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The impact of sanding grit size on color consistency of different wood species used in Canadian furniture… Firoozmand, Mohammad Apr 12, 2013

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The Impact of Sanding Grit Size on Color Consistency of Different Wood Species Used in Canadian Furniture Manufacturing- A Visual Inspection Mohammad Firoozmand WOOD 493 A Report Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Science in Wood Products Processing In The Faculty of Forestry April 12, 2013 i  Executive summary  Wood finishing consists of several preparation steps to the aesthetic appearance of wood and also to protect it from damage. In the very first step of finishing, wood defects such as oil, imperfections, and indentations are removed from the surface using multiple grits of sandpaper. Once the surface has been sanded, stain and finish can be applied evenly to the wooden surface.  The natural color and cellular structure of each wood determine the final result of finishing. Open-grain woods such as oak usually have large pores, they absorb stains very easily and they do not turn blotchy. On the other hand, woods with closed grain structure like cherry and maple have small and dense pores, they do not absorb stain easily and evenly, and they tend to turn blotchy no matter to what grit they are sanded with. Other influential factors on the final result of finishing are stain type and the final sanding grit. To achieve the best results, each wood should be sanded with proper grit size, and finished with appropriate stains and finishes.  In this study, I investigate the impact of sanding grit size on the color consistency of finished wood. For this purpose, samples of seven hardwood and softwood species were sanded using 120, 150, and 180 grit sandpapers, the stain was applied to the sanded wood surfaces using two methods, spraying and wiping stains, and finally the wood was finished with lacquer. For each individual wood species, the combination of grit size and staining method that achieved the best color consistency is reported.  Key Words: wood finishing, softwood, hardwood, grits, sanding, staining, color consistencyii  Table of contents Executive summary ..................................................................................................................... i Table of contents ........................................................................................................................ ii List of tables ............................................................................................................................. iv List of Figures ........................................................................................................................... iv 1. Introduction .........................................................................................................................1 1.1 Background ...................................................................................................................1 1.2 Wood Finishing ............................................................................................................1 1.2.1 Sanding ..................................................................................................................1 1.2.2 Staining .................................................................................................................4 1.2.3 Finishing ................................................................................................................5 1.3 Factors impacting finishing performance .......................................................................5 1.3.1 Natural characteristics ............................................................................................5 1.3.2 Wood products and weathering ..............................................................................7 1.4 Wood cabinets in North America ..................................................................................7 1.5 Research objective ........................................................................................................8 2. Materials and methods .........................................................................................................9 2.1. Sample preparation .......................................................................................................9 2.2. Experiment ................................................................................................................. 10 3. Experiment results ............................................................................................................. 11 iii  4. Discussion ......................................................................................................................... 19 5. Conclusions ....................................................................................................................... 20 2 References ......................................................................................................................... 