BLOG LINKS for WOOD and WOOD FINISHING

Post 582 by Gautam Shah

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These are few links on Wood and Wood Finishing processes and materials. Categories covered are:

● WOOD-TIMBER

● WOOD FINISHING

● WOOD COATINGS

● PAINTS-THINNERS

● COMPOSITES

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Sawn Timber > Wikipedia image by Kotivalo

 WOOD-TIMBER

WOOD RESOURCES Blog Post 217 Dt 14 Oct 2014

SOFTWOODS and HARDWOODS Blog Post 513 Dt 8 Sept 2015

WOOD COMPOSITES Blog Post 378 Dt 28 March 2015

ROSEWOOD Blog Post 376 Dt 26 March 2015

SOME VARIETIES of WOODS of Indian subcontinent Post 126 Dt 12 July 2015

WOOD-BASED PRODUCTS Blog Post 177 Dt 7 Sept 2014

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Finishing a kokeshi in Japan >Wikipedia image by Fg2

WOOD FINISHING

WOOD SURFACE FINISHING Blog Post 472 Dt 13 July 2015

WOOD FINISHES Blog Post 306 Dt 15 Jan 2015

WOOD FINISHES- Dt 22 July 2014

NATURAL OBJECTS and SELF FINISHES Dt 1 Aug 2014

SURFACE FINISHING PROCESSES Blog Post 504 Dt 24 Aug 2015

SURFACE LEVELLING Blog Post 291 Dt 31 Dec 2014

WHAT ONE CAN DO TO A MATERIAL ? Blog Post 334 Dt 12 Jan 2015

JOINTS in SURFACE FINISHES Blog Post 469 Dt 9 July 2015

640px-tobacco_smoker27s_box2c_japan2c_19th_century2c_black_lacquer2c_silver_and_gold_lacquer_on_wood2c_metal_-_c396stasiatiska_museet2c_stockholm_-_dsc09180

Japanese Lacquer ware in the Ostasiatiska museet, Stockholm, Sweden >Wikipedia image by Daderot

WOOD COATINGS

WOOD SURFACE PREPARATIONS for CLEAR COATINGS Dt 28 April 2014

CLEAR COATINGS Blog Post 182 Dt 12 Sept 2014

CLEAR COATINGS- Post 119 Dt 4 March 2015

SHELLAC or LAC COATINGS Dt 26 April 2014

UNDERSTANDING LACQUERS Blog Post 498 Dt 16 Aug 2015

LACQUERS or NC LACQUERS Blog Post Dt 27 April 2014

VARNISH Dt 25 April 2014

COATINGS as thin Surfacing Blog Post 482 Dt 25 July 2015

CLEAR versus PIGMENTED COATINGS Blog Post 553 Dt 29 Nov 2015

PRIMER COATINGS Blog Post 442 Dt 7 June 2015

APPLICATION of COATINGS Blog Post 300 Dt 9 Jan 2015

COATINGS -surface finishing technologies Blog Post 238 Dt 8 Nov 2014

FILM FORMING PROCESS in COATINGS Blog Post 173 Dt 3 Sept 2014

SINGLE or MULTI-COAT SYSTEMS Blog Post 437 Dt 30 May 2015

METAL COATINGS Blog Post 438 Dt 1 June 2015

GILDING Blog Post 471 Dt 13 July 2015

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Exterior Maple Wood deck staining Flickr image by Olger Fallas

PAINTS-THINNERS

SOLVENTS and THINNERS for coatings Blog Post 320 Dt 29 Jan 2015

PAINT THINNERS – 1 Blog Post 416 Dt 8 May 2015

PAINT THINNERS – Part 2 Blog Post 423 Dt 30 March 2015

SOLVENTS for THINNERS Blog Post 492 Dt 9 Aug 2015

OSB-Platte

Wood chips composite board > Wikipedia image by C. Sander and durch Urheber

 COMPOSITES

FILLERS and COMPOSITES Blog Post 169 Dt 30 Aug 2014

COMPOSITES – Part 1 Blog Post 156 Dt 17 Aug 2014

INTERFACE OF MATRIX AND FILLER in COMPOSITES Blog Post 180 Dt 10 Sept 2014

MATRIX of COMPOSITES Blog Post 168 Dt 29 Aug 2014

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Glue laminated Large span wood beam at Richmond Olympic Oval, > Wikipedia image by Thelastminute (Duncan Rawlinson)

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WOOD COMPOSITES

WOOD COMPOSITES

Post 378 ⇒   by Gautam Shah 

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Woods derived from trees and large-trunk plants, consist of timbers, twigs and barks. Woods also include forest-based products, crop wastes, and plant materials like grasses and fibres. Woods have been used for the timbers, for animal feed, as manure and fuel. Many of the wood products have wood in the original form and character, in the re-composed, or derivative form. Wood processing technologies, offer several wood-based products to enhance the peculiar characteristics, overcome the qualitative and sensorial deficiencies, offer new uses, add economic value or ecologically sustain the natural materials.

