Copper pipe for compressed air?
Mark G. Hinch
use in compressed air systems in a shop, but I don't recall
seeing any discussion about the pro/con of using copper pipe
with soldered joints. Seems easier and cheaper than threading
a bunch of galvanized pipe. I think copper should be able to
take the pressure, though I'm not sure how the joints perform
under various circumstances. Comments?
-Mark Hinch
m.h...@att.com
Paul Houtz
: I've seen the debates here about PVC vs. galvanized pipe for
In my area, PVC is not allowed by codes, soldered copper (thick wall)
is allowed.
Joseph Kral
>I've seen the debates here about PVC vs. galvanized pipe for
>use in compressed air systems in a shop, but I don't recall
>seeing any discussion about the pro/con of using copper pipe
>with soldered joints. Seems easier and cheaper than threading
>a bunch of galvanized pipe. I think copper should be able to
>take the pressure, though I'm not sure how the joints perform
>under various circumstances. Comments?
>
>
galvanized pipe. In fact, its probably the most expensive choice.
I haven't read the debates and it seems to me that any of
the above materials would work fine. With PVC though, be sure to use a
grade that is rated for the pressures used.
Paul Houtz
Yes, the copper was more expensive by quite a bit.
The problem with PVC is that it breaks down with exposure to UV
light. Pressurized lines can explode in time.
Kent M. Zickuhr
>I've seen the debates here about PVC vs. galvanized pipe for
>use in compressed air systems in a shop, but I don't recall
>seeing any discussion about the pro/con of using copper pipe
>with soldered joints. Seems easier and cheaper than threading
>a bunch of galvanized pipe. I think copper should be able to
>take the pressure, though I'm not sure how the joints perform
>under various circumstances. Comments?
>
> m.h...@att.com
>
Mark,
I used to work in a building that had all the air runs in
copper. I couldn't tell you what they used for solder but
it would seem to me that whatever is used for water should
be adequate. As far as pressure handling, a washing machine
solenoid valve slamming shut can give pressure spikes (water
hammer) of 200 or more psi (as told to me by a plumber). You
could always call your city inspectors and ask them. I've
found that here in San Jose I can get questions like that
answered over the phone.
Kent Zickuhr
Steve Baker
>I've seen the debates here about PVC vs. galvanized pipe for
>use in compressed air systems in a shop, but I don't recall
>seeing any discussion about the pro/con of using copper pipe
>with soldered joints. Seems easier and cheaper than threading
>a bunch of galvanized pipe. I think copper should be able to
>take the pressure, though I'm not sure how the joints perform
>under various circumstances. Comments?
Can't offer any experience, but the industrial condo my company
recently bought had copper air lines running all over the place. The
previous owner/tenant was of the "industrial strength" variety
manufacturer, at least in terms of local industrial park standards, so
I'm inferring from this that copper is cool. It was definitely
soldered and, as I recall, all 1/2".
Steve Baker
Rick Cheatham
I used to do HVAC work for years and I installed a lot of copper pipe.
I used 15% silver solder, which would easily take 500 psi without
leaking. If you use lead solder and the pipe is able to move, the
solder joint will crack very easily. If one were to use copper for
compressed air, I would recommend silver soldering the joints.
Rick Cheatham
"Mark G. Hinch" <mgh> wrote:
>I've seen the debates here about PVC vs. galvanized pipe for
>use in compressed air systems in a shop, but I don't recall
>seeing any discussion about the pro/con of using copper pipe
>with soldered joints. Seems easier and cheaper than threading
>a bunch of galvanized pipe. I think copper should be able to
>take the pressure, though I'm not sure how the joints perform
>under various circumstances. Comments?
>-Mark Hinch
> m.h...@att.com
Tom Perigrin
P.S.. In my last posting I said laboratories often used copper for
compressed gases.
SAFETY NOTE - Don't use copper tubing for acetylene gas. It can form an
explosive copper acetylide corrosion, which can explode unexpectedly.
---
If I was smart, I'd have a clever .sig
Brian Lewis
>I've seen the debates here about PVC vs. galvanized pipe for
>use in compressed air systems in a shop, but I don't recall
>seeing any discussion about the pro/con of using copper pipe
>with soldered joints. Seems easier and cheaper than threading
>a bunch of galvanized pipe. I think copper should be able to
>take the pressure, though I'm not sure how the joints perform
>under various circumstances. Comments?
