Build Thread How I built a fog-less coolant mister

Hi everyone. I have been building a fogless coolant mister and I thought I would share how I did it. Most materials are available at a home improvement store. I have rigged up a solenoid valve which I can actuate from EMC2. I am pretty pleased with the result, and the total cost was about $120 dollars.
Let's get started:
Step one: Go shopping (any home improvement store will get you started).
I started with the following:
Inline water filer canister (you can bin the filter as all you need is the filter)
Some 1/4 inch compression fittings
Some barb fittings
Some 1/4 inch rubber tubing (length will depend on your machine)
Various pipe fitting (plan on making a few trips)
An air pressure regulator

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Just as an FYI, if anyone is interested, I tried a similar build with all off the shelf parts for those that might have a CNC router but not a mill or lathe. (That's how I started out) I have one part I did use my lathe on and then solder the pieces, but I think it could have been drilled out and epoxy used instead for a very minimal tool build.
Link is here if you are interested, I based everything else on what I found here, so thanks for the great thread.
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Pete

I more or less complete the mister project and was just about buy the receptacle for the coolant when I remembered that I used to like my Coke 'flat' . I used to shake the PET bottle until it was rock-hard. I have no idea what the pressure was but it was undoubtedly much higher than the pressure in the mister system.
I then tested a bottle to 110 psi without problem......so for me the coolant container will be a soft drink PET bottle. The original bottle caps don't have a wide enough surface for the air/coolant fittings so I am now doing a 'cap' for the original bottle cap which can take those fittings.
The advantage of this setup is the fact that, apart from next to no cost (I do have to buy some softdrinks again) I can have bottles of various types of coolant at the ready.

I then tested a bottle to 110 psi without problem......so for me the coolant container will be a soft drink PET bottle. The original bottle caps don't have a wide enough surface for the air/coolant fittings so I am now doing a 'cap' for the original bottle cap which can take those fittings.

Cool idea Mano .. I was wondering about doing this. Have you had success in machining a cap to take the required fittings? What did you find the thread pitch to be on the top cap? I cant find any of those type of water filters locally and don't want to order one.
I was going to weld up a tank from stainless, but I would quite prefer to bea able to see my fluid level at a glance

Cool idea Mano .. I was wondering about doing this. Have you had success in machining a cap to take the required fittings? What did you find the thread pitch to be on the top cap? I cant find any of those type of water filters locally and don't want to order one.
I was going to weld up a tank from stainless, but I would quite prefer to bea able to see my fluid level at a glance

Can't find my camera to show you but it's really simple. Rather than trying to duplicate the thread I am using the original cap but made a 'cap' for the original. I used some stuff like Corian (brand of acrylic countertop material), made the pocket about 5mm bigger in diameter, about the same depth as the original and poured some epoxy into the pocket and pressed the original into it. Make sure you don't pour excessive epoxy, just enough to come almost to the top when pressing the original into the pocket.
When cured, drill your holes. I spaced them 3mm apart. I was lucky enough to have a drill bit of exactly the same diameter as the tubing. No sealant needed at that low a pressure.
My nozzle is from a metal ballpoint refill with the ball removed. Very fine and probably 0.3mm orifice. Shortly after doing that I discovered a long-necked and angled (gas?) welding tip at the hardware store with an orifice of maybe 0.5mm diameter. There is a '4' stamped on it, so maybe it's 0.4mm... dunno... but with my setup I am using 500ml (16oz) of surgical alcohol per 3-1/2 to 4 hours. I can probably do better once I receive the proper needle valve I ordered. Right now I am using some old piece of junk.

Just an FYI on this. It has been my experience that Kool Mist 77 will deteriorate Polycarbonate. It will make it crack, craze and become very brittle. It isn't supposed to do that, but I have seen it happen several times.
I would certainly check on the plastic type of the vessel and steer away from Kool Mist 77 or 78.
Metal or glass like what you see in water seps. for air lines would likely be a good choice.
Nice work on the system though. Very well done.