22 3 Appendix ........................................................................................................................... 23 iv  List of tables Table 1: Different classification of grit sizes and their uses .........................................................2 Table 2:  Wood cabinets used in North America ..........................................................................8 Table 3: Summary of obtained results from the experiments ...................................................... 20 List of Figures  Figure 1: Effects of abrasive particle size on substrate roughness ................................................3 Figure 2: Various types of sandpapers .........................................................................................4 Figure 3: The difference between dye and pigment ......................................................................5 Figure 4: Wood species used in this study ...................................................................................9 Figure 5: Equipment used for sample preparation ........................................................................9 Figure 6: Single arm oscillating spray machine ......................................................................... 10 Figure 7: Comparing finishing results for red alder samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ............................................................................................. 12 Figure 8: Comparing finishing results for beech samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ................................................................................................... 13 Figure 9: Comparing finishing results for cherry samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ................................................................................................... 14 Figure 10:  Comparing finishing results for hickory samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ............................................................................................. 15 Figure 11: Comparing finishing results for maple samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ............................................................................................. 16 Figure 12: Comparing finishing results for oak samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ................................................................................................... 17 Figure 13: Comparing finishing results for pine samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain ................................................................................................... 18 1  1. Introduction  1.1 Background  Canadian furniture manufacturing is a significant contributor to the Canadian economy. This sector has created jobs for 73,783 people in total and contributed $3.8 billion (in 2002 dollars) to Canada?s total GDP in 2011 (Industry Canada 2011). Furniture manufacturing industry includes office and institutional furniture (40.8%), household furniture (38.5%), wood kitchen cabinets (17.9%), and blinds and shades manufacturing (2.8%) (Buisson 2012). Wood kitchen manufacturing is relatively a considerable contributor to furniture manufacturing sector in Canada, providing 20,059 jobs and adding  $1.3 billion  in value added in 2011 (Industry Canada 2011). Wood cabinet manufacturing includes a sequence of processes that refine and prepare the wood to be used for cabinet manufacturing. First, doors and drawer front surfaces are prepared for staining. In this step, wood is machined and sanded and then the dust particles are vacuumed. Next, stains are applied to add color to the wood and also to bring out the natural grain patterns of wood. One of the common problems in this stage is that wood would turn blotchy when the stain hits in. This happens because wood pores are unpredictable; more stain is accumulated in more porous regions of wood and a darker appearance would be appeared in those areas. Scratches also absorb more pigment and because of uneven absorption of stain the wood surface look unpleasant. Sanding before staining is very important since it opens the pores and also eliminates the dents and scratches. After the stain has been dried, a layer of sealer is applied to the surface. Finally, finished doors and drawer fronts are sent to the assembly line to meet up with cabinet components. Each stage is explained in detail as follows.  1.2 Wood Finishing  1.2.1 Sanding  The very first and an integral step of finishing is sanding. Sanding a piece of wood levels the joints and create a smooth surface and prepares the wood to take stains easily by providing a 2  uniform texture and increasing the adhesion ability of the wooden surface.  In sanding, the correct type and grit of sandpaper is an important consideration in order to achieve high quality finish (Bryze 2006). Sandpapers are made of abrasive minerals bonded to a cloth, paper, or polyester backing by means of coats of adhesive (Purdy 2013). Sandpapers are graded based on the number of mineral particles per square inch of them known as grit size (HowStuffWorks 2013). Table 1 compares different classifications of grit sizes.   