Why Is My Epoxy Still Sticky? Causes and Fixes
A sticky pour is the most common epoxy problem there is, and it is almost never the resin's fault. Epoxy does not dry. It cures, through a chemical reaction between the resin and the hardener, and that reaction only finishes the job when it gets the right ingredients in the right amounts at the right temperature.
When a pour stays tacky, one of those three things went wrong. The good news is that where it is sticky tells you which one, and that tells you whether to wait, warm it up, or cut your losses and re-pour.
Start by giving it a fair chance. Superclear resins cure hard to the touch in about 24 hours in a room held between 70 and 84 degrees Fahrenheit, and a Liquid Glass Deep Pour casting takes around 72 hours before it is hard enough to sand. If you are inside those windows, or your shop is cold, it may not be a problem yet. For the full timeline by product, see our guide to how long epoxy takes to dry and fully cure.
First, read the pattern
Before you touch anything, look at where the tack is. The pattern is the diagnosis.
| What you see | Most likely cause | Will it recover? |
|---|---|---|
| The whole pour is evenly soft, tacky or rubbery | Off ratio, or a shop too cold for the reaction to run | Cold: often, once warmed. Off ratio: no |
| Soft or wet patches, streaks or swirls in an otherwise hard pour | Unmixed resin, usually scraped from the bucket during the pour | No, the patches stay soft |
| Hard underneath, slightly tacky on top | Early, or cool. Occasionally humidity | Usually, with time and warmth |
| Sticky only where colour was added | Too much colorant, or an acrylic colorant | No |
The four real causes
1. The ratio was off
Epoxy is not like paint, where a little more or less of something just changes the shade. The resin and hardener react molecule for molecule. Put in too much of either and the extra has nothing to react with, so it stays in the pour as a soft, sticky liquid forever. Adding more hardener does not make it cure faster or harder. It makes it softer.
Superclear resins are measured by volume: Table Top Epoxy and Designer Art Resin are 1:1, and Liquid Glass Deep Pour and Countertop Epoxy are 2:1 (two parts resin to one part activator). Measure every batch in a graduated container. Never pour "about half" by eye.
The weight trap. A 1:1 ratio by volume is not 1:1 by weight, because the two liquids do not weigh the same. If you mix Table Top Epoxy on a kitchen scale, the correct weight ratio is 100 parts resin to 83 parts curing agent, not 100 to 100. Weighing it out equal parts is one of the most common ways people end up with an off-ratio pour while being careful. If you would rather work by weight, the epoxy calculator has a weight tool, and our team at 888-849-0588 can confirm the numbers for your product.
Mixing two different products together, or topping up one product's resin with another's hardener, also throws the ratio off. Keep each kit's two parts together.
2. It was not mixed well enough
Even at a perfect ratio, resin and hardener only react where they actually meet. Streaks of unmixed material cure as soft spots.
The directions are specific here, and they differ by product:
- Table Top Epoxy and Designer Art Resin: stir by hand for a minimum of 3 minutes and a maximum of 5. Scrape the sides, bottom and corners of the container for the first 3 minutes, then stop scraping and keep stirring. Once the mix turns crystal clear, it is ready. Stir like you are stirring hot tea, not whipping cream, so you do not beat air into it.
- Liquid Glass Deep Pour: stir for at least 5 minutes, scraping the sides and bottom as you go. Then transfer the whole batch into a second clean bucket and mix for 3 more minutes, scraping again. The second bucket leaves behind whatever was clinging to the walls of the first.
3. Unmixed resin was scraped into the pour
If your pour is hard everywhere except a few odd soft patches, this is the first thing to suspect, and it is the one people least expect, because it feels like the tidy thing to do.
When you pour, do not scrape the bucket. The film clinging to the sides and bottom of a mixing container is the least mixed material in the whole batch. Scraping it out drops streaks of unreacted resin or hardener into your pour, and they cure as soft, tacky or wet spots. On a deep pour, the product directions also warn that it can cause hot spots.
Leave that last bit in the bucket. It is cheaper than a re-pour.
4. It was too cold
Temperature controls the speed of the reaction more than anything else you can change. Superclear resins do their best work between 70 and 84 degrees Fahrenheit. Cooler slows the cure down. Warmer speeds it up and shortens your working time.
Below about 65 degrees, the epoxy can thicken and even show some crystallization in the bottle. That is not damage, but it is a warning. If the space is too cold, the curing reaction may not take hold at all, and a pour left in that state for too long may never react and start the curing process.
Volume matters too, and not the way most people guess. The reaction makes its own heat, and a larger mass holds on to it. More volume cures faster; a thin, small pour takes longer. A thin coat in a cold garage is the combination most likely to sit there tacky for days.
A fifth, less common one: colour
Colour is added to the resin, so it counts against the chemistry. For Designer Art Resin, keep alcohol dyes, mica powders and liquid pigments to no more than 12% of the mix, and do not use acrylic based colorants, which can react badly with the epoxy. If the only tacky part of a piece is where the colour went in, this is the likely reason.
How to fix sticky epoxy
Match the fix to the pattern.
