The use of multi-component adhesive products in cartridges has become a crucial factor in the wind industry, particularly for on-site repairs. The apparent simplicity of using these cartridges has significantly contributed to their popularity in the wind market. However, to ensure the best application quality, several key areas need to be considered.
All multi-component adhesives require thorough mixing to ensure that the cured material meets the necessary specifications. Therefore, it is essential to select the appropriate mixer diameter and number of mixing elements to achieve a homogeneous mixture. This can be visually verified by checking for streaks or marbling, which indicate inadequate mixing.
Another key consideration is the application temperature, as it impacts the viscosity of the component materials within the cartridge. This, in turn, affects the back pressure and the mixing elements' ability to fully mix the components throughout the mixer. Therefore, it is crucial to evaluate a particular mixer's performance across the adhesive's typical application temperature range to ensure optimal mixing.
Selecting Your Application Gun
Choosing the correct application gun is crucial. Since different multi-component adhesives have specific mixing ratios, the first priority is to select a gun that matches the ratio of your cartridge. In the wind industry, these ratios are typically 1:1, 2:1, and 10:1 by volume.
Application guns can be powered in three main ways, and the choice will ultimately depend on the available power source.
BATTERY AND PNEUMATIC APPLICATION GUNS
The force exerted on the piston can be adjusted incrementally to control the material's flow rate. This linear force applied to the cartridge pistons significantly enhances the consistency of the mixed adhesive. However, excessively high forces should be avoided as they can result in inconsistent flow rates.
MANUAL APPLICATION GUNS
In manual application guns, the force acting on the piston is determined by the gearing within the gun and is generally not adjustable. When the trigger is depressed, the material flow decreases as the pressure in the system is released, and the force drops to zero. This cycle is repeated with each trigger depression. The resulting drop in force leads to an inconsistent mix, thereby making manual application guns unsuitable for use with Sika’s wind products.
HOW TO GET STARTED
The good news is that Sika has already specified the correct mixer for each product and cartridge type, so it's essential to follow these recommendations.
- Prepare the Cartridge: Once the cartridge is loaded into the application gun, remove the blanking plug and extrude 5–10 mm of material to level both components.
- Clean both outlets to avoid cross-contamination.
- Attach the Static Mixer: Affix the recommended static mixer to the cartridge by hand-tightening it.
- Initial Extrusion: Squeeze the trigger to extrude approximately two mixer lengths of material in beads.
- Visually check the mixture for any streaks or marbling, which would indicate poor mixing.
- Commence Application: If the mixture appears uniform, proceed with the application.
- Handling Stops and Starts: For application stops shorter than the mixer's open time, you can restart immediately.
- If the mixer open time is exceeded, replace the mixer, and extrude two mixer lengths of material to ensure proper mixing before resuming application.
- For detailed information, refer to the product data sheet and additional product information sheets specific to each material.
In case of reach out to your Sika technical Service centre for help.
