MOUNTING BRACKET (REAR BRAKE CALIPER) – SANDBLASTING PROCESS
With all of the brake caliper hydraulic pistons now restored to a usable condition, I turned my attention to the caliper bodies themselves. The next step in the restoration process is to strip the factory coating and repaint the calipers in a high-temperature gloss black finish.
From my research, achieving a durable and high-quality paint finish starts with proper surface preparation. Ideally, paint should be applied directly to bare metal wherever possible. When done correctly, the process involves applying an etch primer to the bare surface, followed by the colour coat, and finally a clear coat for added durability and protection.
Because I plan to use an etch primer—which is specifically designed for bare metal as I've mentioned before—I need to remove as much of the original factory coating from the OEM calipers as much as possible.
Up to this point, I’ve had good success using traditional grinding and metal resurfacing techniques to strip coatings from various parts. My initial plan was to use the same method on all four brake calipers. During testing, the bench grinder removed the factory coating effectively, but I noticed it was also altering the surface of the aluminium. I suspect this is due to heat buildup caused by friction from the wire wheel.
(Above) The stripped metal surface appears to show heavy pitting, likely caused by heat buildup during grinding.
Another issue was accessibility—getting the grinder into tight areas proved difficult. Progress was slow, with even a small section taking around 30 minutes to complete.
At this stage, I decided the bench grinder was no longer the best tool for the job. While it could achieve the desired result, it required too much time and effort. It also produced a lot of debris, unpleasant odours, and airborne particles that ended up on my clothes and skin.
For years, I’ve been researching alternative methods for stripping automotive parts more efficiently, and this seemed like the perfect opportunity to upgrade my setup.
So I purchased a Unimac 90L benchtop sandblasting cabinet—the most affordable and compact option available to me. I’ve wanted one of these for quite some time, and after watching countless reviews and demonstration videos online, it became clear how effective sandblasting is for quickly stripping metal parts.
The main reasons I held off previously were the cost and limited storage space. However, after reorganising my workspace and weighing the long-term benefits, I decided it was a worthwhile investment.
This cabinet should significantly improve my workflow—not just for this project, but for future restorations as well. The ability to strip parts down to bare metal in minutes rather than hours is a huge advantage.
https://i.postimg.cc/7hXKQhjw/1_New_Sandblaster_setup.jpg
(Above) The cabinet is connected to a 2.0HP high-flow 60L air compressor and a 1000W dust extractor. I also installed a water trap and air regulator to control pressure and reduce moisture in the air lines.
https://i.postimg.cc/qqQ1ZqWM/1_Sandblaster_Work_Area.jpg
(Above) I also chose a coarse 30/60 grit garnet blasting media, which is affordable and easy to source locally.
I set the air regulator to the recommended 90 PSI (0.65 MPa).
https://i.postimg.cc/KjQ0sjCc/1_Setting_Max_air_pressure_on_regulator.jpg
(Above) Moisture control is critical in sandblasting, as water in the air lines can clog the system. The regulator with a built-in water trap helps minimise this risk.
Before moving on to the calipers, I decided to test the setup on a smaller component—a pair of rear caliper mounting brackets.
Here’s the condition of the brackets before blasting:
https://i.postimg.cc/mkVm6kKF/2_Brackets_Before_Blasting.jpg
(Above) While most of the factory paint coating had been removed, tight areas still retained some of the old paint—exactly where sandblasting should excel.
With everything set, I placed the brackets in the cabinet and began blasting. The results were exactly what I hoped for—fast and effortless. The remaining paint was removed in seconds, and both brackets were fully stripped within minutes.
https://i.postimg.cc/ZnjwDnXC/2_Bracket_After_Blasting_1.jpg
https://i.postimg.cc/wMFwbMnt/2_Bracket_After_Blasting_2.jpg
(Above) Both brackets are now completely stripped back to bare metal, with all of the factory coating removed.
This first test confirmed that investing in a sandblasting cabinet was the right decision. The time savings and improved results are immediately noticeable, and I’m looking forward to using this setup to restore all four brake calipers next.
By
DJ_Party_Favor ·
I need some paintwork doing, and my usual bodyshop is stacked out with work. Does anyone know of a good bodyshop in Norfolk ?
Thanks