How to Seal Porous Objects Before Embedding in Resin

Have you ever tried embedding a delicate object like wood, fabric, or paper in resin, only to end up with disappointing results? You’re not alone. Many crafters and artists face the same issue when working with porous materials — air bubbles, discoloration, and structural damage can ruin an otherwise beautiful project.

The key to success lies in one crucial step: sealing. Sealing porous objects before they come into contact with resin is essential for achieving a smooth, professional finish. It prevents unwanted reactions between the material and the resin, ensuring your final piece looks exactly how you envisioned.

In this article, we’ll walk you through everything you need to know about sealing porous materials properly. From understanding why sealing matters, to choosing the right sealant, and applying it effectively, this guide will give you the confidence to work with a variety of materials safely and creatively.

Whether you’re new to resin crafting or looking to refine your technique, mastering the art of sealing will open up a whole new world of possibilities. Let’s dive in!

Understanding Why Sealing Is Necessary

Before diving into the “how,” let’s explore the “why.” Porous materials — such as wood, paper, cork, fabric, and even some types of dried flowers — have tiny openings or capillaries that easily absorb liquids. When you pour epoxy or polyester resin over them without sealing, several problems can occur:

  • Air Bubbles: The trapped air inside porous surfaces rises to the surface when resin is applied, creating unsightly bubbles.
  • Discoloration: Some materials, especially wood and paper, may release tannins or moisture that stain the resin.
  • Swelling or Warping: Materials like paper or fabric can expand or warp when exposed to resin, ruining your design.
  • Weak Adhesion: Without proper preparation, the resin may not bond correctly, leading to peeling or separation over time.

Sealing creates a protective barrier that prevents these issues. It locks in the material’s structure, minimizes absorption, and ensures a clean, bubble-free finish.

Now that you understand its importance, let’s move on to selecting the best sealant for different materials.

Choosing the Right Sealant for Different Materials

Not all sealants are created equal, and the type you choose depends heavily on the material you’re working with. Here’s a breakdown of popular options and which ones work best for specific items:

1. Clear Glue (PVA Glue) – Ideal for Paper, Fabric, and Lightweight Wood

White school glue or PVA (polyvinyl acetate) glue is a favorite among resin crafters due to its accessibility and effectiveness. It dries clear and forms a strong barrier.

  • How to Use: Dilute slightly with water (about 1 part water to 2 parts glue), apply with a brush, and let dry completely before adding resin.
  • Pro Tip: Apply two thin coats rather than one thick coat to avoid wrinkling or clumping, especially on paper.

2. Epoxy Resin – Great for Dense Woods and Natural Elements

Believe it or not, you can use a small amount of the same epoxy resin you’re working with to seal certain porous materials.

  • How to Use: Mix a small batch of resin and hardener, then apply a thin layer directly onto the surface.
  • Best For: Dense woods like driftwood or bark where a more durable seal is needed.

3. Acrylic Sealers or Mod Podge – Perfect for Mixed Media Projects

Spray-on acrylic sealers or decoupage mediums like Mod Podge are excellent for sealing photos, printed images, or painted surfaces.

  • How to Use: Apply with a brush or spray evenly over the surface. Allow to dry thoroughly.
  • Bonus: These often add a glossy or matte finish, giving your project a polished look before the resin even hits.

4. Shellac – Recommended for High-Tannin Woods

Some woods, like oak or pine, contain natural oils and tannins that can bleed into resin and cause yellowing.

  • How to Use: Apply a thin coat of dewaxed shellac using a brush or cloth. Let dry for at least 30 minutes before resin application.
  • Why It Works: Shellac acts as a powerful barrier against tannins and moisture.

Each of these sealants serves a unique purpose, so choosing the right one is key to a successful project.

Step-by-Step Guide to Sealing Porous Objects

Now that you’ve chosen the right sealant, let’s walk through the process step by step to ensure optimal results.

Step 1: Prepare Your Workspace

Make sure your area is clean, well-ventilated, and protected with disposable plastic or wax paper. Wear gloves and a mask if necessary, especially when working with sprays or shellac.

Step 2: Clean the Object Thoroughly

Dust, dirt, or oils can interfere with adhesion. Wipe down your object with a damp cloth and let it dry completely. For wood, light sanding with fine-grit sandpaper can help create a smoother surface.