>
>-Mark Hinch
> m.h...@att.com
>
I have a copper pipe for compressed air. I use it, at fairly low pressure
(about 20 PSI) in my darkroom (dusting off negatives, airbrushing, etc.).
The line also goes into my shop, and into the garage. I've run about 80 PSI
with no problems.
I put an adapter to 1/4" MIP each place where I wanted to tap into the line,
and then put a female quick-connect on the adapter.
I've been using the stuff for about 5 years with no problems.
Brian
Neil Surch
>
>"Mark G. Hinch" <mgh> wrote:
>
>>use in compressed air systems in a shop, but I don't recall
>>seeing any discussion about the pro/con of using copper pipe
>>with soldered joints. Seems easier and cheaper than threading
>>a bunch of galvanized pipe. I think copper should be able to
>>take the pressure, though I'm not sure how the joints perform
>>under various circumstances. Comments?
>
>recently bought had copper air lines running all over the place. The
>previous owner/tenant was of the "industrial strength" variety
>manufacturer, at least in terms of local industrial park standards, so
>I'm inferring from this that copper is cool. It was definitely
>soldered and, as I recall, all 1/2".
> Steve Baker
>
Well I have found that using copper pipe is better especially if you plan
to spray paint as water will condense inside the pipe easily. So if you
place your air/water seperator filter after a lenght of 4' or greater you
will avoid having "fish eyes" on you painted surfaces. This is works well
after your compressor is running for a while as the air is hotter and carries
more moisture
Ray Page
and that starts the pipe to rust over the full length. Moisture
extracters wont pull all of the moissture out although the filter will
catch the larger pieces of flake rust the air going to the gun will
still be discolored. Over a long run of pipe we would put a "p" trap in
the pipe with a drain in the bottom. This helps somewhat. I talked with
a plumber friend about using copper or even pvc pipe and he said that he
had plumbed air line with both and they give good service, better than
galvanized although he suggested using high grade silver soldier to put
the copper together with.Also be sure and chek the pressur rating on
either one before using. Most shop compressures very seldom run over
125lb. to 150lbs. Also the older galvinized gets and pinhole rust sets
in the weaker it gets, although this takes years unless you are in a
more humid climate. This also applies to the holding tanks on the
compressures themselves.
Ray Page
such as oxygen at the pressure rates that is used. I probably wouldn't
wont' to use it for acetylene or combustible gasses, and wht usually
happens is that the connections and elbows used are not of the same
rating as the pipe especially in copper. I have known people to run the
whole shop in extruded type PVC pipe. I should have said of the PVC
type. Never the less a little common sense has to be used also in any
thing that is done around a shop whether it is at home or a commercial
est. A new body shop is being built here by one of the large Auto.
Dealerships in order to meet Gov. Regs. on clean air and other things
and although I haven't personally seen it, the people doing the work say
that the air lines are of this type. I, myself, having run many of feet
of galvanized in my shops, and having to deeal with it over the yr.s
would rather have copper put to gether with high grade har silver
soldier.
Bruce FitzGerald
I talked with
> a plumber friend about using copper or even pvc pipe and he said that he
> had plumbed air line with both and they give good service, better than
> galvanized although he suggested using high grade silver soldier to put
> the copper together with.Also be sure and chek the pressur rating on
> either one before using. Most shop compressures very seldom run over
> 125lb. to 150lbs. Also the older galvinized gets and pinhole rust sets
> in the weaker it gets, although this takes years unless you are in a
> more humid climate.
There is some really dangerous advice here. Never, ever use PVC pipe for
compressed gases of any kind. The problem is not with the pipe itself, but
the fittings. Any bending of the pipe where it enters the fittings,
especially elbows can stress them far beyond their design loads. With
fluids, you get a crack and a leak, but with compressed gas, you get an
explosion as the fitting fails and a few heavy pieces of shrapnel flying
around your shop. Remember, fluids do not expand but gases do, sometimes
violently. Check the editorial pages of fine woodworking sometime in "89
for a real horror story of what could happen. Copper is best, as it can
deal with the condensation in the line better than iron.
--
Dorothy:
Sick of this place, gone back to Kansas.
Toto
P.S. Taking the shoes. Find your own way home.
