General Guidelines Solutions for Facades Application of Sikasil Weather Sealants. February 2013 / Version 2

Transcription

1 General Guidelines Solutions for Facades Application of Sikasil Weather Sealants February 2013 / Version 2

2 Table of Content Purpose and General Information 3 Introduction 3 1. Areas of Application 3 2. Design and Joint Dimensioning 3 3. Application Limits 4 4. Working Place Conditions 4 5. Surface Pre-treatment and Masking Application of Sika Cleaner P and Sika Cleaner G&M Application of Sika Aktivator-205 (formerly Sika Cleaner-205) Application of Sika Primer Application of Sika Primer-210 and Sika Primer-3N Masking of Areas Adjacent to the Joints 8 6. Processing and Product Application 9 7. Field Adhesion Test Repair Glazing Removal of old Sealant and Preparation of Joint Sealant Application 11 February 2013 / Version 2 / Sika Services AG - 2 -

3 Purpose and General Information This document contains recommendations and hints for the application of Sikasil WS weather sealants and Sikasil FS fire rated sealants. These guidelines are relevant for the following products: - Sikasil FS Sikasil WS-305 CN - Sikasil WS Sikasil WS-605 S - Sikasil WS-680 SC The information herein is offered for general guidance only. These guidelines should be read in conjunction with the relevant Product Data Sheets. This document covers gen eral recommendations, for specific advice please contact the Techni cal Service Department of Sika Business Unit Industry. Introduction Sikasil WS-680 SC is an MS-sealant. All other mentioned Sikasil WS and Sikasil FS products are neutral-curing silicone sealants with a high move ment capability and excellent ad hesion to a wide range of sub strates. The quality and durability of the sealant joint depends on various factors including the cleanness of the substrates, application of the sealant, joint dimensioning etc. 1. Areas of Application Product Sikasil WS-605 S Sikasil WS-305 CN Sikasil WS-680 SC Sikasil WS-355 Sikasil FS-665 Application/Special Property Weatherproofing sealant for glass facades and metal cladding, reduced dirt pick-up and non-streaking on non porous surfaces. Weatherproofing sealant for glass facades and metal cladding. Weatherproofing sealant for self-cleaning glass. Weatherproofing sealant for natural stone applications Non-staining. Fire rated sealant. 2. Design and Joint Dimensioning Joints must be properly dimensioned as changes are no longer possible after construction or sealant application, respectively. For optimum perfor m ance the joint width should be designed accord ing to the move ment capability of the sealant based on the expected movement. The minimum joint depth is 6 mm and a width / depth ratio of 2:1 should be respected, esp. for smaller joints (e.g. 12 x 6 mm). Up to 3:1 is acceptable for bigger buffer joints (e.g. 30 x 10 mm).. February 2013 / Version 2 / Sika Services AG - 3 -

4 Picture 1: Joint design rules Sika offers a comprehensive project service package including design reviews and joint dimensioning. For more information please contact the Technical Service Department of Sika Industry. 3. Application Limits Most Sikasil WS and FS Sealants are compatible with each other, with other engineering silicone sealants manufactured by Sika, and with SikaGlaze IG sealants. For specific information regarding compatibility between various Sikasil and SikaGlaze products please contact the Technical Service Department of Sika Industry. All other sealants have to be approved by Sika before using them in combination with Sikasil WS and FS sealants. Where two or more different reactive sealants are used, allow the first to cure completely before applying the next. Do not use Sikasil WS-605 S, WS-305 CN, WS-680 SC and WS-355 on pre-stressed polyacrylate and polycarbonate elements as they may cause environmental stress cracking (crazing). The compatibility of gaskets, backer rods and other accessory materials with Sikasil WS and FS sealants must be tested in advance for curing reasons. Joints deeper than 15 mm should be avoided. The above information is offered for general guidance only. Advice on specific applications will be given on request. 4. Working Place Conditions Although Sikasil WS / Sikasil FS may be proc essed within 5 to 40 C (41 to 105 F), the optimum application temperature of the sealant (and the substrates as well) is between 15 and 25 C (60 and 77 F). If Sikasil WS / Sikasil FS sealants have to be applied at low temperatures it has to be ensured that the substrate sur faces are free of condensed water or ice. It is recommended after cleaning to dry the substrates carefully with a heat gun and then immedi ately apply the sealant. Please be aware of the fact that the curing speed of Sikasil WS / Sikasil FS depends on the air humidity and temperature: the lower the air humidity and the temperature the slower the product will vulcanise. Movement of joints with non-cured sealant can deform the sealant bead. Later cracks and leakages may be the consequence. February 2013 / Version 2 / Sika Services AG - 4 -

