injection marks?

Modeling Subjects Aircraft
1

Anybody out there have any good tips on removing those pesky hard to get at injection marks on gear doors that have raised rivet detail. I realize they must be filled, but then how do you get in there to smooth it out without damaging the rivets.

I tried the technics page, but nobody was over there.

thanks,

dragonfly

2

Got any pictures? It’s tough to really understand what your problem is with injection marks and the rivets. Most injection marks I’ve seen are in areas that don’t have a lot of detail around them. What’s the model kit?

3

Hey dragonfly! I understand your frustration with the mould marks. I wish the manufacturers would be a little more thoughtful about where they put the mould release pins. I work in 72 scale and really find this frustrating. Sometimes you can use cut down fingernail files or wrap some sandpaper around the tip of a knife blade but you’re bound to lose a little bit of detail.

4

The kit is a Tamiya p-47. The marks are completely surrounded by rows of rivets on all four gear doors. I managed to fill’m but It, just too close to sand. I tried to smooth the putty as best I could with acetone, but without being able to sand, you can still see a ghost of the little round mark.

Dragonfly

5

Sounds like you got rid of the injection mark. As for the ghost, are you woring about it showing through the paint job? Try priming it with gray primer or paint to get it to match in color to the surrounding plastic before painting. I’m assuming it is gray plastic. What color is the plane going to be in that area. Generally, the darker the color the better coverage I have seen over areas I’ve puttied. OD should be fine. Neutral Gray can show sometimes, but usually another coat takes care of it. As for an NMF… it depends on what you use.

6

Quagmyre

Thanks for all the advice, and yes the marks are now barely noticeable. The final color is yel znc chrm. I guess there really aren’t any secrets on sanding in hard to reach places, hopefully we won’t see that kind of stuff very often, specially Tamiya products.

Thanks again, dragonfly

7

Unless you have a Dremel and the right accessories, it’s pretty tough to get into tight places and sand with precision.

Happy to help.

8

Hey Dragonfly, If you have a hole punch used to put stuff in the three ring binders…you might punch out a few circles of your sand paper and then epoxy,or rubber cement them to the end of a pencil eraser.I used my Dremel a couple of times to sand in tight places…I ended up doing more damage than the ejector pin mark had.Anyway,like Quagmeyer and Bstrump,there are many ideas…just experiment and pick the one that suits you best.Hope it works out for ya!

9

A punch set and .01 plastic does a good job as well. I am constanly frustrated with injection pin marks in the worst possible places.

10

Hey Dragonfly, I’m working on the very same kit. One of the techniques I use is scotch invisible tape. For instance, on parts A-16 & 17, I lay a strip of scotch tape over the area of the pin marks. Then I use a #11 and cut the tape around the frame work of the door so that it fits in the recess. The tape covers the entire pin mark and then paint it. I have found that the invisible tape takes paint better than the clear tape. I’ve been using this technique for years and it has never failed to work. I have used the same technique on gear doors like parts A-12 & 13 in which I carefully cut the tape along the edge of the rivets. It covers the pin mark and when it is painted and weathered, it has the appearance of a re-enforcing panel or metal plating. Give it a try on your next project.
Chris