Author Topic: Ever Seen THIS happen???  (Read 835 times)

Offline Chas

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Ever Seen THIS happen???
« on: June 19, 2017, 02:17:31 PM »
I'm in the process of detailing a "new to me" 1976 CDV. It's low mileage (20,000) and been garaged it's whole life. Here's the situation I've encountered: Some of the plastic interior pieces have become so brittle they actually crumble when you touch them. Specifically, I'm talking about the lower left kick panel, the left and right shoulder belt guides on the top of the front seats, the "box" around the front seat armrest, and the two shoulder belt retractors covers on the roof. They were originally factory dyed a tan color. Now, they have completely outgassed and turned white. Touch them and they crack and crumble into dust.

I know the car spent it's life inside......original paint is gorgeous, original half roof is spotless, chrome flawless, seats, dash and door panels are as supple as new, perfect steering wheel. I've resigned myself to the fact that I have to find replacement plastic pieces. But what caused this? Has anyone else ever seen this phenomenon? Was it a bad batch of factory plastic? Wrong type of plastic for the application? As stated, nothing I can do about it, but want to understand why?
1967 Coupe DeVille
1970 Coupe DeVille
1976 Coupe Deville
1983 Coupe DeVille
1964 Buick Electra 225 Sport Coupe
1963 Chevy Impala 502ci Big Block
1977 Harley Cafe Racer
1991 Harley Fat Boy
1957 Harley Hardtail

If you're 25 years old and not a liberal, you have no heart. If you're 45 years old and not a conservative, you have no money!

Offline TJ Hopland

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Re: Ever Seen THIS happen???
« Reply #1 on: June 20, 2017, 08:08:16 AM »
I would guess it was just the type of plastics used in the 70's cars.     I too have seen what you describe.   You would expect it on a typical car that spent time outside because you would see a cracked dash and other signs it was in the sun a lot.    On my 73 its the horn pad and headrests that are a completely different color.   They were like that when I bought the car 20+ years ago now.   I don't think they have got any worse so what ever causes it must have mostly happened in the 10-20 year range. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline "Cadillac Kid" Greg Surfas 15364

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Re: Ever Seen THIS happen???
« Reply #2 on: June 20, 2017, 09:30:47 AM »
Chas,
Unless your particular car had interior plastic material that differed from the norm it must have been exposed to either temperature extremes or perhaps someone used something in an effort to clean or polish them that caused the reaction. Both my 75 which was garage kept and my 76 which was an outdoor car retain the color f all the plastic interior pieces.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline James Landi

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Re: Ever Seen THIS happen???
« Reply #3 on: June 20, 2017, 09:50:47 AM »

Now, you're not dealing with mileage, you're dealing with age.  The good news is that, aside from the nylon gear covering on your timing gear, nothing that you describe is integral to the good functioning of your beautiful car.  In discussions with master mechanics about much newer cars, major functions are related to numerous computer systems, that like the plastics in your car simply deteriorate and stop functioning because of age deterioration.  In the final analysis, most cars were not engineered to provide a human "lifetime" of durability and reliable performance.  I would surmise, however, that cars from the past are much less prone to age related failures.    Happy day,  James

Offline TMoore - NTCLC

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Re: Ever Seen THIS happen???
« Reply #4 on: June 20, 2017, 10:18:55 AM »
I am seeing something similar in my 1979 Sevilles.  The one with the red interior, the litter basket on the passenger kick panel - top trim has turned to dust - every time I vacuum, a little more trim disappears, and I am down to the carpet edge now.  The one with the blue interior is starting to do the same, but not as bad.  The one with the black interior is still pretty much intact.

I think it is just the composition of the plastic, and I suspect it will get worse with age.  Just like the bake-lite pieces in the older cars, these plastic pieces will be weak links in the years to come.

