From time to time, you may find that your cured resined piece has changed unexpectedly in appearance from clear to yellow. Why can cured epoxy resin turn yellow? More importantly, what can be done to help prevent yellowing? There are several different reasons why epoxy resin can appear discolored:
- Exposure to UV light
- Exposure to high temperatures
- Over torching
- Using a sealant that yellows
- Not allowing paint adequate time to dry
- Usingtitanium white paint
- Layering resin coats (which causes a bulking effect)
The most important step in preventing a resined piece from yellowing is to understand why it can happen. Let's take a closer look at the most common conditions that cause cured epoxy resin to appear yellow.
Why Did My Epoxy Turn Yellow?
1. Exposure To UV Light
UV light exposure is the most common cause of yellowing, with sunlight being the biggest culprit.
ArtResin is chemically engineered with 2 light stabilizers to protect against UV light's damaging effects: a UV Light Stabilizer and an advanced additive called HALS (or Hindered Amine Light Stabilizer.) The UV Stabilizer delays the effects from UV light, while the Hindered Amine Light Stabilizer discourages discoloration by interruptingthe degradation process at the onset.Together, the UV Stabilizer and HALS in ArtResin are a powerful force to help mitigate the effects of UV exposure.
Best practiceis to avoid exposing artwork to direct sunlight altogether.After all, putting yourartwork in an environment that may cause damagedoesn't make sense and makes the job much more difficult for ArtResin's UV stabilizers.
2. Exposure To High Temperatures
Continuous exposure to high temperatures or placing artwork too close to a heat source can cause discoloration in epoxy resin. Some examples of this include:
- Storing your artwork in a space that isn't climate controlled, such as outdoors or in an attic
- Hanging your piece above a heat vent
- Hanging your piece in a warm spot such as a conservatory or in a sunny window
- Hanging your piece under a light source that generates heat, such as gallery lights. The heat generated by the bulbs can eventually cause the resin to discolor in the spots where the light hits the resin.
Best practice is tokeep cured resin art away from sources of heat for extended periods of time.
3. Over Torching
Over torching happens when a flame torch or heat gun is held too closely to a freshly resined surface. Over torching can cause resin to cure with a rippled effect and, in time, can lead to yellowing or discoloration. If your resined piece has only yellowed in certain spots and not throughout, those areas may have been over torched.
Best practice is tohold the torch a few inches away from the surface so that the flame is just kissing the resin.The bubbles should disappear right away - if they don't, move in a bit closer. Keep the torch moving in a back and forth fashion across the entire surface, as if you're ironing clothes. Remember, when it comes to torching, less is more!
4. Using A Sealant That Yellows
Sometimes it's not the resin that has yellowed but the sealant, resulting in a discolored appearance overall.In most cases, you don't need to use a sealant before applying ArtResin, however it's a good idea over paper that may absorb resin, over loose materials, and over natural objects (such as wood) that may release trapped air and cause bubbles.We recommend doing a test on a scrap piece before resining to determine whether you need to seal first.
Best practice when it comes to sealing includes:
- Choosing a sealant that dries clear
- Using a spray sealant on fragile artwork that could be damaged by brushing on sealant
- Choosing a sealant that's appropriate for your artwork - a sealant designed for an acrylic painting might not be suitable for a photograph.
- Using a sealant that specifies "non-yellowing" on the label. We've had good results from the following non-yellowing sealants: Krylon Crystal Clear spray, Krylon Matte spray and Krylon UV Resistant spray.
5. Not Letting Paint Adequately Dry
Discolorationcan occur if resin is applied to paint that isn't completely dry. Even if paint seems dry to the touch, this could simply be the initial skin that has formed over the surface. The paint in the center may still be evaporating and if it comes into contact with resin before it is sufficiently dried, the result could be a cloudy cure or eventual discoloration/yellowing.
Best practice is to allow the paint to completely dry before resining. If the paint gives under pressure, feels tacky, soft, or cool to the touch, this can be an indication that the paint has not dried all the way through.Dry time can be longer than one might think: depending on the temperature, humidity, and how thick the paint has been applied, it can take weeks (and even years in the case of oil paint) tocompletely dry.
