Vinyl coating for furniture finish

It is the coating that is made with vinyl resin as the main ingredient. The vinyl resins is the resin resulted from the polymerization of vinyl acetate monomer. According to the name vinyl, there are many types of resins that can be classified as vinyl resins. The vinyl acetate, vinyl chloride, vinylidene chloride, vinyl toluene, are the vinyl resin. But the vinyl resin which is widely used to make furniture finishing material is the vinyl butyral, the resin made from the reaction between alcohol and vinyl butyraldehyd. To make the vinyl clear coating, vinyl butyral resin is modified with phenol resin, shellac or nitrocellulose to increase the adhesion and solubility. Lacquer thinner is added to the mix to reduce its viscosity. The ready to use vinyl coating is usually thin material (the solid content is about 12%). The higher solid content will be followed the high viscosity that make it is difficult to be sprayed. Vinyl clear coating can be used in combination with other types of clear coating such as: nitrocellulose, polyurethane or acid curing.

 vinyl finish for rattan

Vinyl clear coating is mostly used in the furniture finishing process to add the adhesion power of the finishing layer. This vinyl coating is usually used together with other clear coating. The combination with nitrocellulose or cellulose acetate butyrate will increase the adhesion power of the finishing layer. The problem of the vinyl coating is, it has high viscosity while the solid content is relatively low. It makes the vinyl coating is difficult to generate the finial with the thick film. Moreover his drying time is also relatively longer compared with nitrocellulose. The vinyl sealer is difficult to be sanded because it has relative low solid content and no sanding agent can be added to the mixture. The addition off sanding agent even though in small amount will raise the viscosity very quickly and then make more complicated in the application. 

The film is formed from the evaporation of his solvent and can be resolved with his solvent. This film has less resistance to solvents compared with nitrocellulose clear coating. In the wood finishing, the vinyl sealer is mostly used for the wash coat or the first sealer then followed with the NC sealer and NC top coat. It it is recommended when there is adhesion problem with the finishing system. The vinyl clear coating theoretically can be combined with the PU clear coating or even AC clear coating. But however we have to do some test and trial to make sure it works well.
The vinyl sealer is also most used as the coating material for sealer sizing. The sealer size with vinyl give more flexibility for the next finishing process. It can be followed with any finishing system, polyurethane, nitrocellulose, or catalyzed lacquer. 
The vinyl  top coat is rarely be used in the furniture finishing. Same as vynil sealer, it should a thin coat, the addition of matting agent will increase its viscosity. It is only used to finish some special species, such as finishing for: the rattan cane, bamboo, hyacinth, pandanus, banana leaf, etc. The vynil full system finish is merely used when the finish requires strong adhesion and does not require a thick film.

How to care the finish.

We need to care the finish if we want to maintain the furniture to stay longer. The finish is the protection layer from the furniture, the damage for the finish layer can be continuing to wood. The finish layer is the furniture element that needs to be well treated to keep it’s in the good shape. Wood furniture that is well cared could be an investment since someday it may become antiques that have a high value.

There is no finishes that is everlasting, all finish will wear and fade sooner or longer. But the proper maintenance will make the finish can stay longer.

 keep the finishing clean and dry

Here are tips for caring and maintaining the finishing layer.

• Identify the type of the finish.

Each type of finishing materials has different characters, so they need different treatments as well. Now, there are many types of finishing materials, but simply they can be categorized into 2: the “chemical reaction dry” and “evaporation dry” finishing material.

The”evaporation dry” is the finishing materials that dry by evaporation its thinner without chemical reaction in the film forming. Includes this type are: nitrocellulose lacquer, butyrate lacquer, acrylic lacquer, shellac, and varnish. The dry finishing layer is a thermoplastic material which will melt and resolve when it is wet with its solvent. They have low resistance to solvents and chemicals. In general, they also have a lower resistance against abrasion and scratches.
The “chemical reaction dry” is the finishing materials that dry by the chemical reaction together with its thinner evaporation. Includes this type are: polyurethane, acid curing, catalyzed lacquer, precatalyzed, UV coating. The dry finishing layer is a strong thermosetting layer that won’t resolve with the solvent. The finishing layer also has high resistant to the scratches and abrasion.
Water based coatings actually is a non-chemical reaction finished, but he has the higher strength to chemicals, and scratches, but it has low resistant to the solvent.
By knowing the types of finishing materials then we will be able to do better treatment to the finish layer. The information about the finishing type can help us to choose the cleaning liquid when we need to clean the finish surface. We can use alcohol or even acetone to clean the “chemical reaction dry finish” if necessary. But for the “evaporation dry finish" we should choose the cleaning liquid carefully. The cleaning liquid that contains solvent such as: alcohol, acetone, M.E.K will damage the finish.