Offline TJ Hopland

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Re: Ever Seen THIS happen???
« Reply #5 on: June 20, 2017, 12:07:16 PM »
Chas, do you know where your car spent most of its life?    Maybe temp has something to do with it.    Mine spent its first 20 years in Texas so it seems fairly likely that it was in a hot garage. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline Chas

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Re: Ever Seen THIS happen???
« Reply #6 on: June 20, 2017, 12:58:25 PM »
TJ.......vast majority of its life was spent in Louisville, KY. Last 5 years resided in climate controlled splendor in San Antonio, Tejas. Greg.....never thought about the possible cleaner/solvent causation. However, one would expect that prior owners would have cleaned ALL the interior plastic, and as stated, only certain pieces are deteriorating. I should have completed my degree in chemical engineering, and not mechanical...LOL!!!"........What was that famous line in "The Graduate"? "The future, my son, is PLASTICS"!
1967 Coupe DeVille
1970 Coupe DeVille
1976 Coupe Deville
1983 Coupe DeVille
1964 Buick Electra 225 Sport Coupe
1963 Chevy Impala 502ci Big Block
1977 Harley Cafe Racer
1991 Harley Fat Boy
1957 Harley Hardtail

If you're 25 years old and not a liberal, you have no heart. If you're 45 years old and not a conservative, you have no money!

Offline m-mman

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Re: Ever Seen THIS happen???
« Reply #7 on: June 20, 2017, 04:38:06 PM »
Another not often mentioned situation related to plastics is - disposal and recycling.
Plastics are notoriously hard to dispose of.  When placed in a land fill they traditionally do not break down, they have stayed intact for many years.

As part of the process of 'becoming green' automakers (and other industries - notably bottled drinks) have been using and have been forced to use plastic formulations that are designed to self destruct. They are engineered from the date of manufacture to begin decomposing. A disintegration that cannot be stopped with hermetically sealing or other protections.

Self destructing plastics are good for the environment and good for the industry as they make old cars look older, and new cars easier to sell.  8)
1929 341B Town Sedan
1971 Miller-Meteor Lifeliner ambulance
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Near Los Angeles, California

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Offline fishnjim

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Re: Ever Seen THIS happen???
« Reply #8 on: June 21, 2017, 02:15:14 PM »
Good luck finding intact, 40+ year old NOS '70s plastic in good condition.
Plastic parts oxidize just like anything else and can be attacked/aged by UV, humidity, heat, cleaners, etc.  The processing additives and their "breakdown products" can be forced out from repeated heat cycles, so who knows what's left now*.   It gets ~140F inside in the sun and some of these plastics melt above 180, so I'd not be surprised.   The cast pieces usually last better because they don't have to add stuff for extrusion/RIM.
Since only one kick panel is involved, I'd suspect some moisture involvement there from the vent.

There's many iterations of plastic used in the interiors, and they were experimenting a lot at that time, so it's difficult to say exactly what was used where year to year.   Could be anything from ABS to PVC and blends/laminates.  Then there's brand variations.   They make cars to be made, sell, and make money, not last forever.
Archie's LaSalle may have run great, but I bet parts of it didn't survive either.
* - would have to be analyzed.

Offline Bobby B

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Re: Ever Seen THIS happen???
« Reply #9 on: June 21, 2017, 10:38:50 PM »
Chas,
   1971-1973 Mustang Convertibles also suffer from this white flaking "chalk-like" surface on the plastics. Most notably on the upper door panels, armrests, and rear interior quarter window trims.  It renders the panels useless because it leaves no grain and nothing to adhere to. I have also seen it on '69-'72 Chevelles and GTO's. It very well might have something to do with the plastics they might have been experimenting with at the transitional period of changing over from metal. It was that era..... :o
                                                                                                                       Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Offline Roger Zimmermann

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Re: Ever Seen THIS happen???
« Reply #10 on: June 22, 2017, 04:30:24 AM »
The 1980 Old Cutlass I bought new was put in storage in 1988 because I got a job with a company car. I did not sold the Olds because I had no idea how long I would have that job. Indeed, I had it till my early retirement in 2002. At that time, I put the Olds out of storage and I noticed that the hard plastic parts inside the vehicle began to suffer this illness. There was nothing to do against it: if the parts were rubbered too strongly, the plastic disappeared...
I let the parts that way till the car was finally sold in 2006.
1956 Sedan de Ville (sold)
1956 Eldorado Biarritz
1957 Eldorado Brougham
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Offline fishnjim

