Good post Robb.
The toxins are minute until the compressor pistons rings get worn (or do not
fit right from the beginning) and allow oil to enter the cylinders. With the
heat that's generated by compressing air, the oil will partially burn and
create carbon monoxide which coats the red blood cells and prohibits the
transfer of oxygen to those cells and further to the other cells in the
body.
Absolutely right about the oil free compressor!
MMC
"AMPowers" wrote in message
...
BajaJim wrote:
MANY Thanks to Richard Kinch and Bryan Combs for some great replies, it
was clear that they understood I am only going down 6 to 8 feet and
just need a little compressor, similar to those used for small paint
sprayers. I will also have 30A dock service to plug into.

This was my first post and participation and, while I love a little
humor as much as the next guy (see my book The Baja Bash), it was a
little hard finding the worthwhile posts while sifting through others
from people who clearly feel a need to reply to anything and
everything, under the assumption that they know all and should
therefore pass on their pearls of wisdom.


Jim,

I believe that the warnings you received about "oil" based compressors
are based on the concern that you might be exposing yourself to what are
admittedly small amounts of toxins but over long periods of time, all
while working underwater - an environment where one would like to avoid
encountering breathing issues.

To compound this further you will be most likely be exerting yourself
enough to raise your respiration rate which would increase any toxin
absorption rate. Also, because of the "partial pressures" of breathing
gases in increased atmospheres, the percentage of toxin absorbed by your
body goes up dramatically as you go deeper.

If you can avoid using an oil based compressor I would strongly suggest
doing so, especially since inexpensive alternatives exist.

Cheers,

Robb

MMC wrote:
Good post Robb.
The toxins are minute until the compressor pistons rings get worn (or do not
fit right from the beginning) and allow oil to enter the cylinders.
Absolutely right about the oil free compressor!

Thanks for adding your ideas here. Finally some advice based on
training, experince, and still here to give it. Unlike the other past
posts that simply said, "Ive been doing it this way for years and never
had any porblems."

Here is my question for you MMC:

A few comments earlier in this discssion I described a hand pump that
supplied diver air to about 20'. Did you ever run into anything like
that in the service? They were a little (maybe 25 lbs.) two cylinder
thing with a five foot handle that a person push-pulled too operated
the pump. The guy who made the new prototype said he got the idea from
one he saw in an old USN Dive Manual.

Thanks,
Bob

MMC writes:

The toxins are minute until the compressor pistons rings get worn (or
do not fit right from the beginning) and allow oil to enter the
cylinders. With the heat that's generated by compressing air, the oil
will partially burn and create carbon monoxide which coats the red
blood cells and prohibits the transfer of oxygen to those cells and
further to the other cells in the body.

You are confusing heat and temperature, because compressing air does not
generate heat. The existing heat is concentrated into a smaller volume,
raising the temperature, but this does not rise to ignition at 90 psi.
Perhaps you are thinking of scuba tank compressors at many 1000s of psi.

If what you say were true, then working with compressed air in a closed
shop would be even more hazardous, since the air is recycled over and
over through the compressor as it is exhausted into the room. But there
is no CO or oil vapor to be concerned with in those situations.

Mineral oil is not toxic in itself.

You are breathing oil-contaminated air all the time, over a cooking
stove or around 2-cycle engines. No one thinks much of it, because it
isn't a hazard.

So I got the regulators and hoses from this outfit.

http://www.akmining.com/diving.htm

Really the hoses could be any compressor hose from Home Depot but it
was nice to have all the fitting match.

I got a small 12volts compressor that I run off the battery. I may
need to get a bigger one though because It can't quite keep up with
me.

They make these little compressors for trucks tires that run of the
battery. If you only going to use it in a marina, then 110v is great.

I would use an oil less model though. Why take a chance.

Been cleaning the bottom no problems. Even had to use it to dive down
30 feet to retrieve a pot that I dropped overboard.