Wood waste of turnings

Woods are used for constructing geometric or structural compositions, used as filler for forming composites and form the raw materials for many industrial goods. Timbers’ wastes such as very thin or small cuts, chips, shavings, turnings, dust, shavings are used as filler in composites. Leaves are used for manure making or composting. Stems and soft branches yield fiber used for yarn and rope making. Long leaves such as of palms are used for mat weaving, basket making and brooms. Barks and other useless components are compressed and extruded as fuel bricks. Wood derivatives such as its cellulosic matters go through various levels of pulp conversion, and used for boards and casts.

Rice chaffs or husks for particle board making

Wood composites have wood as the filler component. The fillers in the form of could be, Large solids (such as blocks in block-boards), Particulate matter (such as chips, shavings, turning, sanding dusts, farm husks, etc. in particle boards), Sheets (such as for Veneers and plywoods in layered composites), Fibrous materials (for in-fill and reinforcement material in cement and gypsum boards).

Wood and plant products with cellulose as the chief constituents are pulped to produce different grades of materials. This could be soft boards, Hard boards, High, medium and low density (HDF, MDF, etc.) fibre boards. At higher pulping level and with addition of rags it could turn into grey boards, card-boards and paper.

Wood particulate with cement

All wood composites, except the refined cellulosic or pulped formations, require a matrix for bonding of the fillers. The simplest of bonding is mechanical tying. It binds the materials only at selected points, so the filler materials need to have sufficient mass and strength to distribute the stresses. Chemical or glue bonding is the most common method for holding the components. Bonding materials such as adhesives, resins or cementious products are water or solvent based. Polymeric materials are thermosetting or thermoplastic materials and may need heat.

Plywood -a layered composite

Veneer is a thin (as low as 0.6 to 0.8 mm) sheet of wood with uniform thickness, produced by peeling or rotary cut (by rotating a log against a knife), slicing, or by sawing a wood. All parts of a tree such as trunks, round, square or rectangular cut logs, and subterranean part of a trunk with root nodes, and heavier branches, are used for veneer cutting. More than 90 percent of all veneer is rotary cut, but thicker figured wood veneer for furniture and other decorative purposes are sliced. Sawn veneer was considered a wasteful operation, but modern sawing equipments can saw a wood into very thin sections with very little material turning into dust. Some veneer waste is stacked, composed and recut again as veneer. Plywoods are also one form of thick veneers. Veneers form a layered composite. Plywoods are re-composed to form large-span wood beams (20mts) for exhibition halls, malls and departmental stores. These beams are lighter in density and have greater fire-exit time (catching fire and distortion of the structure), compared to a steel beam.

Wood composite beam

Composite wood Bridge

Block boards and Cored plywoods are composite materials with a filler core. Batten or block board and flush doors have a solid or partly filled core of strips of solid woods, which may or may not be glued together. These however, are covered on both sides with sheets of plywood or other composite boards.

Chip boards are entirely made of chips, and other cutting-dressing wastes bonded with an amine resin. Particle boards have particulate matter or agri husks, etc. as the filler, bonded with a resin matrix.

Wood waste or Chip board

Composite boards have a core of polymer latex, styrene or PU foam, encased on both sides with plywoods or other sheets.

Foam cored boards

MDF, HDF, LDF, Soft and Hard-boards are not wood composites, but wood pulp-based products. Mechanical or semi chemical processes are used for pulp preparation. In one process wood or wood waste is reduced to fine size and subjected to a high pressure steam treatment and forced out through a valve to reduce the mass to pulp. In wet felting pulp is cast into sheet form of various thickness, and density is controlled by the pressure. In dry felting process, the pulp is drained, separated and additives are mixed. Additives include glues (1 to 4%), waxes, paraffin, rosin, polymers, colourants, chemicals to improve the resistance to microbes, insects, and fire. Dry felted fiberboard with thermoplastic resin bonding materials are available in low, medium, and high densities. These are extensively used for Panellings and also as a core material for various composites.

Particle board

Hardboard is dry felted Fiberboard with one or both sides finished smooth, available in various densities. The fibres are hot pressed, to form a board bonded by lignin, with small addition of binding agent. Hard boards are available from 3 mm to 12 mm thickness. Tempered Hard boards have one or both face impregnated or coated with a resin to provide better stiffness, wearability and moisture resistance. Hard boards are generally dark in colour due to the use of phenolic bonding media. MDF is fiberboard but with a greater amount of binding agent, almost comparable to a particle board.

Soft-board is very similar to hardboard, with the mass being less cohesive due to the wet felting process. These boards are used for insulation, sound proofing and as tack or pinup boards. Soft-boards with bitumen impregnation were produced for slightly better weather resistance.

Polymer + wood composite board

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