Fitz
gary preckshot
FitzGerald) wrote:
>
> There is some really dangerous advice here. Never, ever use PVC pipe for
> compressed gases of any kind. The problem is not with the pipe itself,
Well, this is good advice, but the wrong reason. The problem is the pipe
itself. PVC eventually becomes brittle when exposed to some chemicals and
light. Unlike copper or iron, when PVC fractures, it breaks into
glass-like sharp edged slivers. In a water pipe, this isn't so serious,
because the pipe fragments have a smaller likelihood of leaving the scene
at high velocity. However, with compressed air, a fracture can result in
shrapnel.
A lot of posters have posted the variant of "gee, we did it and it's still
working great." Bad advice. What they're telling you is that they've been
lucky, so far. Air lines should be made from ductile materials that bend
rather than fracture. Copper is almost ideal. In California, it's against
code to use PVC for air lines. There's a good reason.
An you doubt this, leave some PVC out in the sun for 6 months. Strike it
with a hammer afterwards and note the fracture. Sure, you're not going to
have sun in your shop. But 30 years from now, or maybe 15, you'll be
gimping around in your shop and hear a loud noise. It's called setting a
trap for yourself. I guess if you're a sporting guy, this will just
encourage you.
Gary Peterson
>PVC eventually becomes brittle when exposed to some chemicals
What chemicals in an air system?
> and light.
No direct UV in a shop
> Unlike copper or iron, when PVC fractures, it breaks into
>glass-like sharp edged slivers. In a water pipe, this isn't so serious,
Glass, I don't think so.
>A lot of posters have posted the variant of "gee, we did it and it's still
>working great." Bad advice. What they're telling you is that they've been
>lucky, so far. Air lines should be made from ductile materials that bend
It is called experience. What kind and how much experience do you have in
the commercial woodworking field? Not woodreading, but woodworking.
>rather than fracture. Copper is almost ideal. In California, it's against
>code to use PVC for air lines. There's a good reason.
Which codes are you talking about?
>An you doubt this, leave some PVC out in the sun for 6 months. Strike it
Who has their shop out in the sun?
>with a hammer afterwards and note the fracture. Sure, you're not going to
Who goes around striking their air system with hammers?
>have sun in your shop. But 30 years from now, or maybe 15, you'll be
But if you live in California, you A) won't be living in the same shop 30
years from now, or B) will have slid into the Pacific Ocean <G>
Bottom line is: A properly assembled 3/4"sch40 PVC system running 100-50
psi with a pressure pop off and the lines in places that are not subject to
abuse of negligent employees will last longer than the use of the building
it is in, there is plenty of EXPERIENCE AND STATISTICS to support it.
---- __o GARY PETERSON
--- ._'\<,_ Internet=slo...@slonet.org * gpet...@slonet.org
-- (*)/ (*) BBS=1.805.438.4242 Fido=1:212/3004 AOL=GARYP5837
Tom Perigrin
(Gary Peterson) wrote:
>
> preck...@llnl.gov (gary preckshot) wrote:
>
> >PVC eventually becomes brittle when exposed to some chemicals
> What chemicals in an air system?
I don't know... what chemicals do you use around the shop? If acetone
wafts by your compressor, then you've got acetone in your air system. And
of course, any urban environment has chemicals in the air.
>
>
> > Unlike copper or iron, when PVC fractures, it breaks into
> >glass-like sharp edged slivers. In a water pipe, this isn't so serious,
> Glass, I don't think so.
Well, it doesn't have the conchoidal fracture of glass, but it is sharp
edged fragments. This is why the NFPA and PGI standards for shooting
fireworks out of mortars allows paper, steel, and HDPE, but strictly and
expressly forbids PVC.
> >A lot of posters have posted the variant of "gee, we did it and it's still
> >working great." Bad advice. What they're telling you is that they've been
> >lucky, so far. Air lines should be made from ductile materials that bend
> It is called experience. What kind and how much experience do you have in
> the commercial woodworking field? Not woodreading, but woodworking.
Gosh, do you mean to say one has valuable knowledge if and only if they
have done the deed themselves? It is possible to read accident reports,
and to discover that many accidents involve the use of PVC and high
pressure systems.
What surprises me would be a commercial woodworker who would continue to
use PVC after having been appraised of serious and documented concerns
about it's safety. If an accident DID happen, that would be contributory
negligence... Might as well put jam in his pockets, cause he's gonna be
toast when the lawyers are done.
