Product Information Silicone Sealants Dow Corning …

1 Product InformationSiliconeSealantsFEATURES Resistant to sunlight, rain, sleet,snow, ultraviolet radiation, ozoneand temperature extremes Retains design properties even afteryears of exposure seals remainwatertight and weatherproof Wide temperature range from -60to 177 C (-76 to 350 F) withintermittent temperatures up to200 C (392 F)COMPOSITION One-part RTV Silicone sealantDow Corning 999-A SiliconeBuilding & Glazing SealantOne-part sealant for glazing and curtainwall seal applicationsAPPLICATIONSDow Corning 999-A Silicone Building & Glazing Sealant is intended for build-ing construction applications and is particularly effective for glazing butt and lapshear joints and sealing curtainwall projections and other glass, plastic and metalassemblies. It is also appropriate for general construction applications.

2 It may befactory applied as a primary seal to glass, plastic and metal PROPERTIESS pecification Writers: Please contact your local Dow Corning sales office or your GlobalDow Corning Connection before writing specifications on this SuppliedASTM C 679 Tack-Free Timeat 25 C (77 F), 50% RHminutes10-20 Tooling Timeminutes5-10 ASTM C 639 Flow, Sag or SlumpNilColorClear, white, bronze, lightbronze, black, aluminumand custom colorsAs Cured 7 days at 25 C (77 F) and 50% RHASTM D 2240 Durometer Hardness, Shore Apoints 25 ASTM D 412 Ultimate Tensile Strengthpsi (MPa) 325 ( )ASTM D 624 Tear Strengthppi (kN/m) 25 ( )ASTM C 794 Peel Strengthpli (kN/m) 20 ( )ASTM C 603 Extrusion Rateg/min 350 DESCRIPTIONDow Corning 999-A Silicone Building& Glazing Sealant is an easily applied,one-part sealant that cures in thepresence of atmospheric moisture toproduce a durable and flexible glazingand curtainwall seal.

3 This siliconematerial is chemically stable andshows little change in physicalproperties with addition to the six standard colors,custom colors can be matched tocustomer-supplied Corning 999-A Silicone Building& Glazing Sealant is compatible withmost laminated glass, acrylic andpolycarbonate glazing sheets, and allone-part Dow Corning brand siliconeconstruction Sealants . However, adhe-sion and compatibility must be evalu-ated in each instance prior to sealantuse and one sealant should be appliedonly after the other has fully StandardsDow Corning 999-A Silicone Building& Glazing Sealant meets the qualifica-tions of: Federal Specification TT-S-001543,Class A Federal Specification TT-S-00230,Class A FDA Regulation No. 21 (subject to end usecompliance with any applicabletotal extractives limitations) somecustom colors may not meet thisregulation; contact Dow Corningfor Information Canadian Specification ASTM C 920 specification Chemically acceptable for applica-tion to surfaces and equipment thatmay contact edible products inestablishments operating under theUSDA federal meat and poultryinspection programHOW TO USEP lease refer to the Dow CorningAmericas Technical Manual, Form , for detailed joint design andinstallation DesignDow Corning 999-A Silicone Building& Glazing Sealant should be nothicker than 1/2 inch (13 mm) and nothinner than 1/4 inch (6 mm).

4 Ideally,the ratio of joint width to sealant depthshould be about 2 or polyethylene foam rodis the recommended backup materialfor deep joints; polyethylene tape isrecommended for joints too shallow toallow foam rod. These materialspermit application of a thin bead andact as bond breakers that allow thesilicone sealant to stretch freely withthe joint rabbets and joints should bedesigned to allow installation andretention of the bond-breaking backupmaterial during the installation andcuring of Dow Corning 999-ASilicone Building & Glazing shear joints should have a beadwidth that is equal to, or greater than,the total anticipated DimensionsSmall curtainwall panels and litesshould allow a minimum width of 1/4inch (6 mm) for the sealant panels and lites, or those inwhich a great deal of movement isexpected, should allow a minimumwidth of four times the expectedmovement.

5 Glazing of plastic lites andpanels fabricated from plastic requirelarger than usual joint dimensions dueto the plastic s higher coefficient ofthermal expansion. For these appli-cations, Dow Corning 795 SiliconeBuilding Sealant or Dow Corning 791 Silicone Weathersealing Sealant WorkBonding surfaces on both new andremedial jobs must be sound, dry, andfree of all foreign matter and contam-inants such as grease, oil, dust, water,soap residue, frost, surface dirt andold Sealants or glazing compoundsand protective Corning 999-A Silicone Building& Glazing Sealant will adhere to curedsilicone sealant with a preparatory sol-vent wipe to remove accumulated the surfaces using a clean, oil-free rag saturated with solventsuch as xylol, toluol or methyl metal, glass and plastic surfacesby mechanical or solvent not clean surfaces with soap, deter-gent or any water-based cleaner.

