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Isopropyl alcohol (IPA)

Isopropyl alcohol (IPA) dissolves liquid resin, making it effective for washing parts printed on Formlabs SLA printers and for cleaning resin spills. Wash prints with IPA using the Form Wash, Form Wash L, or the Finish Kit.

Note:

Most Formlabs resins can be washed in IPA with a concentration of 90% or higher. The water content in low-purity IPA may cause the metal parts in your Form Wash or Form Wash L to rust over time. Biocompatible Formlabs resins require IPA with a concentration of 96% or higher.

Isopropyl alcohol is a highly-volatile, flammable, colorless, clear liquid with a strong smell.

Isopropyl alcohol is known by different names depending on location and distributor:

Isopropanol
2-propanol
Rubbing alcohol
Surgical spirits

Notice:

Formlabs does not manufacture isopropyl alcohol (IPA). Always consult the safety data sheet (SDS) from your solvent supplier as the primary source of information for storage and handling.

Handling IPA

Danger:

Always consult the safety data sheet (SDS) from the IPA supplier as the primary source of information. IPA is flammable and should be used and stored away from ignition sources. Store small quantities of IPA in appropriately labeled and sealed containers.

To handle IPA safely:

Wear disposable non-reactive gloves (nitrile or neoprene) to handle IPA.
Work in a well-ventilated area.
Transfer IPA from larger containers with a siphon pump to avoid overfilling the wash bucket or other container.

Cleaning an IPA spill

Spilled IPA presents an immediate fire and health hazard. IPA spills must be cleaned up immediately. Use only disposable supplies to clean up an IPA spill to avoid risk of fire.

To clean up an IPA spill:

Put on a pair of disposable nitrile gloves.
Absorb excess IPA with paper towels.
Clean up any remaining residue using wet paper towels.
Dispose of any tools used to clean up the spill (paper towels soaked with IPA, gloves coated in IPA) with hazardous waste according to local regulations.

Recycling or disposing of used IPA

Over time, IPA accumulates dissolved liquid resin, which reduces its efficacy. For best surface quality, replace IPA when the hydrometer included with the Form Wash indicates when the resin concentration in IPA reaches 10–12% or when the Form Wash L touchscreen indicates.

Disposal

To safely dispose of contaminated IPA:

Consult the safety data sheet (SDS) from the IPA supplier as the primary source of information.
Research your local regulations for hazardous waste disposal. This will most likely involve hiring a waste disposal service. For smaller amounts, check with your local waste disposal service to see if they have any suggestions for removal.
Inform your waste disposal service that your bottle contains IPA with small amounts of methacrylated monomers and oligomers (unpolymerized plastic resin) and trace amounts of photoinitiator. Have a copy of the Formlabs resin safety data sheet (SDS) on hand in case the disposal service attendant needs more information.

Notice:

Do not pour liquid or partially cured resin into drains or dispose of it with household waste. Do not pour isopropyl alcohol (IPA) that contains dissolved resin into drains or dispose of it with household waste. Safe and appropriate disposal methods of used IPA vary by location.

Recycling

For large volumes of IPA, consider using a solvent recycling system, which offers a cost-effective and more environmentally responsible alternative to paying for waste solvent disposal services. Solvent recycling systems use distillation and fractionation processes to remove solutes from waste solvents, making it possible to reuse the IPA to wash parts. The recycled IPA may still have small amounts of monomer in it. Recycling IPA reduces waste disposal costs, emissions that are required to produce solvents, and the cost of purchasing IPA.

Additional resources

European Chemicals Agency (ECHA) Substance Infocard Propan-2-ol [en]