3The best place to find information about these products is a manufacturers website. Try this Google searchChoose a manufacturer that you recognise
4Adhesives work by linking to materials and then solidifying Due to-Solvent loss (including water)Chemical reaction.Cooling of a pre-heated adhesive.
5Other names for adhesives GlueCementSolvent / cement: (used to weld plastics rather than glue)
6BRANZ bulletin 356 suggests:- BRANZ bulletin 356 suggests:- “The commonest cause of bond failure is failure to follow adhesive manufacturers instructions.”
7Storage or shelf life, length of time an adhesive can be stored. Pot life, after mixing time adhesives remain suitable for use.Mixing time, adhesives (like casein or aerolite) require reaction time after mixingbefore it can used.Assembly time, time between adhesive application and the application of pressure.Curing time, time taken to attain sufficient strength.Catalyst/hardener, a substance which initiates adhesive to set.
8Gap-filling, usually in the form of a powdered extender which is added to liquid adhesive. Allows adhesive to bridge wider glue line gaps (up to 1.3 mm) withoutaffecting the strength.
9Thermoplastic, adhesive softens with heat. Thermosetting, adhesive hardens with heat.
10Elastomer, adhesive with elastic or rubber-like properties Elastomer, adhesive with elastic or rubber-like properties. Often marketed as adhesive / sealant.
11Adhesives are often grouped into three types Structural adhesivesConstruction adhesivesWoodworking adhesives
12STRUCTURAL ADHESIVESAre high strength adhesives used inlaminated beams, structural plywood or boat building.
13CONSTRUCTION ADHESIVES Are cartridge grade adhesives that are normally used in conjunction withfasteners for low stress applications i.e. panel bonding.The adhesive is cured by the evaporation of either water or solvent.
14WOODWORKING ADHESIVES Different types of Poly Vinyl Acetates (PVA) and aliphatic resin adhesives dominatethe building-site woodwork glues. PVA is a white coloured, and aliphatic, a cream coloured liquid.
15.Contact AdhesivesTwo types of contact adhesive are available Adoa F2 and Thixotropic Ados F2These glues are strong smelling and are used to bond ,rubber, plastics, timber,laminates,plastic,cork and weatherseals.
17Sealants are a non-rigid (elastomeric) type material, used to waterproof joints or seal joints to prevent air movement between various building components
18Sealants elastomeric nature, allows the sealant to expand or contract within the joints.
19Sealants are generally marketed as “gunable” thick pastes and packaged in cartridges or socks.
20Compatibility of sealant with substrate is important (e. g Compatibility of sealant with substrate is important (e.g. sealants with anacidic cure may not be used to seal joints in concrete products)
21Bathroom and wet area sealants often contain anti-mould inhibitors.
22Common applicationsSeals between pre-cast concrete units ( to weatherproof or stop air movement) Peripheral seals to weatherproof around aluminium joinery. Joints to external cladding and sheathing. Expansion and contraction joints (high differentials of thermal expansion) Waterproofing and sealing in wet areas (bathrooms and showers etc.) Glazing Sealing around pipes (through timber framing, concrete construction) Sealing joints in air conditioning ductwork. Flexible joints (between concrete floors and machinery) As a flexible and waterproof pointing between ceramic, earthenware tiles and stone work (often granite or marble panels)
23The selection of a sealant depends on: Compatibility of sealant with the substrate (will substrate need priming) Width of joint. Movement capability of the sealant (expressed as percentage movement of jointwidth) Interior or exterior application, amount of movement, heat, and chemicals. Ease of installation, tooling off and cleanup (two and three pot sealants aremessy and have limited pot life) Toxic risks Cost
24TYPES OF SEALANTSOleoresinous sealantButyl rubber sealantAcrylic sealantPolyurethane sealant
25TYPES OF SEALANTS Oleoresinous sealant (Secomastic) Called mastic. Seals by remaining putty like (basically linseed oil and whiting with differentoils and fillers to maximise retention of fluids).Accommodate about 5% joint movement.Maximum 5 year life.
