Zinsser B-I-N vs Cover Stain: Which Stain Blocker?
By Nate Sawyer, Editor · Updated July 2026
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Zinsser B-I-N Shellac-Based Primer & Sealer
A shellac-based primer that seals the toughest interior stains and odors, from smoke and water to pet, nicotine and tannin, gripping glossy surfaces without sanding and recoating in about 45 minutes. Trade-offs: high VOC and strong fumes need ventilation, cleanup takes denatured alcohol not water, and it is interior and spot-exterior only.
| Type | Shellac-based |
|---|---|
| Recoat | 45 min |
| Coverage | ~100-125 sq ft/qt |
| VOC | High (~550 g/L) |
| Cleanup | Denatured alcohol / ammonia |
| Use | Interior + spot exterior |
Zinsser Cover Stain Oil-Based Primer/Sealer
A high-hiding oil-based primer/sealer that blocks tough stains and tannin bleed, even on cedar and redwood, and is rated for interior and exterior wood with strong adhesion. As an oil primer it carries strong fumes needing ventilation, requires mineral-spirits cleanup, and its high VOC limits it in some regions.
| Type | Oil-based |
|---|---|
| Recoat | 1 hr |
| Coverage | ~400-450 sq ft/gal |
| VOC | High (~450 g/L) |
| Cleanup | Mineral spirits |
| Use | Interior & exterior |
Our verdict
Choose B-I-N (shellac) for the toughest interior stains and odors and the fastest recoat — it seals smoke and pet odors better than anything. Choose Cover Stain (oil) when you need exterior capability and easier handling with slightly less aggressive fumes. Both need solvent cleanup, but B-I-N wins indoors on odor and stain sealing while Cover Stain is the more versatile interior/exterior tannin blocker.
Frequently Asked Questions
- Which one blocks smoke and pet odors better?
- B-I-N. Its shellac base is the best-in-class sealer for smoke, nicotine, pet and water stains, and it seals odor in a way oil primers do not. For a fire-damaged or heavy-smoker room, B-I-N is the reason the job succeeds.
- Which one can I use outside?
- Cover Stain. It is rated for interior and exterior use, including tannin blocking on cedar and redwood. B-I-N is interior plus spot exterior only, and is not suited to full-exterior or high-moisture exposure.
- How fast can I recoat each one?
- B-I-N recoats in about 45 minutes; Cover Stain in about 1 hour. Both are fast for their categories, and B-I-N in particular lets you prime and topcoat within the same working session.
- How do I clean up after each?
- Neither cleans up with water. B-I-N needs denatured alcohol or ammonia; Cover Stain needs mineral spirits. Both are high-VOC — around 550 g/L and 450 g/L respectively — so ventilate heavily and check local VOC restrictions before buying.
- Which grips a glossy surface without sanding?
- B-I-N bonds to glossy surfaces without sanding, which is a real time saver on varnished trim or previously enameled cabinets. Cover Stain has strong adhesion but is not marketed as a no-sand bonding primer.