Hmmmmm, WHY?!

QUOTE: Originally posted by MontanaCowboy I was working on my latest build, when I stared two ejector pin marks in the face, and saw one was depressed, and one was raised. I have know for some time now that they both exist, but this raised the question, WHY are there two different kinds?

It just depends on how the ejector pin itself sits in the mold during the molding process. If it sits recessed into the mold a bit, the mark will stick out on the part. If the pin sticks out a bit, the mark will be recessed on the part. The ejector pin itself doesn't move at all until the molding is finished, when it then ejects the sprue from the mold. The marks are created during the molding, not during the ejection.
Hope that helps!

QUOTE: Originally posted by J-Hulk QUOTE: Originally posted by MontanaCowboy I was working on my latest build, when I stared two ejector pin marks in the face, and saw one was depressed, and one was raised. I have know for some time now that they both exist, but this raised the question, WHY are there two different kinds? It just depends on how the ejector pin itself sits in the mold during the molding process. If it sits recessed into the mold a bit, the mark will stick out on the part. If the pin sticks out a bit, the mark will be recessed on the part. The ejector pin itself doesn't move at all until the molding is finished, when it then ejects the sprue from the mold. The marks are created during the molding, not during the ejection. Hope that helps!

so if it sat completely and perfectly level all builders would be happy...

QUOTE: Originally posted by Tankmaster7 QUOTE: Originally posted by J-Hulk QUOTE: Originally posted by MontanaCowboy I was working on my latest build, when I stared two ejector pin marks in the face, and saw one was depressed, and one was raised. I have know for some time now that they both exist, but this raised the question, WHY are there two different kinds? It just depends on how the ejector pin itself sits in the mold during the molding process. If it sits recessed into the mold a bit, the mark will stick out on the part. If the pin sticks out a bit, the mark will be recessed on the part. The ejector pin itself doesn't move at all until the molding is finished, when it then ejects the sprue from the mold. The marks are created during the molding, not during the ejection. Hope that helps! so if it sat completely and perfectly level all builders would be happy...

Yup, if the ejector pin sits perfectly flush with the mold, there will be no mark, and all builders will be happy!
Another thing that makes builders happy is when the manufacturer intelligently engineers the molds so that the ejector pins are in inconsequential locations. That way, even if there is a mark, it will never be seen on the finished model, so the builder can ignore it.

That was one thing everyone was happy with when Dragon moved the injector pin marks onto the sprue away from the track links. Even that link and length Shanghai Dragon M1A1 was a nightmare to clean up, n that's one of them easier tracks...