•  Keep the finishing layer dry.

Water is one of the greatest enemy of wood finishing. Stagnant water on the finishing layer can damage the finish layer especially to the lacquer finish, shellac, or varnish. Even the polyurethane, acid curing or water based coating are not designed to hold a puddle water for a long time. The water and humid conditions will also invite fungus that will ruin the appearance of the finish. Since that we need to keep the finish surface to be dry. The water or any other liquid on the finish should be wiped and cleaned and soon to keep the finish dry.

•  Avoid direct sunlight and physical abuses.

No finishing layer can withstand the physical abuses. Several types of finishing indeed could produce such a strong layer such as PU or UV coatings, but they will not be able to withstand the physical treatment that is too harsh. It is very difficult to avoid the physical damage, as long as we use the product, there will be physical interaction that potentially damages the finish. What we can do is to care and handle the furniture carefully to minimize the physical abuses. We may layer a table cloth, glass or plastic layer to cover the top table.

The direct sunlight sends the high energy that will damage the finish. The UV light will cause for the discoloration for the finish. The direct sunlight for the indoor finish will also damage the finish layer to be cracked and chipped off.

• Clean he finish layer periodically

Finish layer can become dirty due to dust, dirt or stain. The dirt that is not immediately cleaned can stick to the finish layer and ruin the finish appearance. The stuck dirt will be more difficult to be cleaned and it may damage the finish. Ideally every time there is any dirt at the finish should be cleaned immediately. The periodically cleaning for the finish layer should be done to keep he finish layer clean.

We need to use the proper cleaning liquid to clean the finish. Avoid the liquids that contain alcohol or solvent. The solvent will dissolve the “non-chemical reaction dry finish" ; shellac, lacquer, varnish and water based. Despite the chemical reaction dry finish layer is resist to the solvent, but we better avoid the solvent liquid to clean the finish.  

• Waxing.

It is the application of wax on the finish. The wax could help the make the finish feel smooth and slippery. The waxing to finish is good way to clean and keep the finish. It could reduce the abrasion and physical abuses in small impact. But the wax coating will not last long in a surface finishing. He will soon disappear and erased after been used for some time.  The application wax will require repetition every period of time. Use the thin and clear wax to clean the finishing layer. Don,t use the thick wax on the finish since it may sticking and smearing to the object being placed on. 

Acrylic paint for wood finishing

The meaning of acrylic paint or coatings is the paint or coatings that use acrylic resin as its main ingredient. In coatings terminology, the acrylic resin is the resin from polymer and co-polymer of esters of methacrylic and acrylic acid. The co-polymers these ester resin with the non –acrylic monomer such as: styrene, butadiene or vinyl acetate are still named as acrylic resin.  The acrylic resin can be manufactured conveniently in several physical forms: the acrylic emulsions, the solvent solution and the powder pallet. The acrylic resins then can be modified in the formulation of the final product.

In the finishing industry, the acrylic resin is usually mixed with other resin to make the specific formula to make coating or paint. The uses of the acrylic resin in the coating industry is very broad. It is one of the most versatile resins used in the coating field. The ad of acrylic resin in the coating will increase the stability, good exterior durability, excellent color retention, resistance to the UV light, and chemical resistance.

There are some types of paint that can be named as acrylic paint. When it is in the coating form, the "acrylic resin" paints could have different properties each other and we might be not able to be mixed them in the finishing application. When we are going to use the acrylic paint, we have to read carefully how it should be used. We always need to follow the technical data sheet and the instruction to get the maximum result.

In the wood finishing, the acrylic paint usually refers to the non yellowing coating (the thinner based paint), the latex paint and the water based paint. 

 latex paint finish

• Acrylic paint (latex paint).

It is a paint containing suspension in acrylic polymer emulsion mixed with pigment. It is available in many colors and most used to the wall paint or the decorative coating. The acrylic paint is diluted with water, but it becomes water-resistant when it dries. This paints also available in the other special form to be used for hand paint.

