Since the 1980s a popular detail on sports cars and luxury vehicles has been the vibrant, colorful brake calipers peeking through the spokes on their shiny alloy wheels.
Whether admired up close or in while in motion, colored calipers add a distinct, signature detail that truly enhances a car’s appearance, making one wonder how such an impeccable, beautiful finish is achieved. On many high-end vehicles today and in the robust aftermarket for automotive parts and accessories, powder coating is the preferred finishing method for colored brake calipers.
So, can brake calipers be powder coated? Powder coating is the preferred finishing method for colored brake calipers. It is an elaborate process requiring complete disassembly of calipers for it to be performed properly but the eye-catching results speak for themselves.
If you are looking to add a splash of color to your existing brake calipers or want to get your car noticed on the road from the next lane over, powder coating is the preferred finishing method for renowned car manufacturers and automotive detail shops around the world.
Before deciding on racing red or midnight black for your calipers, there are certain things you should know so read on to learn more.
What is Powder Coating?
Powder coating is a finishing process performed almost exclusively on metal substrates for decorative or protective purposes.
The powder consists of a free-flowing blend of polymer resins, pigments, curing agents and other additives having the appearance of all-purpose flour and is applied via an electrostatic spray gun that evenly distributes the electrically charged particles onto the grounded target surface.
The item is then moved to a curing chamber (basically a large oven) where under exposure to heat, the dry powder solidifies and hardens into a tough, durable coating that is highly resistant to fading, chipping and corrosion.
Powder coating is frequently used to provide finishing to home appliances such as ovens, ranges, washers, dryers and refrigerators, as well as bicycle frames and automotive parts.
How Are Brake Calipers Powder Coated?
There are three main stages to the process of powder coating brake calipers. They are (1) disassembly and pre-treatment, (2) powder application and (3) curing and re-assembly.
Although opinions may vary as to whether it is necessary to completely dis-assemble calipers prior to powder coating, it cannot be argued that compromising the calipers’ braking function for the sake of aesthetics is simply unwise.
Stage One – Disassembly and Pre-treatment
Complete disassembly of brake calipers is necessary because of the high temperature that is needed to properly cure the powder during the final stage of powder coating.
In particular, the rubber dust boots which serve to keep brake dust and debris away from the pistons and their housings, as well as the rubber piston seals, are susceptible to damage at high temperatures.
These are the various temperature stages of powder coating:
- Powder begins to soften at around 176° F;
- Powder melts at around 300° F; and
- Powder cures and hardens at around 400° F.
The first step of dis-assembly is removing the pistons from their seats. Since they are actuated by hydraulic pressure, the best way to remove them is by using pressurized air in the hydraulic line fitting to pneumatically push them out far enough for vise grips to be used to remove them completely.
The next step will be removing the dust boots and piston seals.
Most calipers consist of two or more cast iron pieces held together by long bolts so these will need to be removed and the pieces separated. Some calipers have clips attached by screws to stabilize the brake pads and these will need to be removed as well.
Basically the calipers need to be completely disassembled so that the main pieces comprising the caliper body can be powder coated individually.
Stage Two – Powder Application
In order for the powder to be evenly applied and properly cured it is imperative that the caliper surfaces be thoroughly cleaned so that they are completely free from any dirt, grime, grease, and brake fluid.
This process begins with a firm brush and degreaser. Many auto detail shops actually bake the caliper pieces at high temperatures (exceeding powder curing temperatures) to burn off any remaining residue.
Once the caliper pieces are clean any holes and openings in the surfaces must either be plugged or covered with high-temperature tape to prevent powder from entering.
This is particularly important for the piston sockets as any powder coating material that manages to get inside can seriously compromise braking performance when the caliper is re-assembled and re-installed on the vehicle.
Powder coating spray guns are electrostatic meaning they imbue the particles with a negative charge as they exit the nozzle. A grounding clip attached directly to each caliper piece causes the charged powder particles to cling to the grounded metal surfaces smoothly and evenly.
Best results are achieved by suspending the caliper pieces using metal wire to allow for 360° spraying.
Stage Three – Curing and Caliper Re-assembly
Once the caliper pieces are evenly coated with powder the next and final step will be curing them by placing them into an oven or similar type chamber. Most powders require a minimum temperature of 400° F to cure properly.
It is crucial to follow the powder manufacturer’s specifications for cure temperature and duration. Curing at less than the recommended temperature or for a duration shorter than the specified time will compromise the end result.
Improperly cured powder coatings can chip, the color can fade or in severe cases the coating can melt under extreme braking.
As with the spraying process, suspending the caliper pieces with metal wire so that they hang freely from the oven rack will ensure even heating and thus proper curing.
Gloss Coat and Decal Application
To achieve a high gloss or mirror finish to the caliper pieces a secondary coat of high gloss powder can be applied midway through the curing process. Although initially whitish and opaque in appearance, once fully cured the result is an immaculate gloss.
Many car enthusiasts insist on prominently displaying either the make of their car or brand of their brakes on the calipers and this can be achieved by applying a highly durable, temperature-resistant decal onto the exposed side of the caliper.
Many auto detail shops will apply the decal prior to the secondary gloss coating so that the decal is underneath this protective layer.
Limitations of Powder Coating
While it is widely considered the all-around best option for finishing brake calipers, powder coating does have certain limitations.
As we have examined, the process of powder coating requires that brake calipers be completely disassembled and re-assembled once the process is completed. For the do-it-yourselfer, this step can be prohibitive and there are even auto detail shops that decline such jobs.
Another concern with powder coating is its susceptibility to melting above certain temperatures.
While everyday driving and braking pose no concern for powder coated calipers, the extreme temperatures that can be achieved during track and road racing can soften and melt powder coating to the point that the material can contaminate pads, seals, and pistons and severely compromise brake worthiness.
Powder Coating vs. Painting
There are several advantages to powder coating compared to painting. First, powder coating provides a thicker, tougher coating that can be more uniformly applied, and cures faster with fewer blemishes.
Next, powder coating tends to be more resistant to chipping, corrosion, and extreme temperatures. Lastly, powder coating offers unique specialty effects such as blending and applying different colors.
Powder coating is also a more earth-friendly option. Conventional paints rely upon solvents that evaporate for their application; these solvents create emissions containing VOCs (volatile organic compounds) which have been linked to global warming and climate change.
Powder coating does not involve any solvents and in many cases, overspray of the powder can be recaptured and repurposed.
There are certain situations where painting is advantageous over powder coating. Generally speaking, painting is far more affordable than powder coating and often does not require disassembly of calipers.
Also, there are certain painting methods employed by high-end brake manufacturers that result in an extremely durable and temperature-resistant coating that is suitable for race cars.
While the time and labor associated with powder coating and the cost of equipment may not justify setting up a powder coating station in your garage to take on this type of project yourself, knowing the meticulous steps of doing the job right will ensure that you find the right professional to do it for you and produce the results you expect.