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Eureka! Zero fog mister

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Karl Townsend

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Feb 22, 2002, 6:47:17 AM2/22/02
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I've used a mister for many years on both lathes and mills. I hate the mess
of flood coolant leaking all over the floor and mist cooling gives about 90%
of the benefit. The major problem with mist cooling is fogging or atomizing
the coolant so fine it floats around in the shop. Since I'm running a
machine many hours a day, I've gotten real sensitive to the fog - it gives
me a sore throat.

Anyway, I read about a low fog mister called a HenchForth Fog Buster here on
this NG. A fellow had obtained a copy of the patent for this unit and made
his own. So, I did the same. This unit was better, but still a slight fog or
smell of coolant would be in the shop. But,it gave me the idea of how to
build a better one. This unit works so well, you can't tell its on - no sign
of fog or odor of mist.

The key to operation is in the relative pressure of the coolant and the
supply air pressure. A standard mister has the coolant unpressurized and
uses 40 - 60 psi air. The Hench unit pressurizes the coolant container to
the same pressure air as the air line. This unit uses a higher air pressure
for the coolant than the air line.

A short explanation of construction:

1. Build a coolant container out of an old 20 lb. propane tank. Make a
removable top to refill coolant (just a 1/2" pipe plug). Weld in a drain
line connection to the bottom of the tank. Provide a way to use a regulator
and air line to pressurize the tank to 20 PSI. The drain line goes to the
mister as a pressurized coolant supply.

2. Provide an air supply regulated to 5 psi. Make a way to shut off both
this line and the coolant line when the mister is not needed. I used
solenoid valves on my CNC machine so an M code can control the mister.

3.The mister unit joins the water line and the air line with a needle valve
to control the amount of coolant delivered. Use a small block of brass to
make this assembly. The air line passes through the block and must be necked
down to 0.100 " dia. so the air velocity is high. At this point, the coolant
line intersects the air line. The coolant line must be very small, I used
0.040 " dia. at this point. Just upstream from where the coolant enters,
there must be a needle valve to regulate coolant flow rate. I just soldered
in a McMaster needle valve - 48965K24.

4. Use a 6" long 1/8" OD brass tube for the mister extension shaft. To the
end of this solder a nozzle. This must be 0.75" long and have an inside
diameter of 0.040".


Again, this unit is a total success for me. It runs up to six hours a day
with absolutely no fogging. Mist rate can be controlled from nearly nothing
to a heavy, nearly flood mist.

Pics:
http://www.metalworking.com/dropbox/Zero%20Fog%20Mister.JPG

Drawing of combining block:
http://www.metalworking.com/dropbox/Zero%20Fog%20Mister.DWG


P.S. The unit was very easy to build with the exception of the nozzle. See
"ARGH - can't drill small hole in copper" thread. <G>
--
An apple a day keeps the doctor away.
Two apples a day gets the doctor's OK.
Five apples a day makes you a fruit grower, like me.

Karl Townsend in beautiful Dassel, Minnesota


Brian Lawson

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Feb 22, 2002, 12:28:22 PM2/22/02
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Hey Karl,

Sounds good! What coolant are you using?

In your text ("Arghh!") I don't see a real reason for using copper to
drill a small hole in. Am I missing something in the reasoning?

My Acad won't "load" your DWG so that I can see it. Any chance of you
doing a posting of the drawing to the dropbox or in PDF?

Looks good! Keep it up!

TIA

Brian Lawson
Windsor, Ontario.

ps... sometimes if the Acad version a DWG was created with is a
"newer" version than the file is being read into, I get something
similar happening. I'm using R13 for Windows. I downloaded the file
to a diskette in a: then renamed it to 8 characters (NOFOGFOG.DWG
heh heh heh), but it still wouldn't "load" into Acad properly. Any
suggestion?
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX


On Fri, 22 Feb 2002 05:47:17 -0600, "Karl Townsend" <Ka...@cmgate.com>
wrote:

Karl Townsend

unread,
Feb 22, 2002, 8:28:25 PM2/22/02
to
You got mail.

I normally use KoolMist 77 but I also have another kind, I don't 'member the
name.

I used copper for the nozzle mostly because that's what I had on hand. I
used plumber's solder to fasten everything so I made it all out of
copper/brass. My next unit is going to try using the plastic flexline and
its nozzle. Much simpler, don't know if it will work. I do know if the
nozzle diameter is too large, you get a spitter, not a mister.

Joe Way

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Feb 22, 2002, 9:09:32 PM2/22/02
to
On Fri, 22 Feb 2002 19:28:25 -0600, "Karl Townsend" <Ka...@cmgate.com>
wrote:

>You got mail.


>
>I normally use KoolMist 77 but I also have another kind, I don't 'member the
>name.
>
>I used copper for the nozzle mostly because that's what I had on hand. I
>used plumber's solder to fasten everything so I made it all out of
>copper/brass. My next unit is going to try using the plastic flexline and
>its nozzle. Much simpler, don't know if it will work. I do know if the
>nozzle diameter is too large, you get a spitter, not a mister.

==============
Karl, could I get a copy of the .pdf or whatever you sent Brian?