Table 1: Different classification of grit sizes and their uses  Source: Flexner (2005) Grit Classification Uses 600-500 Super fine Polishing  400-360-320 Extra fine Sanding between finish coats and final coat 280-224-220 Very fine Sanding between finish coats and final sanding on hardwoods 180-150 Fine  Final sanding on softwoods and preliminary sanding on hardwoods 120-100-80 Medium  Preliminary sanding on rough wood 60-50-40 Coarse Rough sanding to remove paint and Finish The larger grit size means there are smaller mineral particles or cutting edges per square inch of sandpaper and the sanding process results in a smoother surface. However, ultra-smooth surface would not create higher quality finishing result. In fact, it will prevent adhesion of stain to the wood surface (Bryze 2006). No more sanding is required when all mill marks on wood surface and wood defects are vanished (Flexner 2005).   Momber et al. (2008) states that it was Tilghman (1870) that investigated the effect of abrasive grit size on the surface profile for the first time. Tilghman (1870) stated that the grain of the polished surface would be finer when the sand was finer. Later, Bigos (1959), Bullet et al. (1969), Mellali et al. (1994), Kniewald (1993), Abukava et al. (2004), and Day et al. (2005) observed a linear relationship between abrasive grit size and surface roughness for different types of material.   Morcillo et al. (1898) used average roughness as an indicator of surface smoothness and illustrated the relationship between surface smoothness and abrasive particle size as Figure 1. 3   Figure 1: Effects of abrasive particle size on substrate roughness  source:  Morcillo et al. (1989) cited by Momber et al. (2008) In addition to grit size, sandpapers are available in different types based on the mineral used as the abrasive material. Aluminum oxide, silicon carbide, ceramics, and garnet are common types of abrasive minerals shows different types of sandpapers(Flexner 2005). Aluminum oxide is a relatively tough, very sharp, and blocky mineral and the most common abrasive used in woodworking. The highly desirable characteristic of aluminum oxide is its friability in which aluminum oxide fragments under the generated heat and pressure in sanding. Because of this unique characteristic cutting edges in aluminum oxide are renewed constantly and stay sharp for a long time (Purdy 2013, Flexner 2005) . Similar to aluminum oxide, silicon carbon is friable. However, it is such a hard material that sanding cannot fracture the cutting edges. Therefore, it becomes dull faster than aluminum oxide (Purdy 2013, Flexner 2005). Ceramics are the hardest of the abrasive papers. Similar to silicon carbon, they do not fracture to renew their cutting edge; however, they will not dull quickly because of their extreme toughness (Bryze 2006). Garnet is also blocky but it is not friable. It gets dull very quickly but it is very soft 4  and in comparison with other abrasive minerals with the same grit size, garnet produces a very smooth surface (Purdy 2013).  Figure 2: Various types of sandpapers  From left to right: garnet, aluminum oxide, silicon carbide, stearated silicon carbide, and stearated aluminum oxide Source: Flexner (2005) 1.2.2 Staining  Stain is applied after sanding is done and the desired surface is achieved. The main reasons for staining are to change the appearance of one specific type of wood to resemble another species, to create uniform color shades on wood surfaces, and to enhance the grain characteristics of wood (Hatchard 1995). Stains are  made of a colorant, either pigment or dye, suspended in a solvent which can be water, alcohol, petroleum, or an actual wood finish such as shellac, varnish, lacquer, etc. Using pigment in excess would obscure the wood surface appearance while dye is transparent. Ultraviolet sunlight will fade dyes whereas pigments are more resistant to fading. Pigments are capable of lodging themselves in scratches, pores and any wood surface defects causing them to be accentuated. Dye would saturate into wood fiber creating even appearance (Flexner 2005).  Figure 3 illustrates the difference between dye and pigment schematically. 5   Figure 3: The difference between dye and pigment  Source: Flexner (2005) The stain is applied to the wood by spraying it on the wood surface. Depending on the stain type, there are two ways to stain the wood. For thinner solvent base stains (spraying stain), a thin coat is sprayed and left to be air dried. The other way is to spray a heavy coat of wiping stain and to wipe the excess stain after a few minutes. Usually, dyes are grinded to form a very fine powder; they dissolve in solvent and then are sprayed on to the wood surface (Bryze 2006). Wiping stain can be produced either with pigments or dyes (Bryze 2006). 1.2.3 Finishing  The final step in finishing is to apply a topcoat on the stained wood to protect it from scratches, and weather. Shellac, lacquer, varnish, and polyurethane are different types of finishing agents that can be used for this purpose (Flexner 2005).  