By Christopher Brown of OCDCarCare.com
Paint swelling from paint correction, is a major source in frustration in the auto detailing industry.
No detailer enjoys redoing a partial or entire paint correction job. Especially when returning to a vehicle to find defects, that appeared to be gone, and find they are still there; hours or days later.
This gut wrenching condition occurs when paint heats up and swells. Some paint systems have the ability to absorb enough heat to enlarge themselves to levels capable of hiding defects during the paint correction process. After the paint cools down, and the paint stabilizes to its normal state the defects are visible, once again.
In a previous article, OCDCarCare explained paint swelling and the major factors that cause heat during paint correction. That article was focused on in-depth explanation of heat and swelling issues and its primary causes.
This article is intended to provide methods for managing and or mitigating heat produced during all automotive paint correction sessions.
These concepts include frequent and typical situations which auto detailers face on a regular basis. Awareness and use of these concepts can greatly limit heat generation. Or, at least, avoid large amounts of heat during paint correction, which directly lead to paint swell.
1) Know and Understand the Various Substrates of a Vehicle
The material something is made from is called the substrate. In this context, automotive panels and their material composition are the focus.
Understanding how a substrate material dissipates (releases) heat is an important aspect of automotive paint polishing.
In general, metals dissipate heat well. This means it requires more heat to get them warm to hot, and when hot, they cool off rather quickly.
Substrates such as plastic bumpers, carbon fiber panels, fiberglass, or composite plastics behave the opposite of metal. They have very little mass and their material composition does allow for efficient heat dispersion. Therefore they heat up faster and hold heat longer. In fact, some are hyper sensitive to heat, especially when its introduced quickly.
To effectively manage the heat and the swelling of panels during paint correction it is vital to understand:
- The many different substrates which make up a vehicle & their locations
- How those substrates react to heat
If the substrates of a vehicle are unknown, take the time and research the vehicle. A little bit of research can save a LOT of time and frustration to reduce heat when performing paint correction on a vehicle.
2) Heavy Compounding: Allow Panels to Cool Between Steps
This strategy works for all vehicle paint systems for all process with multiple steps of polishing. However, it is especially useful for reducing heat on paints requiring multiple compounding process since they are jacked up. And.. Yes, that’s a highly technical term…
This means vehicle surfaces that require a two-step paint correction, or more, to revive the finish back to life.
A two-step paint correction includes:
- A Compounding Step to remove the defects from the surface,
- A Finish Polishing Step to remove the marks created by compounding.
However, some vehicles are so “wrecked,” “beat (up),” “jacked (up),” “hammered”, or “thrashed,” that they need multiple compounding steps.
When multiple compounding steps are necessary, it is better to allow the area or panel to cool from the first compounding step, before moving onto the next.
A simple method to achieve this:
- Perform a compounding step on Panel A
- Move to an adjacent panel– Panel B. Fully compound Panel B before performing a secondary compounding step on Panel A.
IF the panel is large enough, it may be possible to work to another area (other non adjacent side of a roof or hood) will allow the first section to cool off.
This concept also applies to all paint polishing steps. Allow panels or areas to fully cool between any steps to avoid paint swelling.
3) Size of a Panel or Working Section Influences Heat Build Up Speed
This directly ties into the previous concept and magnifies it.
This size of a object dictates how much heat it can hold.
To demonstrate this, think of heating a standard 10” (~25cm) copper pan with a welding torch. It requires a significant amount time to heat a pan’s surface to 425°F (~218°C) in order to sear a steak.
However, it will take a mere fraction of the time and energy to heat a standard U.S. copper penny to 425°F (~218°C).
Why? Because heat build-up is based on both material composition and the mass of an object.
“How does this relate to heat and paint correction?” you ask.
If a panel is small, it heats up quickly because there is less mass and surface area to disperse heat. Therefore, detailers need to beware of the size of a panel receiving paint correction.
If an area is small, it cannot follow the same process of polishing as used for a hood or a roof. The heat builds much quicker on a panel with a small mass.
Therefore, different processes are necessary on different sized panels. Imagine using the same amount of passes used on a quarter of a roof and then on half of a front fender. the process may only cause the roof to be slightly warm, however it would cause the half fender to become extremely HOT.
4) Avoid Over Cycling Compounds or Polishes During Paint Correction
A polishing cycle is the amount of time a compound or polish is used (worked) over an area to remove defects during paint correction.
Many correction liquids on the market tout features of “long working time.” Well, the length of a polishing cycle MAJORLY influences the amount of heat generated into a paint system. This is magnified when paired with a long stroke Dual Action Polishers (especially a 21mm) and microfiber pads.
Combine this with the tendency of most detailers to over work (over cycle) correction liquids, and lots of heat is generated—QUICKLY!
They key here is to perform a test spot to find how many passes are actually needed for a particular result on each paint system.
5) Limit the use of Paint Swelling Solvents on Surfaces
Using a Combination of heavy solvents, from a few sources, can quick accelerate the speed and level of a paint swelling. Heavy solvents start swelling automotive paint before any paint correction begins. Use of these solvents can greatly magnify the negative impact of heat on automotive paint systems.
The main concept: avoid solvent heavy as much as possible on paint correction surfaces.
Solvents Types to Avoid or Limit Use as Much as Possible Prior To Paint Correction:
- Solvent Prep Solutions. These strip surfaces of traffic film, old waxes, and sealants, as a first step procedure.
- Heavy Compounds Containing Aggressive solvents for “chemical cut”. These solvents actively swell the paint system in order to reach in matrix of the paint to cut deeper.
- IPA (Isopropyl Alcohol) or ‘Panel Wipe’ solvent based solutions to remove left over polishing carrier oils. (A)Limit the use of “panel wipes” as much as possible. Instead of using after compounding, and then again after polishing—just use after polishing.(B)Use the lowest quantity of product to get the job done to limit their impact on paint swelling. This limits the amount potentially absorbed by the paint.
(C))During use, spray them to a towel and then apply to surfaces. Spraying a panel wipe directly to a vehicle’s surface may quickly inject a high amount of heavy solvents into a small area. As a result discoloring, or worse, may occur on sensitive paint systems or substrates.
Combine These Five Concepts To Reduce Heat & Swelling From Paint Correction
There are many other factors, outside these five concepts, that contribute to paint swelling.
However, the concepts listed here apply universally and have a profound effect on all automotive polishing. For the majority of auto detailing projects, if these five concepts are followed then excessive heat and high levels of swelling from paint correction will be greatly reduced.
“ALWAYS Keep Learning to Strengthen Your Passion & Your Business.”
© Christopher Brown – OCDCarCare Los Angeles
- How to Reduce Paint Swelling from Paint Correction: 5 Heat Control Tips - 10 August, 2020
- Detailing Paint Correction: Paint Swelling & Heat Problems Explained - 2 August, 2020
- OCDCarCare on Ammo NYC Podcast: Auto Detailing Lighting – Ep #38 - 21 November, 2019