Mist lube sprayer

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Hukshawn

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So, I've been intrigued with the mist lube sprayer. On my mini mill, I'm always worried about heat, and often get wd40 or oil all over the place. And, the times I had been cutting a groove, been plagued by chips.
The lathe, not so much, but I'm sure it's helpful there too. And frankly, it'll give me something to build. I have some time finally, I finished all my side jobs and am down to just day job.
So, I bought a cheap Chinese venturi style mist sprayer before really thinking about it. A few YouTube videos later I already see problems with the unit alone. You have to run too high air pressure to get enough suction and wind up with too much lube. A big mess...
So, taking many ideas from a few different sources, I've come up with an idea.

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That's the unit.

This is what im gonna do.
IMAG1069.jpg

I have air coming into a solenoid valve so I can control the whole works with a switch, (in writing this, I can already see how I want to rearrange my set up... but I'll get through the explanation first)
Then into a tee to split the air. One regulator will pressurize this old water filter which will contain the lube. I imagine something around 3-5 psi would be enough to push the lube up the tube. (See below)
Then the other leg will go into a regulator into the venturi.
I'll have a metering valve after the lube tank to control the flow, and the venturi has a valve to control the air in.
- having that solenoid in the beginning will be fine for cutting the air, but the tank will still have pressure. So, I may ditch the solenoid valve for just a butterfly valve to control the whole works, and some kind of a shut off valve down stream to control the mist. And maybe a pressure release on the tank to drain it when I'm finished with it...
Lots of little parts, lots of areas to improve, but in my minds eye, this all works!

Then I'll replace that goose neck hose on the venturi with a clear hose that's longer and more flexible going into a finer tip. I've heard the tips that come with this are too big.
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The tank. I discarded the filter, machined the spout that went inside the filter to accept a 3/8" pipe thread adapter to allow me to thread in a 1/8" copper line as a straw.
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I have to go shop for all the little parts and it'll be a month, at least, before the venturi gets here.
But, I'll plug away at the pipe fittings in the mean time. And post along the way.
 
I'm wondering now... with the better models of misters, is the lube mixed with the air AT the tip? Or else you wind up with an air line fill of liquid?
 
I'm not sure why I didn't realize that... I do hvlp lacquer spraying all the time....
 
I have the same type and works fine for me. If I remember correctly it only takes about 40psi to pick up the coolant from my bottle
 
So here's the convoluted setup.
It works, first of all... air comes in, splits into two feeds, one is regulated right to the venturi. The other is into the filter holding tank, that is again metered with a small flow valve down line. Turns out the small valve on the venturi itself does nothing at all.
I have full control over everything here, I can get a very nice atomized mist with a comfortable 35-40 psi.
When I tested the venturi by itself I needed about 50 psi to produce a mist, otherwise I get a splatter effect or nothing at all siphoned. The 50 psi was too much. Blew way too hard. I'd be blowing chips across the garage, and likely running the compressor unnecessarily often.

I need to sort out a way to shut the spray and air off at the tip or close too other wise I get the remaining pressure in the tank pushing fluid out, or I have to close the metering valve inline then reset it back up when I turn it back on.

I tried it out on the lathe and it seemed to work. Kept the tool cool and the chips only then the hay colour rather than blue on a heavy cut.
I'll try it on the mill next time I do a slot, which was the entire purpose of this. To cool and evacuate chips from the cut.

The side effect... The water soluble lube I currently have makes me cough when I breathe in the mist. Almost takes my breath away... That's not gonna be good... And my garage fills up with fog.

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The only way I have found to keep the mist down with the type of mister you have is to crank the air pressure up, get the siphon going then back down the air until its just barely spitting fluid. Other wise I get a room full of mist hanging in the air. It also helps to hang the fluid reservoir up above the mixer valve so you don't need so much air to pull the fluid into the mix. A Micro Drop or Fogbuster set up or home built Fogbuster type is much easier on your lungs and air compressor. For fluid I like Rust Lick, or Cool Mist, neither of them bother my lungs to much if I can keep the mist down.
 
I tried a mist system, once, the mess was ungodly, I got rid of the lube and now just use air, along with a couple of cardboard diverting panels, to control swarf placement. I regulate the air, just enough to move the chips out of the cutting area.
 
Our mister is fine.

You should be able to setup the unit with the nozzle close to the point of cutting and a spray pattern just large enough to cover it.

Ours hits the cutter and often evaporates or goes back to liquid and drops into the table.

We have a drain hole in the back of the table with a hose that goes into an old milk bottle hung by a cord.

Commercial shops have massive spray and collection systems as they are running much higher speeds but for home hobby stuff we are not running that kind of heat load to warrant a fog level of mist generation.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
I had put the unit away after that test. I need some more parts, like a mag base. I'll try it all again next week. It needed some time in the healing bench for me to think of how to work the bugs out.
 
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