Dry Sanding a 1969 GTO by Mike Phillips with 3D Products
How to machine dry sand, compound and polish to remove orange peel, mottling and surface texture to create a show winning finish!
John's 1969 GTO custom, precision built by MirandaBuilt.com
This is a 9-year in the making, custom built 1969 GTO. The majority of the restoration and modifications were done at Miranda Built.com - Precision Built Street Machines. The car was shipped to Ohio where it was painted by Mitch and his team at
The custom paint job is approximately 4 years old and over this time the paint has shifted. The word shift in the custom car painting world can mean 2 different things.
1: Color changing or color shifting paints.
These are paints that actually change colors when viewed from different angles or when ambient light changes around the car. Another term to describe color shifting or color changing paints is chameleon paints. You can find more information about these types of paints here.
2: Paint shifting.
This is a physical change that the paint goes through after it is sprayed onto a vehicles and then over time the paint is physically alters to it's final composition and appearance. Changes in fresh paint occur as the paint fully dries and hardens. Changes also take place when body panels expand and contract with surrounding ambient temperatures. When paint is fresh it is a flexible membrane, it will move with the panel until it finally settles and reaches complete drying and hardness. During this time of shifting, the surface appearance and texture can also change. During this shifting process, the surface texture can change even if the car has already been sanded and buffed.
Backstory
The owner John contacted me after I was recommended by Jeremy Miranda at MirandaBuilt.com to prep the paint for the car's first public debut at the 2022 GoogGuys 24th Summit Racing Nationals presented by PPG.
Traditional cut and buff
Originally, John and I talked about doing a normal paint correction including dedicated compounding and polishing steps followed with a traditional wax. Once the car arrived, John and I inspected the paint closely under different lights.
Here's something any seasoned detailer knows, it's easy to take a paint job in horrible condition and take it to a higher level while at the same time showing the dramatic before and after changes via pictures and video.
It's a lot more difficult to take a great paint job with only minor issues to a higher level and in most cases, there won't be dramatic before and after pictures.
Both types of detailing require the right products, pads and tools as well as the necessary experience and skills, but I would say I working on paint that's already really nice and trying to take it to a higher level on a show car is a lot more challenging than correcting neglected paint on a daily driver.
Surface texture and mottling
The paint is PPG Global Refinish System in Sunset Bronze. When inspecting paint visually, the kind of minor imperfections this paint had were very difficult to see. I did my best to capture the surface of the paint but even with crystal clear pictures it's difficult to see the surface texture and mottling.
Here's a closeup shot of the surface of the paint on the driver's side of the roof.
Here's another picture from the passenger side sail panel.
Change of plans - Dry Sanding
After inspecting the paint with John here at 3D Garage, I asked John if he knew how much paint was sprayed onto the car. He said he wasn't sure but had the painter's phone number. The painter is Mitch Mumbower owner of RelicRestomods.com. I called Mitch and introduced myself, let him know John was at our shop with the 1969 GTO he painted and asked him about the paint job. Mitch confirmed he sprayed 5 heavy coats of clear over the car. About a month later they hard blocked with acrylic sanding blocks starting at #800 followed by #1000, #1500 and then #2000 and then compounded and polished.
For anyone that is not familiar with the process for sanding paint for a show car finish, the system Mitch and his team used is a text-book example of the right way to do it. I described what John and I were seeing at the surface level and Mitch confirmed what I think the issue is and it's the normal shifting of the paint over time. It's been almost 4 years since the car was painted, the normal shifting of the paint is over. Any solvents that needed to evaporate or outgass have done so.
Good to go
I shared with Mitch the 3D Dry Sanding System and told him I would only be using the #2500 grit sanding disc.
I asked him if he thought there was enough paint on the car to safely use this approach to remove the surface texture and mottling and get the paint back to flat again and he said yes, there's easily enough paint to re-sand. With Mitch's information and blessing, I discussed the dry sanding process with John and he gave me the green light to go ahead with this process.
Sanding Test Spot
Before sanding down an entire car I always start with a Sanding Test Spot. I have an experience with a sanding project where the painter sprayed a custom paint job onto a Ferrari. Then he sanded down the entire car. When he went to remove the sanding marks he couldn't get them out. He got my name from someone and asked me to take a look and see if I could get them out. This was back in 1989 or 1990, I wish I would have written down his name and taken a picture of the car.
Here's the deal though, the paint was so hard neither of us using the sanding papers, compounds and tools available at that time could remove the sanding marks. Buffing with the most aggressive compounds, wool pads and rotary polishers we simply couldn't remove 100% of the sanding marks. We could get about 70% of them out leaving behind the deeper scratches. Note that machine sanding discs like we have today were not invented yet. The painter asked me,
What am I going to do?
