Epoxy resin basics: Mixing, processing, typical mistakes
Epoxy resin is strong, adhesive, and chemical-resistant – if processed correctly. Mixing ratio, pot life, and temperature determine the result. These basics will help you work with epoxy safely.
To the point: What is important when it comes to 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 chemically resistant, but sensitive to incorrect mixing and cold temperatures. Pay attention to layer thickness and exothermicity. The information in the technical data sheet is 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).
Mix and process correctly
- Maintain the correct ratio: dose precisely according to weight/volume – eyeballing it is not enough.
- Mix thoroughly: including the sides and bottom of the container, minimizing bubbles.
- Note the pot life: process before the resin gels.
- Layer thickness/exothermic effect: thick pottings generate heat – possibly in layers or with an adapted system.
- Curing/tempering: Temperature according to data sheet; post-tempering improves the final properties.
Pot life, temperature, layer thickness
| factor | Effect |
|---|---|
| Higher temperature | shorter pot life, faster hardening |
| Larger mass/layer | More exothermic activity, shorter pot life |
| Too cold | slow/incomplete hardening |
| Post-tempering | higher final strength/durability |
Guideline 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 (sticky/soft spots),
- Processed too cold
- Applying too thick a layer at once – overheating/cracking,
- Stressed too early.
Exothermicity and layer thickness
Epoxy cures exothermically – 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 thick layers.
Mix like a pro
Measure precisely (use scales, not by eye), mix thoroughly and with minimal air bubbles, ensuring the mixture reaches both the sides and bottom of the container, and ideally transfer the potting mix to a larger container. Incomplete mixing is the most common cause of soft or sticky spots.
Frequently Asked Questions
Why isn't my epoxy hardening properly?
Often due to incorrect mixing ratio, poor mixing, or too low a temperature.
Can I extend the potting time?
Yes, by working at cooler temperatures and preparing smaller quantities – large quantities heat up and shorten the pot life.
Is epoxy UV-resistant?
Many standard epoxies yellow under UV light. Stabilized systems or alternative materials are available for UV exposure.
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 requirements are product-dependent and can be found in the respective technical data sheet.
How SILITECH supports
Tell us the application, layer thickness and requirements – we will recommend the appropriate epoxy system and provide data sheets and processing instructions.
