

The first is the sink mark. This is basically a depression in the surface of the plastic. The first picture shows the sink marks on the Vindicator. They are the vertical depressions on the fuselage. There are a few reasons for them. On the AM kit it appears that there may have been insuffiecent plastic injected to fill a particular part of the mold. This could be due to insufficient plastic or insufficient presure pushing the molten plastic into the cavity. The sink marks on the Vindicator are on a particularly thick cross section of the fuselage. They can also be caused by removing the plastic too quickly before it fully cools.

They can be corrected by using a filler, such as a putty or CA glue and sanding to shape.

Ejector Pin Marks

The second is ejector pin marks. These are the marks, usually on the inside of a part, created by rods that push the plastic out of the mold. These round marks, as seen in the second picture, are on the inside of the AM Vindicator cockpit. Usually these are on surfaces that will not be seen on the completed model or will be covered by another part. But, sometimes they are visible and needed to be filled in. This can also be done with putties or even thin sheet stock.

Injector Stubs

Finally are injector stubs. The third picture shows one on the tail of the CA Walrus. I believe they are the points where excess plastic is extruded from the mold. These are most common in limited run plastic kits, due to low presssure molding. They can be corrected by slimply slicing off with a knife or sanding.