SURFACE MODIFICATIONS

Post 647 -by Gautam Shah

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Natural and Industrially-produced materials require some form of surface modifications or treatments, before being put to functional use, or for readying them for the next process. Surface modification at a basic stage, consist of cleaning and mechanical scrubbing. The surface modifications are for creating use-worthiness by levelling, texturizing, or for application of additional materials for shielding. The surface modification starts with visual observation and touch-feel experience that no foreign materials have remained on the surface, and all loose (removable) materials are removed. These simple processes ensure integrity of the surface.

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The next level of surface modifications are applications like coating, physical-chemical treatments, cladding, mounting, plating, joining, welding, levelling, cleaning, washing, ph balancing, static removal, etc. Surface modifications are intently surface preparation processes and may impart radically different surface qualities such as textures, ionization, etc.

640px-Strasjo_kapell_wood_surfaceAt another level Surfaces Modifications are not attempted, but such situations are negotiated with technologies. These include defining means to override the hindrances of texture, handling issues, electrical and other properties. These technologies also include forming shields around the users, tools and other equipments rather then over objects. The shields are physical layers and non-physical arrangements like restricting the exposure through time-space management.

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In early ages, the surface modification and applications were an integrated process for exploiting the surface of any object. Primitive arts and crafts had a comprehensive treatment that consisted of 1: Modification of the surface, 2: Application of surface forming materials, and 3: Rendering new textures and tonal variations or shades. At a later stage an additional treatments for protection of the new surface were devised.

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Surface modifications are physical, chemical and mechanical processes.

The Physical processes are mainly used to remove unwanted particles or materials (such as rust, nodules, residual deposits, dust or grease, lubricants, cutting-oils, etc.) adhering to the surface. Rubbing, air-dusting, vacuum cleaning, wiping, water-bathing, etc. remove such adhered materials. The particles have remained on the surface due to the holding by surface texture, bonding or ion attraction, and horizontal storage. Washing with soap or a surface active agent (surfactant) can weaken the ion attraction break the weak molecular bond generate by-products that can be removed easily.

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The Chemical processes include acid-alkali treatments and solvent washing. The processes roughen, etch or smoothen the surface. In many instances the resultant by-product is beneficial or neutral, and so allowed to remain on the surface. In other instances a secondary treatment is required just to remove the by-products of the first treatment. Sometimes Surface preparation agents themselves are the primary surface finishes. Such agents cover the surface area as an intermediary film. Such films help in bonding of the final surface finish. Chemical processes also include burnishing, flame-treatments, surface annealing and hardening, cathodic modification, sputtering and material’s depositions.640px-A_brass_utensilTakhat_Niwas_Hall_Interiors_in_Gold_embossing_1

The Mechanical Processes affect the surface superficially. Cleaning of the surface by removal processes include abrading, grinding, rubbing, blasting, planning, chipping, etc. Other mechanical processes alter the surface with newer textures by engraving, patterning, planning, surface deformation, etc.

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Surface modifications processes have been used for body painting, pottery, home building, agriculture, mural or wall artwork, adornments, jewellery, ornamentation, household utilities, tools, musical instruments, etc. Surface modifications were explored pattern making, texture creation, personalization, cultural expression, totem, abstract or symbolic representation etc.

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Surface levelling is achieved by scrubbing or rubbing off the impurities, removing select protruding sections, or by skinning the entire surface area. In later cases there are chances of removing a seasoned or matured face and exposing a fresh one. Partial scrapping of the surface creates qualitatively unequal zones. This is the reason why over the ages levelling ‘plasters’ have been preferred. The ‘plasters’ can be thin coating, or an application of thicker mass. These were often rendered with patterns and textures or ‘loaded’ with minerals and colourants. Wet surfaces were, either, engraved or embossed with patterns to encourage the penetration of colours, to produce a bas or relief effect, or provide a highlighting boundary to the drawn object. Colours were blown as dry powders or applied as pastes and dabbed (pressed) into the wet plaster.

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Gesso, a mixture of plaster of Paris (or gypsum) with size, is the traditional ground. The first layer is of gesso -grosso, a mixture of coarse, un-slaked plaster and size. This provides a rough, absorbent surface for ten or more thin coats of gesso sotile, a smooth mixture of size and fine plaster previously slaked in water to retard drying. This labourious preparation, however, results in an opaque, brilliant white, light-reflecting surface, similar in texture to hard, flat icing sugar.

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BRUSHES

Post 379 – by Gautam Shah

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A brush is a very common tool since ancient times. It is used for scrubbing and spreading, besides many other purposes. It has bristles held in a holder at the end of a handle, or bristles are held together through a tie. Brushes are hand tools at home, for crafts and for industrial processes. Brushes are attachments and also integral parts of the machines. Brushes wipe, polish, texturize and grind the surfaces, spread liquids and powders.

