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crzydrunknmunky posted an update in the group
Q/A & Help Group 9 years, 6 months ago Hey! I’m looking for some advice on how to fill in seam lines. So in the photo I’ve already glued, puttied (Tamiya Basic Putty), (wet) sanded and primed the piece but there’s still a faint line going down the middle. Before priming it felt, looked and seamed (haha get it?) flat. Do you guys have any advice on how to get that flat seam line? and what do I do with the piece now?
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Q/A & Help Group
Can’t see it in this photo… But depending on what’s going on, my suggestion would be one of three things:
If you’ve still got a faint little recessed line, it could be that the putty shrank (putty does this) – just add more, let it dry thoroughly, and sand it again.
If the edges are uneven (creating like a “stair-step” between the two parts) then more sanding is probably the way to go.
If the seam line persists, it may mean that the parts aren’t sufficiently bonded together. In that case I’d either try to reinforce the joint on the inside of the part with super glue, or else crack it apart and re-glue it.
A lot of the time, seams on modern kits can be handled with nothing more than solvent glue and sand paper. Just glue the mating surfaces, press them together (some plastic should squish out) – let it dry thoroughly and then sand it down. If the line is still there, sand some more. That will usually do it. Just be sure the glue has fully dried – otherwise the sandpaper will strip out the softened plastic and make the seam worse.
Thanks a lot for replying! Yeah, I figured that I could only see it because I know exactly where the problem is, but it is a faint little recessed line. From what I’ve read on other places it does seem like shrinking is the culprit. So next time, should I prime right after I finish sanding so I can prevent shrinking? Well! back to more sanding!
The putty shrinkage is just part of how most simple putties work – as part of the hardening process, solvents in the putty evaporate. Priming over the putty before if fully dries would slow the process but not stop it. The way to deal with putty shrinkage, generally, is just to let it happen and then apply more. But there are also alternatives like using CA (super glue) to fill minor gaps, or use a catalyzed putty like polyester putty or light-curing putty.
Priming is helpful because it makes it easier to see whether a seam line is really fixed. It’s not a bad idea to prime once you think the seam line is fixed to reveal things you’ve missed, then do more seam work and prime again when you’re ready.
Hey thanks for all the help! I puttied and sanded it a couple times but the lines were still there so I ended up spraying a really thick layer of primer onto the part and softly sanded it and the seam line disappeared!! I may be using that technique from now on. Thanks for your great help!