Just an FYI on this. It has been my experience that Kool Mist 77 will deteriorate Polycarbonate. It will make it crack, craze and become very brittle. It isn't supposed to do that, but I have seen it happen several times.
I would certainly check on the plastic type of the vessel and steer away from Kool Mist 77 or 78.
Metal or glass like what you see in water seps. for air lines would likely be a good choice.
Nice work on the system though. Very well done.

Hmmm, good info....something to keep in mind but for me it doesn't come into play. PET Softdrink bottles are polyethylene (Polyethylene terephthalate) and I use isopropyl alcohol ..... as someone on this forum said, the place will smell like a distillery.....well, well, coming to think of it, I do believe overproof white rum is cheaper here

Hmmm, good info....something to keep in mind but for me it doesn't come into play. PET Softdrink bottles are polyethylene (Polyethylene terephthalate) and I use isopropyl alcohol ..... as someone on this forum said, the place will smell like a distillery.....well, well, coming to think of it, I do believe overproof white rum is cheaper here

Lol good call MaNo. I just found one of those big dollar store Arizona Iced tea bottles and decided to use that. The cap is much larger in diameter than soda bottles. I am actually going to machine a cap instert with aluminum fittings on it.
How does alcohol work as your coolant? I just bought some Slugger cutting fluid to try it out ... but i am curious why you chose alcohol and what are the performance advantages over oil based coolant? Besides leaving a cleaner surface for welding later

I would warn against it. Alcohol is a fire hazard. In my flood coolant system, it can develop an air bubble or spit and sputter at times. During that time if I am running full speed, the end mill can glow cherry red almost instantly.
Definitely hot enough to ignite alcohol. I would not even consider it.
When I run my face mil, it can be under full flood and still throw sparks depending on what it's cutting.

I would warn against it. Alcohol is a fire hazard. In my flood coolant system, it can develop an air bubble or spit and sputter at times. During that time if I am running full speed, the end mill can glow cherry red almost instantly.
Definitely hot enough to ignite alcohol. I would not even consider it.
When I run my face mil, it can be under full flood and still throw sparks depending on what it's cutting.

Lee, I wouldn't dream of using alcohol with iron or steel or whatever could produce sparks. I am doing mainly alu.
To answer dogmeatk' question.... I never used alcohol before (as a coolant, I mean ) but so far it works well and the work area around machine remain kinda clean. Mind you, Lee's warning should be borne in mind. High rate of evaporation hence cooling was the main reason for trying alcohol. It doesn't mean that I will continue using it.
My main concern right now is the possible removal of lubricants of the machine mechanism itself. I have yet to make a cover for the Y leadscrew. Furthermore, I wonder about corrosion. My little Sherline is still relatively new but in our environment (salt air) most plain steel parts look at least 5 years old despite the fact that I periodically spray WD40 on them. So, will the alcohol remove it as fast as I spray it on?
A machinist here uses kerosene only (on aluminium) although not in a mister (brush only) and some hobbyists I know in Europe use soy oil. I will try that too plus I will try soy/kerosene mix and soy/alcohol. If or when I find Kool Mist 77 locally, I will give that a try too.
Bear in mind that my mill is a little 2010 Sherline so my projects are small too. That little tiny nozzle (made from a ballpoint refill) doesn't use a massive volume of coolant. Although it constantly sprays out miniscule droplets, I am totally amazed as to how little coolant it uses.

I've been going back and forth about building one of these for a while. Well, I finished my 6000rpm spindle upgrade and now it's looking like a mandatory upgrade. I've ordered all the parts I need to build the system, but I'm not sure what coolant or lubricant to use in the system for use on aluminum. Any suggestions?

