Tough-Seal Cures
All the Tough-Seals cure to completion at ambient temperatures. Tough-Seal 21 and 31 are designed to have faster initial gelation times than Tough-Seal 22 and 32.
As a general guideline, 100% complete cure is attained within three to five days at room temperature.
Cure Schedules
To give you the information necessary optimize your production process, the curing schedule data for Tough-Seal is presented in this section. Ambient temperature curing, elevated temperature curing and yes even underwater curing is displayed for Tough-Seal. What could be more convincing that Tough-Seal is indeed not an isocyanate containing urethane than Tough-Seal’s ability to cure underwater?
Ambient Cure
The advancement of cured hardness from gelation through the first several weeks is shown in the first graph where the steep shoulders of the curves equate to early cure progression at room temperature. Again as a general guideline, complete cure is attained within three to five days at room temperature and cast parts are typically handle-able or demold-able overnight after the first 12 to 16 hours.

Heat Cures & Post Cures
Want to get things moving? Tough-Seal is very responsive even to the mildest of heat cures. Heat curing as low as 66°C (150°F) or 80°C (175°F) greatly accelerates property accrual in Tough-Seal. Terminology wise in a heat cure, a freshly mixed and poured part is immediately heated. While under post curing, the potting compound is allowed to gel during an initial period at room temperature followed by some duration of elevated temperature curing.
In the table below, heat cure and post cure effects are shown for a 66°C heat cure, an 80°C heat cure and an 80°C post cure for Tough-Seal 21. Short durations of 15 and 30 minutes of heating are displayed alongside longer times of 1 and 2 hours. The accelerating effects of the heating is tracked by measuring the hardness development at room temperature for 1, 2, 5 and 10 days afterward. Shaded regions denote hardness accrual above 50 Shore A.
Mix & Heat | Initial | +1 Day RT | +2 Days RT | +5 Days RT | +10 Days RT |
15 min / 66°C | 15A | 40 A | 43 A | 53 A | 65 A |
30 min / 66°C | 35 A | 42 A | 46 A | 55 A | 66 A |
60 min / 66°C | 38 A | 47 A | 50 A | 56 A | 66 A |
120 min / 66°C | 50 A | 50 A | 53 A | 57 A | 67 A |
Mix & Heat | Initial | +1 Day RT | +2 Days RT | +5 Days RT | +10 Days RT |
15 min / 80°C | 32 A | 42 A | 44 A | 55 A | 63 A |
30 min / 80°C | 58 A | 62 A | 62 A | 63 A | 65 A |
60 min / 80°C | 62 A | 63 A | 64 A | 65 A | 68 A |
120 min / 80°C | 62 A | 63 A | 64 A | 65 A | 68 A |
Mix & Heat | Initial | +1 Day RT | +2 Days RT | +5 Days RT | +10 Days RT |
15 min / 80°C | 37 A | 45 A | 47 A | 55 A | 67 A |
30 min / 80°C | 52 A | 55 A | 58 A | 60 A | 67 A |
60 min / 80°C | 55 A | 60 A | 61 A | 62 A | 67 A |
120 min / 80°C | 58 A | 62 A | 62 A | 63 A | 68 A |
Underwater Cures
Nothing says “I am not a urethane” like the ability to cure underwater. From a hardness development perspective, Tough-Seal is not phased by an underwater cure. Tough-Seal does not contain isocyanates so while urethanes can foam in your factory on a humid day, Tough-Seal cures void free even underwater. It’s the no-foam solution for your contract manufacturers in Southeast Asia or Central America where humidity effects plague perfect potting.
While we are not suggesting that you should ever outsource your sensitive electronic potting operations to mermaids in Atlantis, one could imagine applications for rubbery elastomer castings in civil or marine applications or even electrical part and cable repair in the field under the worst of weather conditions. So don’t fret if Tough-Seal gets wet!
