Resin Tips, Guidance & Troubleshooting
Updated: Oct 13, 2022
Copyright of Michele Donohue, ArtWorks Resin Canada. All rights reserved.
The original of this blog post was from a few years back, however the blog has been updated with the different resins now being stocked in our store.
Personal Note: This information is updated and added to, as time permits. I have tried to condense a ton of information that I had previously taken notes on for myself to use as a resin artist, (from before I started this resin art supply ecommerce business), plus more I've learned over the years. I am sharing it with others who may find some benefit to it. Resin in general, is finicky so having loads of helpful information to learn from, can also help customers be more knowledgeable for best results with our resin products. Nothing is set in stone, or the same for everyone, but extra knowledge of a product like resin does go a long way to helping with successful projects.
When working with resins, they’re all different. Each type and brand may have different directions and requirements for usage, to ensure the sensitive chemical balance created by the manufacturer, will give you best results.
All resins are not the same. There are various limitations with any epoxy resin, and they each have their pros and cons, which is why some resin artists have different products they use for different projects. Becoming more knowledgeable of a resins pros & cons, helps an artist learn best ways to work with them, or work around them. Resin art has a big learning curve and like any medium, they each take time and practice to master, but once you do, you can achieve the most incredibly rewarding and beautiful results with all of the iCoat epoxy resins, when following their recomme nded use guidelines.
iCoat have been in the epoxy business for close to 30 years. They produce a variety of high-quality epoxy resins. Each product type is formulated specifically for recommended applications. All of their epoxy resins have the latest technology available in UV resistance protection. The iCoat epoxy resins made for use in art , have no VOC's, and do not have a foul odour. These iCoat epoxy resins are also FDA compliant (to FDA 21CFR175.300), much like other leading brands being used in artwork today. Epoxy resins are all scratch resistant, but not scratch proof, however these harder cures will assist in reducing scratches. All iCoat epoxy products if used as directed, cure crystal clear like glass, and have one of the highest gloss shines on the market.
There are a large variety of types of resins on the market for use in many different applications. Each resin has its unique features, pros & cons depending on what it is being used for. Some people like to use a variety of different resins for different purposes, and some prefer working with medium (thicker) or lower (thinner) viscosities depending on desired effects.
For example, there are numerous two-part epoxy resins. Some are designed for art, some designed for casting (craft type for more shallow moulds, or some work best for floral casting, and yet deeper pour types work better for industrial type or deeper pour applications). Some are designed specifically for kitchen countertops (often with higher heat tolerance), some designed for flooring, walls, boats, etc. Every brand has different viscosities, cure rates, heat resistance ratings, work time, & more. Even in each category of resin, there are many types. There are deep pour casting resins made for projects like river tables, but even those need to be poured in layers (typically 2" depths), depending on mass volume required. People often may need to experiment with a few to find which works best for their intended use. For best results, use a resin that is designed for your specific types of projects and follow manufacturers guidelines.
There is also a product called UV Resin (1 part resin), which is not the same thing as a UV rated (2 part) epoxy resin. Some people get confused between them. A UV Resin is cured by using light (like the UV nail polish coatings). UV resin only cures under UV irradiation. It's maximum layer thickness is 1mm, and is typically only suited for smaller areas. I do not carry the type that needs to be cured with a UV light. The two part epoxy resins with a UV rating, is not cured with light, it just means that it has UV inhibitors added to reduce yellowing and surface degradation from UV exposure. Some have more than others, but know that those additives may affect the resin in another area, including price.
There is also polyester & polyurethane resins. These resins both cure very hard like glass, and can be polished to a high gloss, but unfortunately these types of resins are quite toxic & fumey. Polyester resin has a very short work time. Polyurethane is very sensitive to moisture and humidity, which makes it difficult to add any other elements such as pigments, dyes or other inclusions (unless they're specifically formulated).
Please review the helpful information & tips (as well as the safety information provided on website), prior to beginning working with resin.
Epoxy resins consist of a base (bottle of resin - part A) and a curing agent (bottle of hardener - Part B). The two components are mixed in a certain ratio. A chemical reaction occurs between the two parts generating heat (exothermic reaction) and hardening the mixture into an inert, hard plastic. Epoxy coatings are used because of their outstanding chemical resistance, durability, low porosity and strong bond strength.
