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Choosing the right wash solvent

Choosing the right wash solvent

Formlabs generally recommends isopropyl alcohol (IPA, concentration of 90% or higher) for washing liquid resin off printed parts. While IPA is very effective at removing liquid resin, easy to purchase, and fast evaporating, it does have some drawbacks:

  • IPA has a flashpoint below typical room temperature (around 20 °C/68 °F), and therefore generates enough vapor to form a potentially explosive atmosphere in its natural state.
  • Depending on local regulations, IPA may be difficult to procure or to use within buildings.
  • Despite IPA’s low cost, actual operating costs may be higher than expected due to rapid evaporation and the frequency with which IPA may need to be replaced to wash parts effectively.

Depending on your use case and work environment, tripropylene glycol monomethyl ether (TPM) or Formlabs Resin Washing Solution may be a viable alternative to isopropyl alcohol (IPA) for washing parts.

Notice:

Only IPA, TPM, and Formlabs Resin Washing Solution have been validated for use with Formlabs resins and accessories. Do not use other solvents without Formlabs approval. Use of an unvalidated solvent may be hazardous to your health or damage your printed parts or equipment.

Advantages of Formlabs Resin Washing Solution

Using Formlabs Resin Washing Solution poses the following benefits when compared to IPA:

  • Formlabs Resin Washing Solution is non-flammable (flashpoint of 93.5 °C/200 °F, compared to 12 °C/53 °F for IPA) and non-toxic.
  • Formlabs Resin Washing Solution has a lower evaporation rate than IPA.
  • As the solvent dissolves liquid resin, the concentration of resin in the solvent will increase. At higher resin concentrations, Formlabs Resin Washing Solution will continue to clean parts effectively, while IPA with the same resin concentration will need to be replaced.
  • Formlabs Resin Washing Solution is available globally.
  • Formlabs Resin Washing Solution is available directly through Formlabs and its partners.

Disadvantages of Formlabs Resin Washing Solution

Using Formlabs Resin Washing Solution poses the following drawbacks when compared to IPA:

  • Formlabs Resin Washing Solution evaporates very slowly. Printed parts washed in Formlabs Resin Washing Solution must be rinsed with water to remove excess solvent.
  • Formlabs Resin Washing Solution is generally available only through distributors, not local stores.
  • Formlabs Resin Washing Solution is not yet certified for use with Formlabs products in biocompatible applications.

Similarities between Formlabs Resin Washing Solution and IPA

Both Formlabs Resin Washing Solution and IPA share the following considerations:

  • Both IPA and Formlabs Resin Washing Solution (and any water used to rinse excess Formlabs Resin Washing Solution off printed parts) should be managed and disposed of in compliance with local regulations.
  • Consult your supplier’s SDS for IPA and Formlabs Resin Washing Solution before use. Wear disposable nitrile gloves when handling either solvent, including surfaces or parts covered in IPA or Formlabs Resin Washing Solution .
  • Fully dry parts before post-curing.
  • Follow Formlabs instructions when cleaning Formlabs products with any solvent. Both IPA and Formlabs Resin Washing Solution can crack or craze specific plastics.

Why use TPM?

Use TPM as a washing solution if:

  • You cannot use IPA due to flammability issues.
  • You cannot readily acquire IPA due to local restrictions.
  • You are looking for a more economical solvent for washing prints.
  • You print infrequently and find that a significant quantity of IPA evaporates between prints.
  • You are sensitive to the fume smell of IPA.

Why use IPA?

Use IPA as a washing solution if:

  • You want prints to dry quickly after washing.
  • You can store IPA safely and/or are not limited by flammability hazards.
  • You are satisfied with your current print washing process.
  • Post-curing to remove the waxy surface texture left by TPM would affect your workflow.

Tip:

You can use both TPM and IPA in your wash process: wash your parts with TPM, then do a secondary wash with IPA. This yields many of the advantages of washing with TPM without the waxy surface that TPM can leave on some resins. For more information about washing prints with TPM and two-stage wash processes, read the support article on Washing prints with TPM.

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