How To: Filling Larger Gaps with Putty

Now "seams" like a good time to show how to fill larger gaps with putty. Get it? "SEAMS!?"

So, a while back I started a series on filling small and large gaps using styrene cement only. I intended on doing medium sized gaps (like today) and larger ones, but alas, haven't encountered a kit that would allow me to do these...until now!

So doing the Dragon Models War Machine, there are a few gaps that just don't allow the trick of using the cement to act as a seam filler. By the time you sand down to where the plastic is joined, you wouldn't have a recognizable, sturdy piece any more. So we do the next best thing, and that's use putty!

For the sake of this tutorial, I'm using Deluxe Materials' Perfect Plastic Putty. I'm not endorsing this, and there are other putties you can use, but I've found this is the easiest for me to clean up, apply, and sand. I have used other putties I haven't been as happy with, especially anything you can buy at Wal Mart, just FYI.

OK, moving on. The first thing I've learned when using putty is when applied without a plan, its disastrous. At least one of two things will happen...you will either get putty all over the place, including all over the detail of your kit, or, you will sand the putty down, wearing down the detail as well. To prevent this, we use masking tape. Apply it as close as you can to the seam, but not right on top.

First and foremost, this will keep the putty from getting everywhere. From there, we apply the putty, moderately liberally, just enough to fill what's exposed by the tape. That's one nice thing about the Perfect Plastic Putty...you can get a syringe-like applicator (I guess technically it can be used with any brand of putty) that helps control the flow of putty:

I then use a paint shaping tool (a rubber-tipped brush) to spread the putty out. It doesn't adhere to the tool as much as a finger, so I can spread it easier with the tool. PPP is water-based, so if you use water with it to thin the putty out, it can wash parts away. Just spread the putty out, a little on the rough side, so that it is sure to get down in the seam:

From what I understand, Perfect Plastic Putty has an hour dry time, roughly, but as with all things, I apply a test piece to some scrap so I can touch it to know exactly when its dry. After watching a movie, I revisited the putty. I used a medium grit sand paper (320 to be exact). If you do any rougher, you risk chipping the putty. You can go lower if you want, but you're in for a longer time sanding. I lightly sand when its this rough, not putting my weight behind it. The sandpaper, at this grit, would eat detail up, but the tape takes the brunt of the sandpaper's force instead. Sand lightly until you can see the original tape:

Now, its time to remove the tape, since there's no putty left on it. If you remove the tape prior to sanding first, you risk pulling the putty up in a large chunk, which I've done, and is distressing. What you're left with is a decently filled gap, but it still needs smoothing further.

Now, its just lather, rinse, repeat. Use progressively smoother grits (don't just jump to the smoothest!), up to 800 or 1000 grit sandpaper to restore the original smoothness of the plastic. Once you get to that grade of sand paper, you won't see a difference after priming:

And voila, you now have a well filled gap, ready for primer and paint! You may find, after priming, you can still see a shadow of the gap remaining, just go back over it with low grade sand paperand re-prime until it vanishes.

Hopefully this helps fill in your crazy seams! Enjoy!