ALL resins will yellow over a period of time, however, iCoat has been formulated to resist yellowing for a much longer period and has added all the latest available UV inhibitors. It is not possible to determine how long it will take any cured resin brand to start becoming discoloured, as there are too many variables that can effect that. Some of those variables are additives or substrates or items painted over substrate, overheating during work or cure time, and where the art is being displayed. Resin art, much like most original art, should not be displayed in direct sunlight.
Prepare your work area:
Resin can be incredibly messy & sticky. For easier clean up afterwards, cover & protect your work area.
The surfaces resin does not stick well to, are good for your work area: Heavy gauge plastic drop sheets (often used by house painters) can be reused, as resin once dried will peel easily off the thicker plastic (it can rip thinner plastic). Resin will not stick to polyethylene plastics. Laminating plastic does not melt or wrinkle as much as thinner plastic. Parchment paper (or the shiny side of freezer paper) can also be used under resin work surface for easy clean up. Resin does not stick to wax, so a wax paper (waxy side up), can be used. Silicone matts or teflon sheet liners (used in baking) also can work well.
Keep your area clean as possible. Some people like to mist their work room area with water ahead of time, to bring down any dust in the air prior to starting with resin. Some artists have room purifiers running to help keep dust at bay as well (be sure they're not moving air around your curing pieces though). Use a lint roller on your clothing just before you start to work, to remove any hair that may fall into your work.
It's best to have all your supplies ready & near you, before mixing the two parts together, so you don't waste work time (pot life) looking for things you need to use.
Have tweezers or toothpicks handy in case you need to pick out hair, dust or bugs (they seem attracted to resin).
Keep a roll of paper towels handy as well for quick wipe ups as needed.
Also, keep alcohol wipes (Clorox for example) handy for wiping resin off unwanted surfaces prior to it curing.
Work in a well-ventilated area. Some artists are fortunate enough in their resin studio to also set up their studio with an exhaust fan. Even though resin companies state non-toxic and no voc, we like to pre-warn that anyone can be sensitive or become sensitive when using any 2-part epoxies, regardless how safe claims may be. More information on that in the safety page of our website.
Always wear disposable nitrile gloves and keep more handy while working. Latex, vinyl and rubber gloves are not suitable for resin work, because they are not chemical resistant like Nitrile is. If you get resin on your clothing, it will likely not come off again. Wear old clothes with an apron, or painters full body coverup.
***Always double check with a level, that your work surface area and/or substrate is level prior to starting a project.
Prepare your work surface ahead:
If you are working on wood, you will often need to prime and seal the area that you are going to resin, to prevent it from bubbling up through the resin.
Mixing containers & sticks:
Use clean mixing containers & stir sticks (so nothing can contaminate resin).
Silicone containers & mixing sticks are preferred by some artists since they can be reused once wiped clean. But they must be clean!
Many people use wooden popsicle sticks or paint stir sticks, however, be aware it's possible wood may release air into resin during mixing, and cause additional bubbles to mix. Some people find using silicone or plastic stirring tools help reduce added air bubbles. Spatulas with wide bottoms are not ideal for scraping resin off sides.
With iCoat, you can use a drill to mix your resin.
If you are using cups that do not have measurement markings, use a ruler and mark two containers at the same height in order to get an equal amount. Even if you are using a premeasured mix cup, you may want to double check the marking are correct. There has been occassions where the markings are not always correct (which can throw off your results). Here is Tim from iCoat, in a quick Instagram video, showing how he marks cups for measuring resin in click here.
Some cups are not suited for mixing resin. Containers/cups with the #5 on the bottom, are made of polyethylene, and resin is much easier to remove from them, and they can be reused. Lowe's carries them in their paint department, and the smaller 2oz onesare available on Amazon.
Secure hair & loose clothing out of the way so it doesn't land in your work. Resin is hard to remove from hair.
