Blotching can be caused by stain penetrating deeper into some parts of the wood than in others. It depends a lot on moisture in the wood and the types of wood. It is common with woods that have uneven densities. Hardwoods like oak and maple do not usually need blotch protector because due to the hardness they absorb stain consistently across the wood. Softwoods such as pine, birch and some poplars are types of woods that can blotch. The softness of these woods can absorb the stain unevenly. The knots and sap will also affect the absorption of the stain.
To receive a consistent color on your softwoods, before staining use a blotch barrier or a stain base as a precoat. They are usually lower solids. Run a complete test on a sample board of your planned system. If you do not receive desired results, use two coats of a blotch barrier or stain base.
Aqua Coat supplies a high-quality complete system of water-based, eco-friendly, non-combustible, non-flammable, low odor, low VOC and environmentally friendly products. We have a Blotch Barrier, Aqua Tone Stains, Clear Grain Filler, Aqua Thane and Clear Lacquer to complete your project. Visit Aqua Coat at www.aquacoat.com.