Jean Tripier

A number of my paintings are done on surfboards and skateboards, and as a consequence I have learned how to laminate my art work with art resin and solve the most common issues one deals with when adding a thick, glossy and clear coat of resin to your art. Here is my how to and lessons learned guide to resin art, organized in eight sections:

Which art resin should I use to coat my art?

Will resin work on my support?

How do I avoid art resin bubbles?

Other art resin issues and how do I deal with them?

Resin art tips and tricks

Coloring resin

Resin art examples

Resin art resources

 

 

1. Which art resin should I use to coat my art?

 

The materials available to artists for coating their artworks are:

• Epoxy resins, available as a two-part kit of resin and curing agent or hardener that is usually mixed in a 1:1 or 2:1 ratio (4:1 or higher ratios for many industrial applications).
• Polyester resins, usually hardened by mixing with a liquid and highly toxic, high volatility catalyst (MEKP). Most polyester resins also use Styrene, a chemical that is on the watch list of a number of organizations for its potential link to cancer. They tend to be lower strength, more brittle and lower adhesion than Epoxy.
• Acrylic pouring medium, for use on flexible surfaces. They are safe and easy to use but will result in thiner coats with less transparency than Epoxy.
• Varnishes, which I will not cover here as they are impractical for thicker applications. I do use acrylic varnishes prior to applying Epoxy resin, as described in this article.

 —

Among resins, Epoxy is the material of choice for artists because it is extremely strong, durable, versatile and available as either clear casting or laminating resin. Epoxy is relatively safe to use, as long as contact with the skin and eyes is avoided and proper precautions such as ventilation are taken when manipulating both the resin and hardener. Epoxy resin is available at your local Tap Plastics store or via a online merchants such as Art Resin, which specializes in UV resistant epoxy for artists.

— 

A few things are important to know before using Epoxy resin, as they explain most of the issues artists can face when using them:

• Epoxies are thermo-setting plastics –heat is key to proper curing of the resin and hardener mix
• Epoxy resin is combined with a hardener to form a third, solid plastic. The speed of that reaction depends on heat, humidity, size of the mix (large batches will cure faster as the reaction generates heat) and the type of hardener used (fast or slow). In general, slow curing equals a stronger end result. Proper mixing and exact volumes of resin and hardener are required for adequate curing. Most epoxies will be solid to the touch in 5 to 7 hours, but they require up to 48 hours for a complete cure.
• Epoxy has poor UV resistance, and some can have poor water resistance as well. Additives are required to the hardener to improve UV resistance to a level that is adequate for art applications. In most cases, you will want to avoid Epoxies for outdoor applications.

 

My top three Epoxy resins

 

After many experiments with epoxies, I have narrowed down my choices to three options:

• Entropy Super Sap BRT and CCR Epoxy -general purpose laminating (BRT) and casting (CCR) resins that are extremely clear, UV stabilized and with a low viscosity. Entropy is the most eco friendly epoxy resin as it contains no petroleum-based materials but rather uses pine oils and bio-fuels. As a result, Entropy has about half the carbon footprint of petroleum based epoxy resins (4 tons of CO2 per ton of resin, as opposed to 8 tons for most petroleum based resins).
• Ultra-Glo -a very easy to use resin that delivers great results extremely consistently. Unfortunately, it is not eco-friendly. Note that Environmental Technology, the company behind Ultra-Glo, also makes a pricier, “industrial” version with greater UV resistance called EX-74. You can find both Ultra-Glo and EX-74 at Tap Plastics stores. They also sell a lower end solution called EnviroTex Lite via craft stores. All three resins are very similar in terms of handling and I use the term “Ultra-Glo” to describe all three in their application.
• Art Resin-an epoxy resin developed specifically for artists, with focus on ease of use and UV resistance. The resin is available via their web site, with free shipping. I have tested their new resin and find it extremely easy to use and perfect for my uses. Art Resin also has a great FAQ section on their web site that will tell you everything you need to know to start working with Epoxy resins. Art Resin focuses more on clarity and non yellowing resistance than Ultra-Glo -something that is difficult to either evaluate or measure, but that can make the difference in the long term. In particular, Art Resin uses hindered amine light stabilizers (abbreviated as HALS), agents that slow down the degradation of the resin when exposed to light. Art Resin is also distributed in Europe by http://www.easycomposites.co.uk.

