MEK (methyl ethyl ketone) and acetone are both fast-evaporating ketone solvents, but MEK evaporates a little more slowly, has stronger solvency for tough resins, and a higher flash point — while acetone is cheaper, faster-drying and lower in toxicity. Which one you should use comes down to how aggressive a solvent you need and how much open time you want before it flashes off.
This guide compares MEK vs acetone across the factors that actually matter when choosing a solvent — evaporation, solvency, safety, and cost — and gives a simple decision rule at the end.
MEK vs acetone: quick comparison table
| Property | MEK (Methyl Ethyl Ketone) | Acetone |
|---|---|---|
| Chemical formula | C4H8O | C3H6O |
| CAS number | 78-93-3 | 67-64-1 |
| Boiling point | ~79.6 °C | ~56 °C |
| Evaporation rate | Fast (but slower than acetone) | Very fast |
| Solvency / dissolving power | Stronger on tough resins | Strong, but less aggressive |
| Flash point | ~ -9 °C | ~ -20 °C |
| Toxicity | Higher — irritant, nervous-system effects at high exposure | Lower order of toxicity |
| Water solubility | Partially miscible | Fully miscible |
| Relative cost | Higher | Lower |
| Dissolves plastics (e.g. ABS) | Yes, strongly — used as a plastic weld | Attacks some plastics |
Evaporation rate: the main practical difference
Acetone evaporates faster than almost any common solvent — its boiling point is only about 56 °C. That makes it excellent for quick clean-ups where you want the surface dry in seconds, but it can be too fast for coatings, causing blushing or poor flow if it flashes off before the film levels.
MEK evaporates a bit more slowly (boiling point ~80 °C), giving a little more open time and better flow in coatings, while still drying quickly. If you need a touch more working time, MEK is usually the better choice.
Solvency: MEK is the stronger solvent
Both dissolve a wide range of resins, oils and adhesives, but MEK has stronger solvency for tough, high-performance resins — vinyl, acrylic, nitrocellulose, and many polyurethane and epoxy systems. If acetone isn’t cutting a stubborn coating or adhesive, MEK often will. MEK is also used to weld plastics such as ABS, because it softens and fuses the surface.
Safety: acetone is the milder choice
Both are highly flammable and must be kept away from heat, sparks and open flame, with good ventilation and bonding/grounding during transfer. The key difference is toxicity:
- Acetone has a relatively low order of toxicity — the body even produces small amounts naturally. It is still an irritant, but it is generally considered the safer of the two for routine handling.
- MEK is more of an irritant to eyes, skin and the respiratory tract, and high or repeated exposure can affect the nervous system. It needs more careful ventilation and PPE.
For either solvent, wear chemical-resistant gloves and eye protection, work with good ventilation, and keep away from ignition sources.
Cost
Acetone is typically cheaper than MEK. For general cleaning and degreasing where acetone’s solvency is sufficient, it’s the more economical choice. Pay the premium for MEK when you need its stronger solvency or slower evaporation.
Which solvent should you use? (Decision rule)
- Choose acetone if: you want the fastest drying, the lowest cost, lower toxicity, and your material dissolves readily — general cleaning, degreasing, nail-polish remover, thinning fast-dry coatings.
- Choose MEK if: you need stronger solvency for tough resins, a little more open time, plastic welding (ABS), or you’re working with vinyl, nitrocellulose or PU systems that acetone struggles with.
Many formulators actually blend the two (and other solvents) to tune the exact evaporation and solvency profile a job needs.
Frequently asked questions
Is MEK stronger than acetone?
Yes, as a solvent. MEK has stronger solvency for tough resins like vinyl, nitrocellulose and polyurethane, and evaporates slightly more slowly, giving it more working time.
Can I use acetone instead of MEK?
Often yes, for general cleaning and degreasing. But for welding ABS plastic, dissolving stubborn resins, or where you need slower evaporation, MEK usually works better.
Which is safer, MEK or acetone?
Acetone has a lower order of toxicity and is generally the milder choice. Both are highly flammable and must be handled with ventilation, PPE and no ignition sources.
Which evaporates faster?
Acetone evaporates faster — its boiling point (~56 °C) is lower than MEK’s (~80 °C).
Do MEK and acetone mix?
Yes. They are fully miscible with each other and are often blended with other solvents to fine-tune evaporation and solvency.
We supply both solvents in technical grade: Methyl Ethyl Ketone 99.5% (MEK) and Acetone 99.5% Technical Grade, from trial quantities through to bulk, with batch documentation. Browse our full Solvents & Alcohols range or request a bulk quote.
For further independent reference, see the Wikipedia entries on butanone (MEK) and acetone.