I said,
You're going to repaint the car.
And of course I recommended he contact the Rep for the paint line he was using, explain the situation and then try to troubleshoot what went wrong and avoid this issue moving forward.
The reason I share the story above is this - BEFORE you sand down an entire car - do a Sanding Test Spot first, this means sand a section of paint about the size of a microfiber towel and then using the compounds, pads and tools you THINK will work to remove the sanding marks to buff this sanded section of paint.
If you can remove the sanding marks and the results look great - then you're good to go. Move forward and sand down the car then buff it out.
If you find you cannot remove 100% of the sanding marks, you can a few other things like re-sanding and finishing out at a higher grit. You can try using a more aggressive compound and pad combo. But if you get to the point where you cannot remove 100% of the sanding marks without super heating the paint and risking burning through. The STOP. At this point all you have to do is somehow fix this one spot. The Sanding Test Spot saved your from a horrible mess. Just imagine what a headache you would have if you had sanded down the entire car only to find out the paint was so hard you cannot remove your sanding marks.
Sanding exposes the paint defects
After prepping the paint for sanding, I did my test spot to the driver's side of the roof. After making just a few passes with the #2500 grit sanding disc, BEFORE I completely leveled the surface texture I STOPPED and took these pictures.
Sanding levels the very top surface of the paint first. The result from this is it reveals the surface texture. Sanded portions of paint look dull because they are sanded and anything under the very top surface of the paint remains darker or shiny.
Check it out...
See the weird pattern that shows up after sanding? The darker areas are the low spots the sanded areas are the high spots. Over time the paint had shifted from expansion and contracting and after it finally settled the surface was no longer flat.
Compounding Test
Next I buffed a section of the sanded area and I was happy to find out the sanding marks buffed out easily. For my compound I used 3D 510 Premium Rubbing Compound. This compound is formulated to cut HARD clearcoats fast. What I always tell people is this,
If it will cut hard clearcoats fast... it will cut all paints fast
Me? I like to work as fast as I can while keeping my results professional grade, thus anytime I'm compounding I'm using 3D 510.
Go Time
Once I proved to myself via the Sanding Test Spot that my process works, it was time to get busy. I wanted to document and share how long it took me to sand, cut and polish an iconic Detroit Iron Muscle Car so I took a picture of my watch to show the time when I started. Later I have a pictures showing the time when the job was finished.
Here's the car as she arrived to the 3D Garage.
Waterless Wash
When the car arrived it was dusty, that's normal when a car is going through a build process. At this time the owner, who is also a custom interior craftsman, was building and installing the custom interior from scratch as well as the trunk interior.
I tried using a normal waterless wash and while it was working I noticed the film on the car was kind of oily. I also found tree sap or something like it on the horizontal panels.
3D Wipe
Instead of using the traditional approach by using a waterless car wash, I tested and ended up using 3D WIPE, which is a panel wipe for prepping paint for the installation of a ceramic coating. 3D Wipe is a paint-safe water-based, solvent wipe and it easily cut through the film on the car to leave and reveal clean, shiny paint.
Half-and-half pictures showing the film
In the pictures below, I took a moment to show what I'm talking about. The car was covered with a dusty and oily film.
Here's before on the passenger side
Here's half and half...
Here you can see how using 3D WIPE to remove the oily film left the paint crystal clear.
The Baggie Test and Mechanical Decontamination
(Sorry no pictures)
Once I have the car wiped-down, next it was time to do the Baggie Test to inspect for above surface bonded contaminants. Not to my surprise, the paint and the glass were horribly contaminated. Using a new, sandwich baggie to feel the paint and the glass - these surfaces felt like #80 grit sandpaper. No problem but it does mean I'll need to clay the paint and the class before moving to the next step.
To remove the contamination, I used the 3D WIPE with the 3D Detailing Clay Towel.
I could have sanded the contamination off when sanding the paint but here's the deal, trying to sand off contamination will work but it will waste your sanding disc super fast. It's much more time-efficient and money-efficient to simply use a mechanical method to remove the contamination and save your time and your sanding discs for actual sanding of the paint.
Removing vinyl graphics
The back window had the Miranda Built letting on it and with permission from John I removed these as he can replace them after I'm done with the car. I could have clayed the glass and then polished it and simply worked around the lettering but to be thorough and do the job right, the lettering had to come off.
In the elite custom car building world, owning a Miranda Built car is powerful bragging rights.
