Best Sealer: How to Waterproof Acrylic Paint on Rocks, Wood, Glass Crafts

Acrylic paint is a favorite among DIYers for its bold colors, quick drying, and versatility—but it’s not naturally waterproof. If you’re creating hand-painted rocks, wood signs, glass mugs, or outdoor crafts, sealing is essential to protect your design from peeling, fading, or water damage.

Learn how to waterproof acrylic paint on various surfaces by choosing the ideal sealer from the list of tried-and-true sealants, plus tips and troubleshooting help for long-lasting results.

Why Seal Acrylic Paint on Crafts?

• Protects from moisture, fading from UV rays, dirt, and scratches
• Prevents chipping and cracking
• Improves durability for indoor and outdoor crafts
• Adds a glossy, matte, or satin finish
• Soften and peel with moisture exposure
• Wear down with handling

Best Waterproof Sealers for Acrylic Paint on Different Surfaces

Sealer Test: Waterproof Acrylic Paints

Sealer Test for painting outdoor projects:

Richard Markle did a sealer test using the most popular options available on painted rocks and shared his valuable insights.

The rocks were placed outside on crushed rock where they don’t get shade during the day nor protection from the rain. We had 65 days over 100°F the hottest being 109°F. The coldest we got was 31°F. The sealers overall did very well.

Based on this test:

1. Polyurethane: The brush-on Water-based Spar Urethane looks as good as when placed outside with no loss of shine and no fading of paint or cracking. There is not a lot of difference between the number 1st and 2nd place shines.

2. Acrylic Resins: The number two spot is tied between Rust-Oleum’s 2X Ultra Clear and Rust-Oleum’s water based spray on Spar Urethane. (I feel that brush on sealers will always beat spray on sealers because one brush on coat is likely as thick as the three spray on coats.)

The UV resin over Krylon’s UV resist is just as shinny as the number two finishers but the sealer and paint cracked and peeled. The rock may have been dropped putting a crack in the finish allowing moisture under the paint and sealer. The two part resin over Krylon’s UV resist almost completely lost it’s shine. The Mod Podge sealer is a total failure.

Sealer Test

Best Waterproof Sealants for Acrylic Paint by Surface

Related: DIY Resin Crafting: Everything You Need To Know To Get Started

How to Waterproof Acrylic Paint on Rocks?

1. Let the paint dry fully.
2. Lightly wipe the surface with a wet wipe to remove dust.
3. Choose your sealer: Polycrylic for indoor, exterior polyurethane for outdoor.
4. Apply 2–3 thin coats, drying 30–60 min between each.

Related: Cute Owl Rock Painting Wood Slice Craft

Sealant type: Outdoor acrylic sealer spray or polyurethane

Recommended products: Rust-Oleum’s 2X Ultra Clear, Mod Podge Outdoor

How to Waterproof Acrylic Paint on Wood?

1. Let the paint cure for 24–48 hours.
2. Optional: Lightly sand for a smooth surface.
3. Choose your sealer: Polycrylic for indoor, exterior polyurethane for outdoor.
4. Apply 2–3 thin coats, drying 30–60 min between each.
5. Optional: Buff or polish for a professional finish.

Related: How To Add Color To Wood Burning Projects?

Sealant type: Polycrylic, polyurethane (water-based for indoor, oil-based for outdoor)

Recommended products: Minwax Polycrylic, Rust-Oleum Ultimate Polyurethane

Waterproofing Acrylic Paint on Glass or Mugs

1. Clean surface with rubbing alcohol.
2. Use multi-surface or enamel acrylic paint.
3. Let dry or oven-cure (if oven-safe paint).
4. Seal with spray sealer or dishwasher-safe Mod Podge.

Related: Complete Guide: How to do DIY glass painting?

