Many hobbyist automotive painters and refinishing professionals have experienced their fair share of solvent pop paint defects. One of the more common paint problems that mar the refinished surface of a newly painted panel, solvent pop ranks among the most challenging paint imperfections to remedy. Learning about solvent pop can help you avoid costly and time-consuming repairs, including repainting the entire vehicle.
The comprehensive guide below explores the visual characteristics and common causes associated with solvent pop. We’ll also cover how to address solvent pop if it occurs, before focusing on key prevention methods you can implement in your paint booth. Best practices for avoiding solvent pop include using only high-quality products and tools, many of which you can find here at Colors Edge.
What is solvent pop?
Solvent pop, like many other paint problems and imperfections, disrupts the clean, smooth flow of automotive paint across a surface, manifesting both a visual and physical defect. If you run your hand over solvent pop, it almost feels like there’s a rough piece of sandpaper sitting just below the painted surface, with several of the most prominent sandpaper grains poking through. Visually, solvent pop resembles a patch of poorly painted-over sand centralized to one area of a panel.
Solvent plays a critical role in automotive painting. As part of the normal drying process, the solvent evaporates, leaving behind a cured, painted surface. In many different types of paint products—including automotive paint and rattle-can spray paint—solvent accomplishes the following:
- Keeps pigments suspended in a sprayable form
- Promotes atomization during spraying
- Controls flow across the painted surface upon application
However, in the case of solvent pop, the solvent bubbles become trapped beneath the paint’s surface as it dries and either burst or collapse, forming a multitude of surface flaws. In the worst cases of solvent pop, these defects are obvious after the paint begins to cure. Unfortunately, in most cases, painters may not notice solvent pop until the paint has hardened to the point where manual removal offers the only remedy.
Solvent pop vs. fish eye
Distinguishing the difference between fisheye and solvent pop can be challenging without seeing them in person. Both solvent pop and fisheye cause crater-like defects in the painted surface, but fisheye resembles more of a sinkhole, whereas solvent pop looks like the broad mouth of a dormant volcano.
Surface contaminants cause both solvent pop and fisheye, but solvent is the only contaminant that causes solvent pop. Oil, grease, silicone, and moisturizing products—like hand lotion—cause fisheye to occur, whether they’re on the surface to be painted or in the air line to the paint spray gun. Thoroughly cleaning surfaces with a grease remover, adding fisheye eliminator, and ensuring a clean air supply can help prevent fisheye from happening.
What can cause solvent pop?
Identifying the root cause of solvent pop can help you prevent it from occurring in the future. Once you’ve addressed the underlying issue, you can tackle your next paint job with confidence. Here are the most common causes of solvent pop:
- Trapped air or solvent vapor beneath a fast-drying paint surface
- Using a thinner or reducer that dries too quickly for the current temperature or humidity
- Applying paint too heavily or in coats that are too thick
- Not allowing enough flash time between coats
- Spray gun or compressed air pressure set too low or too high
- Drying the paint too fast (excessive temperature or heat applied too close or too soon)
- Improper surface preparation (contamination, poor sanding, or residual rust)
- Contaminated air lines or dirty spray environments
- Poor ventilation or insufficient airflow during drying
- Incorrect hardener or mixing ratios that accelerate curing too quickly
Unfortunately, sometimes there’s a combination of factors contributing to solvent pop, which can complicate resolving the issue. However, making small, controlled adjustments can help you rule out potential causes one by one. It may also be wise to integrate a few test pieces into your workflow after any changes to ensure a solvent-free finish the next time you roll a high-paying project into your paint booth.
Can you fix solvent pop?
Yes, you can fix solvent pop, but remedying this paint imperfection may require fully removing the fresh coat of paint and recoating the panel. In the best-case scenarios, you can wet sand and polish the solvent pop blisters to remove them. Most instances of solvent pop require a middle ground, which can make it challenging to determine the most cost-effective and efficient course of action.
How to avoid solvent pop
Many of the best practices that have served automotive painters for generations can help you avoid solvent pop. Examples include ensuring a clean and contaminant-free paint booth and mixing up paints according to the manufacturer’s recommendations. Below are additional ways you can avoid solvent pops appearing in your freshly applied paint:
- Start with a clean surface: Thoroughly remove wax, grease, and other contaminants that can interfere with solvent release.
- Use only the recommended thinner: Stick to what’s specified on the tech sheet to ensure proper evaporation rates.
- Apply paint in thin, even coats: Wet, controlled films allow solvents to escape without trapping.
- Allow proper flash time between coats: Let each layer dry sufficiently before applying the next.
- Set compressed air pressure correctly: Too much pressure can over-atomize the paint and overload the surface.
- Stay within the recommended drying temperature: Overheating can skin over the surface too fast, trapping solvent beneath.
- Keep heat sources at a safe distance: Direct heat can cause the surface to dry too quickly, leading to bubbling.
- Avoid fast reducers in hot conditions: Fast evaporating solvents in high temperatures increase the risk of popping.
- Control booth temperature and humidity when possible: Stable conditions support even drying and solvent release.
Finally, don’t underestimate the importance of clean, consistent airflow across the painted surface. Good ventilation helps carry solvents away as they evaporate, reducing the likelihood that they’ll become trapped beneath the paint film. It’s a simple step that supports all your other efforts to prevent solvent pop.
Tools and products that help prevent solvent pop
Infrared curing lamps and controlled bake cycles help ensure the paint dries evenly and completely, which is crucial in preventing solvent pop. It’s also important to reference the paint’s Technical Data Sheets (TDS) and follow the manufacturer’s recommendations. Below are additional products that help reduce the occurrence of solvent pop:
- Cleaners and degreasers:Grease, wax, and silicone removers are key to removing contaminants that can contribute to solvent pop and other paint defects.
- Adjustable spray guns: A fine-tuned spray gun promotes proper solvent evaporation after paint application.
- Reducers: Use the appropriate reducer to ensure solvent escapes the paint’s surface without leaving blemishes behind.
- Digital timers: A digital timer or smart spray booth system can help monitor flash times to ensure the paint fully cures.
Colors Edge offers several automotive refinishing products and resources key to reducing the possibility of solvent pop. If you’d like to learn more about reducer use and purposes, check out our corresponding guide on best paint practices.
Steer clear of solvent pop and other defects with Colors Edge
Under the right conditions, solvent pop can happen to any automotive painter. However, learning about and taking the necessary steps to avoid solvent pop can minimize the chances of this paint defect occurring. One of the best ways to prevent solvent pop is to purchase and use high-quality products that ensure as close to a contaminant-free environment as is possible.
If you’re ready to take your automotive refinishing skills to the next level, contact us or call us at 336-378-7872 to learn more about our superior paint products backed by years of industry expertise. We’re happy to help you identify factors that may be causing solvent pop and direct you to the proper resources to help resolve the issue. The rest comes from experience and finding the right tools to achieve your desired results.
