" " wisno wood furniture finishing: Rubbing and polishing 4

Monday, June 21, 2010

Rubbing and polishing 4

Full step rubbing 
 
The rubbing with full step will give an attractive appearance; nice, elegance, clean finishing looked with very high gloss. To perform the complete process of rubbing the preparation should be started from the unfinished product and the finishing process. The thick film layer and a flat surface is a necessary condition to produce surfaces with an attractive appearance in the rubbing process. Although there is some method of rubbing but in principle rubbing consists of two things: the process of sanding to get a flat surface (leveling) and the buffing process to produce the gloss and looked.
  • Leveling (cutting, sanding).
It is a process of sanding on the finishing surface to cut the surface finishing to obtain a flat and level surface finish. To obtain a flat surface, the preparation on the unfinished product is very important. Finishing layer usually ranges about 4-5 mill thick, can not be used to flatten an uneven surface. Of course we still need a thick enough finish layer to provide enough film surface for the rubbing process, but finish layer should not be too thick. Too thick finish layer is high risk to get cracking problem especially with NC coating. Therefore, the preparation of unfinished wood is very important. Make sure that the panel was already flat and even from unfinished conditions; thereby the finishing process can be done quickly, easily and safely.

Sanding the finish layer is done to cut the film surface and remove all the orange peel on the surface finish.
Wet sanding is the most widely used technique for this purpose. It is a sanding process which is using a liquid to absorb heat arising from the friction between the sandpaper and the surface finish. The fluid is usually used is the rubbing oil or rubbing lubricant, a kind of mineral spirit with small amount of wax in it, but if it is not available a soapy water is can be used with a good result.
The sanding on the finish film can be done manually with a hand block, but for big and wide surfaces it is better done by a rubbing machine. The rubbing machines will help speed up the process of sanding since it will do the sanding consistently but it must be handled carefully. Too much sanding will risk of an over sanding and then we need to re coat the finishing layer. and start the rubbing process from the beginning. Start sanding with a # 800 grade sandpaper, until the entire surface is cut and all the orange peel is clean up. For a low gloss (satin finish) then sanding with 800 grade sandpaper is enough, but for a full rubbing process with high gloss result, then the next sanding using finer sandpaper is needed.. To obtain high gloss finish, we need to continue the process by sanding using # 1200 or # 1500 grade sandpaper.

  •  Rubbing.
It is a process carried out after a flat surface was obtained. This process will determine the gloss and looked of the finish result. A low gloss finish can be obtained by buffing with scotch brite or steel wool. The steel wool used is the fine steel wool  (# 0000 grade). Rubbing machine can be used to rub the wide surfaces to make the process can be done consistently. This process will create satin finish, with gloss is about 50  sheen with a soft and elegance looked, but it still leaves scratches mark on the surface.
To obtain the surface with a higher gloss, we need to continue this process by rub the surface with rubbing compound or stone powder. The rubbing compound or stone powder is usually rubbed on the surface by rubbing machine in wet condition. Water is used to solve the rubbing compound and to absorb the friction heat such as in the wet sanding. The rubbing machine with scotch brite and the rubbing compound or stone powder is using to rub the surface until get the desired looked.
This method will reduce the scratches on the surface and create a higher gloss finish. The final gloss is about 90 sheen. 

  •  Buffing
Rubbing process using scotch brite or steel wool always result the scratches from the steel wool or scotch brite. The use of compound or stone powder will raise the gloss and reduce scratches but can not eliminate all existing scratches. To remove all scratches the rubbing process need to be continued with the buffing process. Buffing is the process to increase  the gloss and eliminate the scratches mark The finer compound is used to buff onto the surface using a cloth or wool pad to raise the gloss arise (buff up). A buffing machine is a tool designed to make do buffing with faster and easier.
The buffing process can eliminate or even removes the scratches and result a very high gloss finish. By using the buffing machine a very high gloss finish can be obtained. The final gloss could be more then 90 sheen, higher then the gloss that is obtained by a top coat application. Rubbing and buffing will also produce an elegance and luxury appearance that can not be obtained only from top coat application.
The buffing can also be done manually with a cloth but it still leaves scratches and the gloss obtained will be lower.


 


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