Check clothing doesn't have hair or fuzz that can fall into resin (which causes more work & extra layers of resin). Wear lint free clothing, or use a lint roller on your clothing prior to beginning work. You can buy inexpensive painting suits that are lint free.
Remember to have your box of nitrile gloves ready and other PPE as needed.
Temperature of resin & room, and humidity:
Temperature is extremely important with epoxy resins. Best results and transparency are achieved when temperature is ideal and with lower humidity!!!
A lower temperature with high humidity or unequal mixing of the two parts may cause clouding of the resin. Higher temperatures may cause too fast a curing reaction for some resin art techniques.
Apply resin in correct room temperature, at minimum 21C (70F) to about 24C (75F).
Ideally best results are in the 24C (75F) range. Room temperature must remain consistent through curing process for best cure. Generally, all epoxies become too thick and cure too slowly to be applied at temperatures below 50 or 60 degrees F.
For many epoxies, it is very important that your epoxy is also at room temperature (approx. 20 to 24 C / 70-76F) before mixing. Please note: There are some resins that have different best temperature recommendations, and one is iCoat CE4100 HV requires bottles to be heated, so liquid inside is at 82F, prior to mixing. Please refer to individual products guidelines.
Be careful not to heat too much though. Higher heat will expedite curing, causing pre-mature exothermic reaction, causing yellowing and possibly make it more brittle. Be aware that since heat accelerates curing, warming your resin can reduce working time by about 10 minutes.
If the epoxy is too cold, the molecules are too small to make a complete chemical reaction to make it an inert final product, which can leave chemicals not bonded (which incidentally can be a potential for poisoning). Follow each manufacturer’s instructions to a T. ALL epoxy resins are chemicals, and all the controlled variables must be adhered to. Chemicals are sensitive. Each brand has their own formulation that can be thrown off if not used as directed. Never assume that one type will work the same as another type of resin.
You will know your resin is too cold when it's thick, hard to work with, and cloudy looking due to 1000's of teeny-tiny micro-bubbles which are harder to torch out. Cold resin will also take far longer to cure.
If resin is too cold, you can warm the bottle(s) up prior to mixing. With some brands, you only warm up the Part A-Resin bottle. With iCoat however, they recommend you warm up both Part A bottle, and Part B bottle in hot water (upright in a bucket, sink or tub), until it's room or manufacturer recommended temperature (before mixing two parts together). Keep water well below lid level. Ensure you completely & thoroughly dry off the exterior of the bottles from any water drops (water drops in resin will ruin the chemical process and cause curing issues). Some artists use a seed matt, reptile heating matt or heating blanket to keep their resin warm. Be sure to use those safely.
Very Important Tool: Buy, and then regularly use an digital infrared thermometer gun to check the temperature of your resin. Aim it down the neck of the bottles directly on the resin and hardener (not at the containers), to check real temperature before pouring in to mix cup. Make this a habit to do with every single resin mix you make.
Checking the liquid directly inside the containers, will take the guessing out of it. It is also a good idea to aim temperature gun at the substrate to see if it is cold. Ensure all tools are at room temperature. Cold tools or moulds can shock your resin (and could cause bubbles on edges of moulds). Make sure your resin is at least about 75F to 78F - room temperature (or if using iCoat CE4100 HV, it requires higher temp be reached before mixing). Check each products specific guidelines for best temperature to be used at for best results.
Epoxy resins curing will be affected by ambient temperature being off, as well as humidity levels. Once most of the epoxies have cured, it can handle temperatures below zero degrees F.
iCoat products do not seem to be as sensitive to moisture as another I have used in the past. However in any epoxy resin, humidity plays an important role. The room should ideally be under 50% humidity (for humidity sensitive resins, it's better if it's under 30%). If your environment is humid, look into a dehumidifier or several containers of Damp Rid (available at dollar stores), to put in the room.
Resin Mixing Instructions
Every resin brand or type within a brand, might have different directions. Never assume because you’ve used one, they’re all the same. Some are similar, but they are not all the same, so do thoroughly review and follow each brands own instructions prior to working on your project.
