Does anyone have experience with a “cold gun” that take compressed air and makes a jet of cold air ? e.g. this ?
I wonder if it could work well in situations where air+mist coolant is usually necessary, to not have to use any coolant. It looks like a pricey item anyway, so probably irrelevant for hobby CNC, just wondering.
I found one ages ago, and asked after it on I think the Shapeoko forums — Catalin Voinescu did some calculations and determined that just a compressor works fine for the spindles which can be mounted on a desktop machine.
Air hungry, but effective. As @Winters636 said, not really worth it for hobby work. Aside from the high volume needed, you need a way to get rid of the heat from the hot end, and the air supply needs to be clean and dry to prevent freezing and fouling.
They tend to be used when you need moderate cold air volume (cold, like 0C or lower cold) and refrigeration gear isn’t practical. There are a LOT of places this applies in industry, but the cost of operation is high. They have other uses, and I have used, a few times, handheld heat guns that are essentially Hilsch tubes, and been on a few jobs where the tubes are used as the cold-air source for a cool suit.
They’re vortex tubes. Yes, they work to generate a cool stream of air. They use a TON of air though, and are very, very loud. You can make your own (with a little work) and some really simple parts to try though.
Another option is to mist denatured alcohol. We had a tool and die maker at my day job that either used denatured alcohol in a spray bottle or vegetable oil when he was on a Bridgeport. When he used the vegetable oil it smelled like he was cooking french fries. He was a very good tool maker also, he left my plant to go manage a tool room with 50+ guys under him.
i’m not that familiar but i believe there’s only a small range where the air to fuel would combust. much like the perfect storm required for wood chips. since my machine is housed in an enclosure that resides in a small closet i don’t want to accidentally flood my apartment lol.
until i look into it more compressed air only will have to suffice
i read this on the neo setup guide;
The following must be observed when the machine is operated with cooling lubricant:
During continuous machine operation the area around the machine must be well ventilated or an exhaust system for the removing the cooling lubricant vapour must be installed. When installing the room exhaust system, note whether the cooling lubricant in use is lighter or heavier than air. Install the room exhaust system at the top or bottom as applicable. The AGW values (maximum workplace concentration values) of the cooling lubricant must be below the maximum limit.
In HVAC technology, the following general empirical values are used for the air exchange numbers (i.e. exchanged air per hour):
Hal Clement had a really cool story on this in his collection Space Lash (which was originally publishes Small Changes — one of the few books we had in our house when I was young I read it quite a few times.
As for methanol, yes, it’s toxic, don’t use it as a primary coolant. Using denatured alcohol (ethanol + other alcohol (methanol and IPA are common)) may pose a slight risk if used continuously, in high concentrations, in poorly ventilated environments.
Really, with what we do, read the SDS, open a window, and don’t spray hideous amount of coolant into the air. I use a 75/25 IPA/H2O mixture misted onto aluminum when I mill it and it works just fine. Most of the vapor condenses onto the part and very little aerosolizes to a point where I can inhale it.
I understand your mindset is much more scientist based on facts and studies.
Mine is much more common senses.
Stronger alcohol just means the mix of alcohol.
Regarding Mineral Oil, it is well shared fact that it does accumulate into your lungs till it does something bad.
I remind having read a story on a CNC forum about a guy suddenly having trouble breathing from day to tomorrow, he wasn’t old at all, like in his early forties as I remind.
He went for some medical checks and the results were pretty clear, he has oil based product stuck inside his lungs, like a small pocket of oil, went onto a surgery to remove it asap as the doctor said he had a few months left to live if he don’t remove it, after that he said he moved to flood cooling and wear a mask anytime he work in the shop lol.
I made a lot of researchs regarding filtering and health effects of manufacturing, honestly, I coudn’t find many studies, so I had to resort to read a lot of experiences of individual, some weren’t pretty, but most people are fine althought they know they are taking a risk. Genetics plays a big role too.
It’s up to each to do what they want, I would rather trust my common sense.
Regarding alcohol I would think that it’s less dangerous, but I woudn’t go as far as saying it’s good. It is still a poison.
I’m not sure if you really know how much alcohol is being used…my max consumption rate is around an ounce per hour. Even drinking straight vodka… that’s not even enough to get drunk.
I can guarantee you that fumes from wd40 are 1000% worse than a minimal alcohol setup when used correctly.
Its understandable to be scared of something new, and common sense is great, most people don’t have enough. However, @The_real_janderson and I have actual use experience. Personally ive put gallons and gallons through my system without a single issue or even sign of “fumes”.
Alcohol is different than most yes.
But imo, it can be very safe to use and a very effective coolant/lubrication for a cnc router.