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Finishing Plasters section 2 BESTWALL LIGHT ACOUSTICAL PLASTER This is a mill mixed acoustical plaster which is particularly suited to plaster machine application. It has a sound absorption coefficient of .55 to .60 and will neither bum nor support combustion. Light Acoustical Plaster produces a natural offwhite finish which reflects from 66.8% to 68.9% of the light reaching its surface. This finish may be painted or left undecorated as desired. Bestwall Light Acoustical Plaster should be mixed with clean water only. It is designed to be applied by machine, but may also be applied by hand over gypsum basecoat plaster, monolithic concrete and other surfaces which are firm, clean and free of efflorescence or water soluble sub stances. When applied over low suction bases, it should be applied in three applications, the first layer furnishing suction for subsequent coats. Bestwall Light Acoustical Plaster is packaged in 40 lb., 3 ply, multiwall, natural kraft paper bags. BESTWALL KAUTE ACOUSTICAL PIASTER This is a highly porous plaster with myriad interconnecting air spaces that absorb sound waves instead of reflecting them as do hard, dense sur faces such as wood, glass or ordinarv plaster. When applied to walls and ceilings. Kalite Acoustical Plaster has a noise reduction coefficient of .55 for Vi" thickness and .60 for ^4" thickness. It is ap plied over a gypsum plaster basecoat with ordinary plastering methods. It cannot be applied bv ma chine since this destroys the bubble structure which produces its acoustical properties. Onlv water is added until the required plastering consistency is obtained. Kalite Plaster is fireproof, permanent, and will not lose its sound absorbing qualities. However, it should not be applied where excessive moisture is present. The plaster can be molded to conform with any decorative design. Kalite Plaster has a strong, hard finish and can be cleaned easilv by brushing or vacuuming. It can even be painted with non-bridging paints, without any loss of its acoustical qualities. It is available in two stock colors. Buff and Natural Grav. Bestwall Kalite Acoustical Plaster is packaged in 80 lb.. 2 ply. multiwall, natural kraft paper bags. SGP 0003998 plastering terms ACCELERATOR--Any material added to gypsum plaster which speeds up the setting action. ACOUSTICAL PLASTER--A finishing plaster de signed to correct sound reverberation, or reduce noise intensity. AGGREGATE--Inert material, used as a filler for mixing with any cementing material. The word used with or in connection with plastering usually means sand, perlite, pumice or vermiculite. ARCH--Curved top of opening. Structurally de signed to carry the overhead load to the side members. ARRIS--A sharp edge, forming an external corner at the junction of two surfaces. BASECOAT--The plaster coat or combination of coats applied previous to the finish coat. BED MOULD OR BED--A flat area in a cornice, designed to have enrichments planted later. BLISTERS--Protuberances on the finish coat of plaster caused by application over too damp a base coat, or troweling too soon. BOSS--A Cothic ornament planted at the inter section of mouldings. BRACKET--A superficial structure, usually in an gles forming a frame to support lath. Its main purpose is to save material and weight in orna ments or cornice. BREAK--An interruption in the condnuity of a plastered wall or cornice BROWN COAT--Second coat ol base plaster di rectly beneath the finish coat. In three-coat work the brown coat refers to the coat applied over a scratch coat (first coat). Brown coats are applied with a fairly rough surface to receive the finish coat. In two-coat work the brown and scratch coats are applied in double up method so that brown coat is applied over "scratch" before the scratch coat has set. BUCKLES--Raised or ruptured spots which eventu ally crack, exposing the lath beneath. Most com mon cause for buckling is application of plaster over dry', broken or incorrectly applied wood lath. BULL NOSE--This term describes an external angle which is rounded in order to eliminate a sharp comer. Used largely at window returns and door frames. Advantages are ease of cleaning and its durability. Can be made by running with plaster or obtaining a bull nose comer bead with the proper radius. SGP 0003999 17 Bestwall Bestwall Bestwall Bestwall Bestwall Bestwall Gypsum Plaster Ute-Mix Plaster Satin Spar Gauging Plaster Sunflower Molding Plaster Common Gauging Plaster Kalite Acoustical Plaster Bestwall Bestwall Bestwall Bestwall Bestwall Bestwall Light Acoustical Plaster Keene's Cement Builder's Lime Smooth Finish Lime Speedy Lime Mason's Lime and other gypsum products Bestwall Bestwall Bestwall Bestwall Bestwall Bestwall Metro-Mix Gypsum Form Board Gypsteel Plank Gypsum Lath Gypsum Sheathing Olsen Clips 720 EAST LANCASTER AVENUE e ARDMORE. PENNSYLVANIA SGP 0004000 LIGHTB IS T W A L L ACOUSTICAL PLASTER is an ideal sound conditioner for new work or refinishing ceilings in commercial, institutional or industrial buildings. Restaurants, offices, churches, schools, auditoriums, hospitals and homes can use Bestwall L ig h t Acoustical Plaster for sound conditioning. *U|`0;NG LIGHT ACOUSTICAL PLASTER Bestwall Gypsum Company provides you with "top quality gypsum products through creative research." Bestwall Light Acoustical Plaster is no exception, it is tested and re-tested constantly in the Bestwall Gypsum Company laboratory to assure you of the highest quality product always. Made By: Bestwall Gypsum Company | Sold Through: Bestwall Certain-teed Sales Corporation 120 East Lancaster Avenue 1 Ardmore, Pennsylvania Form No. BW-58121 -REP 10M-9-58-H Printed in U.S.A. SOUND REDUCTION LIGHT REFLECTION COLOR GUN APPLICATION LOW COST EASY TEXTURE 1VDIW0N093 dOOdd3dld %00 L NOIlVDIlddV 3NIHDVW dOd 1V30I 031VdOD3a AHSV3 AllAllD31d3d 1H9I1 0009 lN3Dldd30D NOIlDflOSd 3SION H9IH jajsDjd |DD!jsno:>v ||DMIS39 j ssSdjudapv *ns**o I SGP 0004001 Question 1 How effective is Bestwall Light Acoustical Plaster for noise re duction? 