Skip to main content
Calcimator

Exothermic Heat Calculator

Estimate the peak temperature and heat risk when pouring resin, based on volume, resin type, and ambient conditions.

Inputs

oz
°F

Results

Estimated Peak Temp

166 °F

Risk Level

Low-Moderate — monitor closely

Temperature Rise94 °F
Time to Peak31 min
Total Heat (BTU)57.6 BTU
Resin TypeEpoxy (medium exotherm)
How to Use This Calculator
  1. Enter the pour volume in ounces — larger pours generate more total heat and risk cracking or yellowing.
  2. Enter the ambient temperature in °F; higher room temperatures accelerate the exothermic reaction.
  3. Set the mix ratio to match your resin's label (1:1, 2:1, or 3:1).
  4. Select the resin type: polyester (high exotherm), epoxy (medium), or urethane (low).
  5. Read the estimated peak temperature rise and time to peak to know when to monitor the pour.
  6. If peak temperature is unsafe, split into thinner layers or pre-cool the mold to reduce heat buildup.

How the result changes with Pour Volume

Pour VolumeEstimated Peak TempRisk Level
52229 °FModerate — may yellow or warp
180652 °FCritical — fire/smoke risk, reduce pour volume
3331,168 °FCritical — fire/smoke risk, reduce pour volume
4611,604 °FCritical — fire/smoke risk, reduce pour volume

What each input means

Pour Volume
Total volume of mixed resin being poured at once in fluid ounces. Larger pours generate significantly more heat.
Ambient Temperature
Room temperature where curing takes place. Higher ambient temperatures add to peak temperature.
Mix Ratio
Resin-to-hardener ratio. More hardener (1:1) generally produces more heat than less hardener (3:1).
Resin Type
Polyester resins generate the most heat. Epoxies are moderate. Urethanes generate the least exothermic heat.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Pour Volume = 32, Ambient Temperature = 72, Mix Ratio = 1, Resin Type = 2 = 4 input(s) provided
  2. Calculate Estimated Peak Temp
    Estimated Peak Temp
    166 = 166
  3. Calculate Risk Level
    Risk Level
    Low-Moderate — monitor closely = Low-Moderate — monitor closely
  4. Calculate Temperature Rise
    Temperature Rise
    94 = 94
  5. Calculate Time to Peak
    Time to Peak
    31 = 31

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Resin & Epoxy

Resin Curing Time Calculator

Estimate pot life, demold time, and full cure time for epoxy resin based on mass, ambient temperature, and resin type.

Resin & Epoxy

River Table Calculator

Calculate the total epoxy needed for a river table based on table length, river width, thickness, and average void depth.

Chemical Engineering

Heat of Reaction Calculator

Calculate the standard enthalpy of reaction (ΔH) from formation enthalpies of reactants and products using Hess's Law.

Resin & Epoxy

Epoxy Volume Calculator

Calculate the exact amount of resin and hardener needed for a rectangular mold based on dimensions and mix ratio.

More in Crafts, Hobbies & Games.