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I was getting tired of the old ones. It's really not all that bad. It just interrupted another one of my latest projects. This is a (I think) Revell 1979 Toyota Pickup 4x4 Snaptite. I picked up a month or so ago. It was a decent built-up I wanted to convert to a lowered truck. I got it apart without any issues. I was taking it to strip the paint when I dropped it from waist high onto a linoleum floor. It shattered.ToyotaCalamity.jpg.88f3ebe952e99d946d8ddac1f300609d.jpg

I've never seen that happen before. I didn't throw it, step on it or anything - just an honest drop, and the body was intact with no repairs or modifications beforehand. I've heard of models getting brittle with age, but I'd never seen it. At least it broke mostly cleanly, and I have all the parts. It should go back together pretty easily - the pieces fit back together solidly with no apparent alignment problems.

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I've had brittle plastic from Revell before. I was trying to correct a slight twist in a kit that was made in the early 90s and a fairly gentle twist caused it to shatter about like what you've got there. My body was bare plastic so it wasn't a paint reaction that weakened it.

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You should see the interior that I tried to get out of an '88 Beretta. It was molded in black and just snapped in. When I pushed it forward to get the rear tab loose, the thing exploded in my hand! It busted the front of the tub, the dash, steering wheel and a bucket seat. I believe it's something to do with molded in color styrene. I've worked with much older white styrene and it's not nearly as brittle. 

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3 hours ago, Plowboy said:

You should see the interior that I tried to get out of an '88 Beretta. It was molded in black and just snapped in. When I pushed it forward to get the rear tab loose, the thing exploded in my hand! It busted the front of the tub, the dash, steering wheel and a bucket seat. I believe it's something to do with molded in color styrene. I've worked with much older white styrene and it's not nearly as brittle. 

You might be on to something with the colored plastic, the body that exploded on me was like a metallic black cherry color.

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RE Repairing fractured bodies and large Broken Model Parts . When all of the Putty / sanding / leveling / primer work is done I suggest these two steps prior to paint . Primer Sealer on all visible outside surfaces . Reinforcement under the repair areas . I used a Foil used to insulate home repair seams . Looks like Chrome Tape ot aluminum foil . Flexible on a Roll at all hardware outlets . It will flex while limiting the "Plasticity" as not to rupture re the repair or crack filler in my experience .  Thanx .. 

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I mustered all the King's horses, and all the King's men, and put it together again. It doesn't look too bad; everything lined up pretty good. Now to try to get it stripped without any more problems. Then, AllTheKingsHorses.jpg.5d98d4be7fd1826be301606553770412.jpg

a  bit of putty here and there, and voila! You can see some of the cracks in the fender. I also notice that the front splash pan is missing the bottom bar. So now, I need to come up with a name for it. Humpty Dumpty or Shattered Dreams come to mind.

I'm surprised how much this happens. I've been involved with models for about 50 years, and I had no idea this could happen until fairly recently. Thanks to those who shared their own disasters. 

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Some of the worst plastic I have seen is the root beer brown that one issue of the Revell 56 F100 was molded in.  I have one and the cab broke apart in the box between the time I purchased the kit and when I decided to start to work on it.

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      There are lots of factors at play here:

* The original grade of the plastic. Economics and availability drive decisions of what grade (and therefore how brittle or soft) the styrene or ABS is. JoHan famously molded kits out of whatever they could get in the 80's (I always ended up with dark green or pale orange).

* The color does matter. Some colorants need to run at a higher percentage than other to properly color the finished part. Some colorants require a specific grade of styrene or ABS to be mixed with. Metallic has additional effects. I work in the medical device industry and I have seen very significant changes to the properties of ABS with very slight colorant changes. I would say blue based colors are the worst

* Styrene and ABS age. My company has retain devices stored in ideal conditions (cool dry vault) that are a couple decades old. The properties of these old parts are not the same as freshly molded ones.

* Don't forget UV damage. Styrene and ABS are very susceptible to UV damage. Stabilizing additives can reduce the susceptibility but can not eliminate it. Most of us have seen late 50's / early 60's models that are almost tan from the UV damage.

      Having said all that I love restoring / rebuilding old kits. Brittle plastic is just another challenge like welded on fender skirts and missing glass.

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I have been reading this post with some interest. I haven't experienced any of these problems until a couple of days ago.  I needed a high performance  looking small block for my current  build. I have a few older Revell '69 Camaro Z-28 kits and I'm using the engine from one of those kits. The one I robbed the engine out of happened to be done in blue plastic. The instruction sheet is dated 1990 and that is the only reference I can find to determine how old the kit really is. What I noticed as I was removing different parts from the parts trees was just how brittle the plastic was.  This was especially true when I was removing the carbs. and valve covers from the chrome tree. I don't recall this ever happening to me before on a regular white plastic kit. I wonder if this has to do with the quality of the plastics used at that time, the use of chemicals to color the plastic blue, or what ??  I have redone some older models that date back over thirty years and no such issues. 

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It is a known fact that Polystyrene plastic degenerates with age and it is not only model kits that suffer. Naturally the chemical consistency of the plastic will determine how long it would take before any signs of deterioration take place.

I pulled our Vax carpet cleaning machine out from a dark cupboard where it had sat for at least 7 or 8  years or so unused. The main moulding on the lower part of the machine almost fell apart when I lifted it up where it had gone brittle and cracked up.

It is no small wonder that auction houses and the like tend to shun most models made from plastic kits. The only exception I can think of may be very well made classic Pochers. I am not sure about the durability of models made from resin however, and I guess that time will tell with these.

I have also heard some horror stories about the metal in some but not all collectable and cheap die cast models deteriorating.

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