Wood Prepping: How to Remove Surface Contaminants Before Staining

Wood Preparing

1. The Basics of Exterior Staining Prep
2. Essential Tools and Materials for Staining Prep Work
3. Mildew
4. Chalkiness
5. Cedar Bleed
6. Nailhead Rusting
7. Cracking and Peeling

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The Basics of Exterior Staining Prep

When it comes to surface contaminants, the usual suspects are mildew and mold, chalkiness, extractive bleeding due to tannic acid, cracking, peeling, and blistering of old coating, and streaking from rusty nails. The treatments outlined below should take care of these common problems.

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Essential Tools and Materials for Staining Prep Work

Here's everything you'll need to get it right the first time.

• Clean cloth
• Household bleach
• Sodium metasilicate detergent (for treating chalkiness)
• Problem-Solver® Wood Cleaner
• Oxalic acid based solution (for treating cedar bleed)
• Problem-Solver® Brightener
• Rubber gloves and personal protective gear

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Mildew

Mildew, dirt, soot and other pollutants often appear as black dots or specks on the surface. To determine the correct treatment, apply a small amount of fresh household bleach to these black areas. If the dark discoloration lightens quickly, mildew is present. Dirt, soot and other pollutants will not change color but may simply move within the bleach solution.

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Chalkiness

Surface chalkiness must be removed with a detergent (sodium metasilicate) wash before staining.

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Cedar Bleed

Cedar bleed (tannic acid) is a reddish-brown discoloration that may make old stain applications appear blotchy or uneven. If you think your surface has cedar bleed, call Cabot's Technical Service and Support Department for assistance. An oxalic acid based solution will effectively remove the discoloration.

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Nailhead Rusting

First, identify and remove the source of moisture causing the problem. Coatings can be removed with Problem-Solver Wood Stripper. Apply wood stripper for oil-based coatings with a pump sprayer. Finally, scrape and sand the wood to sound condition. Be sure your surface is clean and thoroughly dry before staining. Use caution when scraping and using wood strippers.

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Cracking and Peeling

First, identify and remove the source of moisture causing the problem. Coatings can be removed with Problem-Solver Wood Stripper. Apply wood stripper for oil-based coatings with a pump sprayer. Finally, scrape and sand the wood to sound condition. Be sure your surface is clean and thoroughly dry before staining. Use caution when scraping and using wood strippers.