Updated: Oct 20, 2022
Epoxy resins are very reactive to temperatures and humidity. Some formulas more so than others, even within the same brand. They are all made and formulated to achieve their different results in different projects. Temperatures, and for some humidity, are one of the most important added factors in achieving beautiful results in your resin creations!!!
When I first started creating with resin (I started with wall art), I was aware the temperatures mattered in the room, and that resin cures had better results in warmer temperature . I did not actually take the temperature in my resin work space, I just thought (assumed), I knew if it was warm enough or cool in the room.
Another resin artist peer I admired, and that I learned a lot from in my early resin days (I shall call her E for short), had mentioned she always checked temperatures of her room and also of the epoxy. I didn't really know what I was looking for temp wise, (plus she used a different type of epoxy), so I just carried on for awhile as I always had. I poured my resin, worked on bubble release, walked away and hoped that when I came back my project would be perfect. Or as we often joked with other peers, I hoped the resin gods would be kind, haha.
Just because something works as it always had for the most part, does not mean I was doing things correctly all those times. I may have just been getting lucky with results many times. And so I kept on doing the same thing for the most part. (Guesswork can be funny that way). So sometimes it worked, but sometimes it didn't. Even when following basic directions, my results weren't consistent, which was costly and frustrating. The house thermometer shows basic overall temperature, and that was what I based a lot on (except when obvious). However, it's common for each room to actually be quite a bit different temperature, also depending on the season, windows (heat or cool air seeps in), and if it was getting more or less sun in the space, and many other factors.
At first my art space was a corner bedroom on the main floor (same space used for acrylics, alcohol inks and at that time, just resin top-coating of art). That room was always the coldest room in the house in the winter, and the hottest room in summer. After a few years, I moved my art studio to a basement bedroom, that has an attached bathroom with a fan vented outdoors. The basement studio has in-floor heating, which is turned on in the cold winter months (so the space is consistently warmer), but it is turned off in the summer months (so it's actually very cold in summer). The opposite temperature issues of my previous art space when I was upstairs.
In Canada, we deal with colder weather issues then many of our resin peers in Southern climates, and we often have pretty big extremes in temperatures ranges. Sometimes, depending on where you are located, we have seen these massive temp changes occur even in the same day. More humid climates, with humidity changes can often add to resin issues.
Seasonal weather changes are one of the most common times, we see issues arise in resin art, regardless where people live. Where sometimes our process that we are certain always worked perfectly before, and we are sure we did everything right like before, but all of a sudden doesn't. And a couple of others experiencing same weather/humidity issues may find similar issues. Since our same process always worked for us artists before, and we know we did all the right things, the first thing we tend to think of, is something must be wrong with the resin. While there is a possibility that a resin might be off, the majority of time (99%), it is not the actual product . So, it becomes a huge learning curve to find out trouble shooting issues, that may in fact be the cause. It is not always a simple thing, because there are SOOO many things it can be. Sometimes, our same processes we do over and over again, might not actually be the correct process, but we get lucky with results over and over again, until one little part of that process is actually discovered to not quite be the right thing, for that particular resin, when the weather changes, or all the stars haven't aligned as they say.
One of the first things I did, in my case, to assist in getting my workspace to a warmer and more consistent working temperature, (and I learned about this particular heater from the same artist peer E mentioned above ), was I purchased a specific space heater, (an oil heater) that doesn't blow air or dust around, and keeps the room consistently at the same temperature it is set for.
This is the unit I bought at Canadian Tire roughly 4 years back, as soon as I saw it at half price sale. It was reg $200 on sale for $100.00.
Just found this unit online at Canadian Tire website, looks looks similar to the one I purchased years back, but better price. As my friend E mentioned, there are numerous heater types out there, but these types of units are safer then many space heaters, and they don't blow air around the space, that can cause dust particles to land in your curing resin pieces.
Having a consistently warm temperature in my cooler basement space, definitely helped my top-coating finishes a lot.
After I started the resin art supply business, I was asked to add casting resin to my website, and I started playing a bit with casting in moulds, so that I could understand the resin more.
To be honest, I was always guessing temperature of the casting resin for first several years as well. It was a thin consistency (low viscosity), so it didn't really need pre-heating much, because warming it wasn't going to change the consistency to be any thinner. Thankfully, most of the time I got lucky and castings turned out great, but sometimes they did not. If it was cool, there was a risk of bubbles and imperfect cures. If it was humid, there were amine blush issues on the top of castings. Again it's costly and frustrating when something doesn't turn out beautifully. So then I had to learn to trouble shoot with casting resin as well. There really is soooo many factors that go into a beautiful finish with both top-coating and casting resins. Each type of epoxy also has its own pros and cons and processes that work best for each formulation, so what one person suggests that works for them, may not work for another, and especially if it's in different environment circumstances, and more so if it's a different brand of epoxy. Amine blush was a common issue (typically but not always, due to a high humidity) with the casting resin I used at that time, but thankfully I have not seen nor heard that issue with the various ones I'm currently using.
As a hobby resin artist or crafter, we often just kept hoping for the best when following instructions.
