Epoxy Resin Basics: Mixing, Processing, Common Mistakes
Epoxy resin is solid, strongly adhesive, and chemical-resistant when processed correctly. Mixing ratio, pot life, and temperature determine the result. These basics help to process epoxy safely.
To the point: What matters with epoxy resin?
Three things are crucial: the exact mixing ratio of resin and hardener, adherence to the pot life and the correct temperature during processing and curing. Epoxy is rigid, strong and chemical-resistant, but sensitive to incorrect mixing and cold. Observe layer thickness and exotherm. The specifications in the technical data sheet are binding.
Properties of Epoxy
- High mechanical strength and adhesion to many materials,
- good chemical and media resistance,
- low shrinkage, but rather rigid/brittle,
- electrically insulating (depending on type).
Mixing and processing correctly
- Maintain the ratio: dose exactly by weight/volume, visual estimation is not sufficient.
- Mix thoroughly: also at the cup wall and bottom, with few bubbles.
- Observe the pot life: process before the resin gels.
- Layer thickness/exotherm: thick castings generate heat, if necessary in layers or with an adapted system.
- Curing/Tempering: Temperature according to the data sheet; post-tempering improves the final properties.
Pot life, temperature, layer thickness
| Factor | Effect |
|---|---|
| Higher temperature | shorter pot life, faster curing |
| Larger mass/layer | more exotherm, shorter pot life |
| Too cold | slow/incomplete curing |
| Post-curing | higher final strength/resistance |
Reference values; the specific suitability depends on the product and application and must be checked in the respective technical data sheet.
Common mistakes
- Incorrect or inaccurate mixing ratio,
- incompletely mixed (tacky/soft spots),
- processed too cold,
- layer too thick at once, overheating/cracking,
- loaded too early.
Exotherm and Layer Thickness
The curing of epoxy is exothermic, it generates heat. With large masses or thick layers, the system can heat up significantly, leading to discoloration, blistering, or cracking. Solution: pour in layers or choose a system designed for large layer thicknesses.
Mixing like a pro
Dose precisely (use a scale rather than estimating by eye), mix thoroughly and with minimal air bubbles, ensuring to scrape the sides and bottom of the cup, and ideally transfer to another container. Incomplete mixing is the most common cause of soft or tacky spots.
Frequently asked questions
Why is my epoxy not curing properly?
Often due to incorrect mixing ratio, poor mixing, or too low temperature.
Can I extend the pot life?
Yes, by working cooler and preparing smaller quantities; large masses heat up and shorten the pot life.
Is epoxy UV-resistant?
Many standard epoxies yellow under UV. For UV exposure, there are stabilized systems or alternative materials.
Sources and technical basis
The information is based on manufacturer data sheets and recognized principles of reactive resin technology. Mixing ratio, pot life, layer thickness, and curing specifications are product-dependent and should be taken from the respective technical data sheet.
How SILITECH supports
Tell us the application, layer thickness, and requirements; we will recommend the suitable epoxy system and provide data sheets and processing instructions.