5 If Sikasil WS / Sikasil FS sealants have to be applied above 40 C (105 F), the Technical Service Department of Sika Industry should be consulted. Field adhesion tests (see Chapter 7) are recommended. In order to get the best quality of the applied joint sealing it is advisable to avoid direct sun radiation during application and curing. Temperatures at non-cured sealants above 60 C (140 F) must be avoided under all circumstances. 5. Surface Pre-treatment and Masking Surfaces must be clean, dry and free from oil, grease and dust. Do not contaminate pre-treated surfaces during any phase of production. If contamination occurs, surfaces have to be pre-treated again. The information in table 1 is offered for general guidance only. Advice on specific pre-treatment methods based on laboratory adhesion tests will be given on request. With the exception of clear float glass, Sika has to test the adhesion of structural silicone adhesives on project basis on production-run samples of the original materials used in the specific project. The use of the surface pre-treatment agents recommended in the laboratory report is mandatory; otherwise any warranty for the adhesion behaviour of Sikasil weather sealants and fire rated sealants is null and void. Table 1: Overview of Pre-treatments Substrate Surface Pre-treatment Float glass (including tempered, toughened, laminated and tinted types) Pyrolytically coated glass Ceramic-coated (enamelled) glass Sika Aktivator-205 or Sika Cleaner P* or Sika Cleaner G & M** Stainless steel Anodised aluminum Polyester powder-coated aluminum PVDF-coated aluminum Concrete Sika Aktivator-205 Sika Aktivator-205 Wire brush and Sika Primer-210 or Sika Primer-3N Natural stone Brush and Sika Primer-210 or Sika Primer-3N * Alternative use of Sika Cleaner P instead of Sika Aktivator-205 must be approved by Technical Service of Sika Industry. ** Sika Cleaner G & M in case of heavily contaminated substrate surfaces. February 2013 / Version 2 / Sika Services AG - 5 -

6 5.1 Application of Sika Cleaner P and Sika Cleaner G&M Sika Cleaner P and Sika Cleaner G&M are solvent-based cleaning agents. For very greasy or oily surfaces use Sika Cleaner G&M which has a better oil/grease removal capability than Sika Cleaner P. Both cleaners are applied by the two-cloth method : 1. Moisten a clean, dry, oil-free and lint-free cloth or paper with Sika Cleaner P / G&M and rub it over the surface. Make sure to turn the cloth or paper to expose new surface, or replace it regularly, in order to avoid wiping residues back onto the surface. 2. Then wipe-off the surface with a clean, dry, oil-free and lint-free cloth or paper. Never wait until Sika Cleaner P / Sika Cleaner G&M have has evaporated from the surface because dissolved contaminants would be left behind. 3. Repeat this procedure until the surface is clean. 4. Drying time: The required minimum drying time at 5-40 C ( F) is 2 minutes. 5. If cleaned parts can not be bonded immediately, protect them against subsequent contamination. 6. If more than two hours have passed since cleaning, always repeat the cleaning process before bonding. For more details about Sika Cleaner P and Sika Cleaner G&M refer to the actual Product Data Sheets (PDS) and Safety Data Sheets (SDS). 5.2 Application of Sika Aktivator-205 (formerly Sika Cleaner-205) Sika Aktivator-205 is not a simple cleaning solvent but contains a bonding agent which forms an activating film on the substrate surface. On some surfaces, for example on certain glossy powder-coated aluminum profiles or glass, this film may be visible and change the appearance of the profile surface. Therefore it is important to apply Sika Aktivator-205 like a primer and to use masking tapes in critical (visual) areas if necessary. 1. Moisten a clean, dry, oil-free and lint-free cloth or paper with Sika Aktivator-205 and apply it on the surface. Make sure to turn the cloth or paper to expose new surface, or replace it regularly in order to avoid wiping residues back onto the surface. If the surface is not free of contaminant, the process has to be repeated. 2. Unlike ordinary cleaning agents, the surface treated with Sika Aktivator-205 must not be dried subsequently with a cloth or paper! February 2013 / Version 2 / Sika Services AG - 6 -