However, for someone who starts to turn their resin craft and art into more of a business, it is recommended to get to know a lot more of the science behind the product you're using, and how it behaves (or reacts) certain ways, and in different environments. This is where a digital infrared temperature gun can assist.
There are different recommendations, for best results with each resin, and sometimes they are actually different for a different formula in the same brand. So it's important, for consistent best results, to learn more about the epoxy itself, and follow each manufacturers recommendations. Over this past year, I was once again reminded one way to learn about how the epoxy is behaving, and to assist it's behavior, is to use a digital IR temperature (thermometer) gun.
I had heard another resin peer (same lady, E mentioned above), said she used a temperature gun, every time she brought out epoxy, regardless of type or brand. But again, I never really realized how much temperature guessing I was doing and I carried on for years, until talking to Tim at iCoat. ***Even after 30 years experience with a ton of types and brands of epoxies, Tim uses a digital infrared temperature gun EVERY time he mixes up a batch of resin. *** In his words, how do you know what your epoxy is actually doing (or how it's behaving), if you do not?!!! Well... I guess I had been guessing for a long time.
I always knew epoxy resins work best in warm rooms, but I didn't know (and truthfully I am still learning), about the actual temperatures needed at various phases, (from pre-mix while in bottles, to mixed and pouring stage, to various phases during curing). Using the digital IR temp gun each and every time, always .... will help an artist to know if resin is reacting, and learn to create more regular and consistent results. Learning this, takes a lot of the guesswork away for an artist. And as you get used to using the IR temperature gun, you will learn what your epoxy is doing, and how to achieve best results based on it's behavior in current environment.
In regards to room temperature, the ICoat showroom is kept at 77F (25c) during the day, so if resin temp is at least 77F, then additional heating is not needed, for some but not all of their resins, (iCoat CE4100 HV for example needs to be pre-heated to 82F, in bottles prior to mixing, to assist it's thicker viscosity to allow better bubble release). I try to keep my art room studio at 77F/25c temp as well while creating and throughout cure process.
But keep in mind, some epoxies (not all) require their liquid resin/hardener to be a bit warmer prior to mixing, to achieve best bubble release results. Sometimes it's a thicker consistency that needs warming to help achieve bubble release, but you must double check with the manufacturer for that product if that is the case. They are not all the same (as some people might assume).
Pre-warming some epoxies, is not recommended by all manufacturers, so again, it important to check with each type of epoxy you use. Some brands only recommend pre-heating their part A bottle, and not their Part B bottle. Also, when preheating bottles, over heating them too much can throw them into pre-mature exotherm. Using a digital IR temperature gun will assist to avoid potential over heating issues.
If my studio space oil heater is turned off for a few days (due to not working in studio), the temperature can drop to well below 70f (21.1). When that occurs, I will need to warm resin bottles, because liquid temp inside bottles will have dropped below 77F/25c.
Our home is usually about 22c (71.6F) and cooler, so if my space heater in the studio is off, I find my resin bottles are even cooler. My studio is in the basement as well, so it’s often cooler downstairs then temp upstairs thermometer reads.
If I’m creating something where I need crystal clear (not using colourants), and bubble free, I will now always be sure to check the temperature of the resin, and be sure it is warmed enough to allow bubbles to release easier when using casting resins. This typically means I need to warm bottles in hot water to achieve correct temperature.
Just because a room is 77, does not mean an item in the room will also be that same temperature. For example, my room is 77f, but when I took temp of the door, it is showing 73.6f (22.7c). Never assume that because your room is warm, that your resin is too. It is best to take lid off, aim the gun down the neck of the bottle, and check your resin liquid temps of both bottles. Aiming at outside of the bottle is not accurate.
This is the IR temp gun I bought at Canadian tire. Any brand of digital IR temp gun should work though. This is just an example.
This next item, is not a necessity item, but another handy tool option to consider, that many busy resin artists use as a time saver, and to assist with keeping their epoxy resin a bit warmer. Some artists store the bottles on top of a warming type matt, such as a seedling matt or reptile matt.
I have personally not used one of these yet. I have purchased one online, I just have not set it up yet in my studio, so am unable to mention its pros and cons just yet. The one I purchased is shown here.
Here is an example of a seed matt that some use to set resin bottles on in their studio, to keep them warm, prior to mixing. . .
While these matts might be handy time savers, keep in mind, even when using these matt type options, you should still be checking and know (for sure ...not guess) what the temperature is of the resin and hardener liquid is, inside the bottles prior to mixing. Again, the use of a digital IR temp gun here as well, allows you to know the resin behavior and status, which helps you to achieve more consistent results. If it's too hot for some reason or too cold, you'll know before mixing.
Another tool that is not a necessity, but some artists in more humid climates find helpful to keep in their resin studio, is a tool that helps show them humidity levels in their space, along with room temperature. Check out hygrometer options you can add to your space if you live in a humid climate.
Here is an example of one that shows both room temperature and humidity. If you do a lot of resin, this temp/humidity tool is helpful to use.
If your home has a humidifier or the weather has changed, it can affect environment conditions in your space, for working with resins as well.
Some of the issues around humidity that I will add here, are covered in one of my first blogs from a few years back. I will copy & paste that info here soon too,