Air compressor question

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I've got air piped with pvc and it's been there over 25 years. Never read
anywhere it wasn't supposed to be used for that. Of course never read that
it was intended to be used for that. Guess it's kinda like an apple, I
never read it was intended to be eaten, we just do it. I've seen pvc used
for air supply pipe in many places and been there many years and never
heard anything dangerous about using it. Send me some documentation of
it failing and hurting or killing someone. Not just one incident but a
pattern. People get killed by slipping getting out of the shower but not
enough to get people upset every time they shower.
pRoger Halstead wrote:
blockquote TYPE=CITEOn Tue, 16 Sep 2003 19:17:35 -0400, "Morgans"
brwrote:
p
br"Rich S." wrote in message
bra /a...
br "Frederick Wilson" wrote in message
br a href="news:FmC9b.365132$Oz4.142857@rwcrnsc54"news :FmC9b.365132$Oz4.142857@rwcrnsc54/a...
br I am still working on home remodel so it will be some time before
the
br airplane gets started. I am pretty darn convinced that I am going
to do
bran
br all wood and fabric airplane. More than likely, the Fisher Tiger
Moth.
br
br Anyway, I have come to the point in my home remodel that I am
going to
br need
br an air compressor. But instead of just getting one that will do
the job
br here, what might I need one for when it is airplane time?
br
br What size and compressor (one or two cylinder) should I look at?
br
br Any name brand preference?
br
br Whichever model you choose, be SURE to listen to it run before you
plunk
br down your money. Some of the new compressors are loud enough to
shred your
br neighbor's panties.
br
br Rich S.
br
brPart of the things to consider is if you will use a lot of air tools,
or go
brelectric.  For a wood airplane, I could see a bit of sanding,
and spraying
brfinish.  A small 30 gal 3 HP compressor would not keep up with
a air sander,
bror spray gun very well.  I like air tools cause they are usually
cheaper,
brlighter, and don't get hot under heavy usage.
br
brIf you can swing it, get a big upright 5 HP , NOT oilless unit, and
put it
broutside if you can.  It saves the ears and the space in the shop. 
All it
brneeds is a small lean-to roof.
pI have one of the big 80 gallon units set at 175 psi tank pressure. 
I
brget very little tank condensation, but it is going outside into a
brsmall shed/leanto.  If you are doing some fine work and that sucker
brkicks on you will have to go hunting to find where the work landed.
brIt's not terribly noisy, but enough that when it comes on unexpectedly
brit will startle you.
pHowever, if I keep it outside I need to figure out how to get the
brcondensation out without if freezing in the tank.
pOTOH it'd be wayyy to big for home construction. Yet when doing metal
brwork such as grinding and cutting with the pneumatic tools it kicks
on
brquite often.  I have a smaller one like the ones used on construction
brsites for nailers and other portable pneumatic tools that works fine
brfor that.  It's just a bit heavy for hauling around, but still
not
brbad.
pRoger Halstead (K8RI EN73 & ARRL Life Member)
brwww.rogerhalstead.com
brN833R World's oldest Debonair? (S# CD-2)/blockquote
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PVC makes great potato guns. Note the one in BWB's grasp at
http://www.jouster.0catch.com/jean-02/p2190041.jpg.

Rich s.
"L.D." wrote in message ...
I've got air piped with pvc and it's been there over 25 years. Never read anywhere it wasn't supposed to be used for that. Of course never read that it was intended to be used for that. Guess it's kinda like an apple, I never read it was intended to be eaten, we just do it. I've seen pvc used for air supply pipe in many places and been there many years and never heard anything dangerous about using it. Send me some documentation of it failing and hurting or killing someone. Not just one incident but a pattern. People get killed by slipping getting out of the shower but not enough to get people upset every time they shower.

We have PVC plumbing 140 psi all over our shop in San Diego. It
occasionally blows out at a joint and it really hurts people's ears. I
don't recommend it but you might get away with it.

We have PVC in our full time shop for 23 years. Never a problem. Just clean
and seal all the joints right. Have 120 psi.

Larry

(Fitzair4) wrote in message ...
We have PVC in our full time shop for 23 years. Never a problem. Just clean
and seal all the joints right. Have 120 psi.