7 3. Drying time: The required minimum drying times are as follows (depending on the temperature in the workshop): 5-10 C (40-50 F): 10 minutes C (50-60 F): 5 minutes > 15 C (> 60 F): 2 minutes In case of doubt, contact Technical Service Department of Sika Industry. 4. If pretreated parts are not bonded/sealed immediately, protect them against subsequent contamination. 5. Adhesives should be applied within 2 hours after the application of Sika Aktivator-205. Otherwise the procedure as described above has to be repeated before bonding. Tightly re-seal container immediately after each use. Sika Aktivator-205 should only be used within one month after opening the can. Discard any Sika Aktivator-205 that has gelled or separated. For more details about Sika Aktivator-205 refer to the actual Product Data Sheet (PDS) and Safety Data Sheet (SDS). 5.3 Application of Sika Primer-790 In very rare cases (e.g. on a few PVDF coatings) the use of Sika Aktivator-205 is not sufficient for a durable adhesion. Sika Primer-790 can be used instead. 1. Ideal application and surface temperature is between 15 C and 25 C (60 F - 75 F). 2. Surfaces must be clean, dry and free from grease, oil and dust. Clean the surface with Sika Cleaner-P / Sika Cleaner G&M (wipe-on / wipe-off) and leave to dry. 3. Apply a thin but covering coat of Sika Primer-790 with a brush, felt, clean lint-free cloth or foam applicator. It shall be applied once only. Make sure that this single application gives adequately dense coverage. 4. Drying time: 20 min. maximum: 2 hours Tightly re-seal container immediately after each use. Sika Primer-790 should only be used within one month after opening the can. Discard any primer that has gelled or separated. For more details about Sika Primer-790 refer to the actual Product Data Sheets (PDS) and Safety Data Sheets (SDS). February 2013 / Version 2 / Sika Services AG - 7 -

8 5.4 Application of Sika Primer-210 and Sika Primer-3N Sikasil WS-355 non-staining silicone sealant for natural stone bonds extremely well to many different substrates even without primer. Nevertheless, for durable water proofing joints on natural stones Sika recommends to use Sika Primer-210 or Sika Primer-3N. Sika Primer-210 and Sika Primer-3N are primers, not cleaning agents. Clean the stone surface from dust, dirt and loose particles. In order to avoid a visible contamination, a masking tape should be applied on the front surface, if necessary. Pour a small amount of Sika Primer-210 / Sika Primer-3N into a clean container and apply the primer with a brush in a thin layer. Never dip the brush into the original primer packaging. Once the primer has been ap plied, it is essential that no more solvent gets onto the surface and that there is no further contamina tion. Leave to dry for 30 minutes and then apply Sikasil WS-355. Apply sealants to primed surfaces latest within two hours. Tightly re-seal container immediately after each use. Sika Primer-210 / Sika Primer-3 N should only be used within one month after opening the can. Discard any primer that has gelled or separated. For more details about Sika Primer-210 / Sika Primer-3N please refer to the most recent Product Data Sheets (PDS) and Safety Data Sheets (SDS). 5.5 Masking of Areas Adjacent to the Joints To assure neat bond lines and protect areas adjacent to the structural joint, use a masking tape. The tape must not touch the pre-treated surface areas to which the silicone has to adhere. Remove the masking tape immediately after tooling the WS joint. Do not wait longer than the skin time. Otherwise joints might be damaged. February 2013 / Version 2 / Sika Services AG - 8 -

9 6. Processing and Product Application After suitable joint and substrate preparation, Sikasil WS / Sikasil FS sealants are gunned into place. For backfilling it is rec ommended to use closed cell, sealant com patible foam backer rods e.g. high resil ience polyethyl ene foam rod. If joints are too shallow for backing material to be employed, it is recommended using a polyethylene tape. This acts as a release film (bond breaker), allow ing the joint to move and the sealants to stretch freely. For more information please con tact the Technical Service Depart ment of Sika Industry. Tooling and finishing Tooling and finishing must be car ried out within the skin time of the sealant. When tooling freshly applied Sikasil WS / Sikasil FS press the sealant to the joint flanks to get a good wet ting of the bonding sur face. Wetting of finshing tools with tooling agents can improve handling but spraying the tooling agent onto the joints and substrates is not advisable. Cure Mechanism Sikasil WS / Sikasil FS sealants cure by reac tion with atmospheric moisture. The reaction thus starts at the surface and proceeds to the core of the joint. The curing speed de pends on the relative humidity and the tem perature (see diagram 1 below). Heating above 60 C (140 F). e.g. by exposure to direct sun radiation, is not advisable as it may lead to bubble formation. At low temperatures the water content of the air is lower and the curing reaction proceeds more slowly. Curing speed [mm] C 35 C 23 C 8 C 50 C / 95% r.h. 35 C / 90% r.h. 23 C / 50% r.h. 8 C / 30% r.h Time [days] Diagram 1: Typical curing speed of Sikasil WS / Sikasil FS sealants at various conditions Removal of Sikasil WS / Sikasil FS Uncured Sikasil WS / Sikasil FS may be re moved from tools and equipment with Sika Remover-208 or another suitable solvent. Once cured, the material can only be removed mechanically. Hands and exposed skin should be washed immediately using Sika Handclean towels or a suit able industrial hand cleaner and water. Do not use solvents! February 2013 / Version 2 / Sika Services AG - 9 -

