Furniture Refinishing with Oxalic Acid

Because it’s easy to work with yet structurally sound, wood has been a favorite material for furniture makers for centuries. When newly made, your wood furniture item is clear, with an even sheen and color, but over time, the wood finish can age or fade. To remove old wood stain or other stains, you may apply an oxalic acid solution to the wood.

 

Oxalic Acid Solution

Oxalic acid, a form of organic dicarboxylic acid, comes from nature, although most brands today are synthetically reproduced in the lab. Oxalic acid is present naturally in some plants, including rhubarb and spinach. The oxalic acid you purchase for refinishing wood may be in crystal form and you will combine it with water before use.

 

How it Works

 

Oxalic acid acts as a bleach on wood, lifting away or lightening stains. Depending on the intensity of the stain, and how deeply it is embedded in the wood grain, more than one application of oxalic may be necessary.

When to Use an Oxalic Acid Solution

You may apply oxalic acid after you remove the old finish from the furniture. This usually involves applying a chemical stripper to the furniture or sanding away the wood finish. After combining oxalic acid crystals with water as directed on the package, you will brush the solution onto the bare wood and allow it to soak in.

Additional Information

The application of oxalic acid will swell and raise the grain of the wood, which can leave a rough feel.  After the furniture dries, you will sand it again to smooth the grain before applying a wood stain or wood finish.

Precautions

Wear chemical-proof rubber gloves and splash-proof eye protection when applying oxalic acid. Like all chemicals, keep oxalic acid out of the reach of children and contact a Poison Control Center in the case of accidental ingestion.

How to Paint Acoustic Asbestos Ceilings

Do not disturb the material.

Known as popcorn ceilings, this asbestos material was popular in the 1960s, and contractors applied the material by spraying it on. If the asbestos texture is crumbling or coming off, painting it may only add weight and make it fall off faster. However, if the texture is still secure on the ceiling, it may be easier and safer to encapsulate it with a coat of new paint. Since this type of ceiling is highly textured, you’ll need to spray on the new paint.

Use an airless sprayer.

1. Remove ceiling light fixtures with a screwdriver. Wear a full respirator with interchangeable filters. As long as the asbestos is on the ceiling, you’re safe; but once you disturb the material, it can crumble into fine filaments. Inhaling these filaments is dangerous.
2. Tape off the top edge of adjacent walls with the type of painter’s tape that includes a roll-out plastic drop cloth.
3. Strain stain-blocking primer through a paint sprayer before adding it to the reservoir of an airless paint sprayer, available for rent at construction rental stores.
4. Spray the entire ceiling with a light coat of the primer, using even side-to-side strokes from a minimum of 12 inches away from the ceiling. Wear the respirator and splatter-proof goggles.
5. Inspect the dry primer coat for areas you may have missed, which may appear as stains bleeding through. If you see any, apply another thin coat of primer.
6. Let the primer dry completely. Fill the reservoir of the sprayer with ceiling paint that you have strained as you did the primer. Adjust the nozzle to deliver a fine mist. Spray the entire ceiling. Let it dry.
7. Apply one or more light coats of paint to the ceiling, letting each coat dry completely before adding the next one.
8. Strip off the painter’s tape and reinstall the light fixtures.

Hints

• Contact your local building authority before painting over an asbestos ceiling. The authority may require an additional coat of a shellac-based solution.

Warnings

• If you’re unsure about the stability of the asbestos on your ceiling or the possibility of asbestos in it, consult a certified asbestos abatement contractor.
• You must let each coat of primer or paint dry completely before adding another. The dampness adds weight to the textured ceiling, which could encourage the bits of texture to fall.
• If the asbestos is crumbling, you cannot paint the ceiling until a professional removes the texture.