Simpact 85A
Urethane plastic · US · manufacturer-sourced
How long before you can demold Smooth-On Simpact 85A?
Short answer
Cast-and-demold plan
Gel, demold and full cure are separate days
- Mix the Urethane plastic to ratio and pour
- Wait for the demold time
- Sand or finish after full cure
This product’s stated stages
- Working time ends4 minutes
- Safe to handle2 hours
- Demold2 days
Worth noticing: Working time is only 4 minutes; the next stated stage, safe to handle, is 2 hours.
Common mistake: Demolding early and leaving a soft, tacky casting that never fully hardens.
Project stage ladder
Demolding, handling, finishing and final use may occur at different times
For casting and impact-resistant parts, identify which stage the stated to demold 2 days milestone actually unlocks. Earlier handling does not prove final cure.
Time demold and cure
Your countdown
Stated times
- Working time ends4 minutes
- Safe to handle2 hours
- Ready to demold2 days
From Smooth-On data sheet · checked 2026-10-25. Anything not listed isn’t stated by the manufacturer.
Manufacturer website: smooth-on.com
Conditions & fine print
- Stated conditions: Not stated in the data sheet
- Pot life and cure time shorten in warm rooms and with bigger batches. Follow the current technical bulletin for mix ratio, mixing and release agents. The chart is a summary; read the product's technical bulletin before you pour.
- Region US. Formulas can differ between countries; check your container.
- Working time ends: The chart gives no temperature.
- Safe to handle: The chart gives no temperature.
- Ready to demold: The chart gives no temperature; its cure column is the last time value in each row.
- Entered from the cited manufacturer documentation. Check the current label for the exact formula and region. Report outdated information
- Actual results depend on preparation, thickness, ventilation, temperature, humidity, mixing and substrate.
Confirm this is your product
Closely named formulas, colors and regional versions can use different times. Match these details to your container before starting a countdown.
- Exact listing
- Smooth-On Simpact 85A
- Variant
- Urethane plastic
- Region
- US
- Listed use
- casting, impact-resistant parts
- Timed stages recorded
- tooling, handle, demold
- Source checked
- 2026-10-25
Documentation: Technical data sheet · Technical Data Chart (no revision date)
Condition attached to the stated time: The chart gives no temperature.
About this product
Simpact 85A is a urethane plastic (Simpact) on Smooth-On's technical data chart, listed with a pot life of 4 minutes and a cure time of 48 hours. Its pot life is number 2 of 3 from shortest to longest in that comparison. This page uses only the chart values; mix ratio, hardness and release details come from Smooth-On's product bulletin.
Using this specific product
Smooth-On Simpact 85A is listed here as the Urethane plastic version for casting and impact-resistant parts. For casting resin, the useful question is not simply whether the surface looks finished—it is whether the exact next-action milestone shown above has been reached.
Before you start
- Confirm the package says Urethane plastic; related versions can use different timing.
- For casting and impact-resistant parts, pay particular attention to accurate mixing, mold material, mass and room temperature.
- The chart gives no temperature. The chart gives no temperature; its cure column is the last time value in each row.
How to check readiness
Check the casting itself for flex or tack before demolding. The technical data chart gives a pot life of 4 minutes. Lift or move the item gently and avoid twisting the bond or pressing finished faces together. Flex the mold away at one edge and stop if the casting bends, tears or remains tacky.
Avoid this mistake
Demold time is not necessarily full mechanical cure.
Compare with similar products
- Compare with Formlabs Grey Resin V5Handling: 30 min there, 2 h here.
- Compare with Anycubic Standard Resin V2Handling: 5 min there, 2 h here.
Questions
How long before you can demold this product?
Smooth-On states: The technical data chart gives a pot life of 4 minutes. Conditions: The chart gives no temperature.. The technical data chart gives a handling time of 2 hours. Conditions: The chart gives no temperature.. The technical data chart gives a cure time of 48 hours. Conditions: The chart gives no temperature; its cure column is the last time value in each row.. These are the manufacturer’s stated times, not a guarantee.
How does Simpact 85A compare with others in its line on the chart?
On Smooth-On's technical data chart, Simpact 85A lists a pot life of 4 minutes and a cure time of 48 hours. Among the 3 Simpact rows in this comparison the shortest pot life is Simpact 60A (4 minutes) and the longest is Simpact 80A-II (15 minutes); cure times run from Simpact 60A (48 hours) to Simpact 60A (48 hours). The chart shows the same pot life and cure time for Simpact 60A, so those lines are told apart by hardness and handling, not by timing.
How soon can Simpact 85A be handled after pouring?
The chart lists a handling time of 2 hours and a cure time of 48 hours for Simpact 85A, with a pot life of 4 minutes. Handling is the earlier milestone; the chart does not give a temperature for either.
How long do I have to work with this product?
Smooth-On states: The technical data chart gives a pot life of 4 minutes. Conditions: The chart gives no temperature.. These are the manufacturer’s stated times, not a guarantee.
How long until this product is safe to handle?
Smooth-On states: The technical data chart gives a handling time of 2 hours. Conditions: The chart gives no temperature.. These are the manufacturer’s stated times, not a guarantee.
What affects how long this product takes to dry or cure?
Pot life and cure time shorten in warm rooms and with bigger batches. Follow the current technical bulletin for mix ratio, mixing and release agents. The chart is a summary; read the product's technical bulletin before you pour. Follow the product label for your conditions.