Our website has a resin calculator page to help determine rough amounts needed. The first calculator on the page is for top coating projects, just enter the dimensions of the piece. The second calculator on the page is for casting projects in different shapes. The third section shows rough amounts suggested for tumbler makers.
iCoat topcoating resins general mixing info (see product pages for specific info):
Use a 1:1 ratio of resin to hardener. Measure equal parts of resin and hardener into a mixing cup. These should be measured by volume. (For an example, if you need a total of 2 oz of mixed resin, you would mix 1 oz of Part A plus 1 oz of Part B.
In round container, pour hardener (Part B) in to mixing cup, then resin (Part A ) into hardener in cup. It's not a rule, but it's easier to mix if the thinner viscosity (part B), is poured in first. Mix thoroughly but for 4 minutes. Be sure to occasionally scrape along sides & bottom of container as well. A plastic or silicone mixing tool works great for stirring the resin. It's very important that epoxy is at proper temperature (approx 72-78 degrees F) before mixing. If the epoxy is too cold the molecules are too small to make a complete chemical reaction to make it an inert final product, and you will notice many more bubbles. If you have mixed for 4 minutes, but still see striations (like strings), than you can mix a little longer until there are no more striations.
iCoat says you can mix their resin using a drill, for all topcoat projects, since the bubbles made in mixing, will be easily torched out. When using a drill, you do not need to mix as long as when hand mixing.
If however, you plan to use this resin in a thin mould, then hand mixing will create less bubbles.
iCoat casting resins general mixing info (see specific product pages for specific info):
In a round container, mix 2:1 ratio by volume (for example 10 ml of hardener to 20 ml of resin). Some casting resins can be mixed by either volume or weight, however iCoat instructions are by volume (if mixing by weight is desired, check product page for weight disparity info. If it's not shown, let me know, and I can contact iCoat). Some artists suggest mixing by weight considered to be more accurate, but volume works is more common and works equally well.
It is a good habit to get into to pour resin (part a), into the hardener (part b). Since the hardener is often the less viscous of the the two, so easier to incorporate the thicker part into the thinner part. Stir well but gently, for 3 to 5 minutes (depending on volume), scraping the sides and bottom of cup. Stirring slowly helps to reduce & avoid adding air bubbles. It is very important that it is properly mixed. (Some people like to pour this mix into a new empty clean cup, then stir mixed resin for another 3 minutes to ensure it's thoroughly mixed. Although we have not found that to be necessary. With some casting resins, a manufacturer may suggest allowing it to sit for up to 5-10 minutes to degas & allow any bubbles to rise to the surface. This is not the case with the medium viscosity iCoat CE4100 HV (please see product page for manufacturer suggestions on that resin, since it is different requirements).
When pouring your casting resin mix into your application, try and pour as close to your pieces as possible. Some people pour the resin down the stirring tool into the mould, if it's got a flat edge. Pour in a linear line, so that resin flows from the front of your piece, to the back. These techniques help to avoid bubble entrapment.
If you have never used a 2:1 resin, just remember to use twice the amount of resin (larger bottle), as hardener (smaller bottle).
Check out our handy resin calculator page (there are 2 calculator options) on the website, to get an estimate of how much total resin is needed for your project. Another way to see how much resin you may need, is to fill your mould with water or clean dried rice, then dump it into a measuring cup. Or use a measuring cup to fill your mould to see how much is used. Then dry mould thoroughly as even a tiny bit of moisture will ruin the cure.
If resin appears cloudy, & your mix is correct, it is likely too cold.
With thinner viscosity casting resins (NOT iCoat CE4100 HV), if you want to dome, glaze or make colour swirls in blanks, allow mixture to set several more minutes for a thicker honey-like consistency. A slow cure resin can take 45 mins to 1 hour to get that consistency. Most people prefer to use a top-coating resin for doming.
Adding Colourants: Important Note:
If you are adding colourants to your resin, the general rule of thumb is to start with about 3% colourant ratio to resin, and only add more if needed, (you can check opacity on your stir stick), but never exceed 10% colourant to resin ratio. Glitters do not colour the resin, so are the exception to that ratio rule, (however be aware that it does affect the chemical balance, and can reduce pot life). Once colours or glitters are added to your mixed epoxy, do not allow it to sit in the cups as the cure process will be sped up by these additions.
