Ratio checks are often used to diagnose a problem with a coating application after the fact but being proactive and checking before any major spraying work commences can benefit productivity. If sprayed off-ratio, material manufacturers are unlikely to back up any performance claims.
Ratio checks are essential in systems mixing two different components just before application, which initiate a chemical reaction that leads to the desired properties of the coating, such as curing, hardening, or adhesion. The components are typically a base component (resin) and a hardener or catalyst.
The importance of ratio checks in this context cannot be overstated due to several reasons:
1. Quality and Performance:
Coatings are formulated to achieve specific performance characteristics, such as durability, adhesion, flexibility, and resistance to environmental factors. Proper mixing ratios ensure that the chemical reaction occurs as intended, leading to the desired properties and performance of the coating. Deviating from the correct ratio can result in coatings that don't cure properly, leading to compromised quality and performance.
Consistency in mixing ratios is crucial to ensure uniformity in the final product. Uneven mixing can result in areas with varying properties, leading to an inconsistent finish, and potentially causing issues like poor adhesion, discoloration, or uneven texture.
3. Curing and Hardening:
The chemical reaction between the components of a coating is responsible for curing or hardening the coating. If the mixing ratio is incorrect, the reaction may not proceed as expected, leading to insufficient curing or incomplete hardening. This can result in coatings that remain tacky, soft, or easily damaged.
Many coatings are expensive, and waste due to improper mixing can lead to significant financial losses. Specifically, costs incurred for reblasting and material wastage.
5. Application Properties:
Coatings with incorrect mixing ratios can exhibit poor flow, levelling, and viscosity properties. This can affect the ease of application, leading to issues such as uneven coverage, drips, sags, and difficulty in achieving the desired finish.
Though preparation of the substrate is often an important factor, properly mixed coatings are more likely to adhere well to the substrate. Inadequate mixing can result in poor bonding between the coating and the surface, leading to adhesion failure over time.
7. Long-Term Durability:
Coatings with incorrect ratios might experience reduced long-term durability, as they might not have undergone the necessary chemical reactions to provide the expected protection against environmental factors, wear, and corrosion.
8. Health and Safety:
Some coatings contain chemicals that can be hazardous if not mixed correctly. Accurate mixing ensures that the reaction occurs safely, minimizing the risk of toxic fumes, chemical reactions, or other safety hazards.
In industrial and professional settings, ratio checks are often performed using calibrated equipment and precise measurement techniques to ensure the correct mixing of components. This practice is a fundamental step in achieving consistent and reliable coating results, maintaining quality standards, and ensuring the longevity of the coated products.
At Spray Plant 2K, we offer training on this with all machines purchased or hired from us. Please contact us if you are experiencing any of the issues raised above.