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The finish

 

 

It may be one of the least known aspects of furniture, and of other objects too. It is material(s) and the work which aims to shape and define the expression of the base material to the outside world. In its most functional sense, finish acts as a protective shield for the material underneath, guarding it against damage from physical or other environmental elements like water or dirt. As the finish material itself has its own characteristics, when applied, it shapes the color, depth, sheen, and even touch of the base material, defining the overall character of the object. 

A refined finish effect for solid wood furniture should be lively, highly transparent, thin but thorough, and full of character. Unless for opaque effect, it should allow the wood grains to be clearly seen even in a dark color. It should be fresh and smooth to the touch. For the finest finish one may even be tempted to gently stroke and enjoy the silky smoothness with the hands. Purely handmade, it should exude a warmth absent in industrialised methods of finishing.

The choice of a finish calls for deep understanding of both the finish and the base material. On top of aesthetics considerations, how do they respond to each other? Is the protection expected fulfilled? Is there any odour or harmful emission? Is there sufficient skill to perform? Is it long lasting? Does it age well and grow into a patina? Is there enough crafting time allowed? Is future restoration possible? It is therefore as much a technical consideration as an aesthetics consideration.

Those who have knowledge on make-up know that no make-up can be pleasing unless the skin foundation is properly prepared. This is also true for furniture finishing. In fact the time and skill required to develop a sound foundation should surpass that for the final finish material at the top. When one appreciates a fine finish, most of the credit should go to the crafting effort in the foundation. Therefore, when viewing the list of finish materials below, one should never forget the unsung hero behind. The finish materials are also not used exclusively, these are quite likely used in different cycles of the finishing process for the best overall effect. And these are used for our solid wood clear finish furniture, other finishes such as spray paint piano finish are not covered here.

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涂漆

 

 

涂漆可能是众多家具特征之中最鲜为人知的一项,对其他物品也一样。它是添加于底层物料的工作步骤与物质,令底层物料的外观或表面性质改变。在最基本的功能性来说,涂漆可以对底层物料提供保护作用,令外来的物质譬如水或尘埃等没有那么容易对底层物料造成损害。因为涂漆物料有本身的物理和化学特性,再加上添加时的方法,这使施加后的物品无论从颜色,深度,光泽,手感等都会作出改变,之后才带出整体感觉。

实木家具的涂漆应该是生动,高度透明,薄但透彻,并且满有性格。除了是全遮蔽的涂漆,否则木材的纹理应该清晰可见,尽管是染深颜色的家具。涂漆也应该手感清新顺滑。最精炼的涂漆往往会吸引用家轻柔抚摸家具表面,享受丝滑的触感。全人手慢工出细作,这涂漆可以散发独一无二的温暖感觉。

选择涂漆的物料与施工步骤需要对涂漆与底层物料有深刻的认识。除了简单的外观特征考虑外,涂漆对底层物料会怎样反应?会否达到需要的附着力与保护?施工与使用时会否产生有害气体或刺激性气味?对公丈的技术水平或工作坊的设备有什么要求?在不同的使用环境有多耐久?经年使用表面会否变得醇厚?容许的生产时间会否足够?将来可否修理?可以看到外观考虑外是一连串的技术考虑。

对化妆有认识的客户会了解如果没有对皮肤作出护理与准备,漂亮的妆容是不会实现的。家具涂漆也一样。对于精品家具,木材表面打基础与底层处理的时间甚至应该比最终的涂漆表面作工时间来得长。我们鉴赏到精细的涂漆表面效果其实很大部分取决于涂漆底层的工作。所以当细读以下的涂漆物料时,不要忘记涂漆底层的无名英雄。以下的涂漆物料也常常在同一件家具的不同步骤被使用,以达到最佳效果。

以下我们只介绍实木家具的涂漆物料,并不包括其他物料,譬如化学喷漆等。

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natural lacquer

Called urushi(うるし)in Japan and qi(漆)in China, it is a natural resin extracted from the sap of a tree called lacquer tree (genus rhus verniciflua) indigenous in south east Asia, found at altitudes between 3,000 to 7,500 feet. The sap is usually gathered when the trees are 10 to 15 years of age, and the trunk at least 10cm in diameter. From June to October, the collector makes parallel cuts in the trunk with a knife. Then the sap, a thick milky-white liquid oozing naturally out of the tree, is scraped off with a spatula and collected.

After the lacquer is extracted in a year, the tree is left to recover for five to seven years before the next extraction. The most a single tree can yield is 50 grams of lacquer, hence its preciousness. After filtering impurities and slowly reducing its water content, the lacquer is ready for use. In its liquid form, the lacquer is highly irritant, but once hardened most people won’t show any allergic reaction.

Natural Lacquer is extremely durable, being able to stand for generations without cracking or chipping. It is very resistant to strong acids and alkalis. It also is water resistant, and heat resistant to 230 degrees Celsius. The only caution is a lacquered object shouldn't receive too much sunlight, because ultra violet light will decompose its molecules.

One major difference of Natural Lacquer from most other types of traditional finish is that it is cured by non-reversible chemical polymerization reaction, not by the evaporation of a solvent. The curing process is also contrary to common knowledge, it cures in a humid and warm room, air-drying is difficult if not outright impossible in most climates. Being 100% natural, it also doesn’t release harmful odour to harm your health.

A Natural Lacquer finish is said to have a life because even after completion, its transparent finish will grow even more crystal clear over time, when more oxygen is absorbed into the finish from the air – which makes the finish even harder. This is different from most other finish, which turns yellow or cloudy when the finish ages.

