It is important to remember, fish eyeing happens with all Epoxy – it can happen across the board with all types of resin - here's how to prevent it!
When working with resin, encountering a perfectly smooth, glass-like finish on your projects is the goal but occasionally, pesky “fisheyes” can appear. These are those frustrating little spots where the resin has receded, leaving a dimpled effect, like the appearance of a fish’s eye. Depending on what resin art interests you – you may hear them called ‘fisheyes, Dimples, Divots, Bare Spot, oil slick, or even resin resistance’.
Fish eyeing can be a real setback, but with a few adjustments to your process, you can prevent it and achieve a flawless finish on your Epoxy resin art, table or even tumbler.
Here’s an example of fish eyeing on a charcuterie board I made a few years back—the natural oils in the wood contaminated the epoxy as it was curing; because I had forgotten to sand the surface prior to pouring my resin
What Causes Fish Eyeing?
Fisheyes typically occur when there’s an issue with the surface preparation or resin mixture. Here are the main culprits I have identified over the many years of working with all brands and types of resins:
Here's an example of fish eyeing on a tumbler I made, because I poured onto an unprimed stainless steel surface, and didn't add enough resin.
If you have ever used silicone oils in your resin pours, such as 'dirty pours'– you may already have experience of fish eyeing. In resin classes we called it dimples or resin blemishes, it is simply a reaction to the oil. Resin and oil are not friends!!!
- Incompatible Additives: Sometimes, additives like pigments, dyes, or glitters can cause fish eyeing, particularly if they’re not mixed thoroughly or aren’t compatible with the resin. A common based culprit is an oil-based pigment.
- Environmental Conditions: Humidity and temperature play significant roles in resin work. Excessive moisture in the air or high humidity levels can disrupt the resin curing process and cause fisheyes to form. Cold hardeners will also contribute to fish eyeing.
- Improper Resin Mixing: If the resin and hardener aren’t mixed thoroughly, or if there’s an imbalance in the ratio, fisheyes and other surface imperfections may occur. This is why measuring exactly is key – don’t second guess your measurements, even if you know it will cure successfully. The ratio being slightly out, Will make all the difference to the final finish.
- The Resin for me! Whilst it can happen with any brand of resin, I have found it doesn’t happen so much these days since changing brands of resin. Holding classes and zooms weekly it is important to have confidence in your resin! – which is why I stick and swear by Apex resins.
Preventing Fish Eyeing in Resin Tumbling and Pouring!
To help prevent fish eyeing, it’s crucial to prepare your surface and control your working environment. Here’s a step-by-step guide to ensure a smooth, glass-like finish every time.
Properly Clean and Prepare Your Surface: Before you start, ensure your art board, mould or tumbler is completely free from contaminants. Here’s how:
Degrease the Surface: Wipe down the entire surface with isopropyl alcohol and a lint-free cloth to remove any oils or residues. Avoid using regular household cleaners, as these can leave behind films or residues.
Wear Gloves: Avoid touching your art surface with bare hands after cleaning, as even natural skin oils can create issues.
Sanding: If your tumbler or art surface is very smooth, consider lightly sanding the surface before applying resin. This gives the resin a better grip on the surface and minimises the chance of fisheyes. In my experience this step should not be missed.
Maintain Ideal Environmental Conditions:
I say it all the time folks, but it is so important! Temperature and humidity play a big role in resin curing:
Temperature: The ideal working temperature for resin is generally between 70-75°F (21-24°C). Resin thickens or cures too quickly in high temperatures and becomes too viscous in cold ones, both of which can lead to uneven distribution. What’s less often mentioned is that the temperature needs to stay consistent throughout the curing process; sudden drops can disrupt the resin’s finish.
After years of experimentation, I've observed that fish eyeing is much more likely to occur if the hardener temperature drops to around 12°C (54°F) or lower. It's crucial to keep the hardener at room temperature—around 18°C (64°F) is ideal. Avoid heating the hardener above this if you're also warming the resin to improve viscosity, as this can lead to flash curing. Keeping the hardener at a stable room temperature is the best way to ensure a smooth, flawless finish.
Humidity: Aim for a humidity level below 85% if possible. High humidity can introduce excess moisture into the resin, affecting its ability to cure smoothly. I try to keep mine between 50-60% - and that works well.
Ensure Proper Resin Mixing: Getting your resin mixture right is crucial:
Accurate Ratios: I know I’ve just mentioned this, but it is so important - Follow the manufacturer’s instructions precisely, as even slight variations in the resin-to-hardener ratio can lead to curing issues, including fish eyeing.
Thorough Mixing: Mix your resin and hardener slowly and thoroughly to avoid air bubbles and achieve an even consistency. Stir for the recommended time, scraping the sides and bottom of your mixing container to incorporate everything evenly.
Be Cautious with Additives: If you’re adding pigments, glitter, or other enhancements to your resin, be mindful of compatibility and quantity. I can’t believe I am saying this, but not everything can be added to resin as a colourant. Somebody once asked me why their resin had resisted in some places in comparison to the rest of their piece. When I delved into the issue, the chap said he had used Sweet Chilli Sauce to colour his resin – that was his problem! Innovative but not ideal!
Check Compatibility: Use additives specifically designed for resin, as some non-resin-specific products can introduce oils or chemicals that disrupt the curing process.
Mix Carefully: Make sure additives are well-mixed and don’t clump. Undissolved clumps can cause irregularities in the finish.
If you do see fisheyes developing, don’t panic! Here are two methods that can help mitigate fisheyes during the resin curing process:
Heat Gun or Torch: Once your resin is poured, gently apply a heat gun or torch to the surface. The heat helps the resin flow and blend better, minimising imperfections. Always ensure you wear a mask when using a heat gun – solvents and resins can become an irritant when heated.
Brush Technique: Use a soft brush or spatula to gently spread the resin into any areas where fisheyes are appearing. This technique helps break the surface tension, allowing the resin to flow back into the dimple. Surface tension is a whole other discussion, but remember some brands shrink ever so slightly when they cure, which can also cause fish eyeing – so always remember to add plenty of resin; in most cases I see – it is because the artist has not added enough resin to their mould or board.
Allow for Proper Curing: Finally, let your piece cure in a stable, dust-free environment. Avoid touching, moving, or disturbing it until fully cured to prevent any unwanted textures or blemishes. This is so important for mould or table pours, moving it before it has set or cured will most certainly offer a chance of resin resistance.
What to Do If Fish Eyes Still Appear?
If fisheyes show up even after taking these steps, you may need to add another layer to smooth things out. Sand down the cured resin layer slightly and clean it well before applying a new coat. This added layer should fill any remaining dimples, giving your piece a smooth, polished finish. If you have made a tumbler, and you can’t sand too much because of the risk of damaging your design, sand areas that can be sanded for optimum chances of a successful cure on the next layer.
Final Thoughts
Fish eyeing can be frustrating, but it’s preventable! By following these tips and refining your process, you’ll be able to achieve beautiful, professional-quality results in your resin tumbling projects. Taking the time to prepare your surface, control environmental factors, and carefully mix your resin will help keep fisheyes and any other imperfections at bay.
Happy resin pouring guys, and may your resin tables, artworks and tumblers always shine with a smooth, crystal-clear finish!