In the wood finishing the acrylic water based paint is usually used to make paint finish. It can give the thick and strong opaque color. It is also can be used to make some special finish effect such as: wash finish, texture effect, crackle effect, etc. The use of acrylic paint in the wood finishing usually is combined with other coating such as: NC, PU or acrylic coating. 

• Oil acrylic paint.

The oil acrylic paint is made of acrylic resin solution or powder form which is mixed with pigments. It is oil base paint. This paint is widely used by the artist painter to do he hand painting. It can produce bright color and available in wide range of color. It is oil base, so it takes long time to dry.  

• Acrylic lacquer.

Acrylic lacquer refers to the non-yellowing lacquer. The acrylic resin in the lacquer wills ad the resistance to the UV light, but the pure acrylic lacquer is rarely used, since it hard, brittle and expensive. The dry film resulted will not turn to yellow. It is used to make the white finish or light color finish, when the film yellowing is not allowed. The acrylic resin that is mixed with cellulose acetate butyrate is the most popular non yellowing lacquer.  

 non yellowing PU for white finish

• Acrylic Polyurethane.

Polyurethane is a polymer that is formed from the urethane polymerization reaction. Urethane produced from the reaction between the poly isocyanate with the materials that have hydroxyl group. When the acrylic is used as the hydroxyl group resin, it is called the acrylic PU. It is the non yellowing Polyurethane coating. It is used to make PU finish for the white color.

• Water based coatings.

The water based coatings is the emulsion aqueous solution. The water based coating is made of acrylic resin, modified acrylic or one component urethane. The water based acrylic resin is the acrylic emulsion. It is similar with the latex paint but it is clear. It is diluted with water, but when it dries it will hard and strong and resistant to the water.  It is produce non yellowing film, fast dry and has high resistance to the chemical, solvent and mechanical abuse. The water based coating now is very popular since the environmentally issue.

Oak burl finish

Oak burl is a premium wood. It is wood from oak trees which have grown in a deformed manner. The oak burl has a light brown color with small knots irregular but nice grain pattern. In the furniture manufacturer the oak burl veneer is mostly used in combination with other wood to make expensive furniture. The oak burl which has a unique and nice pattern is used as the eye catcher for the furniture product.

Although oak burl wood is very attractive but without the the proper finish it will be nothing. The oak burl need the proper finish to let the nice and attractive appearance is showed maximally. The oak burl should be finished in transparent finish according to its unique grain pattern and knots, enhancing it to make nice looking product.

Now in this article we want to share the oak burl finish to make an antique transparent brown finish we did on the oak burl veneer panel. We didn’t do finishing for the furniture product, but the finishing step in here can be adopted to the wood furniture as well.

unfinished oak panel 

Here is the finishing process.

• Glue sizing.

Oak burl veneer has high risk of splitting and cracking. His wood structure make the wood is  brittle and easy moved. To minimize the risk of veneer cracking we did a glue sizing. We layered thin glue on the top of the veneered panel. The glue size was not purposed to make smooth wood surface but mainly to make the oak burl veneer to be more stable. The glue will cover the veneer and make it more stable to make less risk of wood crack. 

• The stain application.

We wanted to make medium brown wood color finish, then we used a brown dye wood stain. The dye stain is the good choice since it is absorbed by the wood to make a transparent, bright color.

The dye stain was applied by wet spray to the entire surface of the wood. To enhance the beauty of the oak burl, then we did smudge pad to the stain layer. We took a cloth, wet it with alcohol and padded the cloth to the stain. The was an uneven coloration according to the irregular pattern of oak burl grain and knots.

To make the stronger burl effect looked, then we did a highlights at the stain. We used steel wool to erase some stain  to enhance its irregular pattern of the grain.

hand pad the stain 

highlight the stain

• Wash coat application.

Wash coat coating was layering to prepare the surfaces for glaze application. One layer of wash coat was sprayed evenly to the wood surface. We let the wash coat for few minutes to dry and scuff sanded the wash coat to prepare smooth wood surface for glaze application.

• Glaze application.

A dark brown glaze was used to make a deep and rich finishing color and to make the finish is looked more antique. The glaze was poured at was dry brushed (stippled) at the surface. The dry brushed glaze was also done to burnish and  darken the edges and corner to make more antique looked. 

dry brush the glaze

• Sealer application.