25 r~w< B''SP'ii!! L-icjht Acoustical Plaster reflect light as well sound? 3 Does Bestwall Light Acoustical Plaster protect against fire as well as sound? Can Bestwall Light Acoustical Plaster he applied bv plaster gun? 5 Is Bestwall Light Acoustical Plaster expensive? Can Bestwad Light Acoustical Plaster he decorated casilv? Answer --Bestwall Light Acoustical Plaster has a noise reduction coefficient of from .55 to .60. Ordinary hard wall and ceiling surfaces reflects about 97% of the noise reaching it and bounces it back and forth in a room. This reflection creates air dis turbances and echoes in a room. This reflection of sound waves from hard wall surfaces is known as "reverberation" and is one of the main causes of sound dis tortion and unsatisfactory acoustics. Bestwall Light Acoustical Plaster ab sorbs about 50r'c of the original sound and soaks up reverberations and echoes fast enough so that sounds produced within a room are not garbled or con fused, but clear and audible for perfect sound control. The sound-ball chart at the right shows the sound absorbing action of Bestwall Light Acoustical Plaster. --Bestwall Light Acoustical Plaster, ufion apvlication produces an attractive nahual while finish which reflects from 67 to 69'r of the light striking its surface. This is important in places such as schools or offices where correct lighting is a must. --Bestwall Light Acoustical Plaster is made of incombustible minerals--it can't bum or support combustion. In fact, the fire protection obtained by using this plaster, in many cases, may cut th, r W of fuc insurance premiums. --Bestwall Light Acoustical Plash r was specially developed for airi.i,. a::on with a plaster gun. and is easily ,i by hand. --Bestwall Light Acoustical Plane- is one of the most economical materials used tor sound conditioning --1'he natural whiti nnish of B. srwaii Ligh: Acoustical Plas'er may o. panned a- i, unit, corat. d as desired. When paint ing. a non-bndg'.ng. breather type of paint dnouid he >pray applied to the urtae,. o! B.slwai! Light Acoustical Planer. SGP 0004002 GYPSUH IRQ DUCTS i-IANUAL Chapter IV Factors Affecting Hose Pressure Using a plaster especially formulated for machine application and maintaining proper mortar consistency are necessary to I:cep hose pressure at a minimum, but there are also several other important factors. 1. Hose length - Pressure varies nearly directly with length of hose used. A pump (cylinder or lioyno) will develop approximately twice as much pressure with a 60* hose as it will with 30' oi the same hose. 2. Hose size - Diameter of hose is definitely a factor. If pressure for 60' of 2" hose is 90 psi, pressure required for 60* of 1" hose would be about , 165 psi. 3. Effect of height - In addition to prossure developed with an length of hose, about one-half pound per sq. inch must be added for every foot the plaster is elevated. For example, if the machine is on the ground and the hose is run up to second floor, which is 30* above ground, there will be an extra 15 psi hose pressure,. It, Proportion of Aggregate - A rich mix (2 to l) will usually result in more pressure than a leaner mix (3 to l). The richer nix will usually have to be slightly thinner than the lean one in order to get same capacity from the machine. 5. Mortars containing venniculite aggregate normally pump with considerably less pressure than those containing either perlite or sand. Remember, high hose pressure results in lower capacity and more machine wear. Bestwal] gun plasters are formulated to pump with as low pressure as possible and at the same time wcrl: good under the tools after being sprayed on the wall or ceiling. Spraying Acoustical Plaster Eestwall Light Acoustical plaster was formulated especially for machine application. It works well in -all type machines. Hose pressure is not normally a problem with this type plaster as it pumps easily with a low pressure. The No zzle The nozzle of all plaster machines are basically the same. The mortar goes through an orifice, most have several interchangeable orifices varying in diameter from I/I4" to 5/8". Compressed air is fed to the nozzle. The amount of air, consistency and type of mix, volume of mix and size of orifice determine the spray pattern. The nozzle operates by emitting a globule of mortar, then air, then mortar. Low frequency cf this cycle results in large globules of mortar while high frequency results in very small globules. To lower frequency: (l) Use lower air pressure (2) Use larger orifice (3) Lf air stem is adjustable, use greater distance from air stem to orifice. To increase frequency, resulting in finer spray pattern, reverse above procedure. Ii.0183 November 1, 1958 SGP 0004003 PLASTERING MACHINES GYPSUM PRODUCTS riAMIAl Chapter IV VJhat To Do When Trouble Occurs With Machine Application Trouble Plaster volume is too low Nozzle clogged with lumps Plaster rebounds from wall in operator's face Rose pressure too high Plaster comes out in stream when brooming Nozzle spray too narrow Aggregate tends to separate out Plaster slumps on wall Cause or Remedy Too much hose being used or pump worn Buildup of fibers, set plaster or foreign matters. Lower air pressure. If spray pattern is lost use larger orfice. . ix too stiff, hose too long or small diameter, fittings clogged or aggregate being 'used requires too high pressure to pump. Increase air pressure. If this does not remedy trouble, use smaller orifice, or use thinner consistency mortar. The air pressure is too low or orifice too large for plaster volume. Using too much aggregate. Happens more frequently when using sand aggregate. Usually due- either to too thin a mix or too much aggregate. I1.CI8U November 1, 1958 SGP 0004004