1.3 Factors impacting finishing performance  The factors that impact the finishing performance of wood include natural characteristics, type of wood product, and weather. Williams et al. (2000) has reviewed the factors that affect the finishing quality. These factors are as follows 1.3.1 Natural characteristics One important consideration in finishing is that wood surface stain absorption varies among different wood species and also within the same wood species. For instance, maple is known to be poor at absorbing stain (Ball 2013) since it is an extremely dense wood with uneven permeability. Maple has an uneven grain pattern which results in uneven absorption of stain (Minwax Company 2013). Here, the natural characters that affect the color consistency of stained wood are reviewed.   6  ? Growth rings Each year, tree species add one growth ring to their diameter. Growth rings are the combination of two growing seasons: earlywood (spring wood) and latewood (summer wood). At the beginning of growing season, wood cells have large open centers and cell walls are thin. This wood is called earlywood or spring wood. As it gets to the end of growing season, cell walls become thick and form the latewood. Hardwoods generate vessels (cells for transporting water and nutrients) throughout the growing season and might be divided into two major groups: diffuse-porous or ring-porous trees. In ring-porous hardwoods, vessels size formed at the beginning of the growing season (earlywood) are much larger than those formed at the end of season (latewood). In diffuse-porous trees, the size of vessels is not changing form earlywood stage to latewood stage. Softwoods do not have vessels and they may show no transition (in one season locations), gradual transition, or abrupt transition as the growing season progresses. The combination of earlywood- latewood determines the growth rings in trees and growth rings affect the finishing property of woods. Wood species can be divided into three groups in terms of their finishing properties.  (1)  Easy to finish : This group includes diffuse-porous hard woods, no transition and gradual transition soft woods.  (2) Moderately easy to finish: semi-ring porous hard wood and abrupt transition soft woods with narrow latewood bands fall into this group.  (3) Difficult to finish: ring porous hardwoods and abrupt transition soft woods with wide latewood bands are in this group. Wood paintability can be determined by considering growth rate, grain angles, and width of latewood bands and transition between them. In general, abrupt transition woods with rapid growth rate and wide latewood band are difficult to paint.  ? Density  7  Shrinkage and swelling is more when wood has a high density. When wood gain or loses moisture content as a result of changes in humidity the dimensional changes are excessive and may cause cracking or flaking. However, density is significant for exterior applications.  ? Moisture content  High moisture content results in poor finishing quality. When moisture content is more than 20% there is a high risk of peeling and blistering.  ? Extractives   Extractives give color to heartwood. Many of extractives are soluble in water and might be carried to wood surface when water is penetrated into to them. The extractives are then evaporated and a yellowish stains is left on wood surface. There are also water insoluble that can cause discoloration of paints and finishes. ? Manufacturing processes  The way that lumber is cut from the log impacts the lumber grain orientation. Vertical grained surfaces are easier to finish than flat-grained surfaces. Surface texture is also another impacting factor. For instance smooth-planed surfaces require less finishing than saw-textured surfaces.  1.3.2 Wood products and weathering Other than surface properties of wood, wood products and weathering are also important factors in finishing quality. Different wood products (e.g. lumber, wood plastic composites, particle boards, etc.) require different types of finishing. Also, wood surface consists of cellulose, hemicelluloses, lignin, and extractives. Each of these organic materials is affected by weathering conditions such as exposure to sun light and rain.  1.4 Wood cabinets in North America Table 2 includes the wood species that were used for cabinet manufacturing in Canada and United states in 2002. Cabinet doors are mainly manufactured from hardwoods. Oak, Maple, and 8  cherry make up 75% to 85% of the wood door market while softwoods make up less than 5% of cabinet doors (Fornitek Canada Corp., 2012). Table 2:  Wood cabinets used in North America   Source: Fornitek Canada Corp. (2012) Species Used in U.S.    Species Used in Canada  Oak 32% Oak 20.6% Maple 26.2% Maple 31.7% Cherry 14.9% Cherry 7% Birch 3.2% Yellow Birch 18.5% Ash 0.9% White Birch 4.0% Hickory 3.9% White Pine 5.0% Radiata Pine 3.4% Douglas-fir 3.6% Poplar 1.9%   Alder 6.7%   Douglas-fir 8.7%   1.5 Research objective  In this study, the impact of using various grit sizes of sandpapers and different types of stains, spray and wipe stains, on consistency and uniformity of color absorption is investigated. 