6 Wipesolvents on with a clean, oil- and lint-free, absorbent cloth. Remove solventbefore it dries, using a clean, dry not flood surfaces with moresolvent than necessary. Make surethat apparently clean surfaces are notcovered with a thin film ofconstruction applying Dow Corning 999-ASilicone Building & Glazing Sealantto nonreflective glass surfaces, primingis usually not required. Priming isusually required on plastic and metalsurfaces. Refer to the SurfacePreparation Guide, Form No. 61-182,for more specific cases where doubt exists, a sampleshould be tested before full-scale adjacent to joints should bemasked to ensure neat sealant not allow masking tape to touchclean surfaces to which the siliconesealant will adhere. Tooling should becompleted in one continuous strokeimmediately after sealant applicationand before a skin forms.

7 Maskingshould be removed immediately aftertooling and before a skin forms (5-10minutes).Linear Feet Per Gallon of Dow Corning 999-A SiliconeBuilding & Glazing Sealant for Various Joint SizesWidth, Inches1/81/43/81/25/83/411/8123261641130 72462051543/16 4112752051641371031/4 307205154123103773/8 1371038268511/2 10377625139 Depth, Inches1 Always follow solvent manufacturer's recommended safehandling Information and applicable federal, state and I: Estimating RequirementsMethod of ApplicationDow Corning acetoxy Sealants canbe applied directly from the caulkingcartridge with either an air-operatedor hand-operated cartridge gun. Donot break the cartridge seal until justbefore backup material or joint filler,setting blocks, spacer shims and tapesas specified. Apply the sealant in acontinuous operation using a positivepressure adequate to properly fill andseal the is recommended and, ifpossible, should be completed in onecontinuous stroke.

8 Tool or strike thesealant with light pressure to spreadthe material against the backupmaterial and the joint surfaces. A toolwith a concave profile isrecommended to keep the sealantwithin the glazing, tool the sealant appliedat the sill so that precipitation andcleaning solutions will not the joint within 10 minutes ofapplication. Remove masking tapebefore a surface skin begins to a surface skin begins to form, itwill be torn off when the tape isremoved, leaving a rough applying the sealant and a skinhas formed, do not disturb the joint for48 sealant should be cleaned offtools and nonporous surfaces while itis in the uncured state, by using asolvent such as xylol, toluol or methylethyl sealant accidentally contactadjacent porous surfaces, the excesssealant should be allowed to progressthrough the initial cure or set-up.

9 Itshould then be removed by abrasion orother mechanical StorageAfter use, simply remove the excessmaterial from the tip. To reopen thecartridge, remove the cured plug fromthe PRECAUTIONSPRODUCT SAFETY INFORMATIONREQUIRED FOR SAFE USE IS NOTINCLUDED IN THIS HANDLING, READPRODUCT AND MATERIALSAFETY DATA SHEETS ANDCONTAINER LABELS FOR SAFEUSE, PHYSICAL AND HEALTHHAZARD Information . THEMATERIAL SAFETY DATASHEET IS AVAILABLE ON THEDOW Corning WEBSITE , ORFROM YOUR DOW Corning REP-RESENTATIVE, OR DISTRIBUTOR,OR BY CALLING YOUR GLOBALDOW Corning Corning 999-A Silicone Building& Glazing Sealant is packaged oz (305-mL) disposablecartridges, which fit ordinary caulkingguns, and (17-L) bulk pails. Itcan be dispensed by many air-operatedguns and most types of bulkdispensing Corning 999-A Silicone Building& Glazing Sealant is not recommendedfor use in applications involving: Structural Silicone glazing Joints where physical abuse orabrasion is likely to be encountered Prolonged water immersion Porous surfaces, such as masonry Building materials that might bleedoils, plasticizers or solvents materials such as impregnatedwood, oil-based caulks, green orpartially vulcanized rubber gasketsor tapes Totally confined spaces, becausethe sealant requires atmosphericmoisture for cure Surfaces sensitive to corrosion byacetic acid vapors (a byproduct ofsealant cure) Surfaces that will be painted (paintwill not stretch with the extensionsof the sealant and may crack andpeel).

10 Complete all painting priorto using sealant Bonding to secondary seal of insu-lating glass units sealed with two-part Silicone Sealants Auto trim Appliance trim ( , adhesive trim)Black Dow Corning 999-A SiliconeBuilding & Glazing Sealant isrecommended for glass-to-glass buttjoints because butt joints sealed withclear sealant may contain smallamounts of air that are trapped duringthe packaging and/or application ofthe sealant. Appearance standardsshould be established and agreed uponprior to sealant Product is neither tested norrepresented as suitable for medicalor pharmaceutical ANDENVIRONMENTALINFORMATIONTo support customers in their productsafety needs, Dow Corning has anextensive Product Stewardship organ-ization and a team of Product Safetyand Regulatory Compliance (PS&RC)specialists available in each further Information , please seeour website, ,or consult your local Dow in USADow Corning is a registered trademark of Dow Corning No.