Date: Thu, 3 Feb 2011 10:38:42 -0800
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: Bad plastic(s)
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ok..
all very nice.
and ..( sorry it got long )
how come the speedometer housing in a vanagon is made of such cheesy plastic
that I've probably never seen one that didn't have broken screw holes where
the speedo or tach/clock screw in ..
yet ...
the plastic instrument cover plastic ........
basically indestructible. I don't think I've ever seen a bad one.
and something I always admired about old fashioned desk type land line
phones ..
either the rotary dial kind or the later kind with buttons for numbers and
letters ..
best plastic in the world !
You could hammer nails I swear, with a hand piece from one of those phones,
or drop one 5 stories probably and they would never ever break.
Now that was great plastic !
Some steering wheels used to be that good too. Like on an old mercedes or
citroen.
and VW sure did under-engineer a lot of plastic parts in vanagons all right.
And sun just eats things.
I don't even keep the front grills on my project vans, especially in summer.
and we have to appreciate the 'sacrificial chrome bumper Plastic End Caps
..
The way those things almost jump off there if you hit anything with them ..
is kinda nice almost. Not hard to patch back on either until the next
event.
Pretty clever VW.
I've gotten some poorly made aftermarket ones lately that just will not
fit.
Shame that we can't count on a part really fitting ..
and when one supplier's parts don't cut it, we have to try another supplier
in hopes of still being able to get a decent part.
That's how it's become lately ..it's not 'do you have it? "
it's 'how good is the part you supply ?" .
and when things are made 10 % below extreme minimum standard of
acceptability.
that's worse than not being able to get the part or tool or whatever. I
just can not fathom how people can manufacture stuff that does not even
work, fit, or last. I can not fathom the arrogance needed to market things
made so poorly they're junk even when brand new out of the box. Please
boycott all cheap junk. What is the point ? Wasting people's time and
the earth's resources ? That's what it amounts to on ultra cheap stuff
often.
Got a 'wrong part' recently ..for a friend's Plymouth Voyager van ..
got like a oddball head light when I ordered a front turn signal lens. The
company credited my card back..but said don't return the part. Cost me 20,
probably cost them $ 4 ...so I just landfill it ? 'tis a joke, a sad
wasteful joke.
Vanagons Rock !
just be very careful with some plastic parts on them.
Scott
turbovans
----- Original Message -----
From: "David Beierl" <dbeierl@ATTGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, February 03, 2011 9:39 AM
Subject: Re: Bad plastic(s)
> At 11:13 AM 2/3/2011, Mark L. Hineline wrote:
>>I'm inclined to go with Karl's idea that the heat makes it worse. But
>
> Heat makes most things worse. A rule of thumb I remember is that
> around room temperature, every 10C rise in temperature will double
> the speed of a reaction.
>
> All non-rigid plastics contain "plasticizers," some of the more
> flexible ones like vinyl upholstery a third of their weight. It
> slowly evaporates - that's the nasty film that magically appears on
> the inside of your windshield and the plastic slowly gets less and
> less flexible and also smaller and smaller. That's what leads to the
> linear shrinkage of the plastic furniture trim in Westys.* High
> ambient temps increase the evaporation rate. I'm sure this is a
> major cause of embrittlement leading to failures at stress concentrations.
>
> *In '82 I bought (in the face of all common sense) a '78 Plymouth
> Horizon. From a Plymouth dealer in New England, though I don't know
> where it had been before. All of the plastic door trim had shrunk
> several inches in length, and the steering wheel had shrunk to the
> extent of a 1/4 wide crack at the exact bottom, exposing the steel
> core. I'll spare you the rest of my Horizon rant.
>
> VW has used a lot of ABS plastic (acrylic-butadiene-styrene) which
> has excellent impact resistance but is rated poor for UV resistance -
> so it's not terribly surprising that grilles and such on the outside
> where they're exposed to UV are getting brittle. However it has good
> ozone resistance. The Japanese mfrs seem to have gone heavily in the
> direction of softer plastics containing I'm pretty sure some amount
> of polyethylene (polythene in UK) which seems to have held up much
> better. Likewise their engineering resins for mechanical parts like
> steering column stalks contain some ingredient that adhesives don't
> like to stick to, and have proven very durable.
>
> That being said, those door handles you mention are of a related
> polyethylene-containing compound, and the ones in Millee's Sally - a
> New Mexico van - look awful. They work fine but they're obtrusively
> scratched up. I've never seen a Toyota from New Mexico.
>
> Their mechanical designers have been behind the curve IMO in
> designing mounting tabs and mounting surfaces to minimize mechanical
> stress, which is something that any plastic hates. *Most* mechanical
> engineers took a long time,* i.e. this was still a noticeable problem
> for example in small electronics up into the '90s, in developing
> fasteners and specifying post dimensions that would not lead to
> splitting of mounting posts in ABS/styrene and similar plastics. A
> split post can usually be laid to the mechanical engineer.
>
> *I once read a long and fascinating article in Plastics yearbook,
> saying in detail that it was long past time that engineers stopped
> treating plastic like metal and started actually learning about
> it. That would have been mid '80s I think.
>
> Many people do not realize that you only get to cut a thread in
> plastic once. You *may* get away with doing it a second time, but
> the third time you will probably lose. Usually this means the thread
> will strip out, but if the plastic has become brittle (and depending
> on the fastener) a post might split. It's very important to reinsert
> screws into the same thread that was originally cut, by reversing
> rotation until the screw drops into the thread and by being very
> conscious of any additional effort over what was required to remove
> the screw, and backing out and restarting if it's
> encountered. Sometimes it's too late, the original thread can't be
> found and you just have to keep going gently and pray.
>
> Likewise it's a great temptation to overtighten fasteners on mounting
> tabs for the instrument panel, heater box and such.
>
> And as Ben points out, kicking the stuff rarely helps it.
>
> That being said, I've simultaneously owned Vanagons (total 3) and
> Toyotas (total 4 Corollas, 1 Camry and 1 H***da Accord) covering the
> same ages, and except for the vinyl dash pad the Toyotas simply do
> not have the inside plastic issues that the Vanagons do, nor do the
> outside fittings lose finish and become brittle the same way. Again,
> this is in New England, a fairly benign climate for plastics.* OTOH
> the Corollas all had/have sealed front running lights with a little
> rubber vent hose, and every one of those little hoses from '84 to '95
> has rapidly perished. Every maker has their blind spots. In the
> case of the '98 Accord that would be their million-dollar
> electronically controlled transmission that nobody outside Japan (and
> maybe in, for all I know) can fix. Shudder.
>
> *The '84 Vanagon was in Scotland until '92. Miserable climate for
> rust, but not bad for plastic, I think. Interestingly the rubber
> connector boots had perished by '92 much more than I expected and
> much more than my '89's have up to the present.
>
> Yours,
> David
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