Topical Defects vs Sub-Surface Defects - Living life on the edge of the razor blade

[Mike Phillips]

Topical Defects vs Sub-Surface Defects - Living life on the edge of the razor blade


Here's a saying I've said for years and below I show you how it applies to doing paint correction.


When I was younger I used to live my life on the edge of the razor blade. Now that I'm older I tend to live my life on the blade of the butter knife. -Mike Phillips



Topical Defects vs Sub-Surface Defects

Here's the deal, all paint defects can be placed into one of these two categories.


1: Topical Defects

1. Surface stains
2. Oxidation
3. Road Film or Traffic Film
4. Surface impurities
5. Type I Water Spots
6. Type I Bird Dropping - Topical Stain Etching
7. Old wax, sealant or coating
8. Paint Transfer

2: Sub-Surface Defects

1. Swirls
2. Scratches
3. Micro-marring from abrasives
4. Micro-marring from pad - also called Pad Haze
5. Hologram scratches
6. RIDS - Random Isolated Deeper Scratches
7. Type II Water Spots - Imprint Rings
8. Type II Water Spots - Crater Etchings
9. Type II Water Spots - Sub-surface water stains - usually only single stage paint
10. Type II Bird Dropping - Fractured/Wrinkled Etching
11. Sanding marks or sanding scratches
12. Tracers
13. Pigtails
14. Scuffing

It's normally fairly easy to remove Topical Defects starting with simple remedies such as washing the car, wiping the car, using a non-abrasive paint cleaner or using any compound, polish or cleaner/wax.


Removing Sub-Surface defects always means removing some measure of paint to LEVEL the highest portions of the paint surface with the lowest depth of the paint defect. This means always using product that contain abrasives and/or sandpaper.



The LIMIT as to what can and what cannot be safely removed is determined by the paint thickness. Factory clearcoats are an average of 2 mills thin. A Post-it Note is approximately 3 mils thin. This means the clear layer of paint you have to work with or abrade is thinner than a Post-it Note. So before tackling any sub-surface defects, hold a Post-it Note between your thumb and index finder and this will ingrain in your brain just how thin this protective layer of paint is on your car.




Other considerations


UV Protection

All the UV protection for the entire matrix of paint, that is the e-coat, primer, basecoat and the clearcoat top layer is in the clearcoat top layer. The more paint you remove the less UV protection will be left to protect the entire matrix of paint over the service life of the car.



Burn-Through - Buff-through - Strike-Through

These are terms used to describe removing too much of the clearcoat top layer that you expose the basecoat or color coat layer of paint. IF you expose the clearcoat top layer the ONLY way to fix the damage is to,



Re-paint the affected area

This normally means you'll have a "blend line" on the panel. That is a definitive section where there is the original clearcoat and a "line" where the edge of the new layer of clearcoat ends after spraying only a section of the panel. A blend repair costs less than re-painting an entire panel and will normally be the option your car insurance covers. On light colored cars the "line" between original layer of paint and the new layer of clear paint will be difficult to see. On medium and dark colors it will be more noticeable and "no" you cannot buff away the blend line as this means you're buffing away the paint job and you will then expose the new basecoat sprayed under the new clearcoat to make the damaged area visually disappear.



Re-paint the panel

This means the entire panel, from edge to edge will be re-painted and thus there will be no blend line. This is the preferred method by car owners to have damage repaired but it will cost more and often times your insurance will not cover it.




Best Practice

Whenever you have a defect you want to try to remove, the best practice is,

Use the least aggressive approach to get the job done



If the least aggressive approach is not working to your satisfaction, then increase the level of aggressiveness in the procedure until you've reached your comfort level for removing paint from the surface.


My normal best practice will be to compound the area with either a foam cutting pad or a wool or microfiber pad for the normal 8 to 12 Section Passes and then stop. Sometimes this will remove the defect but a lot of times all it will do is improve the defect or defects making it or them more difficult to see. This is the safe approach.



Living life on the edge of the razor blade

If you're feeling gutsy - you can try to compound the area with the deeper defects you want to remove to see if they can be removed without going through the clearcoat. Here's how I do this,

Start by doing up to 8 to 12 Section Passes over the effected area. Stop and inspect.

If the defects are removed, move onto polishing and sealing the paint.