How to machine dry sand, compound and polish to remove orange peel, mottling and surface texture to create a show winning finish!
John's 1969 GTO custom, precision built by MirandaBuilt.com
This is a 9-year in the making, custom built 1969 GTO. The majority of the restoration and modifications were done at Miranda Built.com - Precision Built Street Machines. The car was shipped to Ohio where it was painted by Mitch and his team at
The custom paint job is approximately 4 years old and over this time the paint has shifted. The word shift in the custom car painting world can mean 2 different things.
1: Color changing or color shifting paints.
These are paints that actually change colors when viewed from different angles or when ambient light changes around the car. Another term to describe color shifting or color changing paints is chameleon paints. You can find more information about these types of paints here.
2: Paint shifting.
This is a physical change that the paint goes through after it is sprayed onto a vehicles and then over time the paint is physically alters to it's final composition and appearance. Changes in fresh paint occur as the paint fully dries and hardens. Changes also take place when body panels expand and contract with surrounding ambient temperatures. When paint is fresh it is a flexible membrane, it will move with the panel until it finally settles and reaches complete drying and hardness. During this time of shifting, the surface appearance and texture can also change. During this shifting process, the surface texture can change even if the car has already been sanded and buffed.
Backstory
The owner John contacted me after I was recommended by Jeremy Miranda at MirandaBuilt.com to prep the paint for the car's first public debut at the 2022 GoogGuys 24th Summit Racing Nationals presented by PPG.
Traditional cut and buff
Originally, John and I talked about doing a normal paint correction including dedicated compounding and polishing steps followed with a traditional wax. Once the car arrived, John and I inspected the paint closely under different lights.
Here's something any seasoned detailer knows, it's easy to take a paint job in horrible condition and take it to a higher level while at the same time showing the dramatic before and after changes via pictures and video.
It's a lot more difficult to take a great paint job with only minor issues to a higher level and in most cases, there won't be dramatic before and after pictures.
Both types of detailing require the right products, pads and tools as well as the necessary experience and skills, but I would say I working on paint that's already really nice and trying to take it to a higher level on a show car is a lot more challenging than correcting neglected paint on a daily driver.
Surface texture and mottling
The paint is PPG Global Refinish System in Sunset Bronze. When inspecting paint visually, the kind of minor imperfections this paint had were very difficult to see. I did my best to capture the surface of the paint but even with crystal clear pictures it's difficult to see the surface texture and mottling.
Here's a closeup shot of the surface of the paint on the driver's side of the roof.
Here's another picture from the passenger side sail panel.
Change of plans - Dry Sanding
After inspecting the paint with John here at 3D Garage, I asked John if he knew how much paint was sprayed onto the car. He said he wasn't sure but had the painter's phone number. The painter is Mitch Mumbower owner of RelicRestomods.com. I called Mitch and introduced myself, let him know John was at our shop with the 1969 GTO he painted and asked him about the paint job. Mitch confirmed he sprayed 5 heavy coats of clear over the car. About a month later they hard blocked with acrylic sanding blocks starting at #800 followed by #1000, #1500 and then #2000 and then compounded and polished.
For anyone that is not familiar with the process for sanding paint for a show car finish, the system Mitch and his team used is a text-book example of the right way to do it. I described what John and I were seeing at the surface level and Mitch confirmed what I think the issue is and it's the normal shifting of the paint over time. It's been almost 4 years since the car was painted, the normal shifting of the paint is over. Any solvents that needed to evaporate or outgass have done so.
Good to go
I shared with Mitch the 3D Dry Sanding System and told him I would only be using the #2500 grit sanding disc.
I asked him if he thought there was enough paint on the car to safely use this approach to remove the surface texture and mottling and get the paint back to flat again and he said yes, there's easily enough paint to re-sand. With Mitch's information and blessing, I discussed the dry sanding process with John and he gave me the green light to go ahead with this process.
Sanding Test Spot
Before sanding down an entire car I always start with a Sanding Test Spot. I have an experience with a sanding project where the painter sprayed a custom paint job onto a Ferrari. Then he sanded down the entire car. When he went to remove the sanding marks he couldn't get them out. He got my name from someone and asked me to take a look and see if I could get them out. This was back in 1989 or 1990, I wish I would have written down his name and taken a picture of the car.
Here's the deal though, the paint was so hard neither of us using the sanding papers, compounds and tools available at that time could remove the sanding marks. Buffing with the most aggressive compounds, wool pads and rotary polishers we simply couldn't remove 100% of the sanding marks. We could get about 70% of them out leaving behind the deeper scratches. Note that machine sanding discs like we have today were not invented yet. The painter asked me,
What am I going to do?