Sealer is needed to build the film finish and to give protection to the finish color and appearance. We sprayed 2 layer of wet coat sealer on the glaze layer. To times sealer application is needed to make the enough film built. 
Once the sealer was dry we sanded the sealer layer and sprayed the 2nd sealer. We let the sealer dry and sanded the sealer layer to prepare film layer for the top coat application.

oak burl finish panel

• Application of top coat.

We used a medium gloss top coat for the last coat. Forty five sheen top coat was sprayed evenly as the lat coat. And the result was a antique brown transparent oak burl finish with nice and attractive appearance

Discoloration in the outdoor wood furniture.

A discoloration or color change at the wood furniture is a naturally phenomenon especially when we put the wood at the outdoor. Outdoor wood furniture as an object of sunlight, heat and cold of the weather will tend to get the discoloration. The ultra violet ray in the sunlight will accelerate for chemical reactions at the wood that would cause discoloration.

The color changes of the wood can be varied from one part with other parts. The variation of chemical composition inside the wood will make the wood react differently and make different discoloration.
Although it is naturally phenomenon, the color change is not expected by furniture business player and user. Most people want to remain their wood furniture to be durable and unchanged in the form and appearance as long as possible. Moreover, today many furniture sellers dare to give a warranty for their product to keep same during the certain period of time.

Since then several attempts were made to prevent or minimize the occurrence of discoloration at wood furniture. Although it is not possible to stop totally the occurrence of discoloration, but at lest there some way to minimized it.

discoloration at the outdoor teak furniture

Some things that can be done to prevent discoloration

• The finishing process (layering with coating)

Finishing process is one of the logical way to maintain the appearance the wood furniture to remain stable. The finishing layer will cover and protect the wood from contact with the surrounded air. It will prevent or at least minimize the occurrence of the reaction between the wood surfaces with the air environment. As long as the finishing layer is still attached to the surface, then he will be a protector that can prevent the occurrence of discoloration. But for the exterior uses, the furniture requires a special chemical that can withstand the heat of the sun and weather changes in their environment. The finishing materials with acrylic resins are the widely used for outdoor finish. The acrylic resin has high durability to the UV light from the outdoor sunlight.

We as finishing people can easily recognize the outdoor finish material by read the specifications of the coating product. The product for outdoor uses usually has tag in its cane that says it for outdoor uses.  The most commonly used finishing materials for outdoor use are: spar varnish, acrylic PU, water base acrylic, acrylic and polyester.

• Staining

Staining is the trick to reduce the discoloration problem of the wood. The natural wood color that has been coated with a clear coating layer of finish film still tends to get discoloration. The wood will absorb the ultraviolet ray and then react to change its color. The color changes of the wood can vary from one section to another since it is depend on the content of tannins inside.
The wood staining will make the color of the wood becomes more stable. Stain will color the wood so that the wood discoloration will be covered and less visible.
But the special stain is needed for outdoor uses. The stain for outdoor finish should use the pigments materials that are resistant to the UV rays.

• Re coating.

Despite that the finishing layer for outdoor has been designed to be resistant to the outside weather and sunlight, but he still will fade too after a certain time. Exposure to sunlight and weather changes and abrasion from the air will fade the finishing color and film. For those reasons, some finishing materials manufacturers are recommend for refinish or recoating he finish after a certain period of time.
The oil finish is the most common finish that needs to be recoated.  Every 6 months or 1 year the oil finish need to be recoated to keep its performance. The oil finish is simple finish, so the recoating can be done quite easily. The oil finish recoated can be done by brush and wipe the new oil to the old finish.
Some varnish manufacturers also recommend recoating the old varnish layer to maintain the products. They provide varnish that can be applied in a simple manner by brushed. The brushing varnish is much easier to be used to re coat the old finish without have to deal with the complex troublesome finishing equipment ad facility.

How to paint the wood furniture

What is paint finish?.

 high gloss white paint finish

 
The paint is the finishing material in the liquid and thick form finishing material that has specific color. Paint will produce an opaque color or solid color on the surface when it is layered. While the paint finish is the opaque color finish. It is the finishing when the wood base color is fully covered and blocked by the finishing color. The finishing color is fully determined  by the color of the finishing material.
The finishing process of paint finish is similar with the finishing to the transparent finish, but of course with different material. We need the "paint" material to make the paint finish.If the transparent finish we want to show the wood beauty, but in the wood paint finish we have to close and cover the character of the wood.

The finishing process to make the paint finish to the wood furniture.

• Preparation on unfinished wood.

