Concrete & Plaster Bonding Agents

1 Weld-Crete The original chemical Concrete bondingagent incorporates polyvinyl acetatehomopolymer in a patented formula-tion. For exterior and interior will bond new Concrete ,portland cement Plaster , and cementi-tious mixes to structurally sound Concrete floors, walls, columns,beams, steps and can be painted on in a singleapplication 1 to 10 days prior to Concrete Weld-Crete s open time to youradvantage in Bonding to concreteshear walls, where you need a timelapse between application of bondingagent, placement of reinforcing steel,placement of formwork and placement of is also used for bondingsetting beds for ceramic tile and forbonding portland cement Plaster andstucco mixes; and to bond to such surfaces as brick, block, tile, marble,metal, glass block, soundly adhered paint (non-soluble in water), and The original Plaster Bonding agent is a patented formulation incorporatingpolyvinyl acetate for interior use only.

2 Highperformance Bonding of one-coat finish Plaster and/or two and threecoat work to Concrete ceilings, walls,columns, beams, and other structurallysound surfaces. Plaster -Weld prepares the surface to allow you toplaster directly to Concrete over electric radiant heat cable, and tobond cement mortar beds to smoothconcrete for installation of rigid foaminstallation. Concrete , brick, block,glass, ceramic tile, wallboard, metals( sheet lead in x-ray rooms) andmarble are suitable surfaces. Plaster -Weld can be used over paints havingoil, rubber, or vinyl bases, and oversilicone-treated surfaces, as well aslatex & Plaster Bonding Agents8264 Preston Court Jessup, MD 20794 (Weld-Crete & Plaster -Weld )PropertyTest Method & ResultsTensile Bond StrengthASTM C-932for Weld-Crete ,average 485 psi. after 28 C-631for Plaster -Weld , average 304 psi.

3 After28 Bond StrengthASTM C-78( Concrete beamslaminated with bondingagent). 603 Bond StrengthASTM C-1042(slant shearcylinder test). 740 psi. RangeASTM C-932(Weld-Crete );ASTM C-631( Plaster -Weld ) specimens brought to 145 F,no bond Stability5 cycles freeze(-10 F &thaw). Freeze-thaw miceexposed to 30cc volatilized Bonding agentfor 1 hr. Non-toxic, no illeffects after 7 ResistanceASTM E-119(bonded assembly). Passed 2 hr. FireTest 1800 F and 1 hr. HoseStream testsfor fire ; meets Resistance1 Concrete slabsbonded to1/2 gypsum Plaster subjectedto seepage of strong deter-gents & synthetic urine for 10hrs. a day. No bond failureafter 25 consecutive unaffected by alkalinityof ExpectancyLab. tested & field bond;retains strength & & Plaster Bonding Systems Worldwide since 195203050/LARBuyLine 0465 Division 3 & 91.

4 Weld-Crete to job in original container with seals unbroken and use without Storage: Protect Weld-Crete from and surface temperatures must be above freezing duringapplication of Weld-Crete .2. agent : Weld-Crete , Larsen Products Corp., Jessup, to receive Weld-Crete MUST BE CLEAN, free fromloose material, dust, dirt, oil, grease, wax, loose paint, mildew, rust,laitance or efflorescence. If preparing an old Concrete floor surface(steel trowel finish), mechanically scarify the surface and follow withan acid wash and thoroughly rinse with clean water. An economicalmethod for cleaning Concrete floor surfaces is to use a 10% muriatic acid solution followed by a thorough washing. Degreasingsolvents such as Varsol are also to receive Weld-Crete MUST BE STRUCTURALLYSOUND. On newly placed Concrete floors to receive a bonded topping, give the surface a rake or broom finish.

5 Surfaces withform-releasing Agents , curing compounds, hardeners and sealersmust be compatible with Weld-Crete . Glossy painted surfacesshould be dulled with an abrasive. New paint should cure 7 daysbefore applying Weld-Crete . Paints must be firmly adhered to thesubstrate. Do not apply over paints or materials that are soluble inwater. Do not apply over frozen Concrete or plastic surfaces. Weld-Crete may be placed over dry or damp surfaces (eliminate all waterpuddles). Do not apply where hydrostatic pressure is present in thesubstrate. Surfaces should be inspected for excessive cracking andproperly prepared prior to application of the Bonding of Bonding agent : Apply Weld-Crete uniformly, usingbrush, roller or spray, to form a continuous blue film over the entiresurface. Allow one hour to dry. EXCEPTION: FAST SET PATCHINGCEMENTS AND GROUTS MUST BE APPLIED WHILE THE WELD-CRETE FILM IS STILL of Bonding agent : Prior to placement of cementitioustopping, inspect Bonding agent application for continuity of blue filmover the entire Bonding surface.

