Stripping Old Stain & Removing Mill Glaze from Log Railings

When a log railing finish fails, you cannot simply paint over the problem. Applying expensive new sealant over flaking varnish or oxidized wood is a waste of money - the new finish will peel off immediately, taking the old layer with it.

To restore a log railing, you must strip it down to raw, healthy wood. This guide covers the two most common scenarios requiring complete finish removal: dealing with peeling older varnishes, and breaking the infamous “mill glaze” on brand-new lumber.

Scenario 1: Removing Peeling Varnish and Old Stain

If your railing has thin, plastic-like flakes peeling away, a film-forming finish (like polyurethane) was improperly applied. If the wood looks gray and weathered, the penetrating stain has burned off in the sun.

Both situations require removal before refinishing.

Why Mechanical Sanding is Dangerous

Your first instinct might be to grab a belt sander or a destructive power washer. Resist this urge.

Aggressive power washing (anything over 1000 PSI) will blow apart the soft Springwood fibers of pine and cedar, leaving the railing covered in a fuzzy, splintered mess that holds moisture and accelerates rot. Heavy mechanical sanding destroys the natural curves and hand-hewn textures that make rustic railings appealing.

The Chemical Stripping Process

Chemical strippers dissolve the failing finish so it can be gently washed away.

1. Select the Right Stripper: Avoid harsh methylene chloride if possible. Look for sodium hydroxide-based “log strippers.” They are highly alkaline and effectively melt away old oil and water-based stains.
2. Application: Apply the stripper liberally with a synthetic brush or a dedicated pump sprayer. Work in small sections (about 5-10 feet of railing at a time) from the bottom up to avoid streaks.
3. Dwell Time: Do not let the stripper dry. It must remain wet to work. Keep applying light mists of the product or water as it sits for the manufacturer’s recommended time (usually 20-45 minutes).
4. Gentle Rinsing: Use a pressure washer only on a wide fan setting (40 degrees) and keep the wand at least 18 inches away from the wood. Your goal is simply to rinse away the dissolved slurry, not to blast the wood.
5. Neutralization (Crucial Step): Sodium hydroxide strippers darken the wood and leave it highly alkaline. New stains will fail if applied to alkaline wood. You must follow the stripping process by applying a wood brightener (an acid like oxalic acid or citric acid). Spray it on, watch the wood instantly lighten back to its natural color, let it sit for 15 minutes, and rinse thoroughly.

Scenario 2: Breaking “Mill Glaze” on New Logs

If you just installed brand new, smooth-milled cedar or pine railings, you are dealing with a different problem.

When logs run through modern high-speed planers at the mill, the sheer friction and heat melt the natural resins in the wood. These resins harden on the surface, creating a microscopic, glossy crust known as “mill glaze.”

If you apply stain directly over mill glaze, the stain cannot penetrate. It will sit on the surface and peel off within a year.

How to Test for Mill Glaze

Splash a few drops of water on the new, raw logs. If the water beads up and sits on the surface, you have mill glaze. If it absorbs immediately, the wood is ready for stain.

The Removal Process

Removing mill glaze is much easier than stripping old, hardened varnish.

1. Wait if Possible: The easiest way to remove mill glaze is to let nature do the work. Leave the raw railings exposed to the sun and rain for 3 to 6 months. UV radiation and moisture will break down the glaze naturally.
2. Chemical Breaking: If you must stain immediately, use a commercial “mill glaze remover” or a strong wood deck cleaner containing sodium percarbonate (oxygen bleach).
3. Agitation: Spray the cleaner onto the wet logs, let it dwell for 15 minutes, and aggressively scrub the surface with a stiff bristle brush.
4. Rinse: Rinse thoroughly with a garden hose.
5. Retest: Once the wood is completely dry (wait at least 48 hours), perform the water drop test again to ensure the glaze is gone and the wood is thirsty for your new sealant.