Every wood finishing process must be started with the good preparation to the unfinished wood. The wood surfaces must be sanded properly to obtain a flat and smooth surface. Choose the suitable wood if possible. The wood with less and shallow pores and grains such as: maple, ash, jabon, etc, are the better choice to make the paint finish. The wood with large pores and grain such as: oak, mindi, mahogany, teak, are not good choice. The wood with big pores and grains need to be filled to produce even and smooth paint finish.
Paint finish does not require wood with beautiful grain and base color, since the final finishing color and looked is determined by the color of the paint. The wood with varied color base can be used as long as it has smooth and even surface.

But, we need to avoid the paint finish to the oily wood such as: teakwood, pine, cocobolo, rosewood, etc. The oil from the wood will emerge and ruin the finishing color.

• Paint application.

There are many types of paint can be used to do the paint finish. The paint that most widely used for wood finishing are: base coat paint, oil paint and water based paint. 
Water based paint is also known as the latex paint is a water-based finishing materials. The material can produce a thick layer of paint finish with wide range color choices. But he needs a relatively long drying time. The drying is highly affected by the weather conditions at the time application time. In the hot air and low humidity, the drying process can occur quickly, but when the day is cold and humid the drying will take long time.
Oil paint is oil-based finishing materials. It available in many color and with brighter color. This material is usually diluted with mineral spirits or naphtha. This material is not sensitive to the weather but it also needs long drying time.
Base coat is the thinner base paint. This material is made from mixture of organic pigments and clear coat. This material is dry quickly and can be sanded easily. It is the coating that is designed to make paint finish. This material is available in various types, depending to the type of binder used. The NC base coat and PU base coat are the most used. The other type’s base coat such as: AC, Precat or UV base coat also available.
All paint material need to be applied correctly to get the best result. The application by spray is the best option to the wood furniture finish. The spray application will produce the smooth and even paint finish. The other application technique such as: rolled or brushed can be used if the texture paint finish is needed.
Almost all type of spray gun can be used to spray paint. The air spray gun, airless, HVLP or LVLP spray gun can produce a good coating with the proper adjustment and spray techniques. Whatever type of the paint is used, he used should be adjusted according to the spray specification to produce a perfect coating. The paint usually needs to be diluted to reduce its viscosity according to the desired viscosity of the spray gun.
The viscosity around 14 second (measured with NK 2 cup) is usually required to make perfect atomization. The HVLP spray gun work at lower viscosity (about 12-13 second). While the air spray and airless spray gun can operate at a higher viscosity, but the recommended paint viscosity is in the number about 14 second. 
Spray the paint 2 layer wet coat evenly to the overall surface and wait until the paint is dry. The drying time will vary depending on the type of paint used. The NC-base coat usually need about 15 minutes to 30 minutes to dry, while the PU base coat may need 1 hour drying time. The drying time for water based paint depends to the air humidity. In dry air condition, the paint can dry for about 30 minutes or even less, but if the room is cold and humid then the longer drying time is needed. If thick layer paint is layered in the humid and cold air, then we may need for 1 day to let the paint to dry.

sanding the white paint

• Sanding the paint.

Once the first paint layer is dry, usually a rough surface is resulted. The first coat also will display all the wood defects such as: cracks, dents, holes, unevenness, etc. To produce a flat finish we need to sand the paint layer until a smooth and even surface is obtained. We also have to fix all the defects. The cracks, gaps, dents should be filled with putty.  A proper sanding is required to produce the smooth and even surface. The stearated sandpaper with grade # 240 or # 280 to sand the paint surface.Then we need to apply with another layer of paint. We need few layers of paint to make a smooth surface and even color. Usually 2 or 3 layer is needed.

• Clear coating applications.

After the color of the finishing is obtained, then we need to coat the paint layer with clear coat. We can apply sealer then top coat, or just apply the top coat without any sealer. The sealer layer will help to build more thick film, but the thick sealer layer will affect the finish color. For the white paint finish, the color of the film layer may change the color little bit.

Use the top coat and sealer which is compatible with the paint. The same type top coat and paint is highly recommended since it will give the best interface. If the top coat or sealer with different type are used, then it must be ensured that they completely fit with the paint underneath.   See our previous article: compatibility of coating application

Antique light mahogany finish.

Mahogany wood is very popular in the wood furniture industry. Many furniture products in various types and items are made from mahogany wood. With the right model and finishing, mahogany wood can produce very interesting furniture product. Mahogany wood usually is finished in the dark brown or reddish brown color, according with its basic color. The red brown basic color of the mahogany wood makes it is quite difficult to produce light finishing color.

