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Coolant mix guide: brands and practices (asking if it exists, not offering advice)

thunderskunk

Cast Iron
Joined
Nov 13, 2018
Location
Middle-of-nowhere
Hey...

There has to be a thread somewhere, I'm just not finding it. The sales rep stopped in the other day and was ranting/raving about this coolant mix or another for milling. I don't remember what brand he was referring to, but I'm about sick of whatever I'm working with, just not sure what to switch to.

Is there a guide out there to the various brands and types of water-based coolant mixes for milling? Tips on testing?
 
They all suck, and everyone has an opinion about what is best, with no hard evidence to back it up.

If you find a coolant that works, stick with it. Good semisynthetics are the closest thing to a universal coolant. After trying several, we like Castrol Hysol MB 50. Between 8% - 12% works well with our coolant. Too rich and everything starts to get slimey. Too lean and it might start to grow bacteria. Most of the coolant loss in our environment is due to evaporation, so we typically add makeup once or twice a week at ~3%.
 
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I've had some really good coolants, and some that were awful.
The aforementioned Castrol worked pretty well.
Xtreme-Cut 251 worked good. So did Trim Micro-sol.
Many times it's the water that makes the difference.
 
Many times it's the water that makes the difference.

And lack of maintenance!

You have to consistently get any tramp oil/grease from the top of the coolant, and keep the coolant tank relatively clean and chip-free.

If you hand mix, always add the concentrate to water, not the other way around.

Inducing oxygen with aquarium bubblers can help.

Keep the concentration within range. Sometimes older coolant will start separating out of solution, or not mix well to start with.

Coolant is expensive, it's necessary, and it's a pain in the ass.

ToolCat
 
And lack of maintenance!

You have to consistently get any tramp oil/grease from the top of the coolant, and keep the coolant tank relatively clean and chip-free.

If you hand mix, always add the concentrate to water, not the other way around.

Inducing oxygen with aquarium bubblers can help.

Keep the concentration within range. Sometimes older coolant will start separating out of solution, or not mix well to start with.

Coolant is expensive, it's necessary, and it's a pain in the ass.

ToolCat
Correct on all counts.
The aquarium bubbler especially.
 
They all suck, and everyone has an opinion about what is best, with no hard evidence to back it up.

If you find a coolant that works, stick with it. Good semisynthetics are the closest thing to a universal coolant. After trying several, we like Castrol Hysol MB 50. Between 8% - 12% works well with our coolant. Too rich and everything starts to get slimey. Too lean and it might start to grow bacteria. Most of the coolant loss in our environment is due to evaporation, so we typically add makeup once or twice a week at ~3%.


Me and a cpl other guys all picked up a mess'a NOS Castrol semi this last summer at auction. I kept 1000 gals.

The stuff that we have has already been superceeded and it is thin - designed mostly for grinding apps (so maybe run a wee bit richer) but I have to say that it has so far seemed to go real well! No stink yet and in most apps it was just put in over the top of what was there already. It seems to absorb many oils. I don't get much skimmer oil from it, even on way-lube machines.

I'm maybe 6 months in so far.
This is my first experience with a semi.
Full synth likes to rust stuff up.
Full dino likes to go bad.
This stuff? So far so good. Hoping for the best as I have a 5 year supply!


------------------

Think Snow Eh!
Ox
 
I'm maybe 6 months in so far.
This is my first experience with a semi.
Full synth likes to rust stuff up.
Full dino likes to go bad.

This is my experience exactly. Full synthetic is the best on paper, but it is really hard to maintain performance due to constant contamination. Semisynthetic is much more forgiving.
 
I tested at our distributors expense Baser Swisslube Synergy 735 in two machines over 6-months and really like the results. The distributor even cleaned out the machines and coolant tanks for us. We are doing both heavy roughing and finishing of aluminum and it appears to perform really well. One of the cool things is even after 6-months I can see the bottom of the coolant tank, and there does not seem to have the nasty odor other coolants have after 6-months of use. One other detail not to ignore is that we are using DI water which helps.
 
I've been using Hangsterfer's 5080 for about 8 years now, and mix it with distilled water. It doesn't matter which you add first, it works fine at a wide variety of concentrations, it never gets stinky, even if you leave it sit for months, and it doesn't bother my skin. Some have said they don't like the smell, but it doesn't bother me. I mostly cut Ti and stainless with it.
 
Cimcool Cimstar 60C-HFP sucks. It smells something awful. For a few days I lied to myself and said it was better, now it just reeks bad enough noone steps in my shop unless they have to. I'm moving to a new facility. When I clean the machine out, the coolant is getting swapped again.
 
We've used Hocut 795, and switched to 795B recently, which seemed to decrease any staining if parts were left overnight with coolant sitting on them. Mostly running aluminum and steel, and over 5 years and 17 machines, I've only seen 2 machines have their tank go bad. Both cases were machines that were sitting for days/weeks on end, didn't have tank skimmers, coolant concentrations weren't being checked, and had run steel on their last job. I personally think steel dirties coolant more than aluminum, so that's the only reason I put that note in.

It has a bit of a smell, but I haven't noticed it other than when I accidentally hose myself with it. When mixed, the coolant is milky white. After running a lot of brass, it'll turn blue, but keeps running fine and doesn't go bad just because of that. No idea on its price compared to other coolants, as I've only ever used Hocut; runs about $2k for a 50-gallon drum of concentrate, which should make ~700 gallons of coolant. Other than the machines that went bad, we pretty much never clean out a machine completely; only adding fresh mix on top of whatever is in the tank to keep the concentration at 7% (whenever the tank gets low).
 
Hey...

There has to be a thread somewhere, I'm just not finding it. The sales rep stopped in the other day and was ranting/raving about this coolant mix or another for milling. I don't remember what brand he was referring to, but I'm about sick of whatever I'm working with, just not sure what to switch to.

Is there a guide out there to the various brands and types of water-based coolant mixes for milling? Tips on testing?
I have tried dozens and dozens over the last 38 years, yes many will give you free samples to test with. I have had people in here raving too then they tell me oh you also have to add this chemical and that chemical. Nope I should not have to add anything at all, I use 4776 ND from CLC lubricants its not expensive I never add any chemicals and I use it for every thing Aluminum, stainless, low carbon, copper, plastics and many more I use it in the CNC mills and the turning center. I have never had it go rancid and I am not the best when it comes to coolant maintenance in fact I would say I am horrible at it but never had issues it does not leave slime all over everything or allow rust to form on my equipment. When mixing it I dump it in a bucket and say that looks close enough and go from there, never used a refractometer in my life it is a waste of time and money. On some jobs I will just mix it a bit richer and by that I mean what the hell an extra 2 cups in 5 gallons should work because more is better. I have probably tried 50 different coolants over the years and this is the best I have come up with give it a shot see what you think. Contact CLC and see if they will send you out a sample this whole idea of making coolant into a science to me at least is dumb as hell I have been in this business for almost 45 years 38 in my own shop and never put much thought into the "science" of coolant if it is wet does not cause a rash, stink or leave a messy slime it is good and stay away from anything where you have to add anything besides tap water what a scam that is.
 








 
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