wood finishingg for vintage interior room.Bleaching:
If the wood surface requires the removal of an existing finish as above, all traces of paint,varnish and stain must be removed and the complete surface given a uniform sanding with medium coarse paper (120 – 180 grit). If, after sanding, the wood is colored by any remaining penetrating stain that will in any way detract from the new finish, a bleaching agent made with oxalic acid can be applied to lighten the color. If such an agent is used, all residues must be removed because it may affect the properties of subsequent coatings.If a new or “blond” look is desired for the wood, it should be treated with one or more applications of a hydrogen peroxide wood bleach solution. This product will lighten the appearance of wood by bleaching its natural tannin. Hydrogen peroxide bleach can also remove certain unwanted stains, such as those caused by water but this type of product is not meant to remove prepared wood stains that have previously been applied. After the final application of hydrogen peroxide bleach, the wood must be allowed to dry thoroughly before any stain or coating is applied. Under ideal conditions, 68-70°F (20-22°C)
40-50% relative humidity, dry time will be at least 72 hours.
Patching:
If portions of the wood surface are missing, because of chips, nicks, etc. these may be filled using a wood filler. Wood fillers are available in solvent and water based forms. Both are available in a range of colors to closely match the surrounding wood. Solvent-based fillers generally dry faster. All applications of wood filler should be applied in an amount that allows the filler when dry to be sanded down to the wood surface. A word of caution is necessary
here. Most wood fillers contain resins that seep into and help create a bond with the surrounding wood. The resins can affect the penetration of subsequent stains. Therefore, when sanding the wood filler, it is recommended that the immediate surface of the surrounding wood be sanded away to remove traces of the resins. This is especially true if
wood filler has been used to fill brad or nail holes. The remaining resins surrounding the filled holes, if not sanded away, can create a “donut” appearance at each hole after stain is applied. It is therefore recommended that nail holes be filled with putty tinted to match the final wood color only after the first transparent coat is applied. Most fillers can be tinted with addition of pigments, stains or colorants. There are water-based fillers that do not contain resin. These fillers can be reconstituted with water. PLEASE NOTE, wood grain fillers (see below) are not formulated to fill holes, chips, nicks or cracks and should not be used for such purposes.
Sanding:
The purpose of sanding is to remove any dirt, glue and old finish from the wood and provide a smooth uniform surface suitable for staining and varnishing. There is no procedure that 3 affects the appearance of the final finish more than the sanding. The sanding can be done by hand or machine but care must be taken to follow the grain of the wood. It is recommended that the entire surface be sanded uniformly with abrasive paper no more coarse than 60 grit or no finer than 220 grit. More coarse grit will result in more pigment being retained in the wood and therefore a deeper color will appear. To avoid a blotchy appearance it is imperative that the sanding be uniform.
Priming:
It is possible to stain many non-wood surfaces to appear like wood using a stainable primer. If a painted or previously finished surface is in good condition and is compatible with the stainable primer, it is possible to create a stained-wood appearance. Such application can avoid the cost of having to remove the existing finish. Stainable primer can also be applied to paint-grade (finger-jointed) wood in a manner that allows some natural grain to show yet
conceals the union between woods.
Sealing:
Because of the characteristics of certain woods and certain stains it is necessary to apply a sealer or stain controller to prevent the stain from blotching or “wild graining.” A sealer will collect in the more porous portions of the wood and thus limit the amount of stain penetration on those areas and give a more uniform appearance. Other types of sealers can be applied after staining. Sanding sealers are used because they contain compounds that create a microscopically uneven surface that is easy to sand prior to subsequent coatings. Vinyl sealers provide a moisture barrier and are recommended where surfaces may be exposed to water such as restaurants.