 

Which Epoxy resin to choose?

 

• If you care about avoiding CO2 and greenhouse gas emissions and reducing your carbon footprint, the Entropy resin is the way to go -unless you are a very occasional user, in which case your CO2 savings, unfortunately, make very little difference when looking at the massive amounts of epoxy resin used in industrial settings.
• If you do not care about the environmental impact of your resin use, then Art Resin is the way to go as it offers a few advantages for coating artworks -mostly it is easier to mix (1:1 ratio of resin to hardener, as opposed to Entropy which has a 2:1 ratio) and has slightly better viscosity and a better resistance to surface temperatures (which is key to remove air bubbles with a blow torch). The Entropy resin, however, produces a much lower number of bubbles when mixing resin and hardener than Ultra-Glo or Art Resin and is a great resin to work with overall -in my view, it can be worth the (limited) extra work and care.

I recommend sticking with these three resins. If you are doing this for the first time, use Art Resin. If you have some experience using epoxy resins, try out Entropy and see if the bio benefits are worth the additional (slight) complications. Using other resins will lead in many cases to problems with curing times, yellowing, Amine blushing etc. It is simply not worth the risk associated with trying to save a few $ on the resin.  

To get started, you can order the starter kit from Art resin here. As an alternative, I use the one gallon kit as it is much more economical.

 

 

2. Will resin work on my support?

 

Epoxy resin will adhere to any clean, dry, rigid and flat support. Metal, wood, stone, concrete, paper or canvas glued on masonite -all will work.

You may have seen paintings on canvas with a thick, clear coat of resin in art galleries. While in most cases the canvas is glued to a masonite backing, ensuring rigidity and allowing for the use of Epoxy resin, you may see the same look achieved on stretched canvas. The edges are clean of any resin, and there are no cracks in the top layer despite the relative flexibility of the canvas. How is this done?

In that case, Epoxy resins are typically not used. Rather, a flexible and UV resistant acrylic top coat is applied. Acrylic is water soluble and can be sprayed on; if applied with a roller, the edges can be taped and cleaned out of any acrylic before the top coat dries off, giving you a clean edge after removing the tape. Acrylic coating materials suitable for artwork protection include the Sunset Gloss Coat by Lexjet and equivalent solutions such as a Liquitex or Golden pouring medium. Those mediums are milky in appearance but will dry clear. Acrylics dry quickly, and you can apply multiple coats to achieve the desired thickness. The downside of using acrylic top coats is that the finish is not as clear or strong (and thick) as when using Epoxy resin. The main advantages are the easier application, low toxicity, greater flexibility and possible use on less stable or rigid supports. Therefore, while this articles focuses on Epoxy resins, you should explore acrylic mediums if you want to coat relatively flexible materials such as stretched canvas and paper prints.  

 

 

3. How do I avoid art resin bubbles?

 

Bubbles are your number one enemy when layering resin -here is how to avoid them.

 

Why are there bubbles in my resin?

 

First let’s review why we end up with bubbles in the first case. Resin art bubbles appear for three main reasons:

• From mixing the Epoxy art resin with its hardener (air inclusion). Different resins seem to have different propensity to yield bubbles during the mixing process. Ultra-Glo for instance generates many bubbles, much more so than standard Epoxy resin. In my experience, it is nearly unavoidable to introduce air during the mixing of Ultra-Glo. Those bubbles are easy to get rid off however, so do not let the mixing process guide your resin selection.
• From the support itself (air and gas release, solvent contamination, support shrinkage or air trapping). The support you use for your artwork can generate bubbles throughout the curing process, which can make it extremely difficult to get rid of all the bubbles.
• From some form of contamination of the resin due to the presence of solvents, humidity, etc. Epoxy resin is less humidity sensitive than Urethane resin, and different epoxy resins seem to have different reactions to humidity. The fix is simple though -do not mix and cast resin when the air is humid and if the room temperature is too low.

