Poor quality styrene deterioration

[oldscool]

 Am I the only one wondering if the kits we buy today will disintegrate in a few years due to the poor quality plastic that is used these days?  Kind of like the diecast models made from contaminated metal.

[Rocking Rodney Rat]

Plastic is forever. Our kits will outlive us. -RRR

[Ace-Garageguy]

I wouldn't be surprised.

Anyone who's bought plastic consumer or industrial goods in the last few decades (EDIT: and who's been kinda paying attention) has surely seen deterioration to the point of brittleness, breakage, or crumbling...even when said goods have been stored in their original packaging away from light and heat.

While plastic exposed to high temperatures (like under a car's hood) or prolonged and frequent UV (like car interior parts) can be expected to become brittle or crack, items that have never been used should reasonably be expected to remain as-new indefinitely. Unfortunately this is not always the case these days.

Early plastics based on cellulose ("acetate") are notorious for shrinking, warping, or turning to dust, but they were largely abandoned by the early '60s in favor of much more stable petroleum-based materials.

There are some 60+ year old kits that are getting brittle now, but it's not a universal problem.

(I like your "solitude" quote, too.)

Edited May 1, 2021 by Ace-Garageguy

[oldscool]

I've noticed the same thing Bill. Especially with plastic lawn chairs. They used to last for years but now after 2 yrs they break and become useless as well as turn chalky and rub off on my clothing.

With the Chinese using recycled styrene who knows? Will current kits still be buildable after 60 yrs like the old stuff. Of course, most of us on this forum won't be around to find out.

I like your quotes as well.

Edited May 1, 2021 by oldscool

[Ace-Garageguy]

There are also widespread problems with 3D-printed parts deteriorating in a variety of ways, from warping to developing surface stickiness.

There's a whole lotta stuff getting made everywhere with no long-term testing having been done, or the thought that it might be nice to sell stuff that will last a while even occurring to the dwerps.

There were, of course, problems with some resin parts in the past too, when idiots either couldn't read the mixing instructions or just didn't think careful handling and following correct procedures was important.

Human nature doesn't really change much over time.

Edited May 1, 2021 by Ace-Garageguy

[Tom Geiger]

I posted this yesterday in another thread. A 3D printed part I got in 2005. Retrieved it from my display case and it’s turned white (it was milky clear like on the base) and is sticky.

[Fabrux]

Plastic deterioration isn't limited to new kits. How many of you have had MPC kits shatter?

[slusher]

I always wonder why/how some older kits mail bodies was brittle. I always believed it may have been heat. When buying old kits on eBay you have no idea how it was stored...

[ranma]

I know Revell had some kits that were brittle from the start back in the 1980's . One was the '57 Nomad (1/25 ) and a chevy pickup kit . Both were molded in a bronze color. A friend of mine when we were in high school gave me a Revell '57 nomad kit he had got for a gift. He did build model's anymore, and knew I did plus that I liked '57 Chevrolet's. Kit was opened but the parts were factory sealed.  Any time I tried to remove a part from the sprue it would shatter like thin glass.

[CapSat 6]

I have noticed that some older Jo Han kits are like that. I have gotten a few as built ups. I don’t have a lot of these as they are always pricy. I do take some apart to restore, but it seems that the ‘70 Road Runner that I once had (I sold that one off) and a ‘64 Plymouth Sport Fury (molded in red, with the side trim and stock interior pieces) were very, very brittle. The old AMT and MPC builts I have from the same era do not seem to have this problem. 

[Snake45]

45 minutes ago, Fabrux said:

Plastic deterioration isn't limited to new kits. How many of you have had MPC kits shatter?

Never with MPC. Only thing I've ever had shatter was a Monogram '70 Chevelle molded in dark blue metallic. 

[peteski]

There are many types of plastic resins.  Yes, it is all "resin" (not just the Polyurethane resin models cast by small cottage industry which  we call "resin" while calling the mass-produced kits "plastic" or "styrene").  In my experience Polystyrene (resin) is quite stable, while others (including 3D resins) might not be as stable.  If there are no UV blockers added then prolonged exposure to sunlight will make any plastic resin surface deteriorate. 

The cheap lawn chairs (those are *NOT* made from Polystyrene but other resins - check the recycling symbol) probably do not have any UV blockers added, so they get "chalky" sitting outside.  But our Polystyrene or ABS model kits will likely all outlast us.  Most are also painted, and that also provides some amount of UV blocking.

I think we have nothing to worry about when it comes to the Polystyrene (or ABS) models.

Edited May 1, 2021 by peteski

[keyser]

It will outlive us all, brittle or not. 
https://en.m.wikipedia.org/wiki/Great_Pacific_garbage_patch

Smaller one in pic

 

And Family Guy reference. https://m.facebook.com/FamilyGuy/videos/403647657138652/

Edited May 1, 2021 by keyser
Stewie

[PierreR89]

2 hours ago, Fabrux said:

Plastic deterioration isn't limited to new kits. How many of you have had MPC kits shatter?