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Make up brushes

The first brush for painting on cave walls, were formed of twigs, crushed under teeth. Other primitive age brushes were used for sweeping the grounds, made by holding together twigs. The art brush and the sweeping broom, both have flourished across ages, taking on many different forms. Art brushes have had bristles of animal hair and now synthetic filaments. Art brushes have different shapes, thicknesses and sizes. It depends on nature of medium (oil, water-based or acrylic colours), and forms (fine hairiness, heavier marked strokes, or merging washes). The broom has been used to sweep dry and wet areas, heavy items to floor dust, for scrubbing hard stains, for levelling the grounds, cleaning chimney stacks, for separating chaffs from grains and for mud daubing on walls and screeds on the floors.

Street Cleaning Woman Silhouette Sweeping Broom

Hyderabad street cleaning

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Brushes were used for personal grooming since prehistoric times. These were used for making up live humans, decorating dead humans and animal for ritual burials, and for imprinting identity marks on domesticated animals. Animal hair or plant fibres in the form of brushes and in entangled form as scrub (of sea weeds) were used for finishing ‘green’ pottery. Similarly clay and cow-dung floors were patterned with twig brushes. Brushes formed of bird feathers have been used in magic and other rituals.

Water pot scrubber brush

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Chinese and Japanese art and calligraphy began as art of brush strokes or reed points. The expression through the stokes was of weight (intensity of hues), width (angle of the brush or point) and the added wash effects. The brush stroke became an expression in European art from 17th C. The brush was used to apply heavily bodied and intensively hued colours (both options that began to be available then).

A highly decorative badger hair brush dating to Ming Dynasty, featuring dragons inlaid with gold and silver foil.

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To the exclusive art brushes that were formed in 17 and 18th C, Three new varieties emerged. These were water colours brushes, household or architectural oil painting brushes and brushes for very fine quality miniature and graphics work. Water colour brushes required very fine hair so that no marks of strokes were left, and it must hold water thin viscosity medium. Architectural oil paints were applied on wood, masonry and occasionally on metals. Of these surfaces, the masonry was very robust surface, requiring tough bristles. Masonry brush bristles were required to hold the medium within their body without dripping. The work surfaces were extensive so the sizes were very wide. Miniature paintings over mica, leather, bone and teeth materials were already in vogue, but improvements in paint mediums, required finer brushes, often of just few hairs.

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ink brushes

Artist Studio: James Cospito / Dumbo Arts Center: Art Under the

Brushes for cleaning

During late 18th C many new industrial materials and processes were innovated. These required finishing techniques beyond nominal grinding and polishing. New bristles such as harder organic materials like coconut husks, coir, palm leaf bristles, jute, etc. were formed into brushes that could rotate as a wheel, or as continuous looped belting. Surface hardened wires of steel and alloys were also used. These were abrading and polishing brushes, offering better finishes then files and grinders.

Bench grinder wire bristles

Brushed aluminum

Industrial abrasive brushes are used for deburring, burnishing, metal finishing, cleaning of rust, grinding wood panels, and removing nibs from the moulded or extruded plastics. Modern polymer bristles have embedded grinding medial particles to help scrubbing or etching of the surface. Mechanically made strokes, surface textures, engravings, polishing, grinding, etchings, scrapping, etc. often involve tools or methods that are similar to brushing.

Paint application with brush wastes minimum colour compare to other methods. Natural or synthetic bristle brushes are suitable for use with solvent-based coatings. Synthetic bristle brushes are preferred with water-based coatings, because natural bristles tend to swell in water.

Brushes are used for sweeping the floors as in sports, or to play drums. Dental brushes have changed in form and function.

The skip of Team Sweden joins the front end in sweeping a stone into the house at the 2010 Winter Olympic Games in Vancouver

drum brushes

Dental brushes

Brushes are used to clean-up eraser dust of the paper, or draw coloured highlighting lines. Brushes are used for grooming up dogs, clean up fabrics like wool or refresh the suede texture of leathers and fabrics.

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WOOD FINISHES

Post 306 –by Gautam Shah

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Woods are fashioned to a variety of finishes such as bark stripped, chopped, rough hewn, sawn, planned, sanded, etc. Timbers gain variety of finishes due to planned seasoning, ageing and exposures. Such finishes are valued for certain uses and so re-formed on fresh timbers, or old surfaces are restored-altered for specific effects.Timbers offer surface quality that is end of the grains, and faces towards and away from the core.

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Finishes for wood depend on several factors.

Primarily a wood finish depends on its proposed use as a product or composite. The product defines its sensorial and engineering properties. The product also determines, the technology used for sizing and then finishing. The wood for a product is checked, if it is sap inclusive or heart exclusive, type of wood – soft or hard, type of cut – quarter, rift, tangential or slab, etc.