> >with a hammer afterwards and note the fracture. Sure, you're not going to
> Who goes around striking their air system with hammers?
Me, you, all of us. All of us slip, drop hammers, bang things. Normally
all that happens is that a tool drops, hits the bench or the floor followed
by a few choice expletives. BUT, it is possible that the tool would hit an
air system. is it likely? Nope. But it is possible, and why have an
accident waiting to happen when it doesn't buy you much?
Mike Murray
>From: gpet...@biggulp.callamer.com (Gary Peterson)
>Subject: Re: Copper pipe for compressed air?
>Date: Wed, 20 Sep 1995 03:45:30 GMT
>preck...@llnl.gov (gary preckshot) wrote:
>>PVC eventually becomes brittle when exposed to some chemicals
> What chemicals in an air system?
Whatever volatile chemicals you have in your shop that are sucked into the
compressor inlet - polyurethane? model glue? How do you know what an
unexperienced person who is following your advice might have in their shop? Or
in your shop after you sell it?
>> and light.
>No direct UV in a shop
Not in your shop, perhaps. What if someone following your advice has an
outdoor shop? or lots of open windows?
>> Unlike copper or iron, when PVC fractures, it breaks into
>>glass-like sharp edged slivers.
>Glass, I don't think so.
Good, well thought out answer. I like your reasoning here.
>>A lot of posters have posted the variant of "gee, we did it and it's
>> still working great." Bad advice. What they're telling you is that
>>they've been lucky, so far. Air lines should be made from ductile materials
>>that bend.
>It is called experience. What kind and how much experience do you
>have in the commercial woodworking field? Not woodreading, but woodworking.
It is not related to woodworking. Compressed air is a common feature in
industry.
>>rather than fracture. Copper is almost ideal. In California, it's
>>against code to use PVC for air lines. There's a good reason.
>Which codes are you talking about?
>>An you doubt this, leave some PVC out in the sun for 6 months. Strike it
>Who has their shop out in the sun?
See previous answer. Someone out there might.
>>with a hammer afterwards and note the fracture. Sure, you're not going to
>Who goes around striking their air system with hammers?
Are you assuming that no-one would ever bump their air line with a 2x4? Hang a
tool on it because it's handy?
>>have sun in your shop. But 30 years from now, or maybe 15, you'll be
>But if you live in California, you A) won't be living in the same shop
>30 years from now, or B) will have slid into the Pacific Ocean <G>
I see, let someone else be injured when it bursts. Thoughtful of you.
>Bottom line is: A properly assembled 3/4"sch40 PVC system running 100-50
>psi with a pressure pop off and the lines in places that are not subject to
>abuse of negligent employees will last longer than the use of the building
>it is in, there is plenty of EXPERIENCE AND STATISTICS to support it.
But why even take the chance? Who knows who is reading this and might not
know what properly assembled means? How can you tell what place is not subject
to abuse? There are plenty of accidents proving that PVC compressed gas lines
can explode. Copper air lines, even if put together poorly, do not explode.
Once again, why risk it? Is the extra $40 really that important that you would
risk injury to yourself, or a lawsuit from an employee?
> ---- __o GARY PETERSON
>--- ._'\<,_ Internet=slo...@slonet.org * gpet...@slonet.org
> -- (*)/ (*) BBS=1.805.438.4242 Fido=1:212/3004 AOL=GARYP5837
Mike Murray
Mech Engineer
U of Iowa Physical Plant.
And yes, in this case (no PVC compressed gas lines) I AM speaking for my
employer.
Mike Murray
few months ago also.) Does anyone out there have actual citations to give
the doubter? I threw mine away. It wasn't a concern since we don't use
PVC for air. Now that I'm intruding on everyone and playing safety cop I wish
I hadn't.
Hope the next time I post it's about finishing my bookcase. So does my wife.
Mike Murray
Roger Wiegand
>preck...@llnl.gov (gary preckshot) wrote:
>
>>PVC eventually becomes brittle when exposed to some chemicals
> What chemicals in an air system?
All kinds of finishing and stripper-related solvents that are perfectly
happy to attack PVC. They don't have to be on the inside of the pipe.
>
>> and light.
>No direct UV in a shop
Some of us use fluorescents with some UV in their spectra, others have
nice sunny shops. Do you think everyone works in an environment identical
to your own?
