When soluble dye from the substrate seeps through the topcoat, the resultant defect is called Bleeding or Leaching. The defect is also termed Tannin, a kind of brown dye that bleeds from the timber, when it is wet. Many hardwood timbers are affected by Tannin Leaching.
|Improper Sealing of the Organic Red, Yellow and Orange coloured Stains||
• Avoid Red, Yellow and Orange colours since, they generally bleed.
• Use Vinyl Sealer to seal the lacquer topcoat. This prevents bleeding.
• Also, check to see if the Japan colours (Colours that are sacred in East Asia) do not contain any bleeding dyes/pigments
|Certain wood with Natural Resin inside called Tannin bleed. Kwila (Merbau), Spotted Gum, Blackbutt, Balau and Tallowood are some woods that bleed when exposed to rain without a coating or sealant.||
• Wash the timber with deck washes and timber cleaners.
• In most of the cases, this process reduces Tannin bleed.
|Tannin Leaching continues for months in timbers Kwila and Merbau owing to their high Tannin content||Seal with a barrier coat|