Finishing and coating


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report of finishing and coating
-method of finishing and coating process

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Finishing and coating

  2. 2. TABLE OF CONTENT CONTENT PAGES TABLE OF CONTENT 2 ACKNOWLEDGEMENT 3 INTRODUCTION 4 OBJECTIVE 6 METHOD 7 Wood preparation 7 Finishing solvent preparation 7 Finishing application method 7 Sanding wood surface 9 Spraying sealer 9 Top coat application 10 Final product 10 CONCLUSION 11 REFERENCES 12 2
  3. 3. ACKNOWLEDGEMENT Praise to ALLAH the most merciful and the greatest; with permission finished the report on finishing and coating technology. First and foremost, I would like to express my sincere appreciation to my subject lecture Mrs Hafizah binti Rosman for guiding and encourage us in the subject. Thanks to our advisor Mr. Rosli who willingly supervise our final project, giving advice and knowledge. Thanks a lot for giving us the knowledge, sharing the experience and providing guide line finishing the final report. Also, for his willingness to teach the proceeding to finishing the product, using the machine and its function, also give hand in helping us, as without him the work does not run smoothly. A thousands thanks also to all the staff for helping us in conducting the machines and advice for us. Also for all classmate who gives to give the energy and full cooperation in making the project work smoothly. 3
  4. 4. INTRODUCTION Finishing/ Wood finishing The term ‘finish’, when used with reference to furniture or similar wood products. It is also refers to film forming coatings applied to the surface of the wood to protect it and to highlight its appearance. It is state as the process of protecting a wooden surface, especially in the production of furniture.(Richter, Feist, & Knaede, 1995)(Tichy, 1986) Finishing products can be grouped into manageable categories, based on general working qualities and the degrees of protection they offer: waxes, oils, varnishes, shellacs, lacquers and water-based finishes. Different finishes offer varying degrees of protection, durability, ease of application, repair ability and aesthetics. Unfortunately, no single finish excels in all of these categories; a finish that excels in one may fail in another.All wood finishes can be classified as one of two distinctly different types, based on how they dry, or cure. Evaporative finishes--such as lacquer, shellac and many water-based finishes; dry to a hard film as the solvents evaporate. (Water is not a solvent; it's a carrier for the finish emulsion.) These types of finishes will always dissolve in the solvent used to thin them, long after they've dried, so they tend to be less durable than reactive finishes. Most reactive finishes; such as linseed or Tung oil, catalysed lacquers and varnishes; also contain solvents that evaporate, but they cure by reacting with either air outside the can or a chemical placed in the can before application. These finishes undergo a chemical change as they cure, and after that they will not dissolve in the solvent originally used to thin them. Except for the pure oils, reactive finishes tend to hold up better to heat and chemicals. See Common finish products compared for a summary of how the finishes stack up against each other.(Jewitt, 2013) Wood Coating/ Surface coating All measures that are taken to ensure a long life of wood fall under the definition wood preservation. Apart from structural wood preservation measures, there are a number of different preservatives and processes that can extend the life of wood, timber, wood structures or engineered wood. 4
  5. 5. Surface coating covers a wide range of categories and emissions. Major surface coating operations include aerospace, auto refinishing, furniture finishing, metal can coating, and paper coating. Surface coating materials are primarily organic polymers dissolved in a solvent or suspended in an emulsion. The material may be applied to the product by brush or by spraying. (Rosman, 2013) 5
  6. 6. OBJECTIVES Lesson of finishing and coating technology In finishing and coating technology subject (FUR564) we have study about the uses, application, benefits and more about finishing. Finishing is the best way or action by the wood worker after done do their products. Besides, coating also ads on the product more clear on its surface and hide the defect of wood finish product. Objectives of the lesson - To learn the application method of finishing and coating. - To identify the best method suitable used for each type wood finishing. - To learn the use of finishing machine and tools such as spray and brush. - To apply the theory of finishing and coating technology to the real situation in workshop. - To differentiate each part of wood finish stages. Objectives of wood finishing and coating. - To keep dirt out of wood. - To prevent degrade of wood surface as result of abrasion and heat. - To produce visual and tactile qualities. - To bring colors into the wood. - To slow down the moisture exchange with air. 6
  7. 7. METHODOLOGY Wood preparation One of the most important steps in wood finishing is sanding. A thorough sanding is often what separates "acceptable" results from "professional looking" results. Start with a medium grade of sandpaper (e.g. #120) and gradually work your way to a finer grade (e.g. #220). Sand in the direction of the grain for a smooth, uniform finish and remove all sanding dust using a spray air gun or vacuum, dry paint brush or cloth. Look out for dried glue, especially in the joint area. If it's not thoroughly removed by sanding, it will interfere with the staining process. End-grains (areas where the wood has been cut against the grain), such as the front side of a table, tend to soak up more stain than surfaces cut with the grain. With additional sanding to end-grain areas, you can better control the absorption of stain. Finishing solvent preparation - Sealer preparation Thinner 100ml Hardener 100ml 7 AC lacquer 200ml