9  2. Materials and methods 2.1. Sample preparation  In order to achieve the above mentioned objective, 20 samples of different wood species (Figure 4) including maple (Acer macrophyllum), cherry (Prunus virginiana), oak (Quercus garryana), hickory (Carya), red alder (Alnus rubra), beech (Fagus) as hardwood samples and white pine (Pinus albicaulis) as softwood species were collected from Kekuli Bay Cabinetry wood stock. Each workpeice, with dimensions of 305 mm ? 60 mm ? 12 mm, was cut off bars with using an optimizer cut saw (Figure 5a), ensuruing that all samples had the same size. Then, to smooth the surface the samples were sanded using a wide belt sander (Figure 5b). To increase the absorption/adhesion of wood surface for staining, final sanding is done using palm sander (Figure 5c).        Red Alder Beech Cherry Hickory Oak Maple White Pine Figure 4: Wood species used in this study    (a) (b) (c) Figure 5: Equipment used for sample preparation (a) Optimizer cut saw for cutting work pieces (b) Wide belt sander for smoothing the surface  (c) Palm sander for increasing the surface adhesion 10  2.2. Experiment  In palm sanding, each sample was sanded with a 120 grit aluminum oxide paper. For each individual species, 10 of the total 20 samples were stained using spray stain system and the rest were stained using wiping stain system. In both staining methods, an indeed table facilitated feeding the samples to a single arm oscillating spray machine Figure 6, the stain (Thyme 1111528 for spray and Mojave 1003683 for wiping stain) was sprayed over the wood using 4 automatic spray guns under an air pressure of 1100 kPa  for spray stain and 276 kPa for wiping stain. For both staining methods, the stain pressure was set to 100 kPa. An out-feed table guided the stained material out of the system. In spray stain method, the stains were air dried while in wiping stain system the excess stain was wiped off the sample surface using rag. After being fully dried (45 minutes), a lacquer finish (Danspeed 480-512 from Chemcraft) was applied to the stained wood using the same single arm oscillating spray machine. After 24 hours, the samples were scanned for visual inspection of color consistency. After scanning is done, stain was removed from the samples surface using a wide belt sander. The process was repeated with 150 and 180 grit (CAMI Standard or Coated Abrasive Manufacturers Institute) sandpapers.   Figure 6: Single arm oscillating spray machine  11  3. Experiment results   In this section, the results of the experiments which were conducted to observe the effect of sanding grit and different staining systems on color consistency of wood surface are explained for each individual wood species. Red alder is a moderately soft hardwood from Coastal Pacific with diffuse pores and has a fine texture.  This hardwood is extensively used in furniture manufacturing because of its stability, consistent color, and uniform acceptance of stains and finishes (Hoadley 1999). Visual inspection of all alder samples revealed that the color of the wood would be lighter when sandpaper grit size increased. This result is regardless of staining method, sparing or wiping. This is because higher grit sandpaper caused the surface of the wood to be glossier and smoother which reduces the acceptance of stain. For the spraying stain, different sandpaper grit sizes did not have any obvious effect on blotchy areas. Due to the good stain acceptance of the alder, surface color consistency did not changing significantly with sanding grit size.  In wiping stain method and within the same sandpaper grit size, the final wood color was darker and the blotchy areas were less than with the spraying stain. Figure 7 shows the results of visual inspection of color consistency for red alder wood.   12   Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 7: Comparing finishing results for red alder samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain The same results were obtained for beech samples except that with the wiping stain method blotchy areas were more common with the spraying stain method.  Beech is a pale colored medium to hard wood found in northeast U.S. as well as Canada. Similar to alder, beech has diffuse pores and takes stains moderately well but it has irregular patterned growth rings in variable sizes (Hoadley 1999) . When sandpapers with higher grit sizes were used the growth rings were more visible. The scanning results for beech samples are shown in Figure 8.  13   Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 8: Comparing finishing results for beech samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain Cherry is also a diffused-porous hardwood; it is moderately dense, strong, and fine-grained (Hoadley 1999). The results of visual inspection of cherry samples differed from those of alder and beech.  In spraying stain method, when sandpaper grit size increased from 120 to 150 a darker color was achieved and blotchy areas increased.  The lightest color was achieved when cherry samples were sanded with 180 grit sandpaper. Similar to alder and beech samples, stain acceptance in cherry surface was not uniform. Stain and color consistency changed significantly among various sanding grit sizes.  