#Painters North Shore – Roller Application
Jan 13, 2015 Author Sydney Painters; bloomin
Rollers come in a range of sizes, a range of nap (fabric) lengths, ‘and fabric types, generically synthetic or wool. The size, (width), of roller is usually dictated by the area to be painted. The type of nap is usually dictated by the substrate –
• long nap for rough substrates
• short nap for smooth substrates
“Long nap” roller covers will give a heavy textured (orange peel) appearance when used to apply paint to a smooth surface. A typical substrate for “long nap” covers would be bricks, cement blocks, texture coatings, i.e. rough substrates.
“Short nap” roller covers will give a light feint, orange peel appearance when used to apply paint to a smooth surface. A typical substrate for short nap roller covers would be metal cladding, dressed timber, plasterboard, Le. smooth substrates.
Spray painting can be defined as the ability to convert a liquid mass into an atomised spray. This process may be achieved in various ways, the most common being –
• air atomised spray (conventional spray)
• airless spray
Conventional Spray Painting
Air atomised spray is achieved by mixing fluid and air. This is termed “conventional spray painting“. Fluid is sucked into a nozzle mixed with compressed air to form an atomised spray.
Conventional spray painting can be a slow method of application and can develop considerable overspray unless professional, specialised equipment is used, e.g. Pressure Pots, or HV.L.P., (High Volume Low Pressure), and a reasonably high level of applicator skill is achieved.
Conventional spray painting is generally employed to apply Gloss Enamels and Two-pack
Airless Spray application:
Airless spray is achieved by pressurising fluid and releasing it through a small orifice in order to produce an atomised spray. A simple type of airless spray is the common garden hose. Although the principle of airless spraying is constant, the mechanics are a little different. Paint is deposited into a high-pressure chamber, generally by suction, through a nonreturn intake valve, where’ it is pressurised. It progresses from the high pressure chamber, through a non-return valve, into’ the spray line to the gun, where it is released through a spray tip by an opening and closing needle and seat, which is activated by a trigger. The spray tip orifice is tungsten carbide steel, which develops the spray. pattern and controls the amount of paint released. The most commonly used spray tip is a 415 or 417. This is interpreted as an 8″ fan (double the first digit to give fan width – when gun is 300ml from surface) and a 15 thou” or 17 thou” orifice. Prior to commencing spray painting the following items should be checked:
• Filters, to ensure they are clean and not damaged, (e.g. displaying holes), or worn
• All hoses and fittings, to ensure they are rated “high pressure fittings”, and have no kinks or twists.
• Spray unit should be turned on to check that spray pattern increases pressure until no lines, (“tails”), appear in the fan pattern. Excessive pressure will produce a heavy build of paint, excessive overspray,bounce-back and a less than quality finish.
• Adjacent surfaces should be protected by masking up and covering.
Painters Castle Hill , Painters Central Coast
For more information about any Painting and Decorating tasks please Call Bloomin’Good Sydney Painters on 1800 204 145.