# Water-based machining coolants

Water-miscible machining-fluid classes, exact-product property comparisons, sample bases, and limits of composition and performance evidence.

Reviewed: 2026-10-30

Tags: chemicals, machining, metalworking-fluids, emulsions

## Identity and terminology

Master Fluid Solutions lists concentrate pH **9.6–10.0 for TRIM MicroSol 585XT** (semisynthetic) and **9.0–9.3 for TRIM C270** (synthetic). These measurements do not establish working-fluid pH. [MicroSol 585XT TDS][microsol] [C270 TDS][c270] OSHA groups soluble oils, semisynthetics and synthetics separately from straight oils used without water dilution. [OSHA, introduction and section B][osha]

| Class | Classification meaning |
| --- | --- |
| Soluble oil, also called emulsifiable oil | Oil dispersed in water through emulsifiers. "Soluble" does not mean that the oil forms a true molecular solution. |
| Semisynthetic, also written semi-synthetic | Combines water-soluble and emulsifiable components, with less base oil than traditional soluble oils. |
| Synthetic or full synthetic | OSHA describes a water-soluble formulation without petroleum oil. This does not mean absence of organic lubricants or additives. |

These distinctions follow OSHA's section B and glossary. Its semisynthetic example contains 5–30% oil by volume in the concentrate. That historical range is not a current specification for every commercial product. Possible additives have separate functions, including wetting, lubrication, reserve alkalinity, corrosion inhibition, and foam control. [OSHA, appendices 1 and 2][osha].

As explanatory synthesis, "water-based" identifies the intended fluid system, not necessarily a water-rich supplied concentrate. The concentrate, a prepared analytical dilution, used circulating fluid, residual film, and workpiece are different materials. A separately supplied additive is not a complete coolant. A machining-and-grinding product is not restricted to grinding merely because grinding appears in its application list.

## Exact-product examples

The following North American Master Fluid Solutions sheets all carry a footer date of October 30, 2026. Their URLs generate documents, so that date identifies the retrieved copies rather than proving a formulation revision. Each sheet labels its physical properties as typical data.

| Product | Maker classification and application boundary |
| --- | --- |
| TRIM E206, source identifier E206N | Soluble-oil emulsion for ferrous and nonferrous machining and grinding. The maker attributes built-up-edge control to extreme-pressure additives. [E206, page 1][e206]. |
| TRIM MicroSol 585XT, MS585XT | Semisynthetic microemulsion for machining and grinding, including gray iron and titanium alloys. Magnesium is explicitly outside its recommendations. [MicroSol 585XT, pages 1–2][microsol]. |
| TRIM C270 | Synthetic for machining and grinding. The maker excludes machines dependent on coolant splash for mechanical lubrication and qualifies magnesium and zirconium use. [C270, pages 1–2][c270]. |

As synthesis, a class name cannot establish alloy or machine compatibility. Even broad multi-metal claims have product-specific exceptions. Application listings and maker approval tables establish neither a customer's approval nor qualification of every alloy, coating, seal, or downstream finish.

## Properties and sample bases

These are selected entries from page 2 of each sheet, not operating settings. A dash means that the selected table does not provide that property.

| Reported quantity | E206 | MicroSol 585XT | C270 |
| --- | --- | --- | --- |
| Concentrate color | Dark blue | Amber | Colorless to amber |
| Working-fluid appearance | Blue | White microemulsion | Colorless |
| Concentrate pH range | — | 9.6–10.0 | 9.0–9.3 |
| Concentrate flash point, ASTM D93-08 | Above 210 °F | Above 214 °F | Above 226 °F |
| Coolant refractometer factor, % Brix context | 1.0 | 1.2 | 3.3 |
| VOC content, ASTM E1868-10 | 95 g/L | 193 g/L | 110 g/L |
| Source | [E206][e206] | [MicroSol 585XT][microsol] | [C270][c270] |

The concentrate pH entries lack measurement temperature and a specified analytical dilution. None of these tables gives density, specific-gravity reference temperatures, or viscosity. Their flash-point inequalities are lower bounds, not measured ignition temperatures. The VOC entries share a named method but do not quantify machining mist. [E206][e206], [MicroSol 585XT][microsol], [C270][c270].

The sheets' refractometry graphs distinguish a Brix-scale reading from calculated product concentration and use the product-specific factors above. The reported concentration percentage does not state a mass or volume basis. As synthesis, equal instrument readings do not establish equal coolant content across these products, ingredient wt%, oil fraction, or microbial condition. The graphs provide no uncertainty or validation for contaminated used fluids. [E206, page 2][e206], [MicroSol 585XT, page 2][microsol], [C270, page 2][c270].

