Pigtails in paint after machine wetsanding

Mike Phillips · 03-05-2014, 02:07 PM

Pigtails in paint after machine wetsanding

Last week while working on Bill's 1967 Mustang GTA we found pigtail left in the paint after it was machine sanded.

These were primarily in the hood, front fenders and the hood.

Sore Thumb
After the entire car was polished using the Advanced Swirl Remover all of the shallow swirls and scratches had been removed however, deeper scratches like the pig tails still remained and now with no shallow scratches surrounding them to camouflage them they stood out like a sore thumb.

See my article on Random Isolated Deeper Scratches or RIDS for more information.

RIDS - The Definition of RIDS and the story behind the term...

RIDS are different than Pig Tails and Tracers but the fact remains, when you machine polish a car you first remove all the shallow defects and this then reveals all the deeper defects no matter how they were inflicted.

More info on the different types of paint defects here,

Tracers Tracers - RIDS - Pigtails - Cobweb Swirls - Rotary Buffer Swirls - Holograms - Water Spots - Bird Drooping Etchings - Micro-Marring

Machine Sanding = More Control + Cooler for the paint
Instead of getting more aggressive with a compound to remove the pig tails we chose to wet sand the paint using 3M Trizact #3000 Grit Sanding Discs on a Griot's Garage 3" Mini Polisher.

The Defelsko PosiTest DFT Combo Electronic Paint Thickness Gauge

First... this is a custom paint job so the clearcoat will tend to be thicker than a factory clearcoat. Still, I want to measure how thin or thick the total film-build is to give me a big picture idea for what I'm working on.

After taking a few measurements the readings were all fairly consistent so I made the decision with Bill's permission to go ahead and machine wet sand the pig tails and deeper straight line scratches out of the hood and roof.

Small Footprint + Super easy to control
Griot's Garage 3" Mini Polisher is my tool of choice for machine wetsanding isolated defects.

1/4" Interface Pad
Be sure to get an interface pad if you're going to do any machine wetsanding. It makes the sanding process less aggressive and the cushion provided by the foam core helps the sanding disc to conform to curves.

Mist a little water with a drop or two of soap mixed in for a lubricant...

Keep the sander moving and stop and inspect often so you only sand enough to level the surface and remove the defects.

Sanding out defects on the hood....

Tag Team
As I continued around the car sanding out pig tails and RIDS Robert followed me with the Flex PE14 Rotary Polisher, a wool cutting pad and Pinnacle Advanced Swirl Remover and removed the sanding marks.