How to Make Waterproof Sealer for Wood

Seal your deck and outdoor furniture to prevent water damage.

Waterproofing planks and furniture kept outdoors and in high-humidity areas protects against precipitation and water vapor, preventing mildew and extending the life of the wood. Without waterproofing, moisture seeps into wood cracks, eventually causing them to warp and disintegrate. In addition to its protective properties, waterproofing enhances the appearance of wood and prevents discoloration.

Things You'll Need

• Double boiler
• 3/16 lb. of paraffin or beeswax
• 2 gal. of mineral spirits or turpentine
• 5/8 qt. of boiled linseed oil
• 1 quart of 10:1 Penta concentrate
• 1 to 9 ounces of wood stain (optional)
• Airtight glass or metal container

Instructions

1. Melt 3/16 lb. of paraffin wax in the top of a double boiler until liquefied.

2. Remove the wax from the heat and stir in 2 gal. of mineral spirits or turpentine, 5/8 qt. of linseed oil and 1 qt. of 10:1 Penta concentrate.

3. Stir in wood stain, an ounce at a time, until you achieve the desired tone. If you prefer the wood's natural look, omit the stain.

4. Store the sealer in an airtight glass or metal container and allow it to sit overnight before applying it to the wood.

Tips & Warnings

• Keep the 1-gallon mineral spirit containers to mix up more batches of wood sealer later on. You can use a large funnel to refill these containers with linseed oil and mineral spirits.

• Mix ingredients in a well-ventilated area with newspaper to catch spills. Wear vinyl or latex gloves when handling mineral spirits.

References

• The Home Depot: Waterproofers
• Apartment Therapy: How To: Make DIY Outdoor Furniture Water Sealant