Let’s get it straight out of the way: resin is expensive, and the sight of an uneven cure or resin that simply hasn’t cured is enough to make any artist furious! Luckily, an uneven resin surface and/or uncured resin can be easily fixed or avoided, and we’re going to teach you how.
Resin typically yields a glass smooth surface, free of defects including pits, bubbles, or other otherwise unsightly textures.
If your cured piece isn’t as smooth as you expected, there are a few reasons why.
- Improperly mixed resin. Spoiler alert: improperly mixed resin is going to be the cause of many issues related to the integrity of your resin. The resin systems you’ll find will primarily consist of the resin itself, and a hardener; this is commonly referred to as a two-part kit. For many of these kits, it is absolutely essential, crucial, and required that you mix them in exactly even quantities, meaning, if you use six ounces of Part A, you need to use exactly six ounces of Part B. If you eyeball it or try to save money by using a little less of one of them, your resin will either not cure, or it will have defects. Always, always follow the mixing instructions on the company’s packaging, or contact the company for clarification if necessary.
- Uneven curing surface. Resin is usually self-leveling which is fantastic… unless you haven’t placed it on a level surface to cure. Resin will continue to move for a bit after you’ve poured it on, and sometimes, this means it will drip over the edge (which is preferable if you’re trying to seal all of the sides). On a level surface, this movement is how the resin levels. On an uneven surface, you’ll have thin or bare spots in your resin as a result.
- Surface impurities. Many of us use silicone, dimethicone or some other additive to achieve cells, and this doesn’t just disappear once the paint is poured! Many times, once your painting cures, you’ll find that there are shiny spots where your additive has collected. If left uncleaned, this will repel the resin and cause bare spots.
- Overheating the resin. If you use a torch or heat gun to pop bubbles in your resin, it is possible to overheat the resin, which can cause surface defects.
- Wet stirring utensils. It’s a good idea to make sure you have clean containers and stirring utensils to work with, but you must dry them thoroughly before you begin stirring your resin. That moisture will translate into uncured resin or a surface with defects.
These are all issues that are easily avoided by following these simple resin rules:
- Always follow the measuring and mixing instructions on the resin manufacturer’s packaging or website. If you cannot find the instructions, or aren’t sure you understand them, reach out to the manufacturer directly to clarify. You may also be able to find assistance in our Facebook group, as it’s likely someone has used the same brand before!
- Make sure that your curing surface is as level as possible before you apply your resin, especially if you’re using the flood coat method.
- “Clean” your painting prior to sealing with resin to make sure there aren’t any surface impurities. This is most often done using a thin layer of cornstarch to absorb the extra silicone. If you’re still not sure whether your piece is completely free of surface impurities, apply a thin coat of protective sealant like Rustoleum Clear Durable Topcoat (spray) or Polycrylic, allow the sealant to cure, and then pour resin on top.
- Apply heat a safe distance from your piece, and do not concentrate in any one area too long. Hold your torch or heat gun at least five inches from your surface or further if possible. The torch only needs to be close enough to pop the bubbles, if you see smoking, the torch is too close and your resin is scorching. Plus, burned resin smells terrible. Start further away than you think you need to be, and move the heat source closer until you see bubbles starting to pop.
Now, these are all amazing tips if you haven’t actually poured the resin yet, but what do you do if you’ve already got the bare spots? There are fixes.
- Sanding and repairing. You can sand down the resin you’ve already poured and allowed to cure and then pour another flood coat on top of it. When it levels, you will not see the surface imperfections underneath. Make sure that you clean all of the dust and debris from the surface of the sanded piece before attempting to seal again to avoid any unwanted flecks and bumps.
- Simply pour over top. If you do not want to sand your existing resin extensively, you can just pour another layer of resin over top after lightly sanding the whole piece. Again, make sure you’ve cleared any dust or residual debris before pouring the new coat.
Uncured resin is extremely frustrating, especially if you’ve left the piece to sit for 24 hours and, thinking it’s cured, fully commit to putting both hands on it to move it, thus coating your hands in one of the art world’s most difficult-to-remove supplies. Trust me, an artist who once accidentally resined my fingers together. Not my finest hour.
Uncured resin is typically a result of improperly mixed resin. Remember a few minutes ago when we talked about how improperly mixed resin will be the cause of most of your problems? Here’s another one of those problems.
In a two-part resin system, you need the hardener to take your actual resin from a liquid to a solid. For the majority of two-part resin systems, this will mean equal parts. Using a scale is the best way to know for sure that you’ve got equal parts, but you can also use a cup with line measurements on it if you don’t have a scale.
Improperly mixed resin doesn’t automatically mean ratios, though. When measuring your resin and hardener, you want to measure them in separate cups, and then pour the resin into the hardener’s cup. You’ll mix on average for about three to six minutes (check the manufacturer’s instructions), and then you’ll want to take a clean cup and pour that mixture into it, and continue to stir. That stirring time is not a suggestion! If the manufacturer has specified a certain amount of time for mixing, you can be sure that they came up with that number based on extensive research. You may get lucky once or even twice if you speed through this part of the process, but someday it will come back to bite you.
If you’re in a tight spot and you’ve already got the issue of uncured resin, the best thing to do is scrape as much of it off as you can. If the resin is simply sticky or tacky, not scraping it all completely off will not affect the repair process. However, if your resin is still completely liquid, you’ll need to make sure that all of it is removed with a very clean scrape before attempting to apply more.
Once you’ve scraped the piece, patch up any divots or dips with properly mixed resin. Once the patch has dried, sand the top to even it out, making sure to clean off the piece afterwards to avoid any dust or debris finding its way into your final resin. Then, make sure you’ve mixed your resin completely according to your manufacturer’s directions, and pour a new coat.
If none of this works, defective resin is a thing. Sometimes, no matter how diligently you adhere to the instructions, problems will still arise. Very rarely, this can be due to an issue with the manufacturing of the resin. In this case, contact the manufacturer and make sure to include photos and a full, detailed description of your process so that they can help identify the problem.
99% of the time, the blame rests solely on the artist for resin imperfections however, so if your resin isn’t quite right, make sure to take a good, honest look at how you mixed it to identify where you can improve.
Resin can add so much depth and character to your pieces, and the glassy smooth finish is stunning. Do not rush through the mixing and pouring process and be sure to pay attention to your surface, and you’ll have a beautifully enhanced work of art!