How to Harden Sticky Resin

If you’re a resin enthusiast, you’ve probably had a few not-so-successful projects and experiments in your creative space. Maybe you’ve even had instances where resin doesn’t harden correctly. Sticky resin can ruin a project,  and we want to help you learn how to fix uncured epoxy resin. No one wants to have to ditch a project because their resin won’t properly set. Learning how to fix sticky resin is an essential skill that can save your project.

In this piece, we will talk about uncured resin, how it occurs, and how to harden sticky resin so that your projects will be successful. 

Common Resin Sticky Situations

Resin that hasn’t been cured properly is a hassle. You may be asking yourself, “why Is my resin flexible?” Here are three common situations that you may run into with sticky resin:

Sticky, Tacky Resin

If you inaccurately measure your ingredients, don’t mix the resin thoroughly enough, or cure your resin in cold temperatures, you may end up with sticky resin.

Soft and Sticky Spots

Soft and sticky spots sometimes appear on otherwise nicely cured resin. This phenomenon occurs when you don’t properly mix your resin. If this happens, you should scrape off and then sand down the soft resin, and then carefully apply a new coat that has been mixed properly.

Liquid, Runny Resin

You can end up with runny resin if you don’t use the correct 1:1 ratio of hardener and resin or if you use too much color additive. You’ll need to scrape away the runny resin and add a new layer.

These are all tough situations. But we’ve compiled several strategies that you can use to deal with your sticky resin situations. Hopefully, you’ll never need to Google ”what to do if epoxy doesn’t harden” again.

How to Fix Tacky Resin

In this scenario, your resin has started to cure but is tacky. When your resin is tacky, it will stick to objects like the sticky side of tape or an envelope. 

Why Did It Happen?

Your Resin Room May Be Too Cold

You should always cure your resin in a room that has a temperature between 75 degrees and 85 degrees Fahrenheit.  If you are working during a cold season or in a chilly locale, you can use heating lamps in your workspace to keep the resin at its appropriate temperature.

Inaccurate measuring

The 1:1 ratio is a hard rule. When you’re mixing up a batch of fresh resin, make sure to maintain this precise ratio between your hardening agent and your resin.

If you don’t have the right ratio, you will run into the tacky or runny resin.  

Not enough mixing

If you didn’t thoroughly mix your concoction, the hardening agent may be streaked in with the resin, resulting in a bad cure.

How to Fix Tacky Resin

Taking preventative measures when mixing resin is key to ensuring you don’t have to fix tacky resin. If you’ve used inaccurate measurements or haven’t mixed it properly, you may have to make a fresh batch. However, before you throw it in the bin, you may be able to salvage your project. 

Try setting the piece in a warmer area for twenty-four hours. Your resin room should be around 80 degrees Fahrenheit. Resin doesn’t cure well in cold surroundings.

How to Harden Runny Resin

If you have runny resin, it may be more like liquid, or it could have partially hardened but still be gooey, runny, and wet.

Why Did It Happen?

Too Much Colorant

Too much colorant can cause the resin to become runny, even if you used the correct proportion of hardener. 

Measuring by weight, not volume

Most commercial resins are designed to be mixed by volume, not weight. Be careful to follow mixing instructions on the product, including the measurement unit.

How to Fix Runny Resin

You’ll need to entirely remove the wet or runny material. Scrape away the runny resin, remix new resin, and apply a new layer. If necessary, sand the leftover depression, and make sure to cure your resin in a warm space as detailed above.

How to Harden Resin Soft Spots

In an otherwise finely-cured piece of resin, you may have soft spots.

Why Did It Happen?

Did you scrape the sides of your mixing container after pouring?

We recommend that you scrape the sides of your mixing bowl while mixing, but we don’t recommend scraping when you pour your resin. This is because you might pour in the unmixed resin. To avoid this, scrape down the sides as you mix, and gather all your resin in the center of your mixing bowl before you pour it. 

How to Fix Soft Resin Spots

The best way to fix soft resin spots is to scrape and then sand these areas to remove all the soft material. After you have removed and sanded down the entire spot, use a new resin mix to carefully fill in your spot. Once it hardens, sand it again. Add layers as appropriate.

Resin Hardening Tips and Tricks

Knowing how to fix epoxy that won’t dry can save your project. Here are some tips and tricks to help harden sticky resin:

  • Try applying triple-thick polyurethane. After waiting twenty-four hours for your resin to cure, carefully spray on a layer of polyurethane and then wait 30 minutes. Be sure to apply thin, even layers—thick sprays may cloud your surface.
  • When you’re fixing a  sticky spot, you should apply a new layer of resin to your entire project, rather than just the problem area. This process will help you avoid a seam line between the old and new layers.
  • Always remove gooey or runny resin; you can’t fix them. You can leave tacky or sticky resin and use another method to deal with those issues.
  • Keep your colorant at or below 6% of your resin mix.
  • Create a practice project before tackling a large project. You will catch mistakes when you practice mixing and applying your resin.
  • Always follow the mixing directions on the product precisely! Too little hardener in resin mixtures can lead all of the above problems.

Hardening Sticky Resin: Plastic Materials Has You Covered

We at Plastic Materials have been producing products that have been helping resin crafters for years. If you have questions about tacky, sticky, or runny resin, we’d love to help! Contact us with your questions about epoxy resin, polyester resin, and more.