Coatings trowel

Thin coating Trowelled coatings Self-leveling screeds... 

Two-pack epoxy Section 12.3.3. These are widely used to give the maximum protection to concrete surfaces, floors and walls. They can be applied as relatively thin coatings by spray or as thick epoxy surfaces applied by trowel. In all cases, the application must be preceded by adequate surface preparation (see Section 12.6.1). To allow maximum penetration into the concrete the first coat must have a low viscosity. Coal tar epoxies are used where protection is the main requirement. 

Trowelled coatings There are a number of proprietary products available but the majority are based on epoxy resins and applied at thicknesses ranging from 0.5 to 5 mm, depending on exposure requirements. 

Various thermosetting and thermoplastic resins BS 3900 Powder/liquid system in factory. Airless spray/trowel in field Superior chemicai and abrasion resistance compared with enamels. Comparatively expensive. Simultaneous coating internally/externally possible. Various resins available to suit particular requirements. 

FBE-coated pipe requires careful handling from factory to the pipe trench to avoid mechanical damage. Repairs are undertaken with either trowel or brush-applied, liquid two-pack epoxy resin-based paints or by melt sticks of compressed powder. 

Coatings are applied to the outside or inside of the foundation, creating a radon-resistant barrier between the source and the inside of the home. They come in a wide variety of materials including paint-like products that can be brushed on the interior of the foundation, tar-like materials that are applied to the outside, and cementitious materials that can be brushed or troweled on. They cannot be applied to the underside of the concrete floor slab for obvious reasons, so they must be applied to the inside surface of the slab. The effective life of an interior coating can be greatly diminished by damage therefore, care must be taken to provide protection to the material used. 

Lightweight concrete is usually sprayed on, but may be troweled or formed-in-place using reinforcing mesh. Pneumatically applied material is about 20% heavier than poured-in-place lightweight concrete. As with all concretes, moisture creates a corrosive condition at the surface of the steel. Protective coating of the substrate surface is needed to protect against corrosion. 

Mastics are sprayed on a substrate in one or more coats, depending on the desired degree of fire resistance. The final coat of all fireproofing mastics should be rolled or brushed to provide a smooth surface finish. The material should be applied with a sufficient number of coats to prevent running or slumping and sufficient drying time should be allowed between coats. Mastics may also be hand-troweled, if permitted in the manufacturer s specifications. 

The protective medium against fire discussed here is a water-insoluble mastic. Mastic is defined as a material of heavy paste consistency which can be applied with a putty knife, trowel, brush, or heavy duty spray equipment to yield a coating from 1/32 inch to one inch or more. These mastics are of mineral composition, bound by an organic resinous medium, and dry to ultimate hardness by the volatilization of an organic solvent. They are further characterized by high impact strength, and assistance to abrasion, water, and many chemicals. 

Pastes and Mastics. Bulk adhesives such as pastes or mastics are the simplest and most reproducible adhesive to apply. They produce heavy coatings that fill voids, bridge gaps, or seal joints. They can be in the form of high-viscosity extrudable liquid or a trowelable mastic. 

Polyurethane roof coatings can be applied by trowel (Figure 4.8), squeegee or by spray. The product is supplied in two components. It may be used on areas exposed to traffic as well as non-trafficked roofs. The thickness of the cured system is approximately 1 mm. 

Figure 4.8 Trowel application of polyurethane roof coating...

Selfelastomeric materials may be compounded and calendered with a chemical curing agent which will, over a period of time, slowly cure the sheet at ambient temperatures. This type of curing is primarily noted in natural rubber and neoprene sprayed and troweled coatings, and has not, in recent years, been, to the writer s knowledge, employed for total cure of sheet linings. 

To install the block with adhesive/membrane on properly prepared substrates, the adhesive/membrane is applied to the substrate at a minimum Vie" thickness with a trowel. The adhesive/membrane is then troweled on the back, sides and end of the block also at a minimum Me" thickness. The coated block... 

A primer adhesive is first applied to a properly prepared concrete surface. A thin coat of epoxy mortar is then applied with a trowel. While this thin coat is still wet, a fiberglass membrane is rolled into the mortar. The edges of the membrane should be overlapped 2 inches. The mortar will squeeze up through the voids in the fiberglass mesh, resulting in adhesive base to which the final epoxy mortar will adhere. While this first application of mortar is still tacky, the second layer of epoxy mortar is applied over the glass cloth. This second layer may then be screeded and leveled. ... 

Among the various applications which have not been treated in greater detail are the spray coat applications and the underlayment applications. The spray coat applications are based on combinations of cement and other fillers, together with a latex binder. These applications may be applied by banish, roller and trowel, as well as by spray. They are often promoted as a substitute for "rubbing" concrete. 

Troweling Easily automated Very low material losses specially prepared materials only for flat, strip, or panel-type parts wood panel coating... 

Highly pigmented, pasty coatings and viscous putties and fillers are applied by troweling. The materials are applied with a pair of counterrotating rollers. Excess material is smoothed and pressed into the workpiece surface. This method can only be used for flat, striplike, or panel-shaped workpieces (e.g., wooden panels). 

Uses Epoxy for water dilution in combination with amine curing agents, forming fine particle size emulsions useful as modifiers for Portland cement, concrete, mortars, stuccos, grouts, as binders for trowel-applied floor toppings, as bond coats, base coats, membrane coatings, and sealers... 

Uses Diiuent for epoxy systems, for soiv.-free coatings and floorings Features General purpose low toxicity improves adhesion to most substrates incl. oily metal ( 5-10 phr) improves trowelability of epoxy mortars add to resin or curing agent Properties Gardner7 max. liq. sp.gr. 1.04 dens. 8.6 Ih/gal vise. 100cps... 

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