Step 3: Apply the First Coat of Sealant

Using a soft brush or applicator sponge, apply a thin, even coat of your chosen sealant. Don’t worry if it looks milky at first — most sealants become clear as they dry.

Step 4: Let It Dry Completely

Patience is key! Wait at least 1–2 hours for the first coat to dry. If you’re working with thick materials like bark or dense wood, allow extra drying time — sometimes overnight.

Step 5: Apply a Second Coat (Optional but Recommended)

For maximum protection, apply a second thin coat. This ensures full coverage and helps prevent any missed spots from causing issues later.

Step 6: Light Sanding (If Needed)

Once fully dry, lightly sand the sealed surface with very fine sandpaper (like 400 grit) to remove any texture or bumps. Wipe away dust before pouring resin.

You’re now ready to begin your resin project with confidence!

Common Mistakes to Avoid When Sealing

Even experienced crafters can run into issues if they rush or skip steps. Here are some common mistakes to watch out for:

Skipping the Drying Time: Applying resin too soon can trap moisture underneath, leading to cloudiness or bubbling.

Using Too Much Sealant: Thick layers can crack, peel, or create an uneven surface under resin.

Not Testing First: Always test your sealant on a scrap piece of the same material to see how it reacts.

Ignoring Ventilation: Some sealants emit fumes, so always work in a well-ventilated space or wear a respirator if needed.

Overlooking Material Sensitivity: Certain fabrics or papers might react poorly to specific sealants. Do a patch test first.

Avoiding these pitfalls will save you time, frustration, and wasted materials.

Tips for Sealing Specific Materials

Let’s take a closer look at how to handle some of the most commonly used porous materials in resin projects.

Wood

Natural wood adds rustic charm, but it needs careful sealing.

  • Use: Dewaxed shellac or diluted PVA glue.
  • Tip: Sand the wood first to open the grain, then apply 2–3 thin coats of sealant.

Paper & Photos

Photos, book pages, or printed images require a gentle touch.

  • Use: Mod Podge or acrylic sealer.
  • Tip: Apply with a foam brush to avoid wrinkles. Let each coat dry fully before applying the next.

Fabric

From lace to felt, fabric can be tricky but stunning in resin.

  • Use: PVA glue or fabric stiffener.
  • Tip: Apply glue on both sides and stretch the fabric flat while drying to prevent curling.

Cork

Cork has a naturally bumpy texture that can trap bubbles.

  • Use: Epoxy or PVA glue.
  • Tip: Press gently with a roller after sealing to flatten and remove air pockets.

Dried Flowers

Preserved botanicals are delicate and must be handled carefully.

  • Use: Acrylic sealer or epoxy.
  • Tip: Spray lightly instead of brushing to avoid damaging petals.

Each material responds differently, so tailor your approach accordingly.

Troubleshooting Common Issues After Sealing

Even with the best preparation, things can go wrong. Here’s what to do if you run into common post-sealing problems:

Resin Bubbles Appear: Try torching the surface gently with a heat gun or lighter to pop bubbles. If bubbles persist, consider resealing.

Cloudy Finish: This usually means the sealant wasn’t fully dry before resin was poured. In the future, allow extra drying time.

Peeling or Lifting: This could indicate poor adhesion. Sand the surface lightly and apply another coat of sealant before trying again.

Yellowing or Discoloration: This often happens with high-tannin woods. Switch to shellac or a UV-resistant resin to prevent future issues.

By identifying the problem early, you can adjust your method and improve your results with every project.

Conclusion 

Sealing porous objects before embedding them in resin isn’t just a recommended step — it’s a game-changer. Whether you’re preserving a cherished keepsake, creating custom jewelry, or designing a statement piece of home decor, taking the time to seal properly ensures your final product looks polished and lasts longer.

We’ve explored why sealing matters, how to choose the right sealant for different materials, and walked through a simple yet effective sealing process. We also covered common mistakes, tips for specific materials, and troubleshooting advice to help you navigate potential issues.

As with any craft, practice makes perfect. Don’t be discouraged if your first few attempts aren’t flawless — every project teaches you something new. With patience and attention to detail, you’ll master the art of sealing in no time.

So, grab your favorite porous material, pick the right sealant, and start experimenting. Your resin creations will thank you!

And if you found this guide helpful, don’t forget to share it with fellow crafters or leave a comment below with your own sealing tips and experiences. Happy crafting!

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