Higher (iCoat CT60), and medium viscosity (iCoat MV & iCoat CE4100 HV), epoxies being thicker, will need to be used shortly after mixing.
Lower viscosity (iCoat Depth, iCoat TP21 & iCoat TP24), are like water, and depending on project, you may want to let it sit in cup until it gets to a honey like consistency before you add glitter or it will sink to the bottom of the layer your working on. You need to check temperatures though so they don't get too hot in the cup. Some thinner viscosity epoxies need to sit about 45 minutes to an hour depending on your environment, before adding the glitter. You do need to keep a constant eye on it.
When you mix your resin, & it’s a large amount, pour it into several different cups. This is because the more resin you have in one cup, The faster it generates heat, which means the faster it cures. Also if using new-to-you colourants, wait to mix in your paints or pigments until right before you are going to pour that color. Different paints and pigments can cause resin to cure even faster. So when possible wait to add colourant until right before you're going to pour it. but have your colours handy & ready to go as needed. The exception to that would be the white epoxy pastes artists use for wave lacing. Some artists recommend mixing that and letting it sit. I use only items made for epoxy, so I can mix my colours right away.
Resin Heats Up - it’s supposed to, as that’s part of how it cures. It won’t cure correctly if it remains cold. However, If it heats up too much or too quickly it’s called Premature Exotherm! You want to avoid that type of heating up. This is where it's good to know temperature of your resins.
Note, adding anything in to epoxy resin, does affect the pot life (work time) of epoxy resins. However, just keep watch on any & all cups it's mixed in, if it's starting to warm up, it needs to be used ASAP. If it is not used quickly, and an uncontrolled (or premature) exothermic reaction has begun in the cup, it will overheat and get extremely hot in your cup. When this occurs the resin will quickly yellow from overheating/ burning, and will no longer be able to be used. Epoxy resin heating out of control can foam, smoke, give off dangerous vapors and generate enough heat to melt its container or cause nearby items to catch fire. If this occurs, quickly but safely remove the overheating cup on to a fire-proof surface such as a metal tray, then place outdoors. Once cooled, you can dispose of it. To avoid this issue, it is always advised to get your mixed resin on to the substrate as soon as possible. When it is applied in correct amounts for the circumstances, it does not overheat. Overheated epoxy is a user error. It is smart to keep a fire extinguisher in your studio.
Work Time/Pot Life:
After the two epoxy parts (resin mixed into hardener) are combined, there is a working time (pot life), during which the epoxy can be applied or used. Generally the pot life will be anywhere from 10 minutes up to one hour or longer depending on the product type. At the end of the pot life, the mixture becomes very warm (or even dangerously hot), and when past its pot life, it quickly begins to harden & yellow from overheating (pre-mature exothermic reaction) that occurs while still in cup.
iCoat top-coating epoxies have a pot life of about 30 to 40 minutes.
iCoat various casting resins each have a different pot life. Refer to specific item for that information.
In theory, a temperature change of 18 degrees F, will double or half the pot life and cure time of an epoxy. Higher temperatures will lower the viscosity (thin) the epoxy, but also reduce the working time a person has to apply the epoxy. Spreading out the epoxy once mixed, instead of leaving it concentrated in mixing cup or container, will help the potlife (work time).
Pouring Mixed Resin:
Once your resin is mixed pour onto the surface as soon as possible. If working on a panel, and just clear epoxy, pour most of it in the center and a thin line around all the edges, about 1/4” in. The majority in the centre should cover about 65% to 85% of the panel. This is enough to spread over the entire surface (unless there are porous areas).
Using a gloved (nitrile only) hand, or spreading trowel or other tool, pull the resin out to the edges, and all around. Resin has a surface tension and it will stop where it is pulled as long as too much resin has not been poured. Thicker resins will not run over the sides as easily as the thinner resins .
If enough resin has not been made and you need more, there may be clouding or a ridge where the two meet. If this occurs, use your hand in a nitrile glove and attempt to mix the resin more completely on the surface. The resin may need to be warmed with a torch if it has already passed a certain phase (30-50 minutes dependent on resin).
