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ABS Vapor Smoothing Safe Acetone Post-Processing At Home

· 3 min read 3d-printingabspost-processingacetone

Acetone vapor melts the outer skin of ABS just enough to fuse layer lines into a glossy, molded-looking surface. The process is simple but unforgiving about timing: seconds separate a satin finish from a warped blob.

What you need

  • Prints in real ABS, not ASA or PLA; acetone does not smooth PLA
  • Pure acetone (nail polish remover with additives will not work)
  • A glass jar or metal container with a lid, plus a wire rack or foil platform
  • A hot plate or warm water bath, gloves, eye protection, and ventilation

Step by step

  1. Print with supports configured cleanly first, since smoothing happens afterward and locks in any scars. See [[supports-that-snap-clean]] for settings that leave minimal witness marks.
  2. Work outdoors or under a fume hood. Acetone vapor is highly flammable and breathing it is harmful; never heat acetone on an open flame.
  3. Pour a thin pool of acetone into the container, about 5 mm deep, and place a raised rack above the liquid so prints never touch the solvent directly.
  4. Set the prints on the rack, seal the lid loosely, and warm the setup to around 60-70 degrees C using a hot plate or by sitting the jar in warm water. Warm vapor works in minutes instead of hours.
  5. Check every two to three minutes. Surfaces turn from matte to glossy as they soften. Small parts may need only five minutes; large ones take ten to fifteen.
  6. Stop when layer lines blur but sharp corners remain crisp. Open the container and let parts off-gas in ventilated air for at least thirty minutes before handling barehanded.
  7. Inspect for overexposure: drooping overhangs, rounded small features, or shiny drips mean the next batch needs shorter exposure.
  8. For extra control on detailed parts, brush liquid acetone lightly onto flat areas instead of vapor-treating the whole part.

Common mistakes

  • Leaving prints in while doing something else; the finish goes from perfect to ruined within a couple of minutes.
  • Trying the process on PLA, which either does nothing or melts unpredictably, unlike the predictable behavior described in [[petg-vs-pla]] for PETG.
  • Working near ignition sources, including water heater pilots, since acetone vapor pools low and travels.

Related guides

Vapor smoothing is the final step after good support removal covered in [[supports-that-snap-clean]]. If you are still deciding whether ABS suits the part at all, compare material tradeoffs in [[petg-vs-pla]] before committing to solvent work.

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