 

 

Seal your resin art panel

 

The single most important step to avoid resin art bubbles is to make sure your support will not release any air or gases during the resin curing process. A porous support creates bubbles; a sealed one doesn’t.

 

 

If you are using thick wood panels for instance, you are almost certain to see bubbles forming throughout the curing of the epoxy or urethane resin. To avoid them, you must make sure that:

• Your support is as dry as possible
• The top surface of the support or panel is completely sealed using an acrylic varnish or equivalent
• The support is flat, with no air trapped between the panel and the artwork

If in doubt, pour a very thin layer of epoxy resin over your support. Let it cure fully, varnish it using an acrylic / archival varnish before gluing your artwork to the panel. Apply your second, thicker coat of epoxy art resin the following day.

 

 

Benzomatic – The resin artist’s best friend

 

The second vital step is to apply heat to the surface of the resin as it cures to get rid of the bubbles that will emerge. The CO2 released by the blow torch will immediately eliminate the bubbles. It is best to use a small blow torch, one of those typically used in the kitchen, which will give you more precision and focus the heat on the bubbles (too much heat applied over a broad area during the curing process can damage the top layer -apply the flame at an angle, and set your blow torch at its lowest setting while applying heat as quickly as possible).

I use a portable (pencil) flame torch from Benzomatic which works great for both small areas and first pass at larger areas. When used in combination with an Ultra-Glo pour and a sealed support, the flame torch will get rid of all bubbles -guaranteed.

It usually takes about 5 passes and ~20 minutes of careful watching to make sure all bubbles are eliminated; the resin itself takes of course much longer to fully cure. A blow torch will be more effective than a heat gun since it is the combination of heat and CO2 that eliminates the bubbles most effectively. Blowing on the bubbles does work well too -use a hand air duster to avoid running out of breadth!

 

Bubbles and deep resin casts

 

If you are doing deep resin casts (anything more than a quarter of an inch in-depth), you will need to degas the resin, using vacuum at the mixing stage (when most air is entrapped), as bubbles might not all be rising to the top. Alternatively (but less effectively) you can use a vibration table after mixing your components to migrate bubbles to the top; or you can degas the pour itself. Using silicon molds will help reduce bubbles as well. You can also achieve deep coats by multiplying the layers of resin, making sure to apply the new layer before the previous one is fully cured (<48 hours) to ensure a strong bond.  

 

 

 

4. Other art resin issues and how do I deal with them?

 

The other main issues you might have to deal with are:

 

Art resin not curing

If you use the two Epoxy resins listed above and followed the basic instructions (including using the correct curing agent), there are only two reasons why the resin would not cure:

The room temperature is too low: Epoxies require a recommended temperature of 75 to 80 °F for proper curing. Note that both Entropy and Ultra-Glo will cure well at lower temperatures over a 24 hour period of time -I use them with no issues at temperatures of 60 to 70 °F here in San Francisco. However, viscosity and flow, as well as curing, is improved at the higher temperatures.

You used the wrong mixing ratio of resin to hardener or did not mix the resin well enough with the hardener-a typical issue when doing larger batches.

 

To avoid curing issues, follow those five steps-all the time:

• Use fresh resin and hardener
• Mix resin and hardener in a clean, dry container; pour it in a second container before applying to your artwork
• Mix the proper quantity of resin and hardener
• Mix resin and hardener vigorously and thoroughly
• Cure at the highest room temperature recommended in the resin and hardener specifications (typically 80 °F)

 

To fix curing issues:

• If the problem is widespread, scrap off the resin and start all over again
• If you are dealing with soft spots, apply hardener and heat to the problem areas (indirect heat)
• If you cannot use the above steps, your last two options are:
  • Attempting to cure the piece again in a controlled environment offering the appropriate temperature and low humidity (your kitchen oven will do fine if the piece is small enough). Note that most Epoxies will soften at around 140 °F, which means that the ideal temperature setting is somewhere between 80 °F and 140 °F, depending on what you are trying to solve (uneven curing or slow curing).
  • Re-layering the piece -which is a risky procedure I would not attempt unless and until everything else fails. There is a high risk of eventual delimitation of the new layer because of the instability of the old one. If you are re-layering, you must do so before the base layer is fully cured, typically within 48 hours of applying the base layer.

