Pigtails - Need help figuring out cause?

[MattyJ]

Pigtails - Need help figuring out cause?


Hi Mike,

I want to say I'm a big fan and really appreciate your availability and expertise.

My boss and I want to cone to a class with you. We live in Pennsylvania. I'm hoping you or another member can give me some direction with an issue. I was recently hired at a custom car shop after doing details and paint corrections as a hobby for years. I lost my job as a Physical Therapist Assistant and am fortunate to find good work in another field. The cars I'm working on have fresh 1-2 week old clear and are very soft.

They hand sand in jumps of #500 grit to #1000 grit to #2500 grit and want to be able to use power sanders to cut down time and wear and tear on their bodies.

I generally hard rubber block at #1000 grit then go to the DA for 3M Trizact #1500, #3000 and then #5000 then buff with Menzerna 2500 on a FLEX 3401.

However its not been the case with this paint. I have been plagued by pigtails everywhere all over the car after buffing out. I'm using a quality DA sander with 2.5 mm throw 60 psi and slower speed. I had to completely re-sand the car by hand in #2000 to fix most of it. Ive found myself with a rotary buffer, white 3m foam pad and SONAX CutMax just to fix it all.

Could it be the DA sander or maybe the 3M paper?

Any help is greatly appreciated.

 

[Mike PhillipsMike Phillips is verified member.]

Hi Mike,

I want to say I'm a big fan and really appreciate your availability and expertise.

Hi Matt,

Great talking with you over the phone this morning. Let me comment on your info and then I'll summarize our conversation.

My boss and I want to cone to a class with you. We live in Pennsylvania.

Would love to have you and your boss attend any of my classes. I know I'm biased - but I think my car and boat detailing classes are the best in the industry. I also beleive they are the most hands-on in the industry plus - they are fun too.

For yourself and everyone else that will read this thread into the future, here's the link to get more information about any of the classes I teach.


Mike Phillips Detailing Classes

I'm hoping you or another member can give me some direction with an issue. I was recently hired at a custom car shop after doing details and paint corrections as a hobby for years. I lost my job as a Physical Therapist Assistant and am fortunate to find good work in another field.

Congratulations on getting a job at a shop that builds and then paints custom cars. That's a great gig if you can get it. Especially when the owners and the rest of the team truly care about the quality of work they put out including the final results for the paint finish.

Some shops focus on build quality, that is building and bolting a car together and then the paint looks like swirled-out crap. Kind of misses the mark if you ask me.

The cars I'm working on have fresh 1-2 week old clear and are very soft.

As we discussed on the phone, I believe this is where we need to start. I think it's important to always start at the beginning of a process if there are problems and troubleshoot from there. If the clear paint being sanded and then buffed is still soft after 2 weeks - I think this is the problem. In a perfect world, the paint is neither too soft or too hard, it's right in that sweet spot where it can be easily sanded, cut and polished to perfection every time. No guessing, no this or that, just a dialed-in paint system and paint process that results in consistent results on the paint hardness aspect.


Instead of trying different sanding papers or sanding discs; instead of trying different tools, pads and products - I would start first by contacting the Paint Rep for the brand of paint the shop is spraying and just like a Detective, investigate the entire process from start to finish.

Have the Painters go through each step of their daily routine before spraying the paint. Which clear are they using, how are they reducing it, are they using a hardner, a flex agent, "anything" added to the paint. Then take a look at the process after the paint is sprayed, the drying/curing/baking process.

A good Paint Rep should be an expert at looking at the process being used with THEIR product line and be able to troubleshoot if there are any problems and if there are problems leading to soft paint - where the process can be adjusted or tweaked.

Instead of trying to fix soft paint and pigtail problems downstream, try to prevent them upstream.


At least that's how I would start to solve this pigtail problem.

 

[Mike PhillipsMike Phillips is verified member.]

And just to comment...

They hand sand in jumps of #500 grit to #1000 grit to #2500 grit and want to be able to use power sanders to cut down time and wear and tear on their bodies.

