Curious...

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Yes, they will absorb to their saturation level...but most drink containers for carbonated drinks are either thicker or (most common) uses a multilayer construction, sandwiching something like EVOH and a polyamide. I believe the plastic beer bottles use up to 7 layers (maybe more now) of PA-EVOH-PA-EVOH-PA, etc...as for an actual vapor barrier coating, I'm not sure what is used for that, as industrial and food packaging are not my area of expertise.

Just making the bottles thinner (from what I understand) was challenging enough. Thin cross sections are prone to pinholes and uneven strain sections. I would think that the material manufacturers had to really tweak the resin formulation as well as advancements in blow molding technology were used to allow the PET bottles to be as thin as they are now.

PVC is polymerized with water. It doesn't usually absorb, and is used for waterproofing things, as well as for water and drain pipes. Other things can cause it to swell, such as pool chemicals (the reason why chemical balancing of a pool is different based on if it uses a liner or not) or if it is not UV stable. Higher temperatures can also cause problems for softer grades. Of course once again, PVC is not my forte' so to speak, as very little of it is used in medical devices.
Wikipedia has some good info on PVC http://en.wikipedia.org/wiki/Polyvinyl_chloride

Pretty impervious to most things. Even used for underground gasoline storage.

In general polypro and polyethylene have specific gravities of <1 (water is 1),

Styrene will absorb moisture to it's saturation point. It won't "drip through", but it will absorb too much from ambient air to process without drying.

Absorbed moisture needs to be driven out. Most engineering resins specify a -40°c/f (the scales intersect at this point) in a desiccant type system at a specific temperature. The air flow needs to go through the pellets and be fairly well distributed, and the elevated temp drives the moisture from the resin, and then the desiccant absorbs it. Compressed air systems are used more frequently today as well, as the capital investment is much less (no moving parts, no regeneration or changing of desiccant). There are some processors that use a hopper heater for surface moisture on pellets, as well as to generate higher outputs.

I don't think that the absorption rate would apply directly to oil itself, too many other factors involved. The thing about oil losing moisture or evaporation is that the oil system in a vehicle is pretty much a closed system (except for some pollution controls), so I would have to believe there is a good chance most evaporation would be re-absorbed.

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On 07/04/2010 04:49 PM, Tegger wrote:

they most definitely can mix. there are many examples, but a simple illustration is water and chloroform. they "don't mix", but actually they do for binaries in small percentages, and in the presence of a ternary, in this case acetic acid, they do in large percentages:
<
http://www.standnes.no/chemix/images/scrshpic/acetic-acid-water-chloroform.gif
there are loads of other examples. motor oil is far from being a simple isomeric hydrocarbon.
--
nomina rutrum rutrum

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Stewart wrote:

Yes and that in and of itself should make anyone suspicious of the methods used to acquire the data.
    There is an obvious bias in the way the measurements were made. The miles/qt is almost always around 400 miles less for the measurements labeled 1st than for the measurements labeled 2nd. There is not enough info to determine exactly what the source of that bias is. All that can be said is it is extremely unlikely that an honest and accurate accounting of how much oil this engine consumes would show that the oil is being consumed at a slower rate the longer it stays in the crankcase.
-jim     
    

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wrote:

Always checked at ambient temperature, and always checked with the car sitting in the exact same spot, facing the exact same way.

The /calibration/ of the dipstick isn't important. What IS important is that I use the same dipstick, inserted the same way, each time.
--
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On 07/01/2010 06:39 AM, Tegger wrote:

which is always wrong

facing the same way? is oil geomagnetic? or is the vehicle not on level ground?

it's much more important to read the owners manual.
--
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jim beam wrote: oil expands when it

Except that in the real world it makes no significant difference in terms of accuracy. It takes hours for oil that is in the bearings, oil passages to the bearings and head and other crankcase locations to drain back to the pan. That means that in many engines you get the exact same reading when you check the oil a couple of minutes after hot engine shut down as you do when it sat over night.
    Anybody with a brain and sufficient curiosity will easily determine on their own how this works. If you check the oil every 30 seconds after a hot shut for a period of hour (about 120 dipstick checks) you will be convinced that the reading is constantly changing.
-jim
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On 6/30/2010 9:05 AM jim beam spake these words of knowledge:

RFT!!! Dave Kelsen
--
"They don't hardly make 'em like him any more - but just to be on the
safe side, he should be castrated anyway." -- Hunter S. Thompson
  Click to see the full signature.
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Well, if it evaporates, I didn't notice it. Of course, it was synthetic but I went 8k miles over about 5-6 months and added none, and I could not discern any movement on my dipstick (maybe a mm or so?).
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It doesn't.
--
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On 06/30/2010 01:20 PM, Tegger wrote:

you missed chemistry in high school.
--
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On 06/28/2010 04:49 AM, Tegger wrote:

nobody saying anything that you want to acknowledge...
--
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I'm glad to see that I am not alone in hating those Web forums.
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If they had proper threading and default quoting, they'd at least be bearable in spite of all the glitzy, busy graphics.
--
Tegger

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On 07/02/2010 09:06 AM, Tegger wrote:

so set up your own. use slashcode. it's free and it's full threaded.
--
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I'm not seeing any new messages either, by the way.
--
Tegger

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On 6/28/2010 6:50 AM Tegger spake these words of knowledge:

Thanks, Tegger. Us old usenet guys are dying out...
RFT!!! Dave Kelsen
--
"A man's ethical behavior should be based effectually on sympathy,
education, and social ties; no religious basis is necessary. Man would
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On Mon, 28 Jun 2010 06:03:16 -0500, Dave Kelsen

I'm still watching.
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I'm here.
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I have not noticed signs of posts not appearing. I still read here just about daily. Right now I am planning the first timing belt change on my new-used 2003 Civic LX. I have my homemade tool for the pulley bolt figured out. It is a little different from what is at Tegger's site, because it seems there are clearance issues with the newer, say 2001-2005 Hondas for the pulley tools. See http://sites.google.com/site/hondalioness/hexhomemadepulleytool
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Elle ( snipped-for-privacy@gmail.com) writes:

Before you remove the old belt, mark a tooth on the cam cog and a tooth on the crank cog (permanent marker) and count the teeth on the belt between the marks. Write the number down and then count the teeth again! Write the number down, and count the teeth again for a third time! Mark the belt (yellow crayon?) at the cog teeth. Remove belt, compare it to the new belt. Count the teeth out on the new belt (3 times!), and mark with crayon(?). You want it right! People who build engines double check every thing. People who build racing engines triple check. If this is your first timing belt, triple check it or more. You want it 100% right.
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