Refractometers, whole milk, & skimmed milk

Generally the coolant will tend to bead up a bit on the parts when you blow the coolant off with compressed air if / when the mix is sufficient--still, a refractometer is highly suggested...

( Following is courtesy of John )

What you wanna do is make up a small test batch that is richer than what you want to run.....say 10/1....and then you check it, noting your refractometer reading....then you thin the mix, say to15/1 and you note the reading again.....and so on.......until you have enough baseline readings to work with.....

PV,

The Valcool I use seems to prevent rust even in weak solutions.

It doesn't say anything explicitly about it either.

Mark

"Proctologically Violated©®" wrote in news: snipped-for-privacy@rcn.net:

I strongly suggest that you invest in a good refractometer. Expensive, yes, worth the money...yes. We have tested different dilutions, and there can be a wide variance over just a percentage or two of dilution, that effects many things, like tool life, finish, part dimensional stability, loading, etc. We were really suprised at what all it DOES effect. As a matter of fact, it was determined to be so much a critical component, that now the refractometer readings are checked and entered into the SPC system every shift, for every machine. There are control limits set, so that they must take corrective action if it falls outside of the desired range for that process. We found this true of any coolant we have tested, and we've probably tested the vast majority of what's available on the market.

Wow... you must be one humongous shop, bro... If you *had* to endure an error, would you rather the error be in the more concentrated direction, or in the less concentrated direction?

---------------------------- Mr. P.V.'d formerly Droll Troll

Take a look at your MSDS sheets, or info sheets from your coolant supplier. Some say specifically that the refractometer number does NOT equal the actual solution. Can't remember which brand that was, might have been spartan, but if you wanted 5%, you went to about 8 on the refract.

"Proctologically Violated©®" wrote in news: snipped-for-privacy@rcn.net:

There are 1200+ employees. There are well over 100 CNC actual metal- cutting machines in my dept alone. (Not counting the automation, or other equipment, just the ones that actually cut something.) My job involves every one. hehe....Sometime, just try to remember all the G/M codes and what all the buttons do and what screens are what, and where stuff is for 100+ machines....lol....oh...and controllers... lets see... Siemens: Primo, System 3T, 805, 840C, FM-NC, 840D, Op-17. Fanuc: 21iTA, 18iTA, 18iTB, 16iTa, 16iTB Mazak: M32, T2, T+, 640 Fusion-T, 640 Fusion-M, 640 Fusion Pro Index: Couple of OLD ones. Gildemeister: Couple of these....can't remember the names Jetter.... and this doesn't include the proprietary stuff.

I would err on the rich side, if I *had* to err.

PV:

If it's TOO dilute you'll get light rust on your table and vise overnight.

The oil in the coolant can act as a rust inhibitor.

-- BottleBob

Just put about 1/2-3/4 of an ich of concentrate in the bottom of a 5 gallon bucket and fill the bucket 3/4 full. Any higher- it will be too heavy to lift and pour into the machine. I'm pretty sure you will be in the 5-7% range.

Snot test is best.

Umm, careful there. Put the water in the bucket then ADD the coolant. Always add coolant to water. Yes, it makes a difference. Ask Bottlbob :)

when we tested new coolants we would make our own ratio in a five gallon bucket starting with 1:1 and recording the refractometer reading until we got 30:1: note that the coolant was added to the water when we did the 1:1 because sometimes the coolant is so heavy that it just sinks to the bottom of your coolant tank and then is wasted we run our coolant on the refract at somewhere between 4.5 and 8.5 with the heavy mix when we are deep hole drilling and the regular mix at roughly 5.0 this allows the operators to add just water or coolant from our premix tank which is set at 5.0 the savings in premixing and checking the tanks before adding to the level can be a significant savings

Hamei:

Heh, yeah. Virtually all the coolant salesmen/distributors/technicians I've asked this question of (whether to add water to the oil, or oil to the water), have said to add the coolant in last. A little mnemonic to help remember this is to note the spelling of OIL, the letters of which can stand for Oil-In-Last. We used to almost fill a 5 gallon bucket of water and use a one pound coffee can filled to the bottom indentation and pour it into the water in the bucket while stirring the water with a paint mixer driven by a variable speed hand drill, this would give us our desired 10% mix. NOW we have a water pressure driven coolant mixer that screws into the

55 gallon coolant drum and automatically mixes the coolant and is adjustable for concentration. The exit hose is routed to the ceiling and comes down roughly where it can be stretched to reach most of the CNC's.

-- BottleBob

That's the spiffiest. You keep adding kewl labor-saving stuff to the shop until you get it just where you want it. Too bad you're about 87 by that time :-)

Hamei:

Well, life can be a constant process of improvement, of self and your surrounding environment. When that stops, you may as well just take a dirt nap.

-- BottleBob

Even if improvement of "surrounding environment" is in the form of smaller, smoother inserted objects. Sheeit, I'll take it!

Does graduating from the Deepak Chopra School of Enlightenment count as Self Improvement? Does one remain Self-Improved if one washes Deepak's s**en out of one's hair, does one?? On PBS, no less. Goodgawd...

---------------------------- Mr. P.V.'d formerly Droll Troll

Ha ! you need to reread your Daoist tomes :-) I think it's just an averaging process, myself.