But in this article we wrote the finishing process for mahogany wood to make light color. We want to share finishing process to make the mahogany finish with light brown color with antique models. The wood used was crotch mahogany veneer at the panels and solid wood mahogany at the frame.

Finishing process is as follow. 

• Bleaching

To produce the light color from the dark wood we have to lighten the wood base color. And bleaching is the only choice to do that. The reddish brown of crotch is very strong, as well as solid wood, therefore we need a strong bleaching chemical. We used the hydrogen peroxide chemical (part a chemical) and the sodium hydroxide (part b chemical) as the strong bleaching chemical. The combination of both chemical is quite strong to whitened the red color of crotch mahogany.
We mixed 1 part of Hydrogen peroxide and 1 part of the sodium hydroxide and sprayed it to the wood surface until the wood was wet entirely with the liquid. The we put the wet wood under sunlight for about 3 hours to let bleaching chemical reacted and oxidized the wood. After about 3 hours under sunlight the wood was dry and a white wood surface was obtained. But we had to wait for about 24 hours to ensure the reaction was perfectly done.

• 2. Physical distress.

After the waiting for 24 hours and the we were sure that the reaction was completed we started to do the finishing process. The first finishing process was the physical distress. We used nail, chains, files, and stone to rock and hit the furniture. We did the medium distressed according to the light antique finish we want to generate.
The process of distressing damaged the furniture and made some sharp and rough surfaces. We sanded the surface to clean the roughness from the distressing to make smooth surface. The sanding was also done to cut the arisen wood fibers caused by the wetting of the wood at the bleaching process. Sanding also continued to break the sharp edges. The antique finishing didn't allowed the sharp edges. The antique object should be used for long time and every sharp edges has to be wear and smooth. Any sharp edges should be sanded to became smooth and ware.

•   Applications of wood stain.

The bleaching process, that was done correctly produced the uniform color at the wood surface. It makes the color application quite easy to be done, we don't need the equalizer stain or sap stain to uniform the color. We used a light dye stain to be sprayed wet evenly to color overall surface.

• Wash coat application.

Wash coat is used to coat the surface of the wood and protect the stain so as not to be wiped in the glaze application. The vinyl wash coat was sprayed evenly to coat the entire surface, then we wait for about 15 minutes to let the wash coat dry.
After the wash coat dry then did the sanding to the wash coat to cut the arisen wood fibers. Scuffed sanding with # 280 was done to overall surface until a smooth surface was obtained.

•  Glaze application.

Glaze is a very important stain to make antique impression and deep and rich color at the finishing. Glaze was applied by sprayed, and wiped then brushed until it layered at the surface evenly.
To make more life appearance of the grain,  we highlighted the glaze. The steel wool was used to wipe the glaze layer in some part to enhance the wood grain.

We let the glaze for about 1 hour to make sure the glaze thoroughly dry.

• Sealer application.

Sealer is coated to protected the glaze and to built the film layer of the finishing. One layer coat  was applied to protect the glaze layer and to built the film layer.  The NC sealer was wet sprayed evenly to overall surface.  After about 30 minutes waiting the sealer was dry and we used # 280 sandpaper to sand the sealer coat. 

• Antiquing with glaze.

To add to the impression we did the the stain distressed. We uses the glaze to add the antique impression at the finishing. Glaze was dry brushed to fill in and color inside the carving, the holes and dents from the physical distress.
The glaze was also applied to make spatter and cow tail mark to make more dirty and antique looked.
The next process was the second sealer. The sealer was applied by spray as the first sealer.

After about 30 minutes the NC sealer was dry and we sanded the sealer to make smooth surface for the top coat application.

• Application of top coat

Top coat is the last finishing layer to give protection for the finishing appearance and color underneath.  In this process we used a low sheen top coat.  Ten sheen NC top coat was sprayed evenly to coat the entire surface. The top coat needed longer time to dry. We waited about 1 hour to let the top coat dry.

After the top coat dry we continued the finishing process by sanding the top coat layer. We sanded top coat layer with # 280 grade sandpaper to make smooth and even surface. Then we re did the top coat application. A ten sheen NC top coat was sprayed evenly to overall surface. We let the finish dry for  24 hours to ensure the top coat was fully dry.

• Rubbing.