 

Viscosity issues

You can get viscosity issues when applying layers to oily or wet surface, and to surfaces which are not flat. Viscosity issues result in top coats which are bumpy, emulating a golf ball appearance in some cases. The solution is to work with clean surfaces that are as flat as possible, and to apply multiple and thin layers when dealing with slopes. You can also sand each layer with extremely fine sandpaper and a polisher to eliminate the worst bumps between layers. Finally, as noted above, room temperature influences viscosity.

 

Poorly spreading resin

Occurs when using a thin layer of resin on a support that although flat and smooth has small areas that the resin will not adhere to. The problem is that those areas can only be detected once you start pouring the resin. In most cases, the solution is to apply more resin; you can also add resin in the problem areas throughout the curing process, so that the new resin is contained to the problem areas by the surrounding and solidifying resin. Another solution is to apply the resin layer in two steps -first a very thin layer, using a plastic spreader, to make sure the resin is adhering to the support. Second, and immediately following the first step, applying a generous s amount of resin to the entire surface.

 

Blushing

A form of water spotting resulting from the condensation and entrapment of moisture during the curing process. It results in dry spots than will appear to be matte (non glossy) or opaque. Sometimes the problematic spots will be milky or slightly white. Blushing can be very difficult to fix but you can usually avoid it by 1) operating with a  dry support and in a dry environment 2) minimizing the curing time by making sure you are working at the right room temperature or by using accelerators with your resin. If you see blushing during the curing process, you can sometimes minimize it by applying constant heat and / or immediately applying a new coat of resin, which may soften the bottom layer and release the moisture.

 

Blooming (sometimes called leaching)

The migration of water soluble chemicals to the surface of the resin. It leaves a waxy residue on top of the resin coat. If blooming is not too severe, it can be cured by simply using lukewarm water to dissolve the waxy residue. Do not use solvents, and never try to sand off the waxy compound itself or you will end up with a gooey mess.

 

Delamination

layers of epoxy can separate from their support, especially if the original surface is humid or contaminated. When in doubt about the quality of the surface, you can apply a spray acrylic varnish prior to layering the resin. Any issues will appear and they are far easier to fix with a very thin layer of varnish on top than with resin. If you are applying a new coat of resin on top of a previous layer, remember that it is best to apply the new coat within 48 hours as the bond will be stronger if the base layer is still curing.

 

Yellowing

All Epoxy resins will yellow with age and exposure to UVs. You can however minimize yellowing to a bare minimum by following steps:

• Apply archival, UV resistant varnish to your artwork prior to applying the resin -this will seal and protect the artwork from yellowing, and will prevent any bleeding of the colors and pigments from that art into the resin.
• Use clear, high quality Epoxy resins and curing agents -artist grade resins such as ArtResin or Ultra-Glo contain non yellowing agents that minimize the impact of UVs. Note that the non yellowing agent is typically part of the curing agent (or part “B”), which is one more reason why you should always use the curing agent provided with the resin. One cannot add separate non yellowing agents to resin, which is why you need to start with the highest quality, clear grade resin you can get.
• You can also apply UV resistant varnish to the cured resin as a top layer. While I do not do this myself (as I like to keep the mirror like finish of the resin), it can provide additional protection especially for pieces that will be exposed to the sun. You can of course achieve the same result with UV filtering frame glass.
• Minimize exposure to the sun -the best protection is of course prevention. As with any other artwork, keeping your piece out of direct sunlight will have the highest impact on non yellowing.