In wiping stain method, increases in sanding grit size reduced the depth of color and increased blotchy areas. This was similar to wiping staining results of alder and beech. Within the same grit size, wiping stain method produced a darker surface. Figure 9 shows the scanning results for cherry samples.  14   Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 9: Comparing finishing results for cherry samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain Hickory, well-known for its natural look, is an extremely hard, heavy, and strong hard wood with ring pores. One desirable characteristic of hickory is that it takes stains very easily (Hoadley 1999).  Through visual inspection of all spray stained hickory samples, it was evident that sanding the wood surface with 180 grit sandpaper caused the least stain absorption and as result the wood surface color was the lightest. The blotchy areas were largest when 150 grit sandpaper was used and were smallest when 120 grit sandpaper was used. The same results were observed with the wiping stain method. In comparison with spraying stain, the color depth of all prepared samples was less and the blotchy areas lowered with the wiping stain. Figure 10 illustrates the finishing results for hickory samples. 15   Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 10:  Comparing finishing results for hickory samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain Maple is also a diffuse-porous hardwood with evenly-sized pores. Consequently, the wood has a fine texture. Maple wood takes stain moderately well (Hoadley 1999). In spraying stain method, the color of the wood surface was lighter as the sandpaper grit size increased. Higher grit sandpaper caused the surface of the wood to be glossier; therefore, it reduced the wood surface acceptance of stain. Through visual inspection of all the Maple samples, it was evident that sanding wood surface with 180 grit caused less stain absorption and as result the wood surface color was lighter than that of finished with 120 grit.  On the other hand, different sandpaper grits did not have any obvious effect on blotchy areas.  In wiping stain method, color absorption of the wood surface was reduced as sandpaper grit size increased. Through visual inspection of all the Maple samples with wiping stain treatment, it is evident that wood surfaced with 180 grit sandpaper had less stain absorption, and was lighter compared to wood prepared with 120 grit sandpaper. Relative to spraying stain, the color depth 16  of all prepared samples were lower, but the blotchy areas were almost the same as samples finished with spraying stain (Figure 11). Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 11: Comparing finishing results for maple samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain Oak is the most commonly used wood species in Cabinet manufacturing industry. Oak is ring porous hardwood and has a coarse texture since it has prominent rings and large pores. Oak absorbs stains in any color readily (Hoadley 1999).  In spraying stain method, it is evident that sanding wood surface with 180 grit sandpaper caused less stain absorption and as a result the wood surface color was the lightest. Different grit sizes did not have any obvious effect on blotchy areas. In wiping stain method, color absorption of the wood surface was reduced as the sandpaper grit size increased. Unlike other species, the surface color in wiping was lighter that than obtained with the spraying stain within the same sanding grit size. Furthermore, blotchy areas were less evident than with the spraying stain (Figure 12).  17    Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 12: Comparing finishing results for oak samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain Pine is the only softwood studied in this work. It is excellent for staining, its milling is easy; but it lacks hardness and due to its grain pattern it is a poor choice for cabinet manufacturing  according to Hoadley (1999). For the spraying stain, color absorption was lower grit increased and different sandpaper grit sized did not have any obvious effect on blotchy areas. The color consistency did not change significantly among the different sanding grit sizes. For the wiping stain, stain absorption was less than with the spraying stain and overall the color was not as dark as spraying stain. It was observed that wood surfaced with 180 grit sandpaper had less stain absorption, and was lighter compared wood sanded with 120 grit sandpaper. Samples were darker and blotchy areas were less evident than with the spraying stain (Figure 13).   18    Unfinished sample 120 Grit sandpaper 150 Grit sandpaper 180 Grit sandpaper     (a)     (b) Figure 13: Comparing finishing results for pine samples using different sandpaper grits sizes (a) spraying stain (b) wiping stain 19   4. Discussion   As it was stated previously, wood species is an important factor in determining the finishing quality of wood. Hardwoods with diffuse pores are known to take stains easily. As it was expected, diffused-porous species studied in this paper including red alder, beech, cherry, and maple samples showed better color consistency and turned less blotchy than species with ring pores including hickory, maple, and oak. Among diffused-porous species, alder and cherry had more blotchy areas and among species with ring pores maple had the largest blotchy areas.  