What to Do When Resin in Your Silicone Mold Stays Sticky, Soft or Liquid

You carefully poured your epoxy resin into a beautiful silicone mold, waited hours (or days), and instead of a glossy, hard piece… it’s still sticky, soft, or even liquid. Don’t worry — this happens to many resin crafters, especially when they’re just starting out with silicone molds for resin.

In this guide, we’ll walk through the main reasons resin doesn’t cure properly, how to save your piece (or at least your mold), and what to do differently next time to get smooth, fully cured results with your resin molds.

Why Does Resin Stay Sticky, Soft or Liquid in Silicone Molds?

Epoxy resin curing is a chemical reaction between resin and hardener. If anything disturbs that reaction, you may end up with tacky, rubbery, or liquid resin inside your silicone mold. Here are the most common causes:

1. Incorrect Mixing Ratio

Every epoxy system has an exact mixing ratio (by weight or volume) that must be followed. Adding “a bit more hardener” to speed things up or “a bit more resin” to extend working time actually disrupts the reaction and often leaves the resin under-cured or sticky.

• Always follow the manufacturer’s recommended ratio (e.g. 1:1, 2:1, etc.).
• Use measuring cups or a scale for accuracy.
• Never estimate or “eyeball” the resin and hardener amounts.

2. Insufficient or Improper Mixing

Even if your ratio is perfect, the resin and hardener must be mixed thoroughly. If some of the resin is not properly blended with hardener, uncured pockets remain and you’ll find soft or sticky spots when demolding.

• Stir slowly for at least 3–5 minutes, depending on the product.
• Scrape the sides and bottom of the mixing cup as you go.
• Pour into a second cup and mix again if your resin brand recommends it.

3. Too Much Pigment, Glitter or Additives

Overloading resin with pigments, alcohol inks, mica powders, or glitter can interfere with curing, especially in deep or detailed resin molds.

• Use pigments and colorants made for epoxy resin.
• Stay within the recommended percentage (often up to 5–10% of the total mixture).
• If in doubt, use less colorant rather than more.

4. Moisture, Oils or Contamination

Anything you embed in resin (dried flowers, metal charms, beads, photos, etc.) needs to be clean and dry. Moisture, oil, or grease can react with the resin or block proper curing.

• Make sure flowers and natural elements are fully dried and sealed if needed.
• Wipe down metal or plastic pieces to remove oils and fingerprints.
• Ensure your silicone mold itself is clean, dry and free of dust or leftover release agents.

5. Temperature and Humidity Problems

Resin cures best in a stable, warm environment with low humidity. Cold or overly humid conditions can slow or stop curing, leaving a sticky surface or soft resin inside your silicone molds.

• Check your resin brand’s recommended curing temperature (often around 20–25 °C / 68–77 °F).
• Avoid curing in very cold rooms, garages, or outdoor spaces.
• Protect curing pieces from drafts and large temperature swings.

How to Fix Resin That Didn’t Cure Properly

Once you’ve discovered a problem, the main goal is to either rescue the piece or at least save your silicone mold so you can use it again. The solution depends on how bad the curing issue is.

Scenario 1: Resin Is Soft or Rubber-Like, But Not Completely Liquid

The piece may look formed but feels flexible, squishy, or slightly sticky. In this case, you may still be able to remove it from the mold and save the mold for future pours.

Step 1: Freeze the Mold

Place your silicone mold (with the resin piece still inside) into a sealable plastic bag and put it in the freezer for several hours or overnight. The cold can help separate the resin from the silicone.

Step 2: Demold Carefully

Take the mold out of the freezer and gently try to peel or push the resin piece out of the mold. Work slowly to avoid tearing or stretching the silicone.

Step 3: Clean the Mold

Use wet wipes (baby wipes work well) to remove any residue. If necessary, follow with mild soap and warm water, then let the silicone mold dry completely before using it again.

Tip: Don’t try to “fix” semi-cured resin by pouring more hardener over it. The ratio will still be wrong and it won’t cure properly.

Scenario 2: Resin Is Still Liquid or Very Runny

If the resin in your mold is still almost entirely liquid after the full curing time, the ratio or mixing process was likely way off, or the conditions were extreme. This is usually not salvageable.