  8. 8. The ratio of the sealer solvent is 2:1:1; AC lacquer 200ml, thinner 100ml and hardener 100ml. AC Lacquer (Acid cured lacquer) is a synthetic, easy-to-use, high quality lacquer. It’s suitable for indoor wooden furniture. Hard film; good thickness and adhesion; good water, solvent resistance; no cracking, no blistering. (Thanh, 2011) Features of AC lacquer: * Colour: clear transparent or white * Good water, solvent resistance * Good adhesion, no blistering and no cracking * Fast dried paint film, easy-to-use * High solid content of paint film leads to good thickness and gloss * Good for all wood species and rich colours development as required. Finishing application method Finishing application by using spray gun. It can apply sealer as with any coating, with a brush, gun, or pad, but that's not always best. After one coat, end grain and spongy areas may still be insufficiently sealed, while denser flat grain areas are starting to build up too much coating. There's a way around that. Both more and less absorbent areas would be sated, but no excess finish would be piled up on top. While it is not always practical to submerge pieces in a vat of sealer, you can approximate that by flooding sealer on liberally by hand, then wiping it off. Also can use a nylon abrasive pad as an applicator, and then wipe off with paper shop towels while it is still wet. The advantage of this method is that it allows end grain to absorb as much sealer as it can, but wipes any extra off flat grain surfaces that tend to absorb less. Once the sealer is dry, the entire piece is uniformly sealed, and the next coat of finish will lay out the same in all areas.(Dresdner, 2008) 8
  9. 9. Sanding wood surface After the wood dry enough from the sealer stage the surface must be sanding smoothly. Sanding sealer is a specific material developed for the lacquer industry, but somehow the name has spread to things that should, by rights, simply be called sealer. After sanding stage the wood surface must be clean up by using the dry paint brush or clean towel. It is because to make sure the surface of the wood product clears from any dirt. Spraying sealer The AC lacquer once again must be applied to the product before the top coat has been applied on the surface. It is because is a clear or coloured wood finish that dries by solvent evaporation or a curing process that produces a hard, durable finish. This finish can be of any sheen level from ultra-matte to high gloss, and it can be further polished as required. It is also used for "lacquer paint", which typically is a paint that dries to a more than usually hard and smooth surface. 9
  10. 10. Top coat application A high quality medium solids clear acid catalysed lacquers for wood finishing based on non-yellowing resins. Clear finishing coat for solid and veneered timber. Easy application, fast drying and good levelling. Dries to a durable finish with good build.Used coat‐on‐ coat, this product provides a tough, mark resistant surface, very popular for kitchen furniture and home ware. Ideal for production lines in furniture factories. Recommended for spray booth application under solvent extraction conditions. Items are touching dry in about 20 minutes.(speccoats, 1997) Very light colour – ideal for pale timber. Pale colour of base allows bright colours. Available in a range from high gloss to matt. Excellent resistance to marring, scratches, alcohol and water spills. Formulated to resist yellowing in the dark or sunlight for applications where consistency of colour is very important. Final product 10
  11. 11. CONCLUSION Overall, the stages of the application method of finishing product face the failure but it still can be hide by using the finishing and coating. It is fact that, as wood worker we must excellent in hidden the natural defect of wood or artificial defect which is come during the production session. During wood preparation, we also face the failure of the wood we use, unknown species have been choosing from the waste. Most of wood choosing has their own defect such as knot and tiny hollow along the grain of the wood. Besides, the wood has been sanding to make sure it is clear from the dirt or rough surface. Finishing solvent preparation; the solution of the solvent mixture not accurate and it is not follow the standard that we must follow. But it is still can be used to do the finishing. The accurately of the finishing solution necessary follow because of the machine we use to apply the sealer is really sensitive to the viscosity of the solution. Finishing application method; we use spraying method which is can produce uniformly and evenly surface of the sealer at the product surface. Using the spray method has certain disadvantages of application it on the products. It is all about technical problem of machines (sprayer). And also the solvent of AC lacquer also cause of the gun face failure during spray on the product. The AC lacquer easily hardens to the spray and make it stuck during spraying session. It is may cause or effect the production time and also wasting the sealer solution. Sanding wood surface; other student roughly sanding the wood surface and its result that the sealer come out from the wood and need to redo the sealer stage. Sanding wood surface at this stage must be smoothly and use smooth surface of sanding paper. 11
  12. 12. REFERENCES Dresdner, M. (6 January, 2008). Wood workers journal. Retrieved Friday December, 2013, from Sealers and Pore Filler: Jewitt, J. (13 12, 2013). Fine Wood Working. Retrieved Friday December, 2013, from Fine Wood Working: Richter, K., Feist, W., & Knaede, M. (1995). The effect of surface roughness on the performance of finishes. Forest Products Journal, 91-97. Rosman, H. (2013). Component of surface coating. malaysia: uitm. speccoats. (1997). spec coats. Retrieved 14 December, 2013, from acid catalyzed lacquer: Thanh, B. (2011). Btchem. Retrieved Friday Decemer, 2013, from solvent based coating (AC lacquer): Tichy, R. (1986). Interior wood finishing: industrial use guide . Madison, Forest Products Journal, 57-60. 12