I said,
You're going to repaint the car.
And of course I recommended he contact the Rep for the paint line he was using, explain the situation and then try to troubleshoot what went wrong and avoid this issue moving forward.
The reason I share the story above is this - BEFORE you sand down an entire car - do a Sanding Test Spot first, this means sand a section of paint about the size of a microfiber towel and then using the compounds, pads and tools you THINK will work to remove the sanding marks to buff this sanded section of paint.
If you can remove the sanding marks and the results look great - then you're good to go. Move forward and sand down the car then buff it out.
If you find you cannot remove 100% of the sanding marks, you can a few other things like re-sanding and finishing out at a higher grit. You can try using a more aggressive compound and pad combo. But if you get to the point where you cannot remove 100% of the sanding marks without super heating the paint and risking burning through. The STOP. At this point all you have to do is somehow fix this one spot. The Sanding Test Spot saved your from a horrible mess. Just imagine what a headache you would have if you had sanded down the entire car only to find out the paint was so hard you cannot remove your sanding marks.
Sanding exposes the paint defects
After prepping the paint for sanding, I did my test spot to the driver's side of the roof. After making just a few passes with the #2500 grit sanding disc, BEFORE I completely leveled the surface texture I STOPPED and took these pictures.
Sanding levels the very top surface of the paint first. The result from this is it reveals the surface texture. Sanded portions of paint look dull because they are sanded and anything under the very top surface of the paint remains darker or shiny.
Check it out...
See the weird pattern that shows up after sanding? The darker areas are the low spots the sanded areas are the high spots. Over time the paint had shifted from expansion and contracting and after it finally settled the surface was no longer flat.
Compounding Test
Next I buffed a section of the sanded area and I was happy to find out the sanding marks buffed out easily. For my compound I used 3D 510 Premium Rubbing Compound. This compound is formulated to cut HARD clearcoats fast. What I always tell people is this,
If it will cut hard clearcoats fast... it will cut all paints fast
Me? I like to work as fast as I can while keeping my results professional grade, thus anytime I'm compounding I'm using 3D 510.
Go Time
Once I proved to myself via the Sanding Test Spot that my process works, it was time to get busy. I wanted to document and share how long it took me to sand, cut and polish an iconic Detroit Iron Muscle Car so I took a picture of my watch to show the time when I started. Later I have a pictures showing the time when the job was finished.
Here's the car as she arrived to the 3D Garage.
Waterless Wash
When the car arrived it was dusty, that's normal when a car is going through a build process. At this time the owner, who is also a custom interior craftsman, was building and installing the custom interior from scratch as well as the trunk interior.
I tried using a normal waterless wash and while it was working I noticed the film on the car was kind of oily. I also found tree sap or something like it on the horizontal panels.
3D Wipe
Instead of using the traditional approach by using a waterless car wash, I tested and ended up using 3D WIPE, which is a panel wipe for prepping paint for the installation of a ceramic coating. 3D Wipe is a paint-safe water-based, solvent wipe and it easily cut through the film on the car to leave and reveal clean, shiny paint.
Half-and-half pictures showing the film
In the pictures below, I took a moment to show what I'm talking about. The car was covered with a dusty and oily film.
Here's before on the passenger side
Here's half and half...
Here you can see how using 3D WIPE to remove the oily film left the paint crystal clear.
The Baggie Test and Mechanical Decontamination
(Sorry no pictures)
Once I have the car wiped-down, next it was time to do the Baggie Test to inspect for above surface bonded contaminants. Not to my surprise, the paint and the glass were horribly contaminated. Using a new, sandwich baggie to feel the paint and the glass - these surfaces felt like #80 grit sandpaper. No problem but it does mean I'll need to clay the paint and the class before moving to the next step.
To remove the contamination, I used the 3D WIPE with the 3D Detailing Clay Towel.
I could have sanded the contamination off when sanding the paint but here's the deal, trying to sand off contamination will work but it will waste your sanding disc super fast. It's much more time-efficient and money-efficient to simply use a mechanical method to remove the contamination and save your time and your sanding discs for actual sanding of the paint.
Removing vinyl graphics
The back window had the Miranda Built letting on it and with permission from John I removed these as he can replace them after I'm done with the car. I could have clayed the glass and then polished it and simply worked around the lettering but to be thorough and do the job right, the lettering had to come off.
In the elite custom car building world, owning a Miranda Built car is powerful bragging rights.
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