Rubbing is the last finishing process. We did simple rubbing to make a smooth surface finish and more attractive looked antique finish. The finest steel wool ( # 0000 grade) was used to rub the top coat layer until a smooth and even finishing film obtained. 

 antique light mahogany finish

The result was an antique furniture with light brown transparent mahogany color.

Wood veneer.

What is wood veneer?

Wood veneer is a thin layer of wood. It is made of log of timber that is sliced in thin sheet of wood. Wood veneer then is attached at core panel and widely used to make panel board in the furniture industry. Most of the big and wide panels for furniture are made from veneer. With the proper gluing of the correct technique then the panel of veneer panel or plywood is more stable than solid wood panel.

The main properties of wood veneer as:  base color, grains and pores character and the absorption to the finishing material is determined by the type of wood used to make veneer. The character of the wood veneer is also determined by the thickness of the veneer and how is wood sliced. Wood veneer is available in various thicknesses.

The veneer type and quality.

The veneer is widely available in the woodworking industry. The main properties of the veneer such as: the wood base color, the pores and grain character of the veneer is determined by the wood type that is sliced.  The furniture industry can select the veneer type in accordance to the appearance of wood panel board he needs to make furniture. Veneer is available in almost all type of wood,  so we can choose the type of veneer we need quite easy.
Veneer is also available in various grades of quality and thickness. The selection of the veneer is also should consider the thickness and grade of the veneer. To produce the panel boards normally we use the 0.2 mm to 0.5 mm thick. Thick veneer is expensive, while too thin veneer has high risk to get problem in the woodworking process. Thin veneer has the risk of glue bleeding at the gluing and  the “cut off”  at the sanding process.
Other things to be considered are the quality and grade of the veneer. Veneer is made from wood that could have varied properties. The quality of the veneer is according to the quality of the wood that was sliced to made the veneer. Same with the wood the wood veneer is classified according to the veneer grade. But as an engineered wood product the veneer quality can be controlled easier then the wood log. Veneer with high grade to is used to the exposed part of panel board, while the veneer with lower grade mostly used to layer the back panel or the unexposed part.

The storage of the veneer.

 

The veneer is dried at the veneer manufacturer before it is marketed.  The wood veneer is always marketed at dry condition, but the veneer is hygroscopic material, he will absorb and release water according to its environment humidity. The veneer should be stored in a dry room that has a stable humidity. Veneer is usually stored in dehumidifier or conditioning room which is kept at low humidity.

wood veneer panel

The veneer attaching to make panel.

The veneer laminating requires precision work and skillful people is needed. The veneer are cut to the certain size to produce the desired shapes and patterns, then the pieces are jointed together according with the desired pattern. The grafting and unification of the pieces of veneer has to be done neatly, the imperfectness at the joint will be seen at the veneer panel.

The veneer pieces are unified glued together by using special tape or a yarn. The series of veneer is then glued to the core board and pressed until the glue is dry to make a “wood panel”.

According to the gluing process there two kinds of veneering, that are: the hot press and the cold press. Hot press is the veneer process when drying of the glue is done by heat. If the drying is done without heating, it is called cold press. In the hot press a steel panel plate is heated to press and heat the wood veneer, the glue can dry in just few minutes. The temperature of the plate is depend on the type of the wood and glue used, but usually ranging form 70 to 100 degree Celsius.
The cold press is simpler process, it does not use heat, the glue is dry in the room temperature but the longer drying time is needed.
There are many cores can be used i.e.: M.D.F., particle board and laminated wood. Particle board is the most inexpensive materials;  but he is not as strong as the laminated wood or M.D.F.  The veneered particle board panels will also produce "wood looked" panel board, but it will not as strong as wood or M.D.F. It mostly used to make low end furniture product.

M.D.F. is stronger engineered wood product because he is homogeneous and stronger, but it is more expensive material. The M.D.F. usually is used as core material for panel boards when  furniture with better quality is needed.

Laminated wood, or bare core is stronger and more natural. The laminated sengon wood is the most often wood used. Sengon wood is relatively lightweight, inexpensive and durable. The laminated wood should be stronger than the M.D.F. or particle, but since it is wood then it could has varied properties.

There is two important things at the core preparation, the moisture content and surface flatness. The moisture content of the cores should be as close as possible to the moisture content of the veneer. The moisture content should according to the standard of the moisture content of the wood product. The glue used is usually water based, since then gluing process will tend to raise the moisture content of the panel. The moisture content of the core and veneer should be kept at around 10%.
 