Any item getting a layer of resin, should be very clean and dry. If your surface is very shiny/polished, it may require a light sanding to get a better bond. Some manufacturers recommend sanding in between layers if more than 24 hours passed between layers, however I have never done that with resins I’ve used), and never had any delaminating occur. It is very important surface is cleaned of any oils from fingers or other contaminants that could affect final finish & cure.
If you are top coating your acrylic painting with any epoxy resin, it is important to allow your acrylic art layer to cure completely before coating with resin. Many acrylic art pieces with only a thin coat can take up to a full week to cure, many other pieces with thicker or textured paint layers, or medium or heavy body of acrylics, and especially acrylic pours, can take over 2 - 3 weeks to cure all the way through. Dry to the touch, does not necessarily mean it's cured all the way through. If any resin is applied before acrylics are completely cured all the way through, the moisture from the uncured acrylic will effect the curing of the resin negatively, and a nice topcoat will not be achievable. The same applies to anything being used prior to resin topcoat, everything must be fully dried and have zero moisture content.
If it is an acrylic pour with silicone added, ensure you’ve thoroughly cleaned all silicone off painting prior to applying the resin. Silicone and resin repel each other. Gently dry wipe off any silicone residue (it may not be visible) on surface with a soft cloth (t-shirt or microfiber or other soft material). Then using another soft clean cloth use a mixture of Dawn dish soap or other cleaners to clean really well. Then it must be dried thoroughly before applying resin. Some famous acrylic pour artists will actually apply a clear gel varnish coat (or clear sealer with varnish) at this point, prior to putting the resin top-coat on, to ensure a solid coverage over their acrylic pour. Golden and Liquitex both make good artist quality products for that purpose.
If an adhesive has been used to adhere materials to a board, it must be cured and fully dry before applying resin. If it’s not, bubbles can rise to the surface though the wet resin. Those bubbles are not ordinary resin bubbles, and will not likely be as easy to remove. Also, if resin is being used any areas where adhesive is used, be sure it is the type resin will stick to, if wanting resin to cover it.
Recoat / Flood Coat:
The best time to recoat many epoxies is within about 48 hours after the initial coat. Because some epoxies take days to reach full cure, a second coat applied shortly after the first coat will partially fuse to the first coat rather than forming a simple mechanical bond.
with iCoat, each resin type has different recoat or layer timing options. Please refer to product information page for specifics.
iCoat top-coating resins can be recoated in about 8 hours (temperature dependant). It is not necessary to sand between coats unless something on the finish requires it. If sanding is necessary wait 24 hours or more, for ease of sanding.
Resin Coated Sides or UnCoated/Clean Sides on art panels
Some people prefer no resin on their artwork panel sides. We often refer to that as clean sides. Some prefer the resin to flow over the sides, and carry the art design over the panel sides (some refer to it as resin wrapped sides).
For both types of sides, always tape off the bottom of your panel/canvas in advance, for easier removal of resin drips. I use good quality 3M blue painters tape or green Frog tape. If you want clean sides, also add tape to the panel/canvas sides. Be sure to burnish the tape to the board for best bond.
For best coverage over the sides, it helps to have the edge rounded slightly so it can roll over the sides nicely, so a wood panel can be sanded slightly on that top corner edge if it's too sharp an edge.
Some artists like to tape the sides a bit higher then the tops edge, then once they're done working with the resin, they will pull the tape off the sides, so the resin can flow over & coat the sides. This may not be suitable for certain designs however, in case the resin pools up at the tape, it may change your design lines (such as ocean waves). When I'm creating something specific, like a landscape or sunset, I do not use the higher taped edge. You might need to add a bit to areas that are missed on the sides. If your catch surface under neath is clean, you can pick some of the resin up from there (with similar colours), and add it to the spots where resin didn't cover on the sides. Or you can pull some out of the mix cups to add. Or (if lots of resin is on the board), use your heat gun or blow dryer to blow it a bit more over the edge, then take your gloved finger and help it.
Removal of the tape once resin is cured, is easier when using a heat gun (or blow dryer on hot), to loosen the tap