Do not let this list of common issues discourage you from working with resins -if you select the right Epoxies and use the right mixing ratio, the odds are you will not encounter any of them.  

 

 

 

5. Resin art tips and tricks

 

How does one avoid those issues in the first place? Here is a checklist to guarantee a successful resin coat for your artwork:

 

Do not improvise

Sse known ingredients in a controlled environment where heat and humidity are known and manageable.

 

Follow the instructions

Clean containers and mixing tools

Take the time to prepare your environment: avoid dust, direct sunlight and make sure you are working in a well ventilated area. Mix you epoxy resin and hardener in a clean bucket void of any previous resin / hardener. Measure well. Wear gloves. Protect your work table.

Check and check again the integrity of the support layer: you art needs to be set on a rigid support, level, clean, dry and protected (via an archival acrylic spray varnish that deflects UVs – I use Golden’s archival and acrylic matte spray varnish) prior to layering the Epoxy.

Do small batches: I have found that trying to coat more than five pieces of art at the same time can result in disasters… depending on the room temperature, you will have between 30 minutes and 2 hours to layer the epoxy, get rid of bubbles and solve any other issue that might come up. Somehow, trying to do more than five pieces in that time window invariably lead me to problems.

Carefully measure resin and hardener

Match the type of resin you are using with the curing conditions of the environment you work in-for instance, do not attempt to do casting work if you cannot control heat and humidity more than a few hours.

Never use resin or hardener that are at or past their shelf life

Mix larger amounts of resin than you think you will need

Seal your art piece before applying resin -brush in or spray an archival acrylic varnish; if using fabric or canvas, seal the back as well.

 

Keep things simple

Work with hard, rigid surface -not canvas

Work on flat surfaces

Do your first attempts with slightly “grippy” surfaces: paper, not vinyl

 

When in doubt, always test first

With potentially porous or problematic surfaces -test on a blank before committing to the art piece itself

When first using  certain types of resin -test on a blank

 

Protect yourself 

Work in a well ventilated space, use masks, gloves and googles.

 

Clean edges

To get clean edges along your painting, you can do the following:
1. Tape the bottom edges
2. Put the painting so that the bottom edges are not in contact with the table. You can use anything (pieces of wood, bottle caps etc.) to raise the painting from the bottom, ensuring it stays completely flat and level but with the bottom edges had an inch above the table.
3. Pour then resin, ensuring you pour enough resin so that it overflows evenly on all edges
4. You will get clean, resin covered edges and drips accumulating on the bottom edges. Let the resin cure.
5. Sand off the drips on the bottom edges. I use a sander, others use a router to get a very clean cut. You will then be able to remove completely the tape from the bottom edge.

 

6. Coloring resin

 

You can mix any form of pigments to the epoxy resin just after having mixed it in with the hardener. Pigments come in both opaque and transparent versions for that specific purpose (for instance: http://www.uscomposites.com/pigments.html) but any fine, dry pigment (no water based pigment -you do not want any water in the resin) should work.  

 

7. Resin art examples

 

These two skateboard decks are shown before and after the addition of two layers of Entropy Super Sap CLR resin which were left to cure at 66 degrees for 24 hours each -very clear, “candy” like top coat and a great result with a carbon footprint reduced by 50% and the use of recycled skate decks for truly eco friendly art!

 

 

These decks were coated with Ultra-Glo: http://www.tripier.com/skateboard-art/ This surfboard was painted and then laminated with surfboard epoxies -hard work and lots of sanding but the ned result is exceptional! Here are a few shots of resin being applied to three paintings.

 

You can also use resin laminates for your own custom furniture:

 

 

8. Resin art resources

 

Please leave a comment or use the comment form below if you have any questions on resin art processes. As you will see, there are a significant number of questions and answers already, and they provide additional information not found in this article. Good luck with your own experiments and do not hesitate to use the comment form to correct this how to guide or let me know your own techniques, tips and tricks! I will also respond to your questions whenever possible so use the comment form if you are running into issues.