Updated 1 week ago ​by William Holm

Liquid resins are photosensitive materials used for printing on SLA 3D printers. Resins are also known as photopolymers and they are cured (solidified) by UV light - this also includes sunlight. There’s just THE resin, a base material that can be further enhanced with added colors or additives.

Resins usually consist of three basic components: the core of the resin (monomers and oligomers), photoinitiators - molecules reacting to UV light, which initiate the solidifying process, and additives - admixtures that change the color and properties of the resin.

In general, models printed from resin are brittle (even the ones marked as tough). Resin prints are not suitable for outdoors use: the material properties may change after a long exposure to sunlight.

Important safety information

  • Wear gloves to avoid direct contact of the resin with your skin
  • A simple respirator is recommended
  • Keep out of the reach of children and pets
  • Shake the bottle well before every use for around 10 seconds (make sure the lid is securely tightened before doing so)
  • Wash with water and soap in case the resin gets in contact with skin/eyes
  • If you experience itching or any kind of discomfort after skin contact, seek out medical assistance
  • Keep away from light, store in opaque bottles
  • Keep at room temperature (18°-32°C), lower temperature changes the viscosity of the resin
  • Do not store in dusty areas
  • Resin produces fumes - keep the room ventilated during printing
  • Some people may be allergic to resins - in case you experience any kind of discomfort (itching, rash), stop using the machine and contact a doctor
Do not throw resin bottles (empty or full) into regular waste. Liquid resins should be treated as dangerous chemicals and you should follow your country’s laws about disposing of dangerous chemicals.

Types of resins

The wavelength that the SL1 is working with is 405 nm.
The Original Prusa SL1 3D printer will work best with MSLA/LCD resins. Other types might require too much curing-time (the standard being ~6 seconds per layer).

Material type


Standard resin

  • Smooth surface, lots of details
  • Fragile
  • Not suitable for mechanical parts

Clear resin

  • Semi-transparent
  • Can be turned nearly fully transparent through post-processing

Casting resin

  • No ash content after burnout and high wax content
  • Lots of details
  • Great for preparation of casting forms
  • Little to no remnants after burning the resin

Hard and resistant resins

  • Similar to ABS or PP materials
  • Partially flexible
  • Suitable for mechanical parts
  • Low resistance to high temperatures

Heat-resistant resin

  • Highly temperature-resistant
  • Used for injection forms
  • Expensive

Bio-compatible resins

  • Non-toxic, always check for certification!
  • Suitable for dental implants manufacturing
  • Abrasion-resistant
  • Expensive

Flexible resin

  • Similar to rubber (70A hardness)
  • Lower resolution of printed part
We do not recommend mixing resins in between them or with pigment. The properties of the resin (curing time) would change and you could even damage the printer.

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