>
>>A lot of posters have posted the variant of "gee, we did it and it's still
>>working great." Bad advice. What they're telling you is that they've been
>>lucky, so far. Air lines should be made from ductile materials that bend
>It is called experience. What kind and how much experience do you have in
>the commercial woodworking field? Not woodreading, but woodworking.
What does woodworking experience have to do with understanding the
engineering of compressed air systems? Darn little I suspect.
>>An you doubt this, leave some PVC out in the sun for 6 months. Strike it
>Who has their shop out in the sun?
Lots of people do, many of us would like to. Mostly those who work above
ground. They cut little rectangles out of the wall or ceiling and cover
them with glass or plastic that may or may not be UV transparent
specifically to let the sunlight in.
>
>>with a hammer afterwards and note the fracture. Sure, you're not going to
>Who goes around striking their air system with hammers?
>
It could happen with a hammer, but more likely in my shop is a chunk of
tree coming off the lathe in an unanticipated way, or maneuvering a board
in tight quarters. Some of us aren't perfect (yet).
--
Thanks,
Roger
mailto::rcw...@ccmail.monsanto.com
gary preckshot
>
> Glass, I don't think so.
I wrote "glass-like sharp edged slivers." That means *like* glass
fragments. So I guess you're right, PVC is not glass, but I thought that
was obvious.
> It is called experience. What kind and how much experience do you have in
> the commercial woodworking field? Not woodreading, but woodworking.
4 years as an aviation mechanic, 4 years as a machinist/model builder, 4
years as an engineer at Grand Coulee Dam (power plants have extensive air
systems), and 15 years as an engineer at a large national laboratory that
does experiments that make things go bang.
Along the way I've met dumbheads like yourself, and when they were too
stupid to listen to the voice of experience, we sent'em down the road.
Even stupid people have to earn a living, but not near me.
As to have I ever seen a PVC pipe blow up, no. I've seen a lot of things
blow up, including several tons of fertilizer & fuel (intentional
blasting), a 500 Kv circuit breaker, several oscilloscopes, numerous
pyrotechnic devices, an RF-4C Phantom, and random equipment that
encountered conditions it wasn't designed for. I've heard more, from
behind 11 foot thick concrete walls where we retired for prudence's sake
when energizing new equipment.
So, little woodworker, who is so proud of having worked in one little shop
with one little air system, there are more things than are dreamt of in
your philosophy. People who have actually been near things that go bang
are usually not eager to repeat the experience.
Gary
Tom Perigrin
(Gary Peterson) wrote:
>
> t...@mercury.aichem.arizona.edu (Tom Perigrin) wrote:
>
> >Well, it doesn't have the conchoidal fracture of glass, but it is sharp
> >edged fragments. This is why the NFPA and PGI standards for shooting
> >fireworks out of mortars allows paper, steel, and HDPE, but strictly and
> >expressly forbids PVC.
>
> Explosives can not be compared to 115psi of compressed air.
True, although it surprises people to learn that the pressure inside of a
fireworks mortar is only a few hudred PSI. It is true that a large
military gun fires shells with 15,000 PSI and above, but those kind of
pressures and setbacks would destroy the vastly more fragile fireworks
shells (most of which are made whith cardboard casings). So, a slow
burning powder and a loose fitting shell combine to restrict the pressure
to a few hundred PSI.
Now, the problem comes when a shell explodes in the mortar. Then the
pressure goes up to the K PSI range. In that case, we have to worry about
the effect. It is true that we are talking about KPSI. But the mode of
failure will be the same at 100 PSI or 10 K PSI. Copper and brass bulge at
medium pressures, and finally "tear". Steel bulges and can fragment, but
the required pressure is high. The failure modes for HDPE and paper are
relatively safe. The paper does not bluge and fails catastrophically.
There is no intermediate. But when paper fails it simply shreds and the
low mass of the shards prevents them from doing damage. HDPE bulges, and
with enough pressure it stretches and blows open along a side, and
generally remains in one large twisted chunk. PVC fails in a catastrophic
manner. It doesn't bulge or release the strain slowly, it holds until it
shatters, sending dozens or hundreds of sharp edged bits of shrapnel, which
cannot be found via X-ray.
>
> It is equally likely that you will sever the power cord to one of your
> tools and electrocute yourself, do you have ALL of your power cords in
> steel conduit? No, because it is not practical. That is what we are talking
> about, the practicality of PVC air lines.
