Black Swan Plumbers Putty - 15lbs, crack-resistant, stay soft vs Flex Seal MAX 17 oz (2-pack) Black sealant coating

Overall winner: Flex Seal MAX 17 oz (2-pack) Black sealant coating

Key Differences

Flex Seal MAX (A) is a spray-on, waterproof sealant with paintable, watertight finish and a much larger review count; Black Swan (B) is a stay-soft plumbers' putty designed for drain and fixture seals. Choose Flex Seal if you need a sprayable, paintable roof/roof-repair style sealant and broader user feedback; choose Black Swan if you need a pliable putty for plumbing seals around drains and fixtures

Black Swan Plumbers Putty - 15lbs, crack-resistant, stay soft

Black Swan Plumbers Putty - 15lbs, crack-resistant, stay soft

Black Swan • ★ 4.2/5 • Budget

White plumber putty for sealing sinks, drains and fixtures with a stay-soft formula. Customers note good sealability and ease of use, though some report cracking lids and variable softness

Pros

  • stay-soft formula for pliability
  • effective waterproof sealant
  • versatile use for bowls, fixtures, faucets

Cons

  • lid quality issues reported
  • mixed softness and durability depending on user
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Flex Seal MAX 17 oz (2-pack) Black sealant coating

Flex Seal MAX 17 oz (2-pack) Black sealant coating

Flex Seal • ★ 4.3/5 • Budget

Waterproof rubber spray-on sealant that seeps into cracks and holes and dries watertight. Can be painted after drying; easy to coat, seal, and protect. Customers note easy application and effective sealing in some cases, with mixed views on value and durability

Pros

  • easy-to-apply sealant
  • dries watertight
  • can be painted after drying
  • seeps into cracks and holes

Cons

  • mixed durability reports
  • mixed spray quality and mechanism issues
  • mixed leak prevention results
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Head-to-Head

CriteriaWinner
Price Black Swan
Durability Flex Seal
Versatility Flex Seal
User Reviews Flex Seal