26Butyl rubber sealant (Stormseal, Seelastrip) ( turns into a rubber-like compound)Performance is superior to mastic.Uses are limited to bedding in applications and pointing of glazing.Accommodate limited movementMaximum10 year life.
27Acrylic sealant (No More Gaps, Gaps ‘n’ Cracks) Fill gaps prior to painting with non-enamel paintsSeals joints in acoustically designed areas.Accommodate +/- 5% joint movementDesigned for interior use.
28Polyurethane sealant (Uraflex) May be formulated as one or two part sealant.Good flexibility - 25% joint movement.Durability of up to 15 years.Used as a joint sealer (depending on the type selected)
29Polysulphide sealant (Thioflex 600) Manufactured as one, two or three pot (different formulations to address sagresistance, width of joint, on-site conditions etc.)A tough, rubber like sealer with excellent adhesion and 25% joint movement.Used extensively in the construction industry for sealing horizontal and verticaljoints (5 to 50mm wide) between pre-cast and tilt-slab components, and fibrecement sheets.Joint surfaces require priming.Durability in excess of 20 years.
31Acetic acid cure sealant. (Silaflex RTV) Used extensively for glazing applications, expansion and waterproof joints inceramic tiling and stainless steel joints. Used in bathroom and kitchen areas (mould inhibitor required) Withstand long term immersion in water (but not permanent)Not suitable for concrete, fibre cement sheets, galvanised steel orspecified plastic or acrylics. Joint movement 10% Maximum 25 year life.
32Neutral Cure (Silaflex B, Silaflex N, Silaflex NG) Very good adhesion only if used with the right substrate Use Silaflex B for timber, concrete brick and fibre cement sheeting Use Silaflex N for coated and uncoated metals (plumbing & roofing) Use Silaflex NG for glass, ceramic and plasticsMovements up to +/- 10%Maximum 25 year life
33Modified Silicones (also neutral cure) (Silaflex MS) Excellent primerless adhesion to all the substrates mentioned above andparticularly powder coated aluminium. Paintable and won’t stain natural stone. High movement accommodation up to +/- 25% Maximum 25 year life -.Note: Best option for a multi-purpose sealant
34Epoxy urethane (Nitoseal 280) A three part, heavy duty sealant used for sealing internal factory floor joints. Movement capability of up to 10%.
35Epoxy (Nitoseal 281) A joint sealing compound for low movement and hard wearing floor joints.
36Bitumen synthetic rubber (Plastiseal) A flexible gun applied sealant suitable for sealing limited movement joints inretaining walls, basements and the like. Bitumen based is not compatible withother sealants, however it may be used with bituminous tanking i.e. Mulseal.
38Joint Design should aim to: JOINT DESIGNJoint Design should aim to:Reduce the exposure of the sealant to the weatherMinimise the damage to the building should the joint failProvide good access for joint repair or maintenanceGet a width to depth ratio of 2:1 with a minimum depth of 6mm. Some joints mayrequire a 1:1 ratio.Provide a bond breaker at the back of the joint so the sealant adheres to the sides. If the joint fails the bond breaker will be a backup seal.Have clean straight edges at the joints.
39Bitumen synthetic rubber (Plastiseal) A flexible gun applied sealant suitable for sealing limited movement joints inretaining walls, basements and the like. Bitumen based is not compatible withother sealants, however it may be used with bituminous tanking i.e. Mulseal.
40E HEALTH PRECAUTIONSAdhesives and sealants contain hazardous chemicals i.e. formaldehyde andmethyl-butyl ketone.Health risks are caused by:inhalation of the fumescontact with the skinswallowingTo avoid health risks:Read manufactures hazard warningsUse gloves. (Disposable gloves are cheap and easy to use)Wear eye protection if necessary.Working area is well ventilated.Wear a suitable mask if the fumes are likely to be a hazard.