It was expected that the surface color would be lighter when higher grit sizes were used for sanding. This was true for all samples expect cherry samples. For cherry samples, the lightest color was when 150 grit sandpaper was used. No general trend was observed between grit size and blotchiness.  Staining method and blotchiness. However, wiping stain resulted in less blotchy areas than spraying stain for all the species. Furthermore, the samples were darker with the wiping stain than with spraying stain except for hickory samples.   Table 3 summarizes the results of the experiments in this study and recommends the best combination of grit size and staining method that can be used by Kekuli Bay Co. to achieve the best color consistency and the least blotchiness.  In the experiments carried out in this study, the pressure settings for staining were fixed for diffret wood speciese . This study can be extended to study the impact of different liquid and air pressure setting of staining on color consistency and blotchiness. Also, in all of the experiments, one type of spray stain or wiping stain was used. Changing the stain may impact the quality of finishing.  20    Table 3: Summary of obtained results from the experiments          Alder Beech Cherry Hickory Oak Maple Pine Best  color consistency Spraying stain- 120 Grit sandpaper Spraying stain- 180 Grit sandpaper Spraying stain- 120 Grit sandpaper wiping stain- 150 Grit sandpaper wiping stain- 180 Grit sandpaper Spraying stain- 120 Grit sandpaper Spraying stain- 150 Grit sandpaper Worst color consistency  wiping stain- 120 Grit sandpaper    wiping stain- 150 Grit sandpaper  Most blotchiness wiping stain- 120 Grit sandpaper  wiping stain- 120 Grit sandpaper  Spraying stain- 180 Grit sandpaper  wiping stain- 120 Grit sandpaper Least blotchiness    wiping stain- 150 Grit sandpaper     5. Conclusions In this study, the impact of using different finishing methods on the consistency of color of wood surface was investigated. For this purpose, hardwood samples including alder, beech, cherry, 21  hickory, maple, and oak and softwood samples including pine were sanded using different grits of sandpapers. Two staining methods were used to color the wood surface, spraying stain and wiping stain. Altogether, a total of 140 of samples were tested using different sanding grits me (3 different methods), different wood type (7 different types), and different staining methods (2 different methods). It was observed that for a given staining method, various wood species absorb stains differently, and a given wood species colors differently when different staining methods are used. In this study an experimental approach was used in order to evaluate the effects of different sanding and staining methods, and different species on the outcome of the finishing process.  In the experiments although surface preparation, sanding, and stain application are the same for all seven species but the end result differs in each species. Alder showed the best color consistency when the combination of 120 grit sandpaper and spraying stain were used. On the other hand, the worse blotchiness happened when the wood surface is prepared with 120 sandpaper grit and wiping stain is applied. For beech, the best color consistency was obtained when wiping stain was applied on sanded surface with 180 grit sandpaper. Cherry samples had the best color consistency with 120 girt in spraying stain while sanded surface with 150 grit sandpaper has the highest color absorption and blotchiness.  For hickory, through visual inspection 150 grit sandpaper with wiping will have the best result in terms of color consistency and less blotchyness. Maple?s best color consistency was gained when the surface was sanded with 120 grit sandpaper, and spray stained. Sanding with 180 grit sanding paper and spray staining achieved the best color consistency. And finally for pine samples the best color consistency was resulted when stain was sprayed on a surface sanded using 150 grit sandpaper.   22  2 References Ball, T.D. 2013, , Wood Staining. Available: http://sparetimeactivities.net/WoodStain.htm [2013, 03/22]. Bryze, R. 2006, The College of Wood Finishing Knowledge- A Guide to the Business of Finishing Wood, RonBryze.com, Illinois, United States. BUISSON, L. 2012, , Furniture industry. Available: http://www.thecanadianencyclopedia.com.ezproxy.library.ubc.ca/articles/furniture-industry [2012, 04/04]. Flexner, B. 2005, Understanding wood finishing, Rodale Press. Fornitek Canada Corp. 2012, , Wood Cabinets. Available: http://www.solutionsforwood.ca/_docs/reports/Cabinet_Sector.pdf [2012, 0/04]. Hatchard, D. 1995, Wood Finishing- Step by Step Techniques, 2nd edn, The Crowood Press Ltd, Wiltshire, United Kingdom. Hoadley, R.B. 1999, Identifying Wood- Accurate Results with simple tools, The Taunton Press, Connecticut, United states. HowStuffWorks, I. 2013, , What is the difference between the different grits of