[Memran]

I'm looking to buy a mist coolant system (Don't know which one yet), and a "silent" compressor.

The compressor needs to be quiet because it will be right by where I'll be working and I'll have neighbours close by too.
Looking at something like this: Buy Bambi BB24V Compressor from Axminster, fast delivery for the UK.

Free Air Delivered:
@ 1 Bar - 40 L/Min,
@ 5 Bar - 34 L/Min,
@ 8 Bar - 31 L/Min

I know nothing about mist coolant really, so is such a compressor sufficient for chip clearing and for mist-making?

If you also wish to share your mist experience, please do!

[SCzEngrgGroup]

That *might* work, but it will run continuously. With mist, you're running around 20 PSI (about 1.3BAR). No idea what the flow rate is, and it will depend a LOT on exactly WHICH mister you use (FogBuster? Spra-Kool? Other?). My small compressors (1-2HP rated) typically run continuously feeding my FogBuster mister. Personally, I would not bother with anything other than a FogBuster style mister - works FAR better than all the others I've seen or tried.

Regards,
Ray L.

[underthetire]

Well, do you want a full mist system, that gets on everything and stinks up the shop, or a micro drop style. We put the drop style ones on all our open bed cnc mills. I forgot who makes them, but we get the automatic ones that have a built in solenoid to be able to program it. That compressor should run it, but I'm too lazy to convert your modern metric system specs to our bass ackwards imperial system . 3 cfm at 20 psi is about where we run them at.

[Memran]

Thanks for those fast replies!

Free Air Delivered:
@ 1 Bar - 40 L/Min, = @ 14.5 PSI - 1.41 cfm
@ 5 Bar - 34 L/Min, = @ 72.5 PSI - 1.2 cfm
@ 8 Bar - 31 L/Min, = @ 116 PSI - 1.09 cfm

I think that conversion is correct!

So your 1-2 HP compressor runs constantly? This one is 375W = 1/2 HP.

Its not looking good for this little compressor

I've not yet decided on a mist system yet, but if I'm going to need a much more powerful (more expensive) compressor, the whole plan goes out the window

[michaelthomas]

I use a Noga Minicool dual mist setup with Koolmist 77. I can honestly say I have not detected any fog, odor, or any hint of it being a nuisance. I run it for hours at a time.


I couldn't tell you how much air it uses......the shops compressor is huge, and its not in the same building so i wouldn't know how much it runs.

[michaelthomas]

Duplicate post......sorry.

[digits]

I had a similar compressor (Clarke Sssshh) and it was very,very quiet (like a modern fridge) but it was a bit limp. It gave up the ghost quite recently (I don't think I was meticulous enough about checking the oil-level), and I decided to go for a loud high flow one instead.

One thing to bear in mind is that even if your compressor is silent, enough high pressure air to blast chips out of the way probably won't be!

[SCzEngrgGroup]

Well, do you want a full mist system, that gets on everything and stinks up the shop, or a micro drop style. We put the drop style ones on all our open bed cnc mills. I forgot who makes them, but we get the automatic ones that have a built in solenoid to be able to program it. That compressor should run it, but I'm too lazy to convert your modern metric system specs to our bass ackwards imperial system . 3 cfm at 20 psi is about where we run them at.

Have you ever actually used a good mist system? I used mist exclusively for 5 years, and it absolutely does NOT "get on everything", nor does it "stink up the shop". In fact, I get orders of magnitude more mist in the air, more humidity increase (dramatically so), and more coolant on the floor since switching to flood coolant. Using mist, I never once found it the slightest bit objectionable, there was never any hint of mist in the air, nor was there any discernable odor whatsoever.

Regards,
Ray L.

[underthetire]

Yes, and I've worked on machines that people used it on. Sticky everywhere. Yes flood coolant gets everywhere, an can atomize as well. Have you used the micro drop style? Much better all around.

[SCzEngrgGroup]

Yes, and I've worked on machines that people used it on. Sticky everywhere. Yes flood coolant gets everywhere, an can atomize as well. Have you used the micro drop style? Much better all around.

Sticky is a function of the specific coolant you used, not the whole mist concept. I use KoolMist 77 - no smell, no residue whatsoever. No I haven't tried micro-drop. But I need coolant as much, if not more, to clear chips as anything else - I don't see how micro-drop can help with that. And, it would suffer from the same problem as mist - it's near impossible to keep it pointed at the right place all the time, especially when doing deep slotting.

