Veneer finishes for DIY kitchen,built in wardrobe,home office,home storage smartpack cabinet door

Sunday, 2 April 2006

April No. 2 Veneer types

News Letter No. 2

Natural veneers
Natural veneers are made from wood taken from natural trees either plantation forests or taken from forestry concessions for the more exotic timbers. Usually the more expensive timbers are the ones that take the longer time to grow, from 50 years to a couple of hundred years. The logs are cleaned of the bark and then steamed. The logs are then cut into quaters or halves or left in the round. They are then cut into veneers of between 0.5mm to 2 mm depending on the application of the veneer. The process of slicing the veneers is done with a large blade with a static log or a rotating log giving different cuts and grain appearance. The veneer strips are cut into even sizes and are packed back to back or book leaves depending on the end result required. The veneer pressing companies unpack the leaves and stitch them together with a glue technique where the machinery attaches a leaf approx 0.6mm thick to the next leaf until a sheet is made to cover a substrate of particle board or medum density fibre board, the most common being 2400 x 1200mm in size. The substrate is glued and the veneer sheet is then pressed with high pressure and heat to both sides of the substrate. Boards can have two faces in good veneer (good two sides) or one good side plus a balancing or downgraded back veneer usually from the same veneer species but a less attractive veneer (good one side).

Rotary cut- using a broad knife against a rotating flitch (cut and cleaned log). It can be wide enough to make a full sheet of veneer and usually the cheapest and most unattractive grain appearance.Used to make plywoods.
Crown cut or half round slicing- the log is split into half and then the flitch is rotated against a knife sliced giving a cathedral grain appearancefrom the exposing of the innermost growth rings.
Quarter cut- the log is cut into quarters and then sliced giving a straight grain appearance. The flitch is static and the knife moves in this slicing process.
Longitutinal or lengthwise slicing- The knife is moved lenthwise down the flitch giving a variegated grain appearance.

Restructured veneer
Restuctured or the less correct name "reconstituted" veneers are made from birch or poplar plantation trees which are relatively quick growing. The veneers are sliced in the same way as are natural veneers. The sliced leaves are then dyed using a computerised technique which colours the grain or can colour patterns in the veneer. The poplar and birch timber is very light and so lends itself to being dyed. Most restuctured veneers are also impregnated with a UV light inhibitor which decreases the rate of discolouration of the veneer.
The dyed leaves are now glued back together to reform a square log about 300mm thick. The square log is now sliced again across the sheets to make veneer leaves with a very consistent grain and colour throughout the leaf. The leaves are then joined together as with natural veneers by the veneer layer and pressed onto a board substrate.
The main advatage of the restuctured veneer is that the veneer boards are very consistent in grain and colour and so a kitchen can be gaurenteed to have all doors from one side to the other side of the kitchen or robe exactly the same finish. This is not possible with a natural veneer like blackwood or jarrah or even pine.
The other advantage is that with the UV inhibitor impregnation the discolouration of the veneer will be much slower than with natural veneers.
This is why we have chosen restructured veneers for our "Smartveneer" range".

Finishing
All types of veneer need to be lacquered with a coating to protect the veneer from absorbing stains. This can be done with various types of lacquer or polyurethanes and various gloss levels from matt 10%, satin30%, semi gloss 60% to high gloss 90%. High gloss on veneer tends to give a plastic appearance and is not suggested.
Smartveneer is coated with a UV lacquer in 30% satin finish to give the best "wood look" appearance.