Text 5302, 105 rader
Skriven 2005-01-22 10:54:45 av Roy Witt (1:10/22)
   Kommentar till text 5297 av Robert Bashe (2:2448/44)
Ärende: Tire inflation
======================
Hello Robert.

22 Jan 05 08:41, you wrote to me:

 RB> Roy Witt wrote to Robert Bashe on Friday January 21 2005 at 09:39:

 RB>>> That's why air compressors have traps and filters in the lines.
 RB>>> That kind of stuff doesn't get into tires, at least not in
 RB>>> appreciable amounts. Incidently, the main problem is compressor
 RB>>> oil, but that's removed in a trap.

 RW>> But not all air compressors are equipped with those. Mine for
 RW>> instance...

 RB> But you don't run a filling station.

Thank ghod! My dad had filling stations for most of my youth. Finally
figured out that being a mechanic made him more money with less hassle
with the brand affiliation rules. Texaco and DX. Texaco was very implicit
in what a station had to look like and how clean everything had to be. So
was DX, but they were more lenient in their enforcement.

 RB> If you did, you'd have commercial equipment and that always has an
 RB> oil and water trap. To be honest, I didn't even know you could buy a
 RB> compressor without such equipment, since compressed air straight from
 RB> the compressor is pretty filthy stuff - has to be, since the
 RB> compressor has to be oiled and some of the oil mist always gets into
 RB> the air.

I have two compressors. Neither of which has any of that equipment on it,
nor did they come with it. Anybody can go to WW Grainger, or Sears for
that matter, and buy an air compressor. All of those traps and dryers,
etc, are extra. Most home installations have the compressor and nothing
else.

 RW>> I use my water filter when I'm using my pneumatic equipment, when I
 RW>> put air in the tires of my Camaro, but it's not always in the line.
 RW>> I also use a water filter and a dryer when I'm painting with the air
 RW>> gun.

 RB> Your paint surfaces would look pretty cruddy if you didn't, since any
 RB> water in the air would condense when the pressure is removed and the
 RB> spray cools, giving blisters in the paint. Unless, of course, you're
 RB> using a water-borne paint. In that case, you'd probably have no
 RB> problems one way or another.

The only problems I've had aren't because of water in the spray gun. Just
airbourne dirt getting on the surface of the paint job. Easily taken care
of afterwards by color sanding. I do that anyway to get rid of the paint
buildup on taped areas.

 RB>>> Oh, and remember another thing: even if you want to put nitrogen
 RB>>> into a tire, you have to compress it...

 RW>> I would assume then, that the people who sell it for $5 a tire, will
 RW>> have all of the water filters and dryers in line with the nitrogen
 RW>> compressor.

 RB> I think that can be assumed.

 RW>>>> Have the scientist visit a tire shop and have the workers show
 RW>>>> them the insides of tires when they remove them from the wheel.

 RB>>> Curiously enough, I've done just that, in fact quite a number of
 RB>>> times over the years. I'm a scientist with papers to prove it, and
 RB>>> also have worked on cars enough to know what tires look like,
 RB>>> inside and out. The rubber dust you often see on the inside when a
 RB>>> tire is removed from the rim is just due to the abrasion caused by
 RB>>> the tire constantly flexing under load.

 RW>> And the rust?

 RB> On the bead, you mean? Water from outside, possibly also pulled
 RB> between the bead and the rim by capillary force.

Considering that the tire shops use a (soap and water) lubricant to mount
the tire, I'd say it's from the inside.

 RB>>> Remember that cold air contains less moisture than warm air.

 RW>> Not in California.

 RB> Always. The laws of physics apply even in California ;-)

 RW>> Yesterday, during the day with temps in the mid 70s, the humidity
 RW>> was in the 50-60% range. As the day waned, the humidity began to
 RW>> climb and was at dew point before midnite with the temps in the low
 RW>> 50s.

 RB> You just confirmed what I wrote. The amount of water in the air
 RB> didn't change from beginning to end, but when the temperature was
 RB> higher, the relative humidity was lower because the air would be able
 RB> to hold more water.

But you said that warm air held more water than cold air.

 RB> When the temperature dropped, the air could contain less water and
 RB> reached its dew point at some lower temperature.

Just the opposite. The cooler the air became, the more moisture it
contained until it could contain no more and that's when it became fog.


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 * Origin: Flying \A/ Ranch, Santa Ysabel, CA (1:10/22)