After upgrading the motor on my G0704 I now have 6000rpm available. The machine cuts great with a 3F 3/8" AL end mill, but when I tried slotting with a 3/16" end mill I could see chips sticking to the walls and after a few minutes the end mill loaded up and broke. So I ordered all of the parts needed to make one of these misters.
My question is what coolant would you recommend to use on aluminum? I don't feel comfortable using alcohol since my water heater is only a few feet from my mill. I'd also like to avoid oils if possible. I like the results I get with Relton's A-9, but I hate cleaning it off of everything after I use it. The local tool shop carries Kool Mist 77 and 78. If I don't get any other suggestions I'll probably try 77.
Thanks,
Chris

I like the Koolmist that is environmentally friendly. Don't remember which number it is tho.
Wade

I've been going back and forth about building one of these for a while. Well, I finished my 6000rpm spindle upgrade and now it's looking like a mandatory upgrade. I've ordered all the parts I need to build the system, but I'm not sure what coolant or lubricant to use in the system for use on aluminum. Any suggestions?

On tiny fragile cutters, getting the chips out is key, not so much removing heat. I just use an air blast right at the cutter. YMMV
Karl

I've been using an air blast and it worked fine up to 4000rpm, but once I sped up the spindle I started seeing this chip welding problem.
BTW: Wierd. I looked for my post from the other day and didn't see it so I reposted. Sorry for the double.

I finished my mister last night. I think it came out pretty well. I'm pretty OCD about clutter, but I think it is a pretty clean setup. I picked up a Loc-line kit this morning so I'll swap the brass tubing for a 1/8" PTC connector and run the line inside the Loc-line. Someone did that on a thread I saw somewhere but I can't find it now. I also picked up a gallon of Kool Mist 77 so I should be good to go for the next year or two.
BTW: I have a regulator on my compressor, so I set it to 40PSI and set the regulator on the mister air line to 10PSI. It misted OK, but I don't know that it will clear chips that well. I tried 60/20 and that seemed better, but I still think I want more volume. I had a .060"ID nozzle on my air blast setup and it worked well at around 5PSI so I'll try it on the mister and see how that works.

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Chris

Hi, I am thinking about building the mister, but I have a "blank spot" in the old grey matter about the nozzle assembly. In the picture from Chris in the previous post, coming out of the mixer block there appears to be a brass tube with the nozzle on the end. Are the dimensions of this tube critical ir is it just a means of getting the air / coolant mixture to the end nozzle with its narrow (.04") opening?
Thanks for any help
ex-egll

The tube is just for transporting the already mixed air and coolant, the valve directly above is for metering the coolant.

Well i used to tremble, the pet container until it was rock hard. I have no concept, what the pressure was
but it was certainly much greater than the pressure in the mister program.

used forklifts

I used a MIG nozzle as per link in Post #17.
Al.

Thanks, that makes life a lot simpler!
ex-egll

I just built one of these using a very cheap water filter canister. The clear ones at lowes were around $40.00, I found one that works perfectly on Amazon for $8.80. It uses standard 1/4" NPT connections and made for a super easy build.
Amazon.com: 10" Standard Filter Housing, Clear/Black, 1/4" in/out: Kitchen & Dining
-Jim

Perfect timing Jim! Was just about to go and spend $30 at the local hardware store. The Amazon one looked great UNTIL I found out they won't ship to Canada. Found the same filter at AMI for the same price but they want $32 just to ship it.
Thanks anyway!

Hi Jim,
I am thinking of building one of these fogbusters and would like to know where to get the plans for the one you built. Are they available?
Thanks,
Marty
[email protected]

Hi Jim,
I am thinking of building one of these fogbusters and would like to know where to get the plans for the one you built. Are they available?
Thanks,
Marty
[email protected]

Hi Marty, the thread title is "How I built a fog-less coolant mister", so I'd suggest reading this thread.
-Jim

Hi Guys
What are you Guys using in your DIY Fog Blasters (FB)? Anyone using a Flood Coolant Mix? I would think it should work fine. When I get around to building my FB, I want to be able to use the same Nozzle for booth Coolant/Air and Air. I think you can do this by adding a couple Valves. One Nozzle makes for a simpler setup plus you only require one mounting system for the Nozzle.
Willy

Willy, I Have been using Slugger cutting fluid. Mostly because it's the only water soluble cutting lubricant I could find locally.
As for coolant/air and air only, this design already allows for that without adding any more valves. You just close the needle valve for the coolant mixture all the way and then poof, air only

Hi, Finally got around to completing the project today. All went well until I opened up the coolant valve. No coolant! There was plenty of odd sounds and bubbling but no coolant. The problem was solved by putting a second needle valve into the system. This valve went between the solenoid valve and the mixer block. All I can think of is that the water needed more air pressure than the air stream to force it through the system. Anyone else come across this?