I looked at your jpeg and could see only the copper tube which I think
is the coolant line. Where's the air line?

Are you sure the nozzle needs to be 0.040" for 3/4"? Seems like just
the last 1/8" or so would be enough to provide the restriction, and
would be a lot easier to make.

I'd like to point one of these at the toolholders you sold me.

BTW....getting any use out of those ring gages I measured for you a
while back?

Joe
--
Heather & Joe Way
Sierra Specialty Automotive
Brake cylinders sleeved with brass
Delco alternator One-Wire conversions
http://www.brakecylinder.com

Karl Townsend

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Feb 23, 2002, 6:23:12 AM2/23/02
to
I'm not an expert on nozzle design, it might work to have a very short small
diameter section. Here, I just copied the Henchforth patent. Why re-invent
when you can plagiarize?

This is a very small unit, the coolant line is the small (1/8) clear
plastic line coming up from the mister combine block. You can see a very
small needle valve where the coolant goes in. The large (3/8) copper line is
the air line. I made it this size so I could use an old magnetic mount dial
indicator holder to locate the mister. You can see the bar bolted to the
mill right at the top of the photo. (I removed the magnet) If this still
isn't clear I'll take another pic - maybe of the unit on the table.

I didn't hear back from Brian, if you can read the .bmp files, I'll post 'em
to the drop box. There's so many dimension's it hard to make out the actual
part.

On ring gauges, yes, they are a valuable tool to check my inside mics. They
work perfectly. You really shined 'em up nice with that Sunnen hone.

Joe Way

unread,
Feb 23, 2002, 10:29:59 AM2/23/02
to
On Sat, 23 Feb 2002 05:23:12 -0600, "Karl Townsend" <Ka...@cmgate.com>
wrote:

>I'm not an expert on nozzle design, it might work to have a very short small


>diameter section. Here, I just copied the Henchforth patent. Why re-invent
>when you can plagiarize?
>

Me neither. But I made an extended nozzle from brass round stock for
my refillable Shur Shot sprayer. I drilled from the back end with a
1/8"aircraft bit leaving about 1/8", then finished from the front with
#70. Works great, shoots a fine stream a long way.


>
>This is a very small unit, the coolant line is the small (1/8) clear
>plastic line coming up from the mister combine block. You can see a very
>small needle valve where the coolant goes in. The large (3/8) copper line is
>the air line. I made it this size so I could use an old magnetic mount dial
>indicator holder to locate the mister. You can see the bar bolted to the
>mill right at the top of the photo. (I removed the magnet) If this still
>isn't clear I'll take another pic - maybe of the unit on the table.
>

Ah ha. The light dawns. I had mistaken the clear tube for a 1/4"
holder rod.

>
>I didn't hear back from Brian, if you can read the .bmp files, I'll post 'em
>to the drop box. There's so many dimension's it hard to make out the actual
>part.
>

Both of the .bmp files you sent in e-mail come out pitch black in
IrfanView. ????


>
>On ring gauges, yes, they are a valuable tool to check my inside mics. They
>work perfectly. You really shined 'em up nice with that Sunnen hone.
>

====================
Good.

Karl Townsend

unread,
Feb 23, 2002, 7:37:56 PM2/23/02
to
Sorry, I guess I don't know how to convert the file. Is there someone on the
NG that can help me out? I just didled around for 20 minutes without
success.

Alan Rothenbush

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Feb 24, 2002, 12:44:10 PM2/24/02
to
On Fri, 22 Feb 2002 05:47:17 -0600, Karl Townsend <Ka...@cmgate.com> wrote:
>I've used a mister for many years on both lathes and mills. I hate the mess
>of flood coolant leaking all over the floor and mist cooling gives about 90%
>of the benefit. The major problem with mist cooling is fogging or atomizing
>the coolant so fine it floats around in the shop. Since I'm running a
>machine many hours a day, I've gotten real sensitive to the fog - it gives
>me a sore throat.

Great work !

Two questions, if I may ...

1. Is the pressure really only 5 PSI ? That's great news if it is .. I can
use a tiny little compressor. My full size one only runs when I need it,
rarely more than once a week.

2. Any thoughts about using jets from motorcycle carbs instead of trying
to drill tiny little holes ?

Alan

--

Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta

Karl Townsend

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Feb 24, 2002, 7:53:31 PM2/24/02
to
You need 20 psi for the coolant container, but the flow rate would be 0.001
cfm or less. You use 5 psi on the air line.

Give the jets a try - let me know if they work.

jeff toycen

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Nov 29, 2016, 8:44:54 PM11/29/16
to
can somone please put a drawing back up ,, may thanks Jeff

Leon Fisk

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Nov 30, 2016, 8:43:46 AM11/30/16
to

Martin Eastburn

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Dec 1, 2016, 11:27:43 PM12/1/16
to
As the mwdropbox.com says it was the old dropbox we had years ago before
companies sell out or crash. It was hosted by a private company for
years. IIRC, the man that runs it now was able to save the files and
start it up again.

I have a number of posts but enjoy seeing some of the pictures of
members on the site as well. Browse and find gold and rust.

Martin
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