The core should has flat and even surface to make a well attachment with the wood veneer thereon. The sanding for surface calibration with wide belt sander is needed to produce the flat and even core panel. 

Sanding the veneer panel. 

After the cores are attached with veneer and a wood looked panel is made, then the proper sanding is required. The sanding is purposed to remove the tapes that is used to unify the veneer pieces, to clean the dirt or stain and also to produce a smooth and flat surfaces. Sanding to the veneer should be done carefully; too much sanding is risk to cut trough the veneer layer.  The veneer sanding process principally is very similar to the wood sanding. It should be started with # 100 or # 120 grade sandpaper and ended with the # 240 or # 180 grade sandpaper.

Lacquer retarder

Lacquer retarder is the additive to retard or slower the drying process of lacquer. Lacquer retarder is usually already mixed in the lacquer thinner to make the good flow and smooth film. But in the finishing process we may still need to add some lacquer retarder in the application. In a certain conditions when the drying time of lacquer is too fast, or the when slower drying is required we may need to add lacquer retarder. 

Here are some finishing problems can be alleviated by the lacquer retarder.

• Blushing.

Blushing is the formation of fog or a rainbow in the film coating. It is caused by the water vapor that is trapped in the coating film during the film forming. Blushing is happened when we do clear coating application at the humid air, for example at the morning, at the night or at rainy days, especially in certain areas which have high humidity.
If there blushing problem, then we can add some lacquer retarder into the top coat mixture to slow down the drying process. The slow drying process will allow water vapor trapped in the coating film to release and come out from the film layer.

• The rough surface of the film layers.

The surface layer of a finishing film may be rough due to the dust spray that is attached to the film surface during the spray applications. Dust spray could happen because there are some surfaces area that has been dry during the spraying process.This dust spray problem could be occurred at the big product which has large surface area such as a big cupboard or cabinet. The big surfaces could need long time for the spray; the surface that sprayed at first time could be already dry when the spray process is still on going. The dust spray stick at the dry film and make a rough film surface.
We can add some lacquer retarder to let the lacquer layer be wet longer. The wet coating layer will accept the dust spray to be mixed and solved with the lacquer. There will be no dust spray and the smooth film surface is resulted.

• Streaking finish

Streaking is the lines as a "zebra looked" in the finishing layer. The streaking at the top coat could be caused by the top coat layer is drying too fast. The drying time of lacquer cannot be too fast to let every layers of the film coating from each stroke to solve  and mixed with its previous stroke.
We can add the lacquer retarder to solve the streaking problem that is caused by too fast drying. The addition of retarder in the top coat will slow down the drying time of the top coat layer thus allowing each stroke spray can be fused and well mixed.

How to make lacquer retarder?. 
 
Lacquer retarder is made of solvents that has high solubility to the lacquer, but have slow evaporation time. Some commonly used solvent for the lacquer are: buthyl acetate, cellusolve acetate, buthyl cellusolve, p.m. methyl acetate. 

Although it can help a lot, but too much retarder is not recommended. The addition of lacquer retarder should be undertaken only on special case, in the normal condition the addition of lacquer retarder should be avoided. Too much lacquer retarder is wasting and even could cause for finishing problems.

Some problems that could be generated by too much retarder. 

•  Longer drying time.

The addition of retarder will slow down the drying process and it will make the overall finishing process becomes slower. It could be disadvantage in the big volume finishing industries that do finishing job in big volume. The slow drying process is also raise the risk to get the soft finishing layer problems.

• Rough finish film.

Long drying time also increases the risk of a rough film surface as a result of the dust that sticks at the wet surface. The longer wet surface exposed will lead to the more dust attached. This condition will raise the rough problem for the rough finish, especially when the finishing and drying room is not quite clean and free dust.

• Gloss problem.

The addition of lacquer retarders can also lead to the high gloss finish than it should be. The gloss in the top coat is adjusted by the add matting agent in the top coat mixed. The matting agent is particles that will refract light that come to the surface to make a low-gloss finish film. See our article: matting agent in the top coat.
To work optimally, the matting agent should be stay in the top surface of the film coating. The matting agent at the bottom layer make it does not work to refract the the light and affect the film gloss. Too much lacquer retarder can result for too long drying time, and let the matting agent particles to settle at the bottom of the layer film, and the result is the high gloss finishing film.