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Mine is manual but I installed valves as you have drawn. It gives you more control of the mixture at all pressures.

Thanks, glad I hadn't done anything too wrong. Put the second valve in and the FB works as advertised!
ex-egll

Well i used to tremble, the pet container until it was rock hard. I have no concept, what the pressure was
but it was certainly much greater than the pressure in the mister program.

Step 2: start plumbing
This system works by putting air pressure on the top of the coolant to force it out to the nozzle where it is mixed with air. We need to be able to get the coolant out of the bottom of the canister. We will need a special fitting to do that. I did this by turning down a barb fitting and soldering it to a compression fitting. This way I can feed a hose to the bottom of the canister and seal it at the outlet at the top.

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http://www.machinistblog.com/
Or the originals:
I just had about my 100th request to make a copy of my zero fog mister. its
a device to spray coolant without that annoying fog the cheap misters put
out. Anyway I looked up the links and thought I'd repost here also.
Karl
http://www.metalworking.com/dropbox/...Fog_Mister.txt
http://www.metalworking.com/dropbox/...Fog_Mister.DWG
http://www.metalworking.com/dropbox/...Fog_Mister.JPG
http://www.metalworking.com/dropbox/...Fog_mister.pdf
http://groups.google.com/groups/sear...nsend&safe=off

Step 3: build a nozzle
You need to build a nozzle to mix the coolant and air and get that to where you want it. You do not have to follow my dimensions exactly. The key concepts are that you need a very small outlet nozzle to choke down the air flow and maximize the velocity. You also need a small passage for the coolant since the coolant flow rate will be much less than the air flow rate.
I made mine from brass so I could solder it. The pressures in the system are low enough at this point that you could easily use aluminum or something and just epoxy things together. The nozzle is brass rod which I bored from both ends with a 3/32 drill bit (hence the short length). Then I added an extension which is bored most of the way with 3/32, then through with 1/16 drill bits.
See my drawing.
I also whipped up a little mounting arm. You can copy my design if you like. It clamps to the spindle collar and articulates in 3 points. CNC helped for this!

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Step 4: Wrap up the plumbing
I added a solenoid valve and an air nozzle to clear off chips. I also made a mounting bracket. I added the tubing from the nozzle to the canister.

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Step 5: Pause for reflection
The mister works very well. I run about 15psi and the coolant and air use is pretty minimal. I wrapped the tubing in vinyl tape for protection. It looks a bit low rent, but it was the best idea I could come up with.
Mistakes I made that you should avoid:
I initially had plastic lines from the canister to the nozzle. They were too stiff and would pull the nozzle all around as the machine moved. I switched to 1/4 OD vinyl tubing and am much happier.
I initially had copper tubing for the nozzle. This was very flimsy and in my opinion the wrong inside diameter to work properly. The brass is much better. I have seen some examples where a MIG welding tip was used a nozzle. It might work.
The mounting bracket needs to be strong. Mine is too weak.
I added a barb fitting to the end of the tube inside the canister to give it some weight and keep it on the bottom.
Thanks everyone.
-Wes

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great write up!

How does this set up eliminate the fog?

How does this set up eliminate the fog?