Not MPC yet.
But i had a AMT Bandag Bandit made sometime in the 70's and i accidently dropped one framerail when i was trying to unwarp it and it shattered in several pieces.
Many Airfix kits to that were very brittle and if not being carefull the parts would break on the sprue when another was being removed.
Some small 1/72 ICM kits were so brittle that i just never used some parts because they would break.
They have gotten much better now with their modern kits then those that were from sometime in the 90's
 

[lordairgtar]

Resins do suffer from exposure to sunlight and heat. Ask anyone with a car from the 1980s The flexible panels like bumper covers and bumper fillers all get brittle and crack with age. My 80 Seville has that issue. Even the plastic that forms the part that holds the tail lights has cracked and also excretes a sticky syrupy ooze that feels sticky to the touch. I've purchase fiber glass replacements which will be installed when I can get them painted the car colors.

[Richard Bartrop]

5 hours ago, Ace-Garageguy said:

There are also widespread problems with 3D-printed parts deteriorating in a variety of ways, from warping to developing surface stickiness.

There's a whole lotta stuff getting made everywhere with no long-term testing having been done, or the thought that it might be nice to sell stuff that will last a while even occurring to the dwerps.

There were, of course, problems with some resin parts in the past too, when idiots either couldn't read the mixing instructions or just didn't think careful handling and following correct procedures was important.

Human nature doesn't really change much over time.

This is a very good point right here, and when you're going to spend what they want on 3D printed stuff, it would be nice if it lasted for a bit.

Evergreen stock also gets brittle with age, especially the thin stuff.  I have some that's been around, and the thin stuff definitely doesn't want to bend the way it used to.l

[oldscool]

I realize sunlight will deteriorate plastics and paint can protect them but what i really meant was will they deteriorate unbuilt still in the box. Didn't know that 3D printed stuff was doing that. So 3d printed guns maybe not a good idea.

[PierreR89]

19 minutes ago, lordairgtar said:

Resins do suffer from exposure to sunlight and heat. Ask anyone with a car from the 1980s The flexible panels like bumper covers and bumper fillers all get brittle and crack with age. My 80 Seville has that issue. Even the plastic that forms the part that holds the tail lights has cracked and also excretes a sticky syrupy ooze that feels sticky to the touch. I've purchase fiber glass replacements which will be installed when I can get them painted the car colors.

Same with plastic used in the enginebay of any vehicle old or modern.
You dont want to touch it because it will break and if you have to and not being able to work around it without disturbing the plastic part you better be prepared to have a replacement on hand or be very very very carefull.
EVAP lines, vaccuum lines, fuellines, electrical connectors and any other plastic part will break when you are just looking at it for to long when they have been in thousands of heatcycles.

[Fabrux]

4 hours ago, Snake45 said:

Never with MPC. Only thing I've ever had shatter was a Monogram '70 Chevelle molded in dark blue metallic. 

 

2 hours ago, PierreR89 said:

Not MPC yet.
 

The only kit I've ever had shatter on me was the MPC Ridge Runner Bronco kit. 🤷🏻

[Claude Thibodeau]

Hi!

A friend who is in the plastic industry told me that most toys and household items made of plastic must have a high BPA (bisphenol?) content to remain supple or pliable. And this chemical is one of the most expensive component in the mix. Cheap products? Low BPA content. Brittle very early. 

He also indicated that the typical "new car smell" is, indeed, BPA vapors released in the early days after fabrication. Hence older cars not smelling "new" anymore: BPA already evaporated.

Finally, I made a Pro-Touring out of a rare Javelin promo a few years ago. It was made by Johan, in a teal colored "plastic". I broke the cowl while cutting the hood away, and I was NEVER EVER able to glue it back, with ANY glue or solvent, for that matter.

I figured it was some kind of acetate. Who knows?

CT 

[John1955]

When I worked in a plastics factory back in the 1980's, we made styrene model kits and parts. When I pulled out the styrene part from the mold, if it was plain white or light gray, no problems. If molded in a color, it was sometimes fragile. I concluded that certain kinds of color pigment must weaken the styrene. We did make the '57 Chevy Nomad (Revell) body there, molded in metallic bronze, many broke when removing them from the mold. It was a pain in the you know where. 

[Brian Austin]

Some model car styrene plastic recipes might include some clear pellets along with the colored ones.  Clear is more brittle than other colors.

 

On the other hand, I have some vac-formed brick sheets I bought 20 or so years ago that were formulated for UV resistance.  I found it rather rubbery and hard to cut in a straight line.