10 7. Field Adhesion Test The field adhesion test is a qualitative screening procedure that may help to identify poor installation techniques used in the application of sealants and adhesives. This will include poor cleaning, incorrect use of primer, which could include selection of an unsuitable primer or omitting to use a primer when one is required, poor primer application or improper joint design. To evaluate the sealant adhesion on site, a simple hand pull test can be used at the job site. Field adhesion testing should be documented. It is suggested that 5 tests for the first 500 meters and one test per 500 meters thereafter are carried out. Alternatively one test per floor per elevation can be undertaken after the initial 5 tests are carried out. The hand pull test procedure is as follows: Make a knife cut from one side of the joint to the other (perpendicular to the joint) Make two cuts (parallel to the joint) from the horizontal cut approximately 75 mm long, at both sides of the joint, making sure no damage is caused to the substrates surfaces Place a 25 mm mark on the sealant tab Hold a 50 mm piece of sealant firmly just beyond the 25 mm mark and pull at a 90 angle. Check the adhesion of the sealant to both substrates separately, even if they are of the same material. This is accomplished by extending the vertical cut along one side of the joint, checking adhesion to the opposite side, and then repeating for the other surface. Pass/fail criteria for each sealant should be used, 100% cohesive failure is classified as a pass. If any signs of adhesive failure are observed then the sealant manufacturer should be contacted and a more detailed examination undertaken. For specific advice please contact your local Sika representative. Whilst undertaking the field adhesion test you should also inspect the quality of the joint section removed. Check if the sealant completely fills the joint, no voids or air bubbles are present and the sealant joint dimensions are in line with those specified on the drawings. Contact your local Sika representative if you have any concerns related to the sealant adhesion or the quality of installation. Record the test results in a project log book so that the results can be included in the project manual. February 2013 / Version 2 / Sika Services AG

11 8. Repair Glazing If a weather seal joint has to be replaced follow this Sika guidelines. 8.1 Removal of old Sealant and Preparation of Joint Cut out the old Sikasil WS / Sikasil FS sealant so that about 1-2 mm of silicone sealant remains on the metal frame or glass pane, as long as the adhesion to these substrates is perfect. If possible don t scratch out the sealant completely, since this could damage the metal surface. For complicated designs and joint geometries, vibration cutters or similar tools can be used. The cut must be absolutely smooth and must never leave loose sealant parts on the cut surface. Remove the backing material completely. Never clean the remaining surface of the sealant if it is re-sealed immediately after the old sealant has been cut out. If the joint is re-sealed later, it may be necessary to clean with Sika Cleaner P. Since silicone can absorb solvent, clean very carefully using a cloth only sparingly moistened with cleaner. Allow the cleaner to evaporate completely before re-sealing. We do not recommend priming the cut surface. The cleaning step can be avoided by cutting out the old sealant very close to the substrate surface. Just before re-sealing, neatly cut away the sealant with a sharp blade, leaving behind about 2 mm thickness. You can then re-seal on the smooth, freshly cut surface. Masking of Areas Adjacent to the Joints: To assure neat bond lines and protect areas adjacent to the structural joint, use a masking tape. The tape must not touch the clean surface areas to which the silicone has to adhere. Remove the masking tape immediately after tooling the WS joint. Do not wait longer than the skin time. Otherwise joints might be damaged. 8.2 Sealant Application After suitable joint and substrate preparation, Sikasil WS / Sikasil FS sealants are gunned into place. For backfilling it is recommended to use closed cell, sealant compatible foam backer rods e.g. high resilience polyethylene foam rod. If joints are too shallow for backing material to be employed, it is recommended using a polyethylene tape. This acts as a release film (bond breaker), allowing the joint to move and the sealants to stretch freely. For more information please contact the Technical Service Department of Sika Industry. Tooling and finishing must be carried out within the skin time of the sealant. When tooling freshly applied Sikasil WS / Sikasil FS press the sealant to the joint flanks to get a good wetting of the bonding surface. February 2013 / Version 2 / Sika Services AG

12 Legal Notes The information contained herein and any other advice are given in good faith based on Sika s current knowledge and experience of the products when properly stored, handled and applied under normal conditions in accordance with Sika s recommendations. The information only applies to the application(s) and product(s) expressly referred to herein and is based on laboratory tests which do not replace practical tests. In case of changes in the parameters of the application, such as changes in substrates etc., or in case of a different application, consult Sika s Technical Service prior to using Sika products. The information contained herein does not relieve the user of the products from testing them for the intended application and purpose. All orders are accepted subject to our current terms of sale and delivery. Users must always refer to the most recent issue of the local Product Data Sheet for the product concerned, copies of which will be supplied on request. Sika Services AG Business Unit Industry Tueffenwies 16 CH-8048 Zurich Switzerland Tel Fax ctd@ch.sika.com February 2013 / Version 2 / Sika Services AG