Community guideTips & tricks / Post-smoothing
What “sealed” means: water resistance and porosity
“Sealed” is the word you will see most often next to vapor smoothing. Here is what AMT has published about it.
The surface
A printed powder bed part has an open, porous skin. During smoothing the vapor condenses on that skin and evens it out. AMT’s vapor smoothing page says this enhances “the part’s strength, aesthetics, and water resistance”. The SFX and SF2X product pages show a TPU bellows (Forward AM TPU, MJF) with water on its surface, as printed and after smoothing. You can see the pair in AMT gallery: before and after vapor smoothing.
Published results
- Porosity. Protolabs reports reduced surface porosity on vapor smoothed flame-retardant parts, made in HP 3D HR PA 12 FR on HP MJF, with UL94 V-0 compliance (case study, Jun 2026).
- Exposure. Intelligent Energy’s hydrogen UAV casings, smoothed on a PostPro SF100, gained surface sealing, durability and resistance to environmental exposure (case study, Jan 2026).
- Pressure. On SLS PA2200, burst pressure rose by up to +7%42024 after smoothing (whitepaper, Jan 2024).
If your part must hold water or pressure
A sealed surface is not the same as a pressure rating. If your part must hold fluid or pressure, test it under your own conditions, with the wall thickness and geometry you will use in production. A benchmark is a good place to start.
Sources
- Vapor smoothing: SF and X-series family page and SFX, SF2X, SF50, SF100 product pages
- Flame-retardant 3D-printed parts with UL94 V-0 compliance (Protolabs case study)
- Lightweight hydrogen UAV components enhanced through vapor smoothing (Intelligent Energy case study)
- Performance improvements of vapor smoothed SLS PA2200 parts (whitepaper)