Regards,
Ray L.

[Memran]

Thanks for all replies!

I don't have much choice regarding the compressor. I simply have to have a quiet one, and cost will limit me to a fairly small one.

I spent over an hour yesterday manually blowing chips away with a hand held bellows. Not something I want to ever do again!!!

Coolant choice is likely to be KoolMist, but I will get the compressor first.

[MichaelHenry]

I spent over an hour yesterday manually blowing chips away with a hand held bellows. Not something I want to ever do again!!!

Could you use a shop vac to suck them up instead of blowing the swarf around with a bellows?

GMC makes a pretty quiet small compressor that sells for $250 or so but it only puts out around 3-4 cfm.

Mike

[WOTDesigns]

I use the kool mist portable unit, and kool mist 77 at 40 psi and dial it back using the adjuster most of the time. when I first got it I had some rust spots pop up on the table so I upped the concentration and have nothing but great results. the tool and the work piece are COLD when done cutting, chips clear, and I can run tools faster than befor. no problems. no mess. only $80 for the portable unit and I have pulled it off the mill and tossed it on my bandsaw when doing long cuts. just unplug the quick disconnect, pull off the magnetic base and grab the gallon water bottle full of kool mist and its on another machine. great tool.

fogbuster is better than the kool mist sprayer i think... but not better than 4 of them which is what it costs. i want one, but the kool mist unit works too well to justify me spending that much. .

[SCzEngrgGroup]

I've built several of my own FogBusters, for about $30.... the patent is available on-line, and makes it pretty clear how to build one.

Regards,
Ray L.

[Memran]

I've purchased a similar silent compressor, used, on ebay. It was at a price that makes it worth taking the risk on whether the airflow is sufficient.
It should arrive on Friday. Then I'll look at mist systems in a lot more detail, but KoolMist is favourite so far.

[digits]

How are you getting on with your setup?

It didn't take me long to discover that

a) I can use all 5 cfm of my loud compressor doing air-blasts if I'm over generous with the air,

b) 86dB in a confined space, even with ear protection gets tedious really fast...

I tried enclosing the compressor in an MDF box, which did shave off ~9dB, so it was half as loud, but still very loud to my ears.

So finally I caved and bought a Bambi 24V - having done the sums, it is twice as powerful as the silent one I had before, and a lot cheaper than Machine Mart's Clarke Ssssh equivalent.

It sort of works - it is really almost silent - think quiet fridge. I have to put my hand on it to know if it's on when the mill motor is running...

But the airflow isn't quite as impresive as the spec would say - it is only designed for 50% duty cycle, so really you're only going to get ~1cfm out of it. I discovered that even in a room at 10C, it is quite easy to trip the thermal-cutout. Even charging from 0-8 bar with no outlet flow, it gets pretty warm. My current solution is to blast it with a big, noisy desk-fan, which seems to be crude but effective!

That might be enough though - it does seem to clear chips with my current loc-line setup, but I'm going to try a higher-velocity stream using a smaller nozzle...

It is however great for providing silent power to my air-drawbar, so it's definately a keeper! It got me thinking though - perhaps I don't need a compressor for air-blasts, I need high flow at low-noise and low-pressure - I need a blower really. If I see a nice cheap supercharger on ebay, I might have a go at a really high flow 4psi system. Not sure how loud it'd be though...

[WOTDesigns]

supercharger is an interesting idea.

I just posted the other day about adding a check valve to my PORTaMIST on the coolant line to stop it from sucking air back into the system. made it a completely different animal with no air bubbles prohibiting flow. much smoother, more adjustable and the secondi turn the knob must is coming out. amazing what a $10 part can do

[Memran]

Well, its been up and running for a while now, without coolant. It is just about ok for blowing the chips away, but it is extremely nice because of the low noise.

I would not consider it a long term solution though, as the 50% duty cycle means you get half the stated airflow. I'll have to try your idea of he big fan!

[digits]

The big fan seems to work OK - I've spent 3 hours solid cutting without overheating the motor. I did however let the compressor fill the tank completely and then cool down again for 1/2 hour or so before I started taking any air.

[jduke]

Several years ago, I used the air conditioning compressor from a junk car as an air compressor.

It was by far the quietest compressor I have had although if you want any longevity out of one you will have oil in it.

Duke