Wood Router

Quality of wood (jungle -often called firewood, commercial or special timbers, etc.) and form of the product requires very specific method and material of applique finishing. The applied finishes are affected by the nature of wood (soft or hard), level of moisture content, direction grain, presence of gum-resins (aliphatic compounds, waxy and resinous substances), and colour. Overt finishes must take care of grain filling, colour correction (by staining-bleaching), and rectification of anatomical anomalies such as straight or cross grain, knots, shakes, pith, etc.

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Wood sizing, product shaping and finishing, all are affected by the atmospheric conditions (temperature, moisture, wind, dust). Wood finishing technology is product dependent, which in turn is considered in terms of its economic viability. The time and effort involved in finishing a wood product must match its economic, aesthetic and functional requirements. A low quality wood, a low-cost product, or an engineering-structural item whose sensorial qualities are less relevant must receive appropriate treatment.

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Wood products where feel or texture also necessitates visually appealing finish. This process starts with selection wood, grain pattern and its orientation, finishing technique and the coating. In case of restoration and conservation of wood structures and other utilitarian items, one must check the age of wood, decaying agents, presence of moisture, surface contaminants like dust, soot, oil-grease, residues of earlier finishes, burns and marks of singeing, sunken grains, etc. Other important cares include tools and techniques used for surface correction must not physically scrape the surface, chemically affect the surface or leave a residual product. Care is also required that all processes must be reversible (in future if it is realized that this are damaging).

Wood conservation-preservation

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SURFACE PREPARATIONS

Post 196 – by Gautam Shah

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Rif;ing firearms refers to helical groovings into the barrel of a gun for the purpose of exerting torque and imparting a spin to a projectile

Natural and Industrially-produced materials require some degree of surface preparations or treatments before being put to functional use or for readying it for the next process. The next processes could be surface application like coating, cladding, mounting, plating, joining, welding, levelling, cleaning, washing, ph balancing, static removal, etc. Surface preparation could involve processes that induce new surface qualities such as textures, ionization, etc.

Card_scraper_-_making_violinThe surface preparation at simplest level could be checking and assuring, mainly through visual observation and touch-feel that no foreign materials have remained on the surface, and all loose (removable) materials are detached. These simple processes ensure integrity of the surface.

Record Player Music Record Vinyl Turntable Needle

Surface preparation is required for material objects with their own natural or process-formed surfaces. It is also necessary for further processing of material objects and application of surface finish systems.

640px-Takhat_Niwas_Hall_Interiors_in_Gold_embossing_1

Surface preparations are physical, chemical and mechanical processes.

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  • Physical processes are used to remove unwanted particles or materials (such as rust, nodules, residual deposits, dust or grease, lubricants, cutting-oils, etc.) adhering to the surface. Rubbing, air-dusting, vacuum cleaning, wiping, water-bathing, etc. remove such adhered materials. The particles have remained on the surface due to the holding by surface texture, bonding or ion attraction, and horizontal storage. Washing with soap or a surface active agent (surfactant) can weaken the ion attraction break the weak molecular bond generate by-products that can be removed easily.

Hot-dip galvanizing on a steel handrail.

  • Chemical processes include acid-alkali treatments and solvent washing. The processes roughen, etch or smoothen the surface. In many instances the resultant by-product is beneficial or neutral, so allowed to remain on the surface. In other instances a secondary treatment is required just to remove the by-products of the first treatment. Sometimes Surface preparation agents themselves are the primary surface finishes. Such agents cover the surface area as an intermediary film. Such films help in bonding of the final surface finish. Chemical processes also include burnishing, flame-treatments, surface annealing and hardening, cathodic modification, sputtering and material’s depositions.

bookcase-books-bookshelf-267554(1)

  • Mechanical Processes affect the surface superficially. Cleaning the surface by removal processes include abrading, grinding, rubbing, blasting, planning, chipping, etc. There are several surface preparation processes that instead of removing materials, only alter the surface with newer textures by engraving, patterning, surface deformation, etc.

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  • New application of surfaces is made to level or create textured surfaces. Some such processes are integral to art-painting methods. The levelling plasters are made with plastic soils (such as used in pottery), and various qualities of lime or chalk materials. In many instances the powdered mineral and colourants are `loaded’ on a freshly coated `wet’ surface. Colours are also blown as dry powders or applied as pastes and dabbed (pressed) into the wet plaster. Such wet coloured plaster surfaces are then engraved or embossed with textures to facilitate the penetration of colours. Similar techniques are used to produce a bass or relief effects, or provide a highlighting boundary to the drawn object.

Major and Knapp Engraving Co. Park Place, N.Y. Abstract medium print lithograph, tinted

  • Gesso, a mixture of plaster of Paris (or gypsum) with size, is the traditional ground. The first layer is of gesso grosso, a mixture of coarse, un-slaked plaster and size. This provides a rough, absorbent surface for ten or more thin coats of gesso sotile, a smooth mixture of size and fine plaster previously slaked in water to retard drying. This labourious preparation results, however, in an opaque, brilliant white, light-reflecting surface, similar in texture to hard, flat icing sugar.

 

 

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