PVA Pro Tip #4: Coating With Consistency – Frequently Asked Questions
Coating With Consistency: Thinner Use in Conformal Coating
Maintaining consistency in conformal coating application is essential for product reliability and process efficiency. One of the key variables in achieving a smooth, even coat is understanding how and when to use thinner. Below, we answer some frequently asked questions about thinning solvent-based conformal coatings.
Q: Why is thinner typically added to solvent-based conformal coatings?
A thinner is usually added to lower the viscosity of the base coating or to slow down its cure rate.
Q: How does using thinner benefit the conformal coating spraying process?
Diluting the coating with thinner enables an atomized spray head to apply the coating with a clean and consistent spray pattern. It can also help prevent the coating from curing too quickly or clogging the spray tip.
Q: What are the potential problems if not enough thinner is used?
Insufficient dilution can lead to poor spray quality and the formation of trapped bubbles within the coating.
Q: What are the potential problems if too much thinner is used?
Over-diluting the coating can result in uncontrollable spray patterns and significantly longer cure times.
Q: Are all thinners the same in terms of their composition and effects?
No, thinners can have different solvent compositions, which can affect their evaporation rate and other properties.
Q: What are the advantages of using a thinner with a fast evaporation rate?
Thinners with a fast evaporation rate can help to reduce the overall cure time of the conformal coating.
Q: What are the advantages of using a thinner with a slow evaporation rate?
Thinners with a slow evaporation rate can allow entrapped bubbles to escape the liquid film more easily. They can also be beneficial for intermittent processing as they may prevent the spray head from drying out and requiring cleaning as frequently.
Q: Can I get pre-mixed thinner solutions for my conformal coating?
Yes, many coating formulators offer pre-blended thinner packages that are mixed at the proper ratio for specific coating machines or process requirements.
Q: Is a thinner necessary for all conformal coatings?
No, UV curable or silicone conformal coating materials do not require thinners because they have very specific viscosities and thinning could lead to defects or failures.