Japan is laudable with its effort to keep alive the noble tradition of the art of Natural Lacquer, much more so than China. However, most of what they do only apply to small household if not decorative objects. They also tend to use opaque and coloured lacquer rather than keeping the original transparency of the Natural Lacquer. The base material can be soft wood, bamboo, and even orange peel! 

In mastering Natural Lacquer on hard wood in a massive scale, we are probably quite unique in the whole world.

Please view below a series of photos showing how the Natural Lacquer progresses from its source all the way to a fine finish.

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漆,英文 Natural Lacquer, 日文 うるし (Urushi), 是一种天然树脂,从漆树树皮下收采的汁液提炼而成。漆树学名为 rhus verniciflua, 普遍生长在东南亚三千至七千五百尺的山上。当树龄大概十到十五年,而树干直径最少十公分,树皮汁液就开始给开采。每年从六月至十月,开采者就会徒手爬上漆树,在树皮上刻刮出一条一条的平衡沟槽,溢出的白色汁液就会被一个特制的金属刀收集。

当一棵漆树被收采后,它应该“休息”五到七年才再次被收采。每棵漆树全个生命周期只可以给收采五十克的汁液,所以漆异常宝贵。当把漆树汁液的杂质清除后,汁液会被慢慢熬制,并把多余的水分挥发掉。这就变成可以使用的漆了。在这液体状态下漆不可与空气接触,否则会开始化学反应,开始变硬。这状态下的漆也会刺激皮肤,但当漆硬化后还能被其刺激皮肤的人绝无仅有。

用漆来处理的器具异常耐久,可以世代使用而不会爆裂或崩开。漆也对酸碱等的化学物质有抵抗性,并且防水,还能抵受至 230 摄氏度的高温。唯一弱点是漆不可长时间受日晒,因为紫外光会破坏漆的分子。

漆跟大部分传统涂漆物料最大的分别是它的固化过程。它是经过一个无可逆转的化学聚合过程,而不是经过溶剂的挥发。所以漆比其他传统的物料稳定得多。同时漆的固化环境也跟一般涂漆物料不一样。它需要一个潮湿而温暖的密闭环境才可以完全固化。在一般的室内环境漆的固化就困难得多了。也由于因为漆是全天然,所以制成后完全不会挥发有害物质或气体。

漆器常常给形容为有特殊生命力,因为尽管制造完毕,漆还会慢慢吸收空气中的水分子,令表面更坚硬透明。这跟其他的涂漆很不一样,因为大多的涂漆经年累月后只会变黄或变得暗哑。

日本在延续漆器这高尚工艺方面比中国造得更好。但他们主要只是将漆应用在小器皿或装饰物件上。同时大部分的涂漆效果都是不透明的黑漆或红漆,厚厚的一层遮盖着底下的物料 - 包括软木,竹,甚至是橙皮!

把漆的工艺尽情发挥在大型硬木家具上,我们可能是全世界独特的承传者了。

请看以下的照片,显示漆从收采到最终涂漆时的工艺过程。

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shellac

It is a light yellow or orange colored animal resin, the secretion of the lac beetle found on trees in India and Thailand. It is dissolved in alcohol, and dries to form a clear and durable finish, though slightly yellowish. Its use is most well known in the French polish, where the surface is repeatedly buffed to yield a high gloss effect. It is a key finish material used to make fine furniture in the west over the past couple of centuries, with the process called Japanning because it is used to mimic the result of Natural Lacquer.

Different from Natural Lacquer it dries by the evaporation of the solvent material. This property causes the finish to be reversible, in other words solvent can be lethal to a finished piece of furniture because its subsequent application can ruin the fine finish, but at the same time the finish can be repaired with relative ease.

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虫胶(士力)

虫胶的行内名称为士力,是一种黄色至橘色的动物胶脂,从一种遍布于泰国印度等地称为 lac 的小虫所分泌的物质。用酒精溶解后就可使用,在家具表面固化后就变成透明而耐用的涂层,尽管轻微泛黄。它最有名气的使用场合是用在“法国涂漆”上,公丈会不断用沾有士力溶液的棉球在家具表面不停摩擦,让涂漆表面闪闪生光。它是西方过去几百年重要的家具涂漆物料。其涂漆过程也被称为“仿日本”,因为士力的涂漆光泽如果技巧优良的话跟漆有点相近,而当时西方人认为日本就是漆的发源地。

跟漆不同,士力固化只是因为溶剂给挥发掉而不是化学聚合过程。所以士力的涂漆可以还原;换言之当一件用士力涂漆的家具碰到酒精的话就很危险了。但这也让士力涂漆的家具相对上比较容易在将来维修。

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wax / wax oil

It is used either in its own right, or as a final protection to other finish materials. Depending on the application requirement, we may use pure beeswax, which is the natural wax secreted by young bees; or wax oil, which is a pre-combined mix of plant based oil and wax. On top of further shielding the wood from environmental humidity change, it also adds to the surface smoothness and lustre.

Of all the three finish materials covered, wax / wax oil usually yields the most natural finish, that is enabling the original character of the timber to be displayed in its full. It is also the easiest to maintain over time. However, it won't achieve the elegant lustre of shellac, let alone Natural Lacquer.

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蜡/蜡油

这可以单独使用,或作为其他涂漆家具的最后修饰或保护面。看使用情况,我们可能会用天然蜡譬如蜜蜂蜡,或是预先混合的植物油与天然蜡质。除了增加抵抗空气或其他物质对木材的影响外,也能提高表面的润滑与光泽。

在以上三种的涂漆物料中,蜡/蜡油可以制成最天然不加修饰的涂漆效果,让木材表面天然的毛孔与木纹质感发挥极致。这也是三者中最容易打理的涂漆,但它不能单独达到士力的光泽,更遑论漆了。

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