CalG,
Most misters use a venturi effect to pull coolant up from a reservoir to a mixing block to mix it with air. The side effect of this venturi is that the coolant is atomized, or turned into tiny, tiny droplets dispersed in the air. This atomized coolant is not dense enough to to follow the stream of air and can float up as "fog".
A fogless system uses air pressure to force the coolant from the reservoir to the mixing block. The coolant droplets are much larger (and there are fewer of them). These larger droplets tend to stay inside the air stream and avoid forming "fog".
See this diagram which I lifted form Bob Warfield's site www.cnccookbook.com.
IMAGE(http://www.cnccookbook.com/img/ZeroFogMister/BlockDiagram.jpg)

Good tech, thank you.

Ahh
Air stream entrained coolant drops. Makes sense Thanks

I have a cautionary note:
You are using a clear plastic domestic water filter housing.
My shop has used these for coolant filters for years without problems and I have suggested their use many times here on factorydaily. Recently, however, someone did install one and the plastic housing fractured making a bit of a mess with coolant all over the place.
With your setup the housing is under air pressure, not liquid pressure, and when it is almost empty of coolant it is almost full of air at 15 psi; if this housing fractured it could fling plastic shards around.
A metal shroud around it may be a good idea.

My house water pressure ranges from 40-70 psi!
What a watery mess if one of the two filters would just Crack!

My house water pressure ranges from 40-70 psi!
What a watery mess if one of the two filters would just Crack!

Yes but then you could sue them.
My thought was that they cracked in use on a machine because they were subjected to pressure cycles every time the coolant pump turned on, leading to a fatigue effect; in a house application the pressure stays constant nearly all the time.
It was on a Haas machine with the high flow pump that generates around 20-25psi.

I have a cautionary note:
You are using a clear plastic domestic water filter housing.
My shop has used these for coolant filters for years without problems and I have suggested their use many times here on factorydaily. Recently, however, someone did install one and the plastic housing fractured making a bit of a mess with coolant all over the place.
With your setup the housing is under air pressure, not liquid pressure, and when it is almost empty of coolant it is almost full of air at 15 psi; if this housing fractured it could fling plastic shards around.
A metal shroud around it may be a good idea.

I think a cheaper solution would be to get one of those big ball buckets they use for baseball (if you buy a tub of sunflower seeds those buckets)
http://ak.buy.com/db_assets/large_im.../206226886.jpg
and just place it in there.

Just make sure the top half of the filter unit cannot fly out like an air propelled mortar.

The water filter canister is rated for over 100psi, and pressure is pressure, whether it is water or air. The commercial unit from Hench uses the same sort of clear canister. Of course, if you drop the canister or something, it will be weakened. Still, I am only at 15psi.
I will try to post a video of the unit in action.
-Wes

The water filter canister is rated for over 100psi, and pressure is pressure, whether it is water or air...

No, pressure in the form of a gas can be much more hazardous than pressure in a liquid. Liquids do not compress, at least not measurably at low pressures, gases do compress. When a pressure vessel containing a liquid ruptures the pressure is lost almost instantly and the escaping liquid does not propel the fragments of the container anywhere. When a pressure vessal containing a gas ruptures the gas expands rapidly, potentially propelling fragments of the container in all directions at high speeds.
You can choose to disbelieve but you can demonstrate the difference quite easily. Fill a balloon with air, stick it with a pin and you get a bang and the balloon tears widely. Fill a balloon with water to the same volume, stick it with a pin and you just get a sploosh.. The pressure inside the balloon is the same in both cases.

Geof is absolutely correct! I have seen the results of both. When I was young and stoopid, I used some pvc on an air line. Fortunately, when it let go, I was not in the building! As a fire protection engineer, I have seen water pipes burst and the result is a lot less dramatic:})

I am not going to tell anyone they should not be careful with pressure vessels.
Everyone understands that gases are compressed under pressure. No one is trying to say that explosive decompression is not dangerous. However, I have a 500% safety factor at 20psi. These units are in widespread commercial service. I doubt Hench would still be selling Fogbuster units if the coolant canisters all exploded. I also feel that using the water filter canister is much safer than the homemade jobs I have seen while researching for this project.
This may be a good time to say that this unit is potentially dangerous and operates under pressure. All users should understand the risks of this type of device before undertaking its construction or operation.
I will leave it at that.

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