I started using epoxy resin 5 years ago. During these 5 years I have learned quite a few things, the most important one being that epoxy in Canadian temperatures is tough. Epoxy is finicky and really likes being warm. When you live in an area that is winter for 10 months of the year, that makes things a little tricky. I have tried numerous brands and types of epoxy for various applications such as countertops, molds and tumbler making. I will go through some of the common issues that I have faced with epoxy, the solutions I have found useful and the strengths and weaknesses that I have found with each brand/type. The information I am giving is strictly my opinion and you should always follow manufacturer recommendations.
Please use proper PPE when working with epoxy resin.
Microbubbles
Microbubbles are way more prominent in cold epoxy. The reason being that cold epoxy is THICK and the thicker it is, the more air that gets trapped when stirring. Using a metal or silicone stir stick helps but if your epoxy is too cold it will still hold air. If you start with tons of microbubbles, you will finish with micro bubbles. A torch helps but, in my experience will not remove them all without burning. If you start with less bubbles you end with less/no bubbles. The best solution that I have found is warming your epoxy before mixing it. I place mine in front of a space heater while I get everything else ready to go. You want your epoxy to be around 27 C (or 80 F) before you pour it. It will pour and mix so much easier. I also leave my tumblers in front of the heater to slightly warm them if they feel cold. Do not let your tumbler or epoxy get too hot, this will cause the epoxy to be too thin. Alternatively, if your tumbler is cold and the epoxy is warm, the epoxy cools quick and causes it to thicken and trap air. If you do notice that you have some bubbles, a quick pass with a torch is all that is needed. A torch will pop the bubbles, a heat gun will not.
Really long cure times or epoxy that stays tacky for days
When epoxy stays tacky it is usually because your ratios are off or you did not stir it enough, but some epoxies will not cure properly in cooler temperatures. The epoxies with longer cure times are prime example of this. If you are sure you do not have more part B than part A, and you stirred the epoxy for 3 minutes or longer, then the temperature may be causing you issues. If your epoxy has a cure time of 12 hours or longer, and your house/shop temperature is less than 24 C (75 F), using a space heater (to warm the air not the tumbler) may help. I find 26-27 C (78-80 F) to be ideal epoxy curing temperatures.
These are my experience with the resin brands that I have tried. Just because I don’t love a brand doesn’t mean you won’t love it. My only goal here is to help by sharing knowledge of what I found works and doesn’t work with each brand in cooler climates. Your experiences may vary.
Evirotex Lite Epoxy
This epoxy is easy enough to work with, but I find it doesn’t cure really hard. The result being a surface that scratches easily. It also yellows pretty fast. I do not recommend it for many things.
Art Resin
I found this one to be ok but it’s a lot like envirotex, it doesn’t cure hard and yellows quickly. Easily found online and would be good if you’re just starting out.
Resinate professional
I accidently order this one by accident instead of the original. I do not have experience with the original because I disliked the Pro so much. I used the pro only twice but each time, the smell induced a migraine. It’s really strong, I use a respirator so I didn’t notice at first but the smell literally does not go away. On top of that, this resin is so finicky and takes forever to cure, you cannot mix any inks or colorants in to it besides the ones specially formulated for it. I can’t speak on the yellowing because I stripped both tumblers due to smell.
CCDIY Medium Viscosity
This one I will admit, I was ready to throw the towel in on. It’s a thin epoxy that has a longer cure time and I find these the most difficult to work with. Warming this epoxy helps tremendously and the thinness of it keeps it from forming many bubbles. It NEEDS to be mixed for longer than 3 minutes and it really loves heat. This epoxy will require many layers for covering chunky glitter, so I really only use it for my last coat.
CCDIY Fast Set
This is one of my most favorite epoxies. It is touchable in about 2 hours, only needs to be mixed for about a minute and helps me get through tumblers quickly. If the epoxy is clear when I use it and not yellow then I have found no yellowing on light cups 6+ months after. It is however not supposed to be used on light colors because it very well could yellow quickly. It is also thicker and does accumulate some microbubbles, but nothing a quick torching won’t fix. Warming it before mixing it helps tremendously.
CCDIY Artist Resin
When they tell you that you need a propane torch for this one, listen. I have always used butane because propane always had too much force and created fisheyes for me. Well this epoxy is THICK, and it does get bubbles but they are so easy to pop with a propane torch. This epoxy doesn’t move with the force, so unless you hold it in one spot and burn the epoxy, you shouldn’t have an issue. This epoxy has a cure time of about 10-12 hours. It has an amazing shiny finish. You do need to mix it for 3+ minutes. It also loves heat. I mean, I keep my space heater on it for 4 hours and crank the heat in the shop overnight (24-26 C, 75-78 F) and it still takes the full time to be able to handle it.
Stone Coat Art Coat
Super thin epoxy with a long curing time, 24 hours soft cure. The extended work time means you can remove any bubbles, dust or other imperfections if they come up. It is super durable once fully cured though (7 days). I get no bubbles in this epoxy but only use it as a top coat because its so thin and requires so much time. It also loves heat. If I keep it warm enough it cures enough to handle in 8-10 hours. This is a premium epoxy. It cures super hard and part B has yet to yellow on me despite letting it sit in the sun. This is my hands down favorite epoxy top coat. Ok for use after 72 hours but continues to get harder for 30 days. Mix for at least 3 minutes. (24-28 C is the best temps for curing in my experience). Amazingly shiny finish that is flawless even on flat black.
Stone Coat Quick set
Fast setting epoxy that is extremely comparable to CCDIY fast set. I use this on any tumbler that has a glitter base and all the way up to the top coat on any darker tumblers. Part B is quicker to yellow so shouldn’t be used over light colors. In saying that though, I have and I have found that if part B isn’t already yellow when I mix my epoxy it doesn’t change the color of my light colors any faster than any of the cheaper brands of epoxy. A top coat is also preferred over this epoxy because it tends to have a stronger smell. To me it smells a little fishy but I have gotten used to it and hardly notice it anymore. It isn’t terribly overwhelming but may linger without a layer over it.
Art Works resin
This is IMO a great epoxy for beginners. I do recommend warming it before use because it will make a ton of micro bubbles if you don’t. It is pretty easy to get along with. I generally mix it until it’s clear and streak free, then apply, torch quickly, wait a few minutes and torch again. This epoxy is thicker so good over chunky glitter, it’s dry and not sticky in about 6 hours. 8-10 if it’s not kept really warm but I find this to be the easiest to work with in cooler temps (19-22 degrees 66-71). Part B yellows pretty quick in the bottle but I haven’t really noticed it on white tumblers, if they started white, they still look white to me months later. This is the one I grab for my middle coats.
I will continue to add more epoxy as I try them or remember ones I have forgotten.