Coolant Mister

[Hawkeye]

I decided to try to make a mist coolant gizmo, loosely based on some I've seen on the internet. The main push for this was getting a flood coolant nozzle with magnetic base through the local tool store.

Some that I've seen use two pressure regulators. One for the air flow at the nozzle, one to pressurize the liquid supply bottle. I decided to try using just one, mostly because I didn't buy a second one when it was on sale recently. Mine uses one regulator to adjust the air flow through the nozzle, with that pressure also entering the bottle to push the coolant out. The tube coming vertically out of the brass fitting carries the liquid to the nozzle.


Rather than mix air and coolant before they go down the flexible tube to the nozzle, I ran a thin nylon tube down the middle of the flex to carry coolant to the nozzle itself. I filed three notches around the opening of the original nozzle to allow good air flow out past the thin tube. There is also an insert made from 1/16" O.D. brass tubing in the end of the tube to restrict the flow.


I made up an aluminum block to allow mounting of the flex tube and connect the air and coolant lines. In my first attempt, I used the valve that came with the nozzle assembly. Leaked like a sieve. The screw on the top of the fitting is a needle valve I made from a bolt, to regulate the amount of coolant coming out.


Today, I picked up a small needle valve at the hardware store and reworked the regulator stage. Now there are no leaks and I can turn the coolant flow as low as I want.


I haven't tried machining with it yet. I'm going to work out a better method of hanging the supply bottle so the rig can be easily moved from machine to machine. Reports from other builders indicate that coolant usage is quite low. I'm using a semi-synthetic water-soluble oil for my first trials.

 

[AlanR]

The Noga one that I have uses two tubes also, inner and outer. Air flows though the outer one and fluid is sucked up to the tip through the inner one by the Venturi effect.

It works really well at many air pressure levels with a real simple plunger valve to turn the air on and off and provide pressure regulation.

 

[ddmunroe]

I decided to try to make a mist coolant gizmo, loosely based on some I've seen on the internet. The main push for this was getting a flood coolant nozzle with magnetic base through the local tool store.

Some that I've seen use two pressure regulators. One for the air flow at the nozzle, one to pressurize the liquid supply bottle. I decided to try using just one, mostly because I didn't buy a second one when it was on sale recently. Mine uses one regulator to adjust the air flow through the nozzle, with that pressure also entering the bottle to push the coolant out. The tube coming vertically out of the brass fitting carries the liquid to the nozzle.

Good effort there Hawk ....
I too would like to make one but I say this about just everything ..... which can result in fewer things getting made period. In my case anyway.
I like this system : a fogger as oppossed to a mister http://www.tormach.com/blog/eliminate-the-haze-with-the-fog-buster/ $365.00 bit pricey though

I don't like the full flowing coolant that typical systems use.
Too Messy
Nice work anyway interested to see it working
dd)

 

[MikeWi]

Good effort there Hawk ....
I too would like to make one but I say this about just everything ..... which can result in fewer things getting made period. In my case anyway.
I like this system : a fogger as oppossed to a mister http://www.tormach.com/blog/eliminate-the-haze-with-the-fog-buster/ $365.00 bit pricey though
View attachment 78857View attachment 78858View attachment 78859
I don't like the full flowing coolant that typical systems use.
Too Messy
Nice work anyway interested to see it working
dd)

Take a good like at the photo, and you can build your own version for less than $100. That's what I did anyway. The water filter holder is $25 for example.
EDIT: Didn't mean to make that sound like I'm the only one who did it. several threads here from others who have done this.

 

[Hawkeye]

The reason I ran the inner tube was to avoid the fog effect. There are many posts around the net complaining about shops quickly filling up with fog when the liquid gets too atomized. I'm pleased with the droplet pattern my system is giving.

I welcome any comments and posts showing alternate methods that members have actually built. Let's make this a resource for people to use in designing and building their own coolant systems.

 

[JimDawson]

My old mist coolant system finally gave up. The tag on it said ‘DON’T USE ANYTHING BUT APPROVED COOLANT’, OK, I ignored that. I don’t think it liked my WD-40 / kerosene mix (my preferred coolant for aluminum machining), so I replaced it with a one-inch air line oiler that I had laying around. It worked pretty well as a mist coolant system except it required frequent attention, OK for one-off parts and short runs, but a pain for continuous production. I needed more coolant capacity and a more consistent output.

WARNING: DO NOT TRY THIS AT HOME. Pressurizing a flammable liquid with air is really dangerous. IT COULD EXPLODE!!! But then I’m about half crazy anyway. (Hold my beer and watch this.) I actually tested a small amount in a small container, under safe conditions at 120 PSI just to see if it would blow, it didn't, but it should have.


I went to Harbor Freight and bought their 20lb pressurized sand blaster. What I wanted was the pressure tank. It holds about 3 gallons, has a large screw on cap, and will handle up to 160 PSI. (I am running it at about 60 PSI). Then I went to my junk shelf and found enough parts to make it all work.




The solenoid valve allows me to turn it on with a switch or control it from the computer.

The blue lines are air, and the black lines are liquid. The filter is a Toyota fuel filter I had on the shelf. The valve just to the left of the regulator dumps the air in the tank when the inlet air is shut off. Not really needed, but I had it on the shelf.


An adjustable pressure relief valve (just to the right of the tee) maintains the tank pressure at about 15 PSI above the outlet air flow pressure so that the coolant always has positive pressure relative to the air stream and will always flow into the air stream. This way I get constant volume of coolant at any input pressure.




The flow controls allow fine adjustment of the liquid and mix air stream, the big disk magnet allows me to stick it in any convenient location. The output can be adjusted from a pure liquid stream to a fine fog.


Had I not had all of the parts on the shelf this would have been a bit expensive, but I have scrounged a lot of stuff over the years.