Larry

Been in lots of places that used it and seen lots of failures. You do
know that Sch 40 and 80 both have an ultimate tensile strength of
only 7400psi at 73 deg. F.,( black iron is about 10-15 times that )
and that by the time you get to around 90deg F., that is reduced by
almost 50%? By the time you run the numbers for the data given in ASTM
D1784, the code that your pvc pipe is rated by, when you do all the
required derates and apply all the safety factors required for sound
engineering practices, 1" PVC is rated to handle about 4psi working
pressure. It also might interest you, in that the code specifically
states that the rating is good for incompressible liquids only and
that pvc and cpvc are to never be used in a compressible gas system
without revising the pressure ratings to those found under ASME B31.3.

BTW...if you are a commerical shop, the use of pvc like this will get
you some nice little code violations if the inspectors ever look
notices it, or OSHA visits.

Craig C.

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I'm no engineer and don't have a lots of formal smarts but common sense
tells me  if the following is true, then PVC is useless as tits on
a boar hog for any use. 4 psi???
p"when you do all the required derates and apply all the safety factors
required for sound engineering practices, 1" PVC is rated to handle about
4psi working pressure."
pL.D.
pCraig wrote:
blockquote (Fitzair4) wrote in message ...
br We have PVC in our full time shop for 23  years. Never a problem.
Just clean
br and seal all the joints right. Have 120 psi.
br
br Larry
pBeen in lots of places that used it and seen lots of failures. You do
brknow that  Sch 40 and 80 both have an ultimate tensile strength
of
bronly 7400psi at 73 deg. F.,( black iron is about 10-15 times that )
brand that by the time you get to around 90deg F., that is reduced by
bralmost 50%? By the time you run the numbers for the data given in ASTM
brD1784, the code that your pvc pipe is  rated by, when you do all
the
brrequired derates and apply all the safety factors required for sound
brengineering practices, 1" PVC is rated to handle about 4psi working
brpressure. It also might interest you, in that the code specifically
brstates that the rating is good for incompressible liquids only and
brthat pvc and cpvc are to never be used in a compressible gas system
brwithout revising the pressure ratings to those found under ASME B31.3.
pBTW...if you are a commerical shop, the use of pvc like this will get
bryou some nice little code violations if the inspectors ever look
brnotices it, or OSHA visits.
pCraig C.
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"L.D." wrote in message
...
I'm no engineer and don't have a lots of formal smarts but common sense
tells me if the following is true, then PVC is useless as tits on a boar
hog for any use. 4 psi???
"when you do all the required derates and apply all the safety factors
required for sound engineering practices, 1" PVC is rated to handle about
4psi working pressure."

L.D.

Craig wrote:

It works great at what it is intended for, when installed correctly, and
that is cold water supply. The temperature is the big issue, when dealing
with pressure. Any building inspector has a piece of pvc blown up from 3/4"
up to about 3", found after someone incorrectly installed it hooking up a
hot water heater.
--
Jim in NC

"Craig" wrote
Been in lots of places that used it and seen lots of failures. You do
know that Sch 40 and 80 both have an ultimate tensile strength of
only 7400psi at 73 deg. F.,( black iron is about 10-15 times that )
and that by the time you get to around 90deg F., that is reduced by
almost 50%? By the time you run the numbers for the data given in ASTM
D1784, the code that your pvc pipe is rated by, when you do all the
required derates and apply all the safety factors required for sound
engineering practices, 1" PVC is rated to handle about 4psi working
pressure. It also might interest you, in that the code specifically
states that the rating is good for incompressible liquids only and
that pvc and cpvc are to never be used in a compressible gas system
without revising the pressure ratings to those found under ASME B31.3.

OK, I can accept at face value that PVC isn't meant to handle compressed air
Compressible vs incompressible fluids, no problem.

But out of curiosity, how do you get from a 7400 psi under ANY conditions to
a safe working pressure of 4 psi?
That requires dividing 7400 by 2 almost TWELVE times!!!
Are there twelve (or more) separate conditions that each compromise the
tensile strength by 50% (or more)??!?!?

Just wondering, Eric