We are talking cost/benefit analysis here. In fact, in my old shop (I am
moving) the leads to my outlet boxes are in conduit, and any cord that goes
across the floor was in a cable run made out of a beveled and hollowed 2x4.
Of course, the cords to my hand tools are not in conduit, but that is
because the cost of flexibility and utility, and the raised likelyhood of
an accident due to increased cumbersomeness, makes the equation work out in
benefit of "normal" power cords.
I don't see that PVC offers advantages that outweigh the known
disadvantages. Thus, if/when I install a compressed air system (I am
moving right now) it will be in copper or steel. Thius is simply my
personal choice, in that I am willing to spend $20 or $40 more on copper,
to reduce the risk to myself and my workers by some small but
non-negligable amount. Some people value their health and safety less
highly than I do mine. That's their choice.
> BTW, what are your air line made of?
I was using flexible rubber in my old shop. The compresser was more or
less centered, so a 20' line managed to get to most of the tools without
problems. On the other hand, my shop was primarily used by myself, and
occasionally by 1 or 2 people making a short production run. We didn't
need multiple simultaneous takeoffs. If I did have a larger shop, I would
use copper plumbing.
In my professional life as a chemist all compressed gas lines are steel or
copper.
>
> >If I was smart, I'd have a clever .sig
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> I resisted <G>
Thanks
---
I still don't have a clever .sig
Gary Peterson
>> >PVC eventually becomes brittle when exposed to some chemicals
>> What chemicals in an air system?
>I don't know... what chemicals do you use around the shop? If acetone
>wafts by your compressor, then you've got acetone in your air system. And
It does not seem like good advice to keep flamables near an air compressor.
I keep my flamables in an old gym locker, locked , out doors in the shade.
>of course, any urban environment has chemicals in the air.
Which will probably kill you faster than exploding PVC lines <G>, which is
why I live in a rural environ.
>> Glass, I don't think so.
>Well, it doesn't have the conchoidal fracture of glass, but it is sharp
>edged fragments. This is why the NFPA and PGI standards for shooting
>fireworks out of mortars allows paper, steel, and HDPE, but strictly and
>expressly forbids PVC.
Explosives can not be compared to 115psi of compressed air.
>Gosh, do you mean to say one has valuable knowledge if and only if they
>have done the deed themselves? It is possible to read accident reports,
>and to discover that many accidents involve the use of PVC and high
>pressure systems.
No, what I mean to say is that I and everybody that I know that uses PVC
has never had any problems when it is installed and maintained correctly.
And that reading of accident reports that don't give all of the detailed
circumstances (how much pressure, properly installed, which schedule of
pipe, wether or not it is outdoors, if the system is exposed to chemicals,
if the line was in a location subject to abuse/impact, ect.) does not give
you the true picture.
Incidently, how many of the people who innocently asked "Is it OK to use
PVC pipe for an air line?", do you think are going to subject the system to
the obscure industrial worse-case conditions that you and I have described?
I guess what bugged me the most is to see opinions so adamantly expressed
as though they are from first hand knowledge rather than theoritical
supposition based on third hand, indirect heresay.
The neat thing about this nuzgrup is that it is people recounting their
first hand experiences about woodworking.
How many accidents are you aware of FIRST HAND? And what were the complete
circumstances?
>> >with a hammer afterwards and note the fracture. Sure, you're not going to
>> Who goes around striking their air system with hammers?
>Me, you, all of us. All of us slip, drop hammers, bang things. Normally
>all that happens is that a tool drops, hits the bench or the floor followed
>by a few choice expletives. BUT, it is possible that the tool would hit an
>air system. is it likely? Nope. But it is possible, and why have an
>accident waiting to happen when it doesn't buy you much?
It is equally likely that you will sever the power cord to one of your
tools and electrocute yourself, do you have ALL of your power cords in
steel conduit? No, because it is not practical. That is what we are talking
about, the practicality of PVC air lines.
I don't know this first hand, but a fellow cabinetmaker who has employees
told me that with certain restrictions OSHA permits PVC. Again I don't know
this first hand, but for the fun of it, I will look into it. Fortunately,
I don't have to deal with OSHA.
BTW, what are your air line made of?
>If I was smart, I'd have a clever .sig
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I resisted <G>