6 Do not apply new Concrete tofrozen Weld-Crete . Reapply Weld-Crete over areas not satisfactorilycovered. Protect the applied film from dirt and debris until the freshconcrete overlay is in of Concrete toppings shall be over Weld-Crete in a minimum 1/2inch thickness on surfaces shown and specified. Provide for a buttjoint at adjacent edges. All joints must duplicate the joints in thesubstrate and all joints must be sealed against water isolation joints or cut with a dry vacuum saw. Cut controljoints not more than one half the depth of the Concrete standing water from newly bonded Concrete toppings can be applied as soon as the film is dry, ordelayed a week to 10 days, with no effect on the bond. Follow sameapplication for overlays on precast hollow core floor systems. FollowPortland Cement Association accepted industry standards for protection of newly bondedconcrete.

7 Do not use a wet type saw to cut isolation joints onnewly bonded Concrete overlays. Seal all joints against water Concrete Shear to application of Weld-Crete , set all anchors on existingwall as shown and specified. Apply Weld-Crete as directed, thenproceed with placement of reinforcing steel, erection of forms andplacement of Concrete . Seal all joints against water of Portland Cement Terrazzoa. Apply Portland Cement Terrazzo over Weld-Crete to surfaces asshown and inch Portland Cement Terrazzo Flooring: Install terrazzodividing strips prior to application of Weld-Crete . Follow NTMA specification for monolithic terrazzo. Do not allow standing water orwet materials to remain on newly bonded terrazzo surfaces. Seal alljoints against water Application of Portland Cement Portland Cement Plaster over Weld-Crete on surfaces asshown and specified.

8 NOTE: Portland Cement Plaster can be appliedas soon as film is dry, or delayed a week to 10 days, with no effecton the bond. Seal all joints against water and Three Coat Applied: Apply scratch coat a minimum of3/8 inch over Weld-Crete on surfaces as shown and : Do not scratch through to the Weld-Crete film. Allow to dry24 hours. Follow with second and third coat applications. Seal alljoints against water Coat Spray Applied: Apply a thin dash coat by hand or sprayover Weld-Crete and allow dash to firm up and become hard. Applyfinish coat 3/8 inch thick. Seal all joints against water : Weld-Crete helps equalize suction on vertical applications,which produces a more uniform finish coat. For less than 3/8 inchthickness, refer to Acrylic Admix 101 . of Mortar Setting receive ceramic tile, precast terrazzo, etc., application of mortar Setting beds shall be a minimum of 3/8 inch thickness overWeld-Crete on surfaces as shown and specified.

9 Seal all jointsagainst water of Non-Shrink Fast-Set Mortars and of non-shrink fast-set mortars and grouts shall beover Weld-Crete while Weld-Crete is still tacky. Seal all jointsagainst water of of bedcoat for Simulated Stone Finish (Marblecrete)shall be a minimum of 3/8 thickness over Weld-Crete on surfacesas shown and specified. Seal all joints against water Guide SpecificationsBonds new Concrete , stucco, tile setting beds, and terrazzo to any structurally sound surface, interior and exterior. Divisions 3 & 91. Plaster -Weld to job in original container with sealsunbroken and use without Storage: Protect Plaster -Weld from Environmental and surface temperatures must be above freezing duringapplication of Plaster -Weld . adjacent finish surfaces with masking tape, soap powderemulsion, or a commercial product, specially formulated for protec-tive use in agent : Plaster -Weld , Larsen Products Corp.

10 , Jessup,Maryland3. to receive Plaster -Weld MUST BE STRUCTURALLYSOUND AND CLEAN, free from loose material, dust, dirt, oil, grease,wax, loose paint, mildew, rust, laitance, or efflorescence. Formrelease Agents , curing compounds, hardeners, and sealers must becompatible with Plaster -Weld . of Bonding agent : Apply Plaster -Weld uniformlyusing brush, roller, or spray to form a continuous pink film over theentire surface. Allow to dry one hour. (NOTE: Painted surfaces mustbe sound, washable and firmly adhered to the substrate. Glossypainted surfaces should be dulled with an abrasive.) Newly paintedsurfaces should be completely dry before applying Plaster -Weld .Application of wallpaper to newly bonded plastered surfaces shouldbe delayed 90 Inspection of Bonding agent : Prior to applying Plaster , inspectbonding agent application to assure a continuous pink film over theentire Bonding surface.