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If you have ever labeled a media bottle, flask, or TC plate only to have your writing dissolve when sprayed or wiped down before going into the BSC or smeared from the IPA on your gloves, you know the frustration. We got curious (it's kind of our thing), so we ran a quick bench test on five common permanent markers to find out which ones hold up to 70% isopropyl alcohol (IPA).
The Setup
We wrote on a TC plate lid with each marker, let them air dry, then sprayed the lids with 70% IPA and gently wiped with a lab wipe.
The Contenders
We tested a standard Sharpie, Amazon Basics permanent marker, Industrial Sharpie, Pilot Super Color maker, and a Kokuyo Research Lab marker.
The Results
The Pilot and Kokuyo stood out immediately for writing quality, both producing notably dark, legible marks. The Sharpies were functional but noticeably less bold. The Amazon basics marker was nearly illegible from the start, with significant feathering and bleeding on the lid surface. The Kokuyo also has some minor feathering, though it sill wrote dark.
Then came the IPA. The Pilot and Kokuyo were the only survivors. Everything else disappeared.
Our Take
For general lab use including media bottles, flasks, cryovials, or anything that gets sprayed before entering the BSC or goes into a water bath, both the Pilot Super Color and the Kokuyo Research Lab marker are solid choices. Neither would work well for super fine writing like on microcentrifuge tube lids, but for larger labeling tasks they perform well.
The Kokuyo has a finer point, useful for smaller labels or denser writing. The Pilot has a broader tip, better for quick large labels or on lab tape. The Pilot Super Color is fully refillable and the better value (grab the Pilot Super Color here or stock up on Pilot refills here). The Kokuyo Research Lab pen costs more per marker but is worth it if you need a finer line.
One important note on the Pilot: store it tip-down. Many Amazon reviewers report receiving dried-out markers, which might be a storage issue. Keep the tip facing down and it will stay ready to write.
Note: We did not test the xylene-free Pilot formula. That may be a follow-up experiment.
The Bottom Line
If you markers are disappearing after you write and spray, switch to the Pilot Super Color.
Have a marker brand we missed? Send us your recommendations. We love a good bench test.