Surface Prep Ledger

Viscosity. Grit. Chemistry. The unglamorous math that makes the magic possible.
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The Philosophy of Prep

They want to talk about the color. They want to talk about the final coat, the shimmer, the way the light hits the curve of the wall. Fine. But I am here to tell you that the color is just the skin. The bone is the prep.

This ledger is my confession. Every number here is a lesson learned on a cold morning in Ashland, scraping drywall mud off a wall that refused to hold. Every sequence is a promise kept to the surface. We do not rush. We do not skip. We measure.

Macro texture of sandpaper grit—the abrasive promise of the prep

Grit Sequences: Drywall to Finish

Stage Grit Range Tool Dust Management Visual Check
Initial Leveling 60-80 Orbital Sander (5") HEPA Vacuum w/ shroud No visible knife marks; matte uniformity
Fine Smoothing 120-150 Pole Sander (long reach) Inline filtration bag Finger-test smooth; no ridges
Final Polish 180-220 Hand Sanding Block Tack cloth wipe-down Silky drag; zero dust haze
Spot Repair 220+ (wet/dry) Felt Pad Damp rag final Invisible transition to base
Note: Wet-sand only after primer cure. Dry-sand kills the gloss you're trying to protect.

Primer Viscosity Table (Sheen Control)

Substrate Primer Type Target Viscosity (KU) Thinner Ratio Cure Time @ 70°F
New Drywall (Unprimed) PVA Sealer 85-95 KU None 2 hours
Patched Joint Compound Shellac Spot Primer 60-70 KU Denatured Ethanol 5% 45 minutes
Wood Paneling Bonding Primer 100-110 KU Xylene 2% 4 hours
Previously Painted (Latex) Acrylic Adhesion Promoter 90-100 KU Distilled Water 3% 1 hour
Measured with Ford Cup #4. Temperature compensation required below 60°F (+1 KU per °F drop).

The Ashland Dust Protocol

Contaminant Removal Method Verification Test Failure Mode
Joint Compound Dust HEPA Vacuum + Microfiber Wipe White glove swipe Fish-eyes in topcoat
Oil/Grease Residue TSP Substitute (1%) pH Strip (target 7.0) Beading/Crawling
Mold Spores EPA-Registered Biocide UV Light Scan Re-emergence within 30 days
Efflorescence Acid Wash (Phosphoric 10%) Rinse pH Neutral White Bloom Through Film

This ledger grows with every job.
Next entry: The Potluck Chemistry—how salt ratios affect binding agents.