How To Harden Sticky Resin

October 8, 2019

If your epoxy resin hasn't cured properly, it means that the chemical reaction between the resin and hardener was not able to take place. Sticky resin is typically caused by inaccurate measuring or under mixing.

Why is my resin still sticky?

The three most common sticky issues are:

Liquid, runny resin

This can be caused by not following the correct 1:1 mixing ratio of resin and hardener, or by adding too much colorant. The liquid resin will need to be scraped off before you pour a fresh coat.

Sticky, tacky resin

This is often caused by inaccurate measuring, not mixing thoroughly or by curing in cold temperatures. Try moving your piece to a warmer spot: if it doesn't dry, re-pour with a fresh coat of resin.

Soft spots

If you have soft, sticky or wet spots on an otherwise perfectly cured surface, you may have scraped the sides of your mixing container when you poured. Doing this may have caused unmixed resin and hardener stuck to the sides of your container to get scraped out onto your perfectly mixed resin. To fix this, you'll need to scrape off any liquid resin as best you can and pour a fresh coat.

Resin that remains sticky days after being poured will stay sticky indefinitely until measures are taken to fix the situation. Be sure to measure and mix your resin properly, so this problem will not occur again:

Measure ArtResin in precisely equal amounts by volume:
Adding too much of either resin or hardener will alter the chemical reaction and the mixture will not cure properly.
Mix ArtResin thoroughly for at least 3 minutes:
Scrape the sides and bottom of the container as you mix: improperly mixed resin stuck to the sides and bottom won't be able to catalyze and therefore won't be able to cure, leaving sticky spots in your resin that just won’t harden.

In this video, we take a closer look at the three most common sticky situations, why they happened and, most importantly, how to fix them.

Sticky Situation #1: Runny Resin

What It Looks Like:

Liquid, runny resin
Resin that may have thickened somewhat but is wet and gooey

Why It May Have Happened:

You did not follow the 1:1 ratio between resin and hardener: ArtResin requires equal parts of both resin and hardener in order to cure. Adding more hardener will not make the resin cure faster or harder.
You may have measured by weight, not volume: ArtResin was formulated to be measured in equal amounts by volume.
You may have accidentally mixed two parts of resin or two parts of hardener: the chemical reaction requires equal parts of resin and hardener in order to harden.
You may have added too much resin colorant: never add more than 6% of the total combined volume of resin and hardener (eg. 50ml resin + 50 ml hardener = 100 ml total would require no more than 6 ml of colorant.)

How To Fix Runny Resin Problems:

Directions:

If you have areas with runny or gooey resin, you'll have to scrape off as much wet material as you can.
If you don't remove all the wet material, it could eventually leak out from under the new resin coat.
Once you've scraped your piece down, go ahead and pour a fresh coat of carefully measured and thoroughly mixed ArtResin.

Sticky Situation #2: Tacky Resin

What It Looks Like:

The resin has started to cure but the surface is still tacky, like the sticky side of tape

Why It Happened:

The temperature of your resin room may be too cold: the ideal temperature in which to cure resin is 75-85F or 24-30C for the first 24 hours.
Inaccurate measuring: always measure ArtResin in precisely equal amounts, by volume.
Under mixing: mix thoroughly for at least 3 minutes, scraping the sides and bottom of the mixing container as you stir.

How To Fix Tacky Resin:

Try moving your piece to a warmer spot for 24 hours to see if it dries.
If temperature was not an issue and your resin is simply tacky, count yourself lucky: this is the easiest fix of all 3 sticky situations. In fact, as long as you don't have any wet, gooey areas (if you do, any wet or liquid resin needs to be scraped off) you don't need to do a thing: go ahead and pour a fresh coat of carefully measured and thoroughly mixed ArtResin directly over the entire tacky resin surface. When the fresh resin cures, you'll never know you ever had a sticky resin issue.

Sticky Situation #3: Soft Spots

What It Looks Like:

Random soft or wet spots on an otherwise perfectly cured resin surface.

Why It May Have Happened:

You may have scraped the sides of your mixing container after you poured: although we recommend scraping the sides and bottom of your container when you're mixing, we DON'T recommend scraping when you pour your ArtResin onto your artwork ( like you might if you were scraping cake batter out of a mixing bowl and into a cake pan. ) If any unmixed resin or hardener stuck to the sides gets scraped out onto your artwork, you'll end up with soft wet spots in your cured resin.

How To Fix Sticky Resin:

Sand down perfectly cured areas with coarse sandpaper, such as 80 grit. Wipe up sanding residue with a damp paper towel.
If you have areas with runny or gooey resin, you'll have to scrape off as much wet material as you can. If you don't remove all the wet material, it could eventually leak out from under the new resin coat.
Once you've scraped your piece down and your piece is clear of any sanding dust, then go ahead and pour a fresh coat of carefully measured and thoroughly mixed ArtResin.

So remember .....

If You Find Yourself With Sticky Resin:

If it's liquidy: scrape it off
If it's tacky: leave it
If you have areas that have cured perfectly: sand those parts down, thoroughly wiping away the sanding residue
Leave your fresh resin coat to cure for 24 hours: your piece will look good as new!

To Avoid Sticky Resin In The First Place:

Make sure you resin in a warm environment ( 75-85F or 24-30C is best )
Don't add more than 6% colorant to your resin mixture
Check the ratios and measure your resin and hardener in equal amounts by volume
Mix your resin thoroughly for at least 3 minutes
Scrape the sides and bottom of your mixing container as you stir
Don't scrape when you pour

If you follow these instructions, you will end up with a beautiful, glossy, hard ArtResin finish! Leave any questions or comments below - we would love to hear from you for the curing process.

Do you want to learn more about troubleshooting epoxy resin? Read our guides below:

ArtResin: Made By Artists, For Artists.

About the author: Joanne Wright

I'm Joanne, the Marketing Content Writer at ArtResin. Originally from Canada, my home is now Indianapolis, Indiana. My love of all things creative and my entrepreneurial heart means I’ve worn many hats over the years including fashion producer & stylist, retail store owner, t-shirt designer, and even vegan baker! I...

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