If the defects are not removed and you want to try more sections passes, then repeat the section pass motion only shrink the size of the area you're buffing down to about a 12" by 12" area and make approximately 4-5 section passes then stop and inspect. Repeat until you're happy.

If at any point you turn your tool over and see the color of the basecoat on the face of your buffing pad, well then here's my quote for that situation,


Words cannot describe the heart-sinking feeling that overwhelms you when you discover you've burned through the paint -Mike Phillips




Living life on the blade of the butter knife

My advice is for most people and most cars, (with the factory thin paint), go ahead and buff the area with a compound and cutting pad for approximately 8 to 12 section passes and then STOP. Whatever you get is what you get. Learn to live with the defect or defects and move on in life. In most cases you will have at a minimum improved the defect or defects to the point that they won't bother you as much and a lot of time you'll be the only person that knows where they are.



Throwing the dice

If you're felling lucky! And if the defects REALLY bugs you then here's what you do. Take your car to a couple of high quality body shops with stellar reputations among the hard-core car guys in your home town, this would be the body shops or (technically called Collision Shops), that others take their restoration projects too for a custom paint job. For example, this is where Jim took his 1965 Chevelle to get painted after he spent 6 years restoring the car.

Ask them how much money it will cost to repaint the entire panel where the defects are located?


If you're comfortable with this price and willing to pay it IF you buff through the clearcoat, then go for it. Buff and buff and buff until the defect is removed. Then in a worst-case scenario you do buff through the clearcoat, then you've already internally accepted the bad news and budgeted for a professional re-paint.



Hope this helps you to figure out how to proceed with the paint defects in your car's paint.

[Mike Phillips]

Continued....



Related topics


What it looks like when you buff through the clearcoat - Burn Through - Strike Through - Mike Phillips



When to stop buffing - Or - How far should you go to remove swirls and scratches?



How do you know when to stop buffing?



Clearcoats are thin by Mike Phillips



RIDS and Feathersanding - A Highly Specialized Technique by Mike Phillips



Two Types of Bird Dropping Etchings



3 - Types of Water Spots - Type I, Type II and Type III



Wetsanding - Fresh Paint vs Factory Paint



Wetsanding removes paint - Compounding removes paint - Polishing removes a little paint



"Use the least aggressive product to get the job done"



Factors that affect how aggressive or non-aggressive a product is...



Dr. ColorChip How-To Videos with Dan McCool and Mike Phillips - CompetitionReadyTV.com and Autogeek.com

[Mike Phillips]

Continued.....


Related topics


How to do a proper Test Spot

EVERYONE should to a TEST SPOT before buffing out an entire panel or an entire car. If you don't know how to do a Test Spot - I show you EXACTLY how to do it starting at the 12:30 minute time stamp in the below video.


How to do a proper Section Pass

Everyone should know what a SECTION PASS is, why to do one and how to do one. I share this at the 19:45 minute time stamp in the video below.






If you're new to machine polishing with ANY brand or type of orbital polisher - information and techniques I share with the Porter Cable polish will still apply to the polisher you own. This video is incredibley information-rich and technique-rich.

[Mike Phillips]

Shared here,

Used Car - Spots on hood

[Mike Phillips]

Shared here,

Accidentally burned through clear coat

[axel06]

you will never forget the feeling once you notice that you have remove to much clear coat, or burn an edge

[Mike Phillips]

you will never forget the feeling once you notice that you have remove to much clear coat, or burn an edge

Agree Axel.

I actually explained this exact thing, that is this quote,


Words cannot describe the heart-sinking feeling that overwhelms you when you discover you've burned through the paint -Mike Phillips



In the video we shot yesterday.

How deep is too deep?

[Mike Phillips]

More info...




Related articles on this topic,

Considerations for removing paint defects - the BIG PICTURE

Topical Defects vs Sub-Surface Defects - Living life on the edge of the razor blade

When to stop buffing - Or - How far should you go to remove swirls and scratches?

What it means to remove a scratch out of anything...



And avoiding swirls, scratches, water spots and oxidation

Things you need to wash a ceramic coated car by Mike Phillips

When it comes down to maintaining a scratch and swirl free finish - it all comes down to how you touch the paint - Mike Phillips

How to safely wash a ceramic coated car by Mike Phillips - Traditional Hose & Bucket Approach

How, why & when to inspect your microfiber towels when detailing cars