Cleaning & Stripping
The first phase of restoration is the proper cleaning of all the furniture. If the finish is not very damaged and it is not necessary to remove the layers of old varnish, the elimination of grime and dirt will suffice. To do this, either warm water and a natural soap or a solution of water and ammonia can be used.
When the wood has thick layers of varnish, or when the colour of the piece is uneven from continuous use, the piece should undergo a stripping process.
Stripping is also used when the wood is of good quality and you wish to return it to its natural colour and grain. Tests show that methylene chloride is the most active solvent known today for removing all types of hardened paint films and clear coatings such as varnish.
“Grey” timber is dead timber fibre caused by the weathering process. To remove the grey, wash with Tile Doctor Super Power Clean, rinse thoroughly, then when dry, apply a varnish, sealer or stain to protect the timber in future.
Sanding is a very important process in all tasks related to carpentry, because it helps to prepare the surface to receive the final finish, which will leave the surface smooth to the touch. Keep in mind that a good sanding will result in an excellent finish!
Sandpaper is a strong paper with glass dust or sand on one of its sides, bonded with an adhesive product. The difference between various types of sandpaper is the coarseness of its grit, which is specified with a system of numbers printed on the back of the paper. This enables the restorer to achieve various finishes and a very smooth surface.
To begin the sanding process, coarse sandpaper is used, followed by a finer one for the finish. As can be seen in the table below, the coarser grit corresponds to the number 40 and the finest to the number 400:
Sandpaper can also be used by wrapping it around a wooden block with flat sides, one of which should be covered with a layer of cork, so as to not scratch the wood being sanded. This sanding block should have small enough dimensions that a person will be able to use it with a single hand.
An electric belt sander is used for large and flat surfaces. This is a machine that is made of lightweight materials and that holds a sandpaper belt that rotates at high speed. All sanded surfaces require a final rubbing with a fine or extra fine steel wool pad to remove the marks left by the sandpaper and to adequately prepare the surfaces for the final finish.
Instead of steel wool, fine-grit wet sandpaper can also be used for the sanding. Its numbering goes from 400 to 2000. Before using this type of sandpaper it is necessary to wet it in water.
Genkem Wood Filler can be applied over imperfections with a spatula, smoothing it out over the surface of the wood and eliminating the excess. Make sure all holes and crevices are perfectly filled. It is always necessary to do a final sanding, which will remove excess wood filler and blend it into the wood surface.
When it comes to the colour of the filler, it is important to keep in mind that because of its composition, the varnish that will be applied over it will not stain it. It is preferable to use a filler that is in the same colour as the wood, so once the piece of furniture is varnished, there will be no irregularity in colour.
Repairs should be completed before removing the old finish, as they generally involve regluing and it is very difficult to remove glue from raw wood. The surface will not accept stain or the new finish properly if the glue is not completely removed. Generally, the glued area will dry a lighter colour than the surrounding area when the finish or stain is applied over the glue. To remove old glue or glued joints, we recommend Tile Doctor Bitumen and Glue Remover, used as per instructions on the container. To determine if the old glue is completely removed, wet the area with water. There should be a contrasting colour between the areas free and not free of glue. We recommend using a good quality wood glue such as Genkem’s Carpenter’s Cold Glue or Genkem’s Quickset Woodweld or Genkem’s waterproof wood glue – Genkem Cascamite.
Raising Dents Or Depressions And Straightening Boards
To raise dents or depressions, it is first necessary to remove all of the old finish. After this has been completed apply a hot, wet, white towel over the dent and apply a hot steam iron to the surface. Repeated application of this process may be necessary. As steam wets the wood, the wood swells, thus filling the dent or the depression. Allow the area to dry overnight and sand smooth.