Ultra Clear Epoxy: Non-Yellowing Formulas Compared
Updated 17 October 2026
When a pour is meant to show off something beneath it, such as a flower inlay, a spalted slab or a fibre-optic starfield, the resin has to disappear. That is the promise of ultra clear epoxy: a water-white finish with no blue or yellow cast, which stays that way for years rather than slowly turning the colour of weak tea. This buyer’s guide explains what separates a genuinely premium ultra clear formula from a standard “crystal clear” label, how UV stabilisers work, and how to run your own side-by-side water-white test before committing to a big pour.
It sits within our wider epoxy resin guide, which covers resin types and uses in general.
What makes an ultra clear epoxy different?
Almost every epoxy is sold as “clear”, but clarity has three separate parts, and premium ultra clear epoxy resin aims to do well on all of them:
- Initial colour: how water-white the cured resin is on day one. Lower-grade resins can have a faint yellow or blue tint visible in thick sections.
- Optical clarity: absence of haze, cloudiness or micro-bubbles. This depends on formulation, mixing and cure conditions.
- Colour stability: how well it resists yellowing over time from UV light, heat and oxidation. This is where premium formulas earn their price.
Our general guide to clear epoxy resin focuses on technique for glass-like results. This page focuses on choosing the material itself.
Why epoxy yellows
All epoxies yellow eventually. The chemistry that makes the resin tough, typically aromatic bisphenol-based resin and amine hardeners, absorbs ultraviolet light, which breaks bonds and creates coloured by-products. Heat speeds this up, and some hardeners also yellow by oxidation in the dark, even in the container. Resin left in a sunny window will show it fastest; a table in a dim room may stay clear for many years.
Formulators slow yellowing in three main ways: choosing less UV-sensitive hardeners, adding UV absorbers that soak up UV before it reaches the polymer, and adding light stabilisers that mop up the free radicals UV creates.
UV stabilisers explained
The two additive families you will see mentioned on data sheets are:
| Additive | How it works | Strength |
|---|---|---|
| UV absorbers | Absorb UV light and release it as harmless heat | Protect the bulk of the resin, more effective in thicker sections |
| HALS (hindered amine light stabilisers) | Trap free radicals formed by UV and regenerate, so they keep working | Excellent long-term protection, especially near the surface |
Premium formulas usually combine both. If you want to understand the chemistry, the overview of hindered amine light stabilisers on Wikipedia explains why they last so well. Note that “UV resistant” never means “UV proof”. Our guide to UV resistant epoxy resin covers outdoor and window-lit use in more detail.
Ultra clear formula types compared
Rather than ranking brands, it is more useful to compare the categories of product you will meet:
| Type | Typical pour depth | Clarity and stability | Best for |
|---|---|---|---|
| Coating / table-top ultra clear | Up to about 3–6mm per layer | Very high gloss; often good UV packages; cures fast so heat-related yellowing in the pot is low | Flood coats, bar tops, sealing artwork |
| Medium-pour ultra clear | About 10–25mm | Good balance; slower cure helps bubbles escape | Trays, inlays, flower pieces |
| Deep-pour ultra clear | About 25–100mm+ in one pour | Excellent water-white clarity when cured cool and slow; most expensive | River tables, castings, embedments |
| Standard “crystal clear” craft resin | Thin layers | Often fine on day one, faster yellowing | Small crafts where cost matters most |
For thick river table pours, the cure exotherm also matters: too much heat in a deep section can tint the resin. See our guide to deep pour epoxy and our breakdown of the best epoxy for a river table.
What to check on the data sheet
- Colour (Gardner or APHA/Pt-Co value): lower numbers mean less colour. Premium resins often quote a very low value for the resin part.
- UV stabiliser content: look for explicit mention of UV absorbers and HALS rather than just “UV resistant”.
- Maximum pour depth and mass: exceeding it causes heat, cracks and discolouration.
- Mix ratio: by weight or volume; see our guide to two part epoxy for why accuracy matters.
- Shelf life of the hardener: hardener can yellow in the container, so buy fresh stock and store it sealed, cool and dark.
- Food-contact statement if you are making serving pieces; see our food safe epoxy guide.
Run your own water-white test
Manufacturer photos are taken in perfect conditions, so the best ultra clear epoxy for you is the one that wins on your bench. A simple comparison:
- Mix small, identical batches (around 50–100g) of each candidate resin exactly to ratio.
- Pour each into identical clear silicone moulds to the same depth, ideally a depth close to your project, such as 25mm.
- Cure side by side at the same temperature, ideally 20–24°C.
- When cured, place the pucks on a sheet of plain white paper next to a glass of water and photograph them in daylight. Look edge-on as well as from above; tint shows most through the thickest dimension.
- Put one puck from each resin on a sunny windowsill and keep a twin in a dark drawer. Compare monthly.
Within weeks you will usually see which formula holds its colour best in your conditions.
Getting the clearest result
- Seal porous wood first with a thin coat to stop air bubbles rising into the pour; see our wood epoxy guide.
- Warm the bottles in a water bath to around 25°C to lower viscosity and release bubbles.
- Mix slowly to avoid whipping in air, and use a heat gun or torch lightly to pop surface bubbles.
- Keep dust off with a cover during cure.
- Wear nitrile gloves and eye protection and work with good ventilation.
Cost
Premium water-white resin typically costs noticeably more than standard craft resin. As a broad guide, expect typically £25–£60 ($30–$75) per litre for premium coating and deep-pour systems, with discounts on larger kits. For a large river table, resin is often the biggest material cost, so it is worth testing before buying in bulk.
Watch it being made
Watch our first light-up resin table being made in the workshop, with dragons and creatures appearing in the resin art, and the colours, pours and finishing shown step by step.
Resin Art Dragons and creatures in resin art table My First Light-Up Resin Table. More builds on the Go Bespoke YouTube channel.
Frequently asked questions
Is ultra clear epoxy resin really non-yellowing?
No epoxy is completely non-yellowing. Ultra clear formulas with good UV packages yellow much more slowly, especially indoors and away from direct sunlight.
What is the clearest epoxy resin?
The clearest results usually come from premium deep-pour or coating resins with low colour values and UV stabilisers, cured at the right temperature. Running a small side-by-side test is the best way to judge.
Can I use ultra clear epoxy outdoors?
Epoxy is not ideal for constant outdoor sun. If you must, use a formula with strong UV stabilisers and consider a UV-resistant clear top coat.
Why did my clear epoxy turn yellow in the bottle?
Hardeners can oxidise in storage, especially once opened. Store both parts sealed, cool and dark, and use within the stated shelf life.
Thinking about a crystal-clear river or fibre-optic table without the risk of a cloudy pour? Contact us about a bespoke commission.