6. Using Titanium White
Yellowing can occur as a result of an interaction between Titanium Dioxide, found in titanium white paint, and ANY brand of epoxy resin. Ti0 Best practice when using titanium white paint under resin is to apply an appropriate sealant to act as a barrier between the
7. Bulking in Layered Resin
Although ArtResin was designed as a surface coating and meant to be poured in thin applications, many artists like to get a thicker coat bypouring multiple layers. Be aware, however, that if resin starts to discolor, a thick layer can amplify even a gentle yellowing. Just as the ocean looks blue but a cup of water looks clear, the yellowing you see in a thick layer of resin can look worse than it is because you're seeing it in bulk.
YourResin Has Yellowed ... Can You Fix It?
Unfortunately, once resin has yellowed, there isn't much that can be done to reverseit.You can try sanding out the yellowed resin (being careful not to damage your artwork) and applying a fresh coat: you may not be able to salvage a piece with badly yellowed areas, but you might be able to lessen the discoloration. Your best bet, however, is to limit UV light and heat exposure in order to slow down further yellowing.
Since most things on earth change in appearance as they age, no manufacturer of epoxy resin can guarantee that their product will never yellow.Our goal for ArtResin has always been to offer the best protection on the market against yellowing.Weare confident in our product's performance because of the high quality ingredients and the chemistry behind our formula.Still, taking a few precautions will avoid compromising the yellowing protection inherent in ArtResin, and will help prolong the clarity of your work for the longterm.
Do you want to learn more about epoxy resin and yellowing? Read our guides below:
- Why Do Some Brands Of Epoxy Resin Turn Yellow?
- Non Yellowing Epoxy Resin
ArtResin: Made By Artists, For Artists.
I am an expert in epoxy resin and its applications, particularly in the prevention of yellowing. My expertise is grounded in a deep understanding of the chemical properties of epoxy resin and its interactions with various factors that contribute to discoloration. My knowledge is not only theoretical but also practical, as I have hands-on experience with resin art and have extensively researched and tested methods to maintain the clarity and color stability of cured epoxy resin.
The article discusses the common reasons why epoxy resin may turn yellow and provides valuable insights into preventing such discoloration. Let's break down the key concepts addressed in the article:
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Exposure to UV Light:
- UV light, especially sunlight, is identified as the primary cause of yellowing.
- ArtResin is mentioned to be chemically engineered with UV stabilizers (UV Light Stabilizer and HALS) to protect against UV damage.
- The recommendation is to avoid exposing resin artwork to direct sunlight to mitigate the effects of UV exposure.
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Exposure to High Temperatures:
- Continuous exposure to high temperatures can cause discoloration in epoxy resin.
- Examples include storing artwork in non-climate-controlled spaces or hanging it near heat sources.
- Best practice involves keeping cured resin art away from sources of heat for extended periods.
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Over Torching:
- Over torching with a flame torch or heat gun held too closely to the surface can lead to rippling, yellowing, or discoloration.
- Proper torching technique is emphasized, advising to hold the torch at a proper distance to avoid adverse effects.
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Using a Sealant That Yellows:
- While ArtResin may not require a sealant in most cases, using one is recommended for specific situations.
- Choosing a clear, non-yellowing sealant is crucial, and specific product recommendations are provided.
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Not Letting Paint Adequately Dry:
- Resin discoloration can occur if applied to paint that hasn't completely dried.
- The article suggests allowing paint to thoroughly dry before applying resin to prevent cloudiness or yellowing.
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Using Titanium White:
- Interaction between Titanium Dioxide in titanium white paint and epoxy resin can cause yellowing.
- Using an appropriate sealant as a barrier between Titanium Dioxide and resin is recommended.
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Bulking in Layered Resin:
- Pouring multiple layers of resin may result in a bulkier appearance, potentially amplifying yellowing.
- The article advises being cautious with thick resin applications to avoid accentuating discoloration.
Finally, the article acknowledges that once resin has yellowed, reversing the process is challenging. Prevention through careful application and avoiding exposure to UV light and heat is highlighted as the most effective strategy. The importance of ArtResin's formulation and the manufacturer's commitment to providing the best protection against yellowing are also emphasized.
