soft or weak styrene in kits

[62rebel]

those of us with some years behind us remember the MPC styrene from the 70's... soft, to the point where you couldn't easily sand the stuff! it would also "peel" away from cut areas, where you'd remove parts from the sprue... i almost never modified an MPC kit because of that.

so what, you may ask, since MPC isn't around any more?

because, in my building of my latest trade, a Model King reissue '79 F350, i've encountered styrene almost of that composition! the last time i built a regular issue F350 (out of a Destroyer kit), the styrene was rigid and tough (and RED) and i've already cracked a piece of my "new" one (aaaargh) .....

i noticed when i popped together a Polar Lights snap kit (it still needed gluing in several areas) that the styrene (possibly ABS?) was tough and "plasticky"... almost like polyethylene like toy soldiers.

is there a switch being made in the formula for some reason? bad batches, possibly?

[Marc @ MPC Motorsports]

I have built and restored many a vintage MPC kit and don't recall styrene of that type. Now, the grey styrene that AMT was using back in the 1990's and 2000's is another story.

[Evil Appetite]

I picked up 12 Lindberg SuperBee kits at a liquidation warehouse last year and noticed that they seem to be made of what seems to be really brittle plastic. I have one that I bought upon release that doesn't feel that way. Of all the kits I've bought over the years that's the only kit i can recall ever having that kind of plastic.

As for MPC kits I built many back in the early 80's, i dont recall having that issue..but..recently I built the 67 Streaker Vette and oddly enough some of the pieces were the way you described. The body was fine...but some of the other parts had that kind of consistency.

[MikeMc]

Sounds like they have gotten brittle due to age and heat.....GO SLOW!!

[62rebel]

makes me fell kinda like Jim Phelps.... your mission, should you choose to accept it, is to finish this kit without breaking more than 25% of the parts. as always, the secretary disavows any knowledge...

mission accepted! now; if my freaking COLD would let me do more than one simple task before either sneezing my rump off or having to drain Lake Mead into a hankie.... woof.

[Art Anderson]

I once had the experience of having the body of an original MPC Gurney Eagle Indy Car kit actually delaminate, while removing masking tape from the paintjob (was building Jerry Grant's '69 Bardahl Eagle, which was painted a black and white checkerboard pattern all over the body shell.

As for the softer polystyrene blends used today--those are as much a function of modern-era model car kits than anything else--thinner section body shells, with a lot of "tumblehome" in the sides of the bodies (meaning the body shells of the cars modeled in kit form had lots more curve to them than the relatively slabsided bodies of the 50's though mid-60's, meaning that the model kit body shell has to be able to flex outward, in order to come off the inside core mold (which makes the inner surfaces of the body shell. Try that with the much harder styrene blends used in the early days of model car kit production, a body shell like I described would merely split and break apart. So, the factories producing model car kit bodies have tended to use the softer blends of polystyrene.

Art

[RickRollerLT1]

Funny. My Lindberger '40 Ford I built last year from the L-700 w/trailer set was like that too, but it was REALLY thin and molded in almost transparent white plastic.

I also had that happen with teh resto-rods '69 chevelle, and that was bought from an LHS.

[paul alflen]

WHEN THE MOLDING IS DONE IN CHINA ,WHAT DO YOU EXPECT? IF THEY RUN OUT OF STYRENE DO THEY SUBSTITUTE A CHEAPER PLASTIC?

[Abell82]

The softer plastic and axles through the engine blocks are why I never got into AMT kits.

[Chuck Most]

I've noticed the plastic coming off in layers on a few kits- worst one for me was the Lindberg Dodge L-700 reissue from a few years back, but I've had it happen on EVERY manufacturer's kit at one time or another.

[Darren B]

Now that its mentioned I do recall seeing that on a few kits I built in the past but mostly to revell/monogram kits, where parts of it (just the body) would flake up in layers around the edges of the body mostly front end or rear end or both.

Edited December 28, 2011 by Darren B

[Agent G]

Dragon Models Limited (China) has some of the best styrene going as far as armor is concerned. It is a joy to work with.

I recall a Polar Lights '04 GTO kit that was molded in black. I used the interior and engine in another car, and it was like sanding vinyl.

It responded well to liquid cement, but man I'm glad I didn't have any body work.

G