Evenly tacky, and the room was cold
This is the most recoverable case. Bring the space up into the 70 to 84 degree range and hold it there, then give the pour a few more days before you judge it. Keep dust off it while you wait. Many "failed" pours in cold weather simply cure late.
For next time, warm the bottles, not the mix: bring a pot of water to a steady 75 to 80 degrees, stand each bottle in it until it comes up to temperature, then let them cool back to around 70 to 75 degrees before you start mixing. Do not mix first and then try to warm the batch.
Evenly tacky after several warm days
If the whole pour is still soft or rubbery after it has had several days in a properly warm room, the ratio was off, and waiting will not fix it. The extra resin or hardener has nothing left to react with.
The honest fix is to remove it. Scrape and cut away the uncured material, clean the surface thoroughly with 90% or higher isopropyl alcohol until no stickiness remains, let it dry, and start again with a carefully measured batch. Do not pour fresh epoxy over a layer that is still soft or wet. New resin will not cure the old resin, and the soft layer underneath stays soft.
Soft spots in an otherwise hard pour
The hard areas are fine. The soft spots will not firm up on their own. Once the rest of the pour is fully hard, dig or cut out each soft spot down to solid material, clean the area with isopropyl alcohol, then sand the surrounding surface and fill or recoat over it with a properly mixed batch.
Hard underneath, slightly tacky on top
Give it time and warmth first. If the surface is still tacky once the pour is otherwise hard, sand it with 220 to 320 grit and wipe it down with 90% or higher isopropyl alcohol, then pour a fresh coat over it. That is the same prep the directions call for any time you add a layer to an epoxy surface that has already hardened. There is more on layering in our guide to how many coats of table top epoxy you need.
If you are not sure which case you are looking at, send a photo or call us at 888-849-0588 or superclear@fgci.com. We would much rather help you diagnose it than have you pour a second layer over a problem.
A pour that stays sticky is not the same as one that is still curing
"Hard to the touch" and "fully cured" are different milestones. A Superclear pour that feels hard at 24 hours is still gaining strength, and it reaches full cure and maximum hardness at 30 days. A slight softness under a fingernail in the first week, or a surface that marks more easily than you expected, is usually a pour that is still curing, not one that failed.
Stickiness is different. A properly mixed pour in a warm room does not stay tacky to the touch for days. If yours does, work through the causes above.
Prevent it next time
- Warm the room first. Get the shop into the 70 to 84 degree range before you open the bottles, and keep it there through the cure.
- Warm cold bottles in a water bath, then let them settle back to about 70 to 75 degrees before mixing.
- Measure by volume in a graduated container, or use the correct weight ratio if you weigh it. For Table Top Epoxy that is 100 to 83, not equal parts.
- Mix for the full time. 3 to 5 minutes for Table Top and Art Resin; at least 5 minutes plus 3 more in a second bucket for Deep Pour.
- Scrape while you mix, not while you pour.
- Keep batches to the size the product can handle. Table Top and Art Resin are mass sensitive: mix a maximum of about 2 quarts at 74 degrees, and never more than a half gallon in one container.
- Keep colour within limits, and skip acrylic colorants.
- Leave it alone. Deep Pour castings start to get tacky after 24 hours; do not disturb them for 72.
Not sure you are pouring the right product for the depth? Our guide to how deep you can pour epoxy in one layer covers the limits for every Superclear resin. Browse Superclear Table Top Epoxy and Liquid Glass Deep Pour for the full directions on each product page.
Frequently asked questions
Will tacky epoxy eventually dry?
Sometimes. If the room was too cold, warming it into the 70 to 84 degree range often lets the cure finish over the next few days. If the ratio was off, or unmixed resin ended up in the pour, the tacky areas will not cure on their own no matter how long you wait.
Why is my epoxy still sticky after 24 hours?
At 24 hours in a warm room, Superclear coatings should be hard to the touch. If they are not, the usual causes are a cool shop, an off ratio, not mixing long enough, or scraping unmixed material from the bucket into the pour. Deep Pour castings are slower and are not expected to be hard until around 72 hours.
Can I pour more epoxy over sticky epoxy?
Not over a layer that is still soft or wet. Fresh resin will not cure the layer underneath. If the surface is only slightly tacky and the pour is hard underneath, you can pour the next layer while it is tacky. If it has hardened, sand with 220 to 320 grit and clean with 90% or higher isopropyl alcohol first.
Does adding more hardener make epoxy cure faster?
No. The resin and hardener react in a fixed ratio, so extra hardener is left over and keeps the pour soft. Measure exactly to the ratio on the product.
Why is my epoxy sticky in some spots but hard in others?
Soft patches in an otherwise hard pour almost always mean unmixed material got into the pour, most often from scraping the sides and bottom of the mixing bucket while pouring. Those spots will not firm up and need to be cut out and refilled.
How do I get sticky epoxy off a surface?
Scrape away as much of the uncured material as you can, then clean the area with 90% or higher isopropyl alcohol until no tack remains. Let it dry completely before you pour again.
What temperature does epoxy need to cure?
Superclear resins work best between 70 and 84 degrees Fahrenheit. Below about 65 degrees the epoxy thickens, and if it stays too cold the curing reaction may never take hold. Larger pours generally want the lower end of that range.
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