Sealant type: Clear acrylic sealer spray or dishwasher-safe Mod Podge

Recommended products: Krylon Crystal Clear, Dishwasher-Safe Gloss

Tips for Best Results

1. Dry you paint: Wait at least 24–48 hours before sealing. Moisture trapped beneath sealant can cause bubbling or cloudiness.
2. Use a clean, dry surface for best adhesion.
3. Avoid humid or cold environments when sealing.
4. For outdoor projects, choose a UV-resistant sealant.
5. Spray-on: Shake well and hold 10–12” away. Spray in a well-ventilated area.
6. Brush-on: Use a soft-bristle brush for even application
7. Most sealants need 24–72 hours to fully cure. Avoid handling or moisture during this time.
8. Label check: Make sure the product is non-toxic, weatherproof, and compatible with acrylics.

Eco-Conscious Tips

1. Use non-toxic, water-based sealants
2. Choose low-VOC paints and finishes for indoor use
3. Reuse containers and clean brushes with biodegradable soap
4. Opt for biodegradable sealers or natural wax alternatives where possible

Cleaning and Care Tips for Sealed Projects

• Glassware: Hand wash only unless sealed with dishwasher-safe formula
• Outdoor crafts: Reapply sealant annually for best protection
• Indoor decor: Dust gently; avoid harsh cleaners

FAQs:

Is acrylic paint waterproof after it dries?

No, acrylic paint is not fully waterproof once dry. It becomes water-resistant, but exposure to moisture, rain, or washing can cause peeling or fading. To make it truly waterproof, apply a clear acrylic sealer or varnish over the paint.

What’s the best sealer for acrylic paint on wood crafts?

The best sealers for acrylic paint on wood include:

• Polycrylic (indoor and outdoor)
• Mod Podge Outdoor (for decorative use)
• Clear acrylic spray sealant (for quick coverage)

For durability, use multiple thin coats, sanding lightly between layers.

How to make hand-painted mugs waterproof and dishwasher-safe?

• Use multi-surface or enamel acrylic paints that are:
• Labeled “dishwasher-safe”
• Oven-curable (bake at 300–350°F for 30 minutes)
• Then seal with a non-toxic dishwasher-safe sealant, or use clear epoxy resin for a high-gloss finish.

Related: 50 EXTRAORDINARY Mug Painting Ideas

What is the best sealer for outdoor painted signs?

For painted signs exposed to rain or sunlight:

• Use exterior-grade polyurethane, marine varnish, or UV-resistant sealant.
• For rustic or distressed wood signs, opt for polycrylic with matte finish.

Can you use Mod Podge to seal acrylic paint?

Yes, Mod Podge works as a sealer, glue, and finish for many surfaces like wood, canvas, and paper. However, regular Mod Podge isn’t waterproof—choose Mod Podge Outdoor or Dishwasher-Safe Mod Podge for extra protection.

How many coats of sealer should you apply for waterproof results?

For full protection:

• Apply at least 2–3 thin, even coats
• Let each coat dry 30–60 minutes
• Lightly sand between coats for smooth finish

Can you use clear nail polish to seal acrylic paint?

It’s not recommended. Clear nail polish may yellow over time, peel, or react with acrylic paint. Instead, use a clear acrylic spray sealer or polycrylic designed for crafts.

Why is my acrylic paint peeling after sealing?

Common causes include:

• Not letting paint fully dry before sealing
• Applying thick coats of sealer too quickly
• Using the wrong type of sealant for the surface
• Fix it by sanding lightly, repainting if needed, and using a compatible sealer.

Projects ideas for painting and sealing:

Glass Surface: DIY Bowl and Glass Mushrooms Garden Decor

Rocks: Paint a DIY Christmas Tree and Snowman Rock Art

Wood: DIY Hand-Painted Kitchen Wood Sign Using Printer Paper Transfer

Waterproofing your acrylic-painted crafts ensures they last for years to come—rain or shine. Whether you’re decorating signs for your kitchen or painting mugs for a gift, choosing the right sealer and applying it correctly is the key to success.

You will also like:

Rock painting craft ideas with pebbles and stones

62 Nature inspired outdoor projects

55 Unique Seashell Painting Ideas