Jeannette AA6JH
Bristol32
S/V 'Con Te Partiro'
http://www.eblw.com/contepartiro/contepartiro.html

On 20 Apr 2006 12:29:35 -0700, "BajaJim" wrote:

Am wondering if anyone has set up a small air compressor rig, 110V,
similar to the ones used by divers for hull cleaning services. I assume
just a small oil-less compressor and couple it directly to a stock dive
regulator? I only need it dockside in a marina with 30A seervice.

THANKS for any input

Hello:

Okay, I appologize for that my sarcastic remarks earlier. However,
after a long run I am much more relaxed.

For the "I wanat to go diving" folks who were asking for air supply
advice.

But for real try this........................

Oregon State University DIve Ops guy, Jim Washburn used an old USN hand
operated diver air supply pump to guide a new lilght weight v3resion
for shallow water applications.

I am not talking about the big two person pump designed put a Mark V
down, rather somthing much smaller.

The shallow water pump weighs about 25 pounds and is pumped by one
person. The diver uses a "special" low preasure demand stage for the
regulator.

The pump is prettey cool. Stone age technology. Maybe four moving
parts. And the beauty is that only one person is needed topside to work
the pump.

Where do you get one??

Jim was cosidering manufaturing and sell the pumps. But because of
libility issues decided to shelve the idea.

However.......... if you are interested call Oregon State University
and ask for Jim Washburn, College of Oceaneering. I have a set of plans
but Jim is there to do just that. Help the tax payers benfit from tax
paid research projects.

Two bighest problems with this set up:
1) limited to about 20' depth
2) need a person topside to operate the manual hand pump.

The advatges:
1) No fuel,oil,noise
2) Stone age relibility, simplicity, light, CHEEP

Helpful Bob.

On 20 Apr 2006 12:29:35 -0700, "BajaJim" wrote:

Am wondering if anyone has set up a small air compressor rig, 110V,
similar to the ones used by divers for hull cleaning services. I assume
just a small oil-less compressor and couple it directly to a stock dive
regulator? I only need it dockside in a marina with 30A seervice.


I've been using a diaphram type compressor for about 28 years. I think
they call them "pancake" compressors now. Totally oilless, using a
rubber diaphram. About 30 PSI max. It came with a 117 VAC motor, belt
driven. I replaced the motor with a 12 VDC wheel chair motor for
live-aboard use (take off the gear box and fit a pulley).

Get an "old" regulator. Take off the 1st stage and disable the 2nd
stage so you get free-flow. I bought some fittings/adapters so I use
regular water hose as an air hose.

If one wants to go this route, and have it run at 12 volts, a good
"motor" to drive it is an original VW bug GENERATOR. Not an
alternator. Connect the F (Field) terminal to the B (Battery)
terminal. This is the +. The - goes to the case or ground terminal.
This will draw about the same current as the wheel chair motor, about
10A, and give plenty of power.

Rick


------------------------------------------------
Absolute safety is a concept promoted by those
without the guts to live in the real world.
------------------------------------------------

Rick Morel wrote:
On 20 Apr 2006 12:29:35 -0700, "BajaJim" wrote:

------------------------------------------------
Absolute safety is a concept promoted by those
without the guts to live in the real world.
------------------------------------------------


I think Absolute safety is a great goal. Most times not relaistic
but.......
Personnaly, I follow this:

"Its the second mouse that gets the cheese."

Observe.............anticipate.................... improve and
innovate.
Relationships with friends and coworkers tend to be longer this way

Bob

How often are you planning on using this? I just use a scuba tank
with a 40' hose to do all my maintenance.... no worries about maint or
worn rings or electricity.

If you use it a lot, contact brownies third lung. They make a safe
electic unit as well. Sure it costs a few more bucks but we are
boaters... If you can't right the checks, stay on the dock!!!!!





Bob wrote:
Rick Morel wrote:

On 20 Apr 2006 12:29:35 -0700, "BajaJim" wrote:


------------------------------------------------
Absolute safety is a concept promoted by those
without the guts to live in the real world.
------------------------------------------------



I think Absolute safety is a great goal. Most times not relaistic
but.......
Personnaly, I follow this:

"Its the second mouse that gets the cheese."

Observe.............anticipate.................... improve and
innovate.
Relationships with friends and coworkers tend to be longer this way

Bob