sandpaper?. Available: http://home.howstuffworks.com/difference-between-grits-sandpaper.htm [2013, 03/22]. Industry Canada 2012, , Canadian Industry Statistics. Available: http://www.ic.gc.ca.ezproxy.library.ubc.ca/cis-sic/cis-sic.nsf/IDE/cis-sic31-33tabe.html [2012, 04/04]. Minwax Company 2013, , Staining Interior Wood. Available: http://www.minwax.ca/wood-finishing-101/staining-interior-wood/ [2013, 03/22]. Momber, A.W. 2008, Blast cleaning technology, Springer. Purdy, S. 2013, , Knowing how it works is the first step in choosing the right abrasive. Available: http://www.jamarco.com/91b_Technical/sandpaper/Making%20Sense%20of%20Sandpaper%20-%20Page%204%20-%20Fine%20Woodworking.htm [2013, 03/22]. Williams, R.S., Jourdain, C., Daisey, G.I. & Springate, R.W. 2000, "Wood properties affecting finish service life", Journal of Coatings Technology, vol. 72, no. 902, pp. 35-42. 23  3 Appendix  This Appendix includes the scanning results for all samples.  Scanning results for Alder samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Alder samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Alder samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30  24  Scanning results for Alder samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Alder samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Alder samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20  25   Scanning results for Alder samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Alder samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Beech samples- Raw material           1 2 3 4 5 6 7 8 9 10 26   Scanning results for Beech samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Beech samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Beech samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 27   Scanning results for Beech samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Beech samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Beech samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 28   Scanning results for Beech samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Cherry samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Cherry samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 29   Scanning results for Cherry samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Cherry samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Cherry samples- Raw material           1 2 3 4 5 6 7 8 9 10 30   Scanning results for Cherry samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Cherry samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Cherry samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 31   Scanning results for Hickory samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Hickory samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Hickory samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 32   Scanning results for Hickory samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Hickory samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Hickory samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 33   Scanning results for Hickory samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Hickory samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Maple samples- Raw material           1 2 3 4 5 6 7 8 9 10 34   Scanning results for Maple samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Maple samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Maple samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 35   Scanning results for Maple samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Maple samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Maple samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 36   Scanning results for Maple samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Oak samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Oak samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 37   Scanning results for Oak samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Oak samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Oak samples- Raw material           1 2 3 4 5 6 7 8 9 10 38   Scanning results for Oak samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Oak samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Oak samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 39   Scanning results for Pine samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Pine samples- Spraying stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 Scanning results for Pine samples- Spraying stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 40   Scanning results for Pine samples- Spraying stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40 Scanning results for Pine samples- Raw material           1 2 3 4 5 6 7 8 9 10 Scanning results for Pine samples- wiping stain- 120 Grit sand paper           11 12 13 14 15 16 17 18 19 20 41   Scanning results for Pine samples- wiping stain- 150 Grit sand paper           21 22 23 24 25 26 27 28 29 30 Scanning results for Pine samples- wiping stain- 180 Grit sand paper           31 32 33 34 35 36 37 38 39 40    

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