Step 1: Pour Out the Uncured Resin

Carefully pour the liquid resin out of the silicone mold into a disposable container. Wear gloves and protect your workspace.

Step 2: Clean the Silicone Mold Thoroughly

Wipe out as much residue as possible with paper towels or wipes. Then wash the mold with warm water and mild soap, and let it dry fully. A clean and dry resin mold gives your next pour a fresh start.

Scenario 3: Resin Is Mostly Cured, But the Surface Is Sticky or Tacky

This is very common with resin pieces. The piece is hard underneath but has a sticky surface that attracts dust and fingerprints.

Option 1: Post-Cure with Gentle Heat

If the cured piece is out of the mold and heat-resistant, you can:

• Place it on a non-flammable surface in an oven preheated to about 50 °C (122 °F).
• Warm it for around 30 minutes.
• Turn the oven off and let the piece cool down gradually inside.

This “tempering” process can help complete curing and reduce tackiness on the surface.

Option 2: Add a New Top Coat of Resin

If the stickiness is only on the very top:

• Lightly clean the surface and remove dust or release residue.
• Mix a fresh batch of resin and hardener carefully, using the correct ratio.
• Pour a thin, even top coat over the piece and let it cure fully under ideal conditions.

A well-mixed top coat often seals the surface and leaves you with a smooth, glossy finish.

How to Prevent Sticky or Soft Resin in Silicone Molds

The best fix is prevention. By fine-tuning your resin process and taking good care of your silicone molds for resin, you’ll avoid most curing problems before they happen.

Why Proper Curing Matters for Your Silicone Molds

When resin cures correctly, your silicone molds last longer, demolding is easier, and details stay crisp. But when resin remains sticky or liquid, it can stain, swell, or even tear the mold. Each failed pour not only wastes time and material — it can also shorten the life of your favorite resin molds.

By following the tips in this guide, you’ll protect your molds, reduce failed projects, and enjoy more satisfying results from every resin pour.

Quick Pre-Pour Checklist for Resin & Silicone Molds

Before you pour resin into any silicone mold, quickly run through this list:

• ✔ Resin and hardener measured according to the manufacturer’s ratio?
• ✔ Mixture stirred slowly and thoroughly, scraping sides and bottom?
• ✔ Silicone mold clean, dry, and free of dust or leftover resin?
• ✔ Embedded items completely dry and free of oil or grease?
• ✔ Pigments and additives resin-safe and used in modest amounts?
• ✔ Room temperature and humidity suitable for curing?
• ✔ Pour thickness within the product’s recommended limits?

FAQ: Sticky Resin and Silicone Molds

My resin is still sticky after 24–48 hours. Is it ruined?

Not always. If the piece is mostly hard with a slightly tacky surface, you can often fix it with a gentle post-cure (low heat) or by adding a new top coat of properly mixed resin. If the entire pour is soft or liquid, it’s usually better to remove what you can and start again with a fresh batch.

Can I add more hardener to fix uncured resin?

Unfortunately, no. Epoxy needs the correct ratio from the beginning. Adding extra hardener later won’t “balance” the mix and often makes the problem worse. It’s better to cut your losses, clean your silicone mold, and mix a brand-new batch correctly.

Does freezing really help with stuck resin?

Yes, freezing can be a lifesaver for your molds. When resin is soft but not fully cured, freezing helps it contract slightly and makes it easier to pull out of the silicone without tearing or stretching the mold.

What if only the top of my resin piece is sticky?

Try gently cleaning the surface, then either post-cure with low heat or pour a thin new layer of perfectly mixed resin over the top. Allow the new top coat to cure in a stable, warm, low-humidity environment for the best results.

Upgrade Your Results with Quality Silicone Molds

Reliable curing starts with good practices — and good tools. High-quality silicone molds for resin give you crisp details, easy demolding, and longer mold life, especially when you follow the mixing and curing tips above.

If you’re ready to level up your resin projects with durable, detail-rich molds:

👉 Explore premium silicone molds at Fynzio and find the perfect resin molds for coasters, jewelry, decor pieces and more.

Happy creating — and may your next demold be perfectly cured and satisfyingly smooth! ✨