GlassCast® Resin River Table Handbook
Page 7
Avoiding Overheating / Exotherm
The GlassCast range of resins, in common with all epoxies, generate heat as part of the curing pro-
cess. In order to ensure that the resin does not overheat during mixing and curing, it is essential to
make sure you stay within strict limits of ambient temperature, time-in-pot and pour depth, as well
as avoiding localised overheating from direct sunlight, nearby radiators or heat guns/hair dryers.
Failure to do so could result in damaged resin, or in extreme cases, resin smoking or igniting.
The recommended working temperature for GlassCast is 18-20°C. When working in higher ambient
temperatures, pay attention to the reduced pot-life and maximum pour depth, as shown below.
Ambient Temperature
15°C
(minimum)
20°C
(recommended)
25°C
(maximum)
Maximum Time in Pot (Pot-Life) 80mins 60mins 40mins
Maximum Pour Depth
Into a thin-walled mould (silicone/plastic)
50mm 40mm 30mm
Maximum Pour Depth
Into wood or an insulating mould
25mm 25mm 18mm
Initial Cure Time 96hrs 72hrs 48hrs
Ambient Temperature
Epoxy resins are highly sensitive to ambient temperature (room temperature) throughout their cure.
For best results, we recommend working in a consistent room temperature of 18-20°C. GlassCast can
be used in temperatures from 15 to 25°C but higher temperatures will reduce the pot-life and the
maximum pour-depth of the resin significantly. Never work in ambient temperatures exceeding 25°C,
or exceed the maximum pour depth for a given ambient temperature (as shown in the table above)
otherwise the resin could dangerously overheat, especially on larger pours.
Maximum Time in Pot (Pot-Life)
As soon as the resin and hardener are mixed together, the curing reaction begins. Due to the volume
of resin all in one place, mixed resin in the pot will begin to gradually warm up. The amount of time
that mixed resin can stay in the mixing pot before it overheats is known as its pot-life. Once you’ve
mixed your resin, make sure you use it within the pot-life stated for your ambient temperature (see
table above). Once you’re done, if you have more than the maximum pour depth of leover resin in
the pot, place the pot outside - just in case it starts to overheat.
Maximum Pour Depth
The thicker the pour, the more the heat builds up as the resin cures and so it is important to stay
within the maximum pour depth for the ambient temperature you’re working in. Care needs to be
taken when pouring into or around insulating materials such as wood or foams as they will retain
heat and will reduce the maximum depth that can be safely poured at a given temperature. Never
exceed the maximum pour depth listed for the temperature you’re working in; doing so will almost
certainly result in potentially dangerous overheating of the resin.