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Re: Ever Seen THIS happen???
« Reply #11 on: June 22, 2017, 08:37:25 AM »
There is a chalking mechanism, but I only know it well in PVC.   The TiO2(white inert powder/UV absorber) additive remains when the plastic breaks down leaving a white residue.   This is why it's difficult to get certain colors in exterior plastics, siding, etc.   They don't weather and fade/chalk badly.   I assume other plastics will follow similar and of course they've always used a lot of other inert powder fillers; calcium carbonate(limestone), fumed SiO2, etc. for cost and processing.
If you find good NOS trim in the box, undamaged, I'd be doing something to protect it like armorall or clear acrylic coatings*, keep it out of the sun as much as possible.   I'd also make a silicone mold of the part or digitize, so it can be reproduced in the years hence.   They can 3D print these type parts today.
As far as restoration, I don't think you'll be able to restore flexibility, but you can clean off/sand the surface, fill/repair(w/ epoxy), and paint.   That will slow down any further degradation.   Some of the plastic trim parts were painted from the factory because the base plastic was not tintable to match.  Use a paint for plastic and there's paint codes for interior colors same as exterior.
Just so happens, I was in graduate engineering school in '76 and spent 30 years in PVC additives, so I'm familiar of the plastics industry practices since that time but retired 8+ years now.
* - we sold an acrylic top coat for PVC extrusions, so I know acrylics will work for protection.

Offline bcroe

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Ever Seen THIS happen???
« Reply #12 on: June 22, 2017, 08:50:42 AM »
Quote from: m-mman
Self destructing plastics are good for the environment and good for the industry as they make old cars look older, and new cars easier to sell.  8)       

Thats true.  I have come to the point of just ignoring the interior plastic in my cars. 
External I might replace with painted metal or fiberglass.  And the cars with plastic
engine parts will be gone while todays old cars are still running.  Bruce Roe

Offline dochawk

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Re: Ever Seen THIS happen???
« Reply #13 on: July 01, 2017, 04:29:56 PM »
When I went to put the hard boot on my `72 convertible, the entire panel it fastens to crumbled when I turned the latch piece.

I assume that I'll be learning a bit of woodworking and replace these panels and other parts with bloodwood . . . unless someone scans them and publishes for 3d printing . . .
hawk
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline bcroe

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Ever Seen THIS happen???
« Reply #14 on: July 01, 2017, 04:59:33 PM »
Quote from: dochawk
  When I went to put the hard boot on my `72 convertible,
the entire panel it fastens to crumbled when I turned the latch piece.

I assume that I'll be learning a bit of woodworking and replace these panels and other
parts with bloodwood . . . unless someone scans them and publishes for 3d printing . . .
hawk   

3D printing may be the answer for this limited market, when someone
gets serious about it.  I suppose the OEMs will try to interfere claiming
copyright infringement...     Bruce Roe

Offline dochawk

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Re: Ever Seen THIS happen???
« Reply #15 on: July 01, 2017, 05:32:27 PM »
We had visitors at my home-brew club from a coop shop facility a few months.  They have a shop with their own presses, lathes, 3d printers, and what have you. 

I'll probably join when I get to that point.

Dues are about $60/month!



hawk
1972 Eldorado convertible, 2001 Deville DHS (daughter), 1997 Eldorado ETC (and now my wife wants an Eldorado!)

Offline olds34dude

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Re: Ever Seen THIS happen???
« Reply #16 on: July 01, 2017, 09:22:09 PM »
I had a 30,000 mile 1967 442 that I sold in the late 90's, a beautiful car with a perfect original interior, right down to the original carpet. I lived in fear of having to do work behind the dash, I.e. change a bulb, as the plastics there were very brittle and likely to break with a light touch. ...and to think it was barely over 30 years old at the time! Another reason to like my 30's cars better! D Varney
D. Varney

Offline jsanford

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Re: Ever Seen THIS happen???
« Reply #17 on: July 02, 2017, 09:29:10 AM »
If the plastic is just oxidized (turning white) then using a heat gun is often effective. The shoulder belt guides on my Eldorado had turned white, heat gun made them look like new.

Jeremy
Jeremy
Sacramento, CA
1981 Eldorado
2016 ELR