Professional use only - from the 24th August 2023, adequate training is required before industrial or professional use of this product.

Should you require training, visit - https://www.safeusediisocyanates.eu/

Sikaflex 403 Tank & Silo is a 1-part, moisture curing, elastic sealant. It is designed for sealing steel containers built in sections such as enamelled steel or stainless steel tanks. The Product is resistant to liquid manure, silage liquids and is suitable for sealing domestic and municipal sewage systems

Uses:

• Sealing segmented or bolted steel tanks including wall to floor connection joints
• Tanks for the anaerobic digestion process including Biogas tanks
• Liquid manure tanks
• Drive-in silos for agricultural use
• Agricultural stables
• Silage clamp retaining walls
• Domestic and municipal sewage treatment plants including waste water
• Floor joints where very high chemical resistance is required

Quick Links - Click To Jump To Section:

   
• Features & Benefits
• Surface Preparation
• Application Notes
• Chemical Resistance

Features & Benefits

   
• 1-part, moisture curing, polyurethane elastic tank and silo sealant
• Designed for sealing steel containers built in sections such as enamelled steel or stainless steel tanks
• Resistant to domestic and municipal sewage, liquid manure and silage liquid
• Good mechanical resistance
• Very good resistance to specific chemicals
• Very good tear propagation resistance
• High modulus of elasticity
• Movement capability of ± 20 % (ISO 9047)

Surface Preparation

The substrate must be sound, clean, dry and free of all contaminants such as dirt, oil, grease, cement laitance, old sealants and poorly bonded coatings which could affect adhesion of the sealant. The substrate must be of sufficient strength to cope with the stresses induced by the sealant during movement.

• Use techniques such as wire brushing, grinding, grit blasting or other suitable mechanical tools to remove all weak substrate material
• Repair all damaged joint edges with suitable Sika repair products
• Completely remove all dust, loose and friable material from all surfaces before application of any activators, primers or sealant
• Where joints in the substrate are saw-cut, flush away all slurry material and allow joint surfaces to dry

For optimum adhesion, joint durability and critical, high performance applications such as joints on multistorey buildings, highly stressed joints or extreme weather exposure, use the following priming and pretreatment procedures:

Non-Porous Substrates

Enamelled steel, aluminium, anodised aluminium, stainless steel, galvanised steel, powder coated metals or glazed tiles:

• Clean and pre-treat using Sika Aktivator-205 applied with a clean cloth or Sika Primer 3N applied with a brush

Consult the tank manufacturer's instructions for their specific preparation and priming recommendations.

Other metals, such as copper, brass and titanium-zinc:

• Clean and pre-treat using Sika Aktivator-205 with a clean cloth
• Wait until the flash off time has been achieved
• Apply Sika Primer-3 N or Sika Primer 115 by brush

PVC Substrates:

• Clean and pre-treat using Sika Primer-215 applied with a brush

Porous Substrates:

Concrete, aerated concrete and cement-based renders, mortars and bricks:

• Prime surface using Sika Primer-3 N applied by brush

For more details of the primer or pre-treatment products refer to the individual Product Data Sheet.

Note: Primers and activators are adhesion promoters and not an alternative to improve poor preparation / cleaning of the joint surface. Primers also improve the long term adhesion performance of the sealed joint. Contact our Technical Department on 0113 2455450 (option 2) or send a message to [email protected] for additional information.

Application Notes

Important Notes:

• Installation - Strictly follow installation procedures as defined in method statements, application manuals and working instructions which must always be adjusted to the actual site conditions
• Curing Time - Putting the Product into service too early can result in a reduction of the long-term stability of sealed sections. Allow the Product to fully cure before it is exposed to mechanical or chemical stress
• Corrosion - Corrosion protection is dependent on the thickness of the sealant layer. For butt or lap joints the Product provides effective protection at an application thickness of ≥ 8 mm
• Resistance to chlorine - The Product is resistant to chlorine for tank disinfection and dosing purposes only. Contact the tank supplier for guidelines and detailed conditions on dosing and disinfection
• Use on Bituminous, natural rubber or EPDM rubber substrates - These substrates can leach oils, plasticisers or solvents that can degrade the sealant causing the Product to become tacky. Do not use the Product on any building materials which leach oils, plasticisers or solvents
• Absorbency of natural stone substrates - Staining from plasticiser migration may occur when used on cast, reconstituted or natural stone such as granite, marble or limestone substrates. Do not use on natural stone substrates
• Swimming pools - Do not use to seal joints in and around swimming pools
• Alcohol affecting the curing mechanism - Exposure to alcohol during curing may interfere with the curing reaction and cause the Product to be tacky
  • a) Do not expose the Product to alcohol containing products during the curing period

Application:

• Apply masking tape where neat or exact joint lines are required
• After the required substrate preparation, insert a backing rod to the required depth
• Prime the joint surfaces as recommended in substrate preparation
• Note: Avoid excessive application of primer to avoid causing puddles at the base of the joint
• Prepare the end of the foil pack or cartridge, insert into the sealant gun and fit the nozzle
• Note: The Product is supplied ready to use
• Extrude the Product into the joint ensuring that it comes into full contact with the sides of the joint and avoiding any air entrapment
• IMPORTANT - Do not use tooling products containing solvents
• As soon as possible after application, tool the sealant firmly against the joint sides to ensure adequate adhesion and a smooth finish
• Use a compatible tooling agent such as Sika Tooling Agent N to smooth the joint surface
• Remove the tape within the skinning time of the Product after finishing
  • For lap joints such as in enamelled steel containers consult the tank manufacturer for specific application advice

Over-Painting the Sealant

IMPORTANT

• Tacky paint over the sealant - Some paint systems may exhibit plasticiser migration that will cause the painted surface to be tacky.
  • Consult the paint manufacturer for specific advice on over-painting sealants
  • Trial the paint system with the Product prior to undertaking the project
• Cracking paint over the sealant - Rigid paint systems reduce the elasticity of the Product and may crack when used on joints subject to movement
  • Do not use rigid paint systems to over-paint joints subject to movement

• The Product can be over-painted with most conventional paint coating systems
• Prior to application test the paint system for compatibility
  • Allow the Product to fully cure before over-painting
  • Carry out preliminary trials to test the paint for compatibility in accordance with ISO/TR 20436:2017 - Buildings and civil engineering works — Sealants — Paintability and paint compatibility of sealants

Colour Variation

• Note: Colour variations may occur due to the exposure in service to chemicals, high temperatures or UV-radiation, especially with white colour shade
• This effect is aesthetic and does not adversely influence the technical performance or durability of the product

Cleaning Of Tools

• Clean all tools and application equipment immediately after use with Sika Thinner C
• Hardened material can only be removed mechanically
• For cleaning skin, use Cleaning Wipes

Chemical Resistance

Chemical attack

• Chemical resistance is only effective after the Product is fully cured and is dependent on the chemicals, their concentration and their temperature
• Exceeding the stated performance limits could cause depolymerisation of the sealant
• Analyse the content, exposure time and temperature of the chemicals
• Design the joints for the intended conditions
• Sikaflex 403 Tank & Silo is resistant to:
  • Water
  • Sea water
  • Liquid manure
  • Silage liquid
  • Dilute alkalis
  • Neutral water based dispersed detergents or cleaners
  • Domestic and municipal sewage
• Sikaflex 403 Tank & Silo is not resistant to:
  • Concentrated organic and inorganic acids
  • Organic solvents
  • Chlorinated or aromatic hydrocarbons