After much hard work cutting, pressing, edging and sanding now comes the polishing. So many pictures seen at exhibitions have suffered badly from a poor finish. It takes a long time to do the job right and unless you are one of those very lucky people who have access to professional spraying equipment with clean air rooms and specialised drying facilities you will be obliged to use hand finishing methods, so that is what we shall be concentrating on. There are many ways of achieving a good finish and no two people will fully agree on which is the best method, but we suggest you try this way initially and then modify it in the light of further advice and experience.
Your picture is now flat and smooth all round so we repeat, you must get rid of the Number 1 enemy of all finishing - DUST!
Before your polish bottle is even undone, you must remove all traces of dust from your picture. However well you have cut there will be minute gaps together with open grain veneers which will appear as white streaks or marks. A gentle vacuuming will remove a lot of the dust and the remainder can be got rid of by use of a clean fine brush followed by wiping with a lint free cloth dampened (NOT WET) with white spirit or a tack rag.
There are many polishes available from the traditional french polish to the modern two part finishes. There are numerous articles on this subject and these can be sent to you by e-mail or snail mail.
The polish that most Marquetry groups start their beginners off with is cellulose sanding sealer and it is usually applied with the finger. This is very forgiving and produces consistent results. Other modern polishes such as Rustins, AC Lacquer and Bar Top are however becoming popular (The finger method is not suitable for these polishes).
Start by dipping a finger into the sanding sealer and with firm circular movements work the sealer into the grain of the veneer, about 2 square inches at a time until the whole face of the picture has been covered. Then apply a coat of polish to the edges. Allow this first coat to dry for about 24 hours before attempting to apply further coats. Subsequent coats of polish are applied using the same method as for the first coat but not such firm pressure is needed.
These further coats of polish can be applied at ½ hourly intervals. Remember that each time you polish the front of the picture, apply polish to the sides as well. It is important not to put the polish on too thick as you can find to your regret that if sanding sealer is applied too thickly it is prone to crazing after a while. We suggest putting on about 12 coats of polish on the front and then repeat the same process for the back of the picture again remembering to polish the sides each time that you apply a coat to the back. You don’t have to be a mathematical genius to work out that you have twice as much polish on the sides as you have on the back or front. The reason for this is that when you start rubbing down, you will find it very easy to rub through the polish on the sides unless you are extremely careful, and for peace of mind, it is better to have the extra coats which allow for a margin or error. When polishing is finished, leave for about a week to allow the polish to harden before starting to rub it down. We use "LUBRISIL" silicon carbide paper, which contains its own lubricant, wrapped around a cork sanding block. We have found that a 240 grit paper is an ideal paper to use initially. With the paper wrapped around the block, start rubbing down in the same direction as the main grain of the picture using a moderate pressure. This action does tend to clog the paper so you must periodically clean the LUBRISIL paper to prevent small build up spots which could damage the picture.
It is important to remove the dust created regularly to stop build up. As rubbing down progresses, check the surface of the picture by holding it up to the light to look for any hollows or patches on the polish film. Any hollows will show up as shiny spots and it is necessary to keep rubbing down until the whole surface is absolutely flat and universally dull in appearance with no shiny spots.
Put the LUBRISIL paper aside when this stage is reached and take a piece of ‘wet and dry’ paper, grade 400, and after liberally applying water or white spirit to the surface of the picture, work in a straight line motion over the picture. Use firm pressure at the start, gradually reducing the pressure as you progress and remember to keep the surface wet at all times. Repeat this procedure using 800 and 1000 grade ‘wet and dry’ until all scratches are eliminated. Wash off the surface before each change of paper grade.
When the surface is free from all ridges , scratches and blemishes the final stage can be started. Pour a little ‘T CUT’ car rubbing compound onto a piece of soft rag and apply to the surface using firm pressure in a circular motion. As you feel the rag drag ease the pressure. Concentrate on small areas of about 2 square inches until all traces of the minute fuzziness left by the abrasive papers has disappeared. As each area is completed, the surface should be wiped with a soft cloth. This final stage will leave the surface with a high gloss finish. If matt or satin is desired, the surface should be gently rubbed over with a piece of grade 0000 wire wool dipped in a good quality wax polish and then buffed with a soft cloth.