## A differently conditioned measurement

ROCOL's UK ULTRACUT 370 EP technical sheet, revision code 0826, describes another semisynthetic. Its density is 1.00 g/cm³ at 20 °C by ASTM D4052. Its pH of 9.5 belongs to the stated 20:1 analytical dilution, not the concentrate. The ratio's mass or volume basis, pH temperature, and pH method are unstated. Values are typical, not specifications. [ROCOL TDS, page 2][rocol-tds].

As explanatory synthesis, density has mass-per-volume units. Specific gravity is a ratio requiring a reference density and temperature basis. Density at 20 °C cannot supply an unstated specific-gravity convention. Similarly, pH at a named dilution cannot replace concentrate pH. The ROCOL SDS leaves product kinematic viscosity unavailable. Its separate methyl-benzotriazole viscosity entry belongs to an ingredient, not the mixture. [ROCOL SDS, sections 9 and 11][rocol-sds].

## Composition and free-of limits

The ULTRACUT 370 EP GB-English SDS is version 3.0, revised June 16, 2026 and printed August 17, 2026. Selected ingredient disclosures include 2,2'-iminodiethanol at 5–15%, an orthoboric-acid compound with 2-aminoethanol at 2.4–10%, and sodium pyrithione at 0.1–1%. The percentage heading does not specify mass or volume. [ROCOL SDS, sections 1 and 3][rocol-sds].

As synthesis, an SDS ingredient table is not a complete formulation. Its ranges cannot establish the undisclosed water fraction by subtraction. An explicitly stated ingredient wt% would instead mean ingredient mass per total product mass, a different quantity from coolant-product concentration in water.

ROCOL's TDS claims absence of bactericide, silicone, chlorine, formaldehyde, nitrites, and animal-derived materials. The SDS discloses sodium pyrithione and an associated allergy statement. These documents do not reconcile the bactericide wording with that disclosure. As synthesis, that wording does not prove sterility or absolute ingredient absence. [ROCOL TDS, page 1][rocol-tds]; [ROCOL SDS, sections 2–3][rocol-sds].

MicroSol 585XT separately claims no nitrites, triazines, phenols, or chlorinated or sulfurized extreme-pressure additives. C270 names chlorinated and sulfurized extreme-pressure additives among its exclusions. These are exact-product formulation claims, not class definitions, current-lot assays, or analytical detection limits. [MicroSol 585XT, page 1][microsol]; [C270, page 1][c270].

## Performance and coverage limits

ROCOL claims compatibility with hard and soft water, low foam, residual corrosion protection, and resistance to degradation. Its sheet supplies no hardness range, named foam test, corrosion result, or microbial challenge data. Those claims do not define universal water-quality limits or comparative performance. The sheet's dilution statements and calibration-table range also differ, leaving an ambiguous application limit. [ROCOL TDS, pages 1–2][rocol-tds].

E206's emulsion-stability and tramp-oil-rejection claims, MicroSol 585XT's foam and sump-life comparisons, and C270's low-mist and corrosion claims likewise lack controlled numerical tests in these sheets. No universal ranking of cooling, lubricity, tool life, or biological stability follows. All three sheets qualify their information by formula version and uncontrolled use conditions. [E206, pages 1 and 3][e206], [MicroSol 585XT, pages 1 and 3][microsol], [C270, pages 1 and 3][c270].

Water-based does not mean hazard-free. ROCOL's SDS classifies the mixture for skin irritation, serious eye damage, reproductive toxicity, repeated-exposure organ toxicity, and chronic aquatic hazard. Its section 11 also contains qualification wording that does not consistently match the positive classifications. That inconsistency does not establish hazard absence. [ROCOL SDS, sections 2, 11–12][rocol-sds].

Coverage includes the complete three-page sheets for each TRIM product, both ROCOL technical-sheet pages, all eleven ROCOL SDS pages, tables, graphs, qualifications, and PDF images. OSHA coverage is limited to the introduction, classification discussion, relevant glossary entries, and additive tables. Master Fluid Solutions' linked SDS access requires a customer login or request; no exact-product TRIM SDS was obtained. Proprietary composition, current-lot properties, independent performance trials, other regional formulas, and customer-specific qualification remain unknown. This reference establishes no manufacturing formula or machining, maintenance, microbial-control, or disposal procedure.

## Related reference

[Surface-finishing processes](../../processes/finishing/index.md) describes downstream process context. Coolant application claims do not establish compatibility with a subsequent finish.

[osha]: https://www.osha.gov/metalworking-fluids/manual
[e206]: https://www.masterfluids.com/na/en-us/data-sheet/di.php?pid=E206N
[microsol]: https://www.masterfluids.com/na/en-us/data-sheet/di.php?pid=MS585XT
[c270]: https://www.masterfluids.com/na/en-us/data-sheet/di.php?pid=C270
[rocol-tds]: https://rocol.com/wp-content/uploads/2026/06/ULTRACUT-370-EP__-GB-1.pdf
[rocol-sds]: https://rocol.com/wp-content/uploads/2026/05/ULTRACUT-370-EP__-GB.pdf