Making MA&PA 27

[peteski]

Squadron shrinks over time, getting worse as time goes on. The Testors stuff seems to dry/evaporate very quickly, which I am guessing is when the shrinking will happen. Once the styrene cement is evaporated, only the styrene in it is left behind. So it does shrink at first, sure, but not months, years down the road like Squadron.

I actually used ot make my own filler by dissolving styrene in styrene cement, but having it pre-made in a tube is much more convienient.

The shrinkage percentage is closely related to the thickness of the application.  The thinner layers of putty will shring less and the solvent will evaporate quickly.  If applied in thicker layers, some of the solvent will get trapped  under the dried top "crust" and will take long time to evaporate through that "crust"  When using solvent-based putty  it is important the apply it in multiple thin layers, with wait time between layers.  Sure, it is possible that Testors used less solvent than Squadron (the putty might be thicker) and also the solvent mught be more volatile (evaporates quickly).

But the best (and repeatable) results are achieved when using the 2-part putties which harden by chemical reaction and have no appreciably shrinkage.

Most people have CA glue in their adhesive's arsenal. CA hardens by chemical reaction., and like mentioned here, it works well as a non-shrinking putty (it can be filled with a powdered material to give it more body).  The cure can be speeded up by applying some accelerator (I use BSI brand). But make sure to sand the CA glue within few hours of cure.  CA is a type of acrylic which keeps on hardening (for about a day) after cure to a point where it becomes harder then styrene.  When that happens, it will be difficult to feather it properly.

[mmagliaro]

JB Weld epoxy works nicely as a filler.  It takes a long time to harden, but it is pretty easy to sand and file it, and once it cures, it doesn't shrink.

[peteski]

JB Weld epoxy works nicely as a filler.  It takes a long time to harden, but it is pretty easy to sand and file it, and once it cures, it doesn't shrink.

By the same token 5-minute epoxy should work just as well. Or even better, because the gray color epoxy gets much harder than the surrounding styrene. That will make it more difficult to feather in the puttied area. 5-minute epoxy is softer when set.

[Ed Kapuscinski]

Ok, so after all this discussion about body filler... I want to know if it's really going to matter.

I mean, I'm talking about filling in minor body gaps. Like, thinner than a knife blade gaps.

Am I really going to have to worry about Squadron Green shrinkage in those situations?

[DKS]

Am I really going to have to worry about Squadron Green shrinkage in those situations?

No. Carry on.

[Ed Kapuscinski]

No. Carry on.

Ok, cool, that's what I thought.

Sometimes, you guys... lol.

[mmagliaro]

For minor fill jobs like that, I agree, I wouldn't worry about shrinkage.  Although I might just stuff a sliver of .005" styrene into the gap with some liquid cement and sand it afterward instead of bothering with a filler.

As for the JB Weld being hard and using 5-minute epoxy instead... believe it or not, that is contrary to my experience.
JB Weld sands and files pretty easily.  It isn't "hard as a rock" when it sets, like the reputation implies, but it's dry and rigid.
The 5-minute epoxies in my experience tend to remain more "rubbery" after they cure, which makes them a pain
to sand or file (if you've every tried sanding rubber, you know what I mean).

There are even times when I prefer a 5-minute or 15-minute 2-part epoxy to JB because they remain more flexible, and depending on the application, that makes their bond hold up better.

[davefoxx]

Sometimes, you guys... lol.