Wow!

Starting the sanding proess at #500 grit sounds really coarse, heck even #800 grit would sound course to me.

Is there a ton of orange peel in the paint or other defects that need to be sanded flat?

Seems to me, with a decent finish coming out of the paint booth, a person could start by blocking out at #1500 grit to get the paint flat. If you really need to cut faster then drop down to #1200 or #1000 but starting at #500 grit is something I would reserve for flattening out gel-coat.

I generally hard rubber block at #1000 grit then go to the DA for 3M Trizact #1500, #3000 and then #5000 then buff with Menzerna 2500 on a FLEX 3401.

The above sounds like a process I would use. With the Nikken brand of finishing papers - you might be able to start at #1200 or #1500 grit. These are an electronics grade finishing paper that offers faster cutting with more uniform sanding mark pattern than conventional wet/dry automotive sand papers.

I'll send you some to test out.

However its not been the case with this paint. I have been plagued by pigtails everywhere all over the car after buffing out.

So here's what's happening - assuming you're right about the paint being soft - the pigtail problem is not being caused by stray grains of abrasives coming off the Trizact sanding disc and then being trapped between the disc and the paint - it's a result of the soft paint EASILY being abraded.

Then when you go to buff out, the shallow pigtails buff out first and any deeper pigtails that remain stand out like a sore thumb.

If the above scenario is in fact the situation - using a more aggressive compound or more aggressive pad or more aggressive tool may remove the pigtails faster and more efficiently - but the root cause of the problem is the paint - not the process.

This is why if it were me - I would start by calling your Paint Rep and asking them to pay a visit to the shop to go through the process from start to finish. That is from squirting the paint to final polish and wipe-off. Most established brand of paint should be more than happy to provide technical assistance and old-fashioned customer service to ensure the reputation of their brand.

IF not - there are other paint companies that will be more than happy to invest in your success with their brand.

I'm using a quality DA sander with 2.5 mm throw 60 psi and slower speed.

That's really tiny. I'm going to guess the orbit stroke is close to 5mm or 3/16 inches. I have a Dynabrade finishing DA Sander and I believe mine is 3/16" - I'll check.

I had to completely re-sand the car by hand in #2000 to fix most of it. Ive found myself with a rotary buffer, white 3m foam pad and SONAX CutMax just to fix it all.

Not only is sanding and buffing a car twice a lot of work and time - it's also removing a lot of the precious paint the painter sprayed.

Could it be the DA sander or maybe the 3M paper?

Any help is greatly appreciated.

I wish I were there to do some testing and I would be better able to diagnose the root cause of the problem and dial-in a process that worked and produced consistent results from car to car. But I'm not.


Working on soft paint is difficult. Every aspect, sanding, buffing, polishing and even wiping. It's also going to be a problem for the final owner of the car. What we all really want and need when it comes to car paint is something that's not too soft nor too hard but right in the sweet spot where anyone with a basic Porter Cable dual action polisher can work on it.


I have your shipping address, I'll get some Nikken Finishing Papers and the new SONAX Ultimate Cut 6" out today.


Please keep us updated and thank you for your trust and for reaching out to me. I appreciate it.



:cheers:

 

[MattyJ]

Hello again, Mike. Thank you for taking The time today To help me troubleshoot the issue Im having. I spoke with the owner , who also paints and he contacted the paint rep today. He mentioned he has been looking at a baking systen to install to help, but is diligent about getting the paint system worked out first. .

To clarify about their sanding procedure , I meant to say the shop traditionally goes in jumps of 500 grit at a time; They start with 1000 Grit rubber hard block then 1500, 2000, 2500, and polish from there. They Previously have produced world class finishes but admit it takes alot of work to get them flat and cut by hand. They have had no luck with orbital machine sanding as they had the pigtailing issues.

I look forward to trying out the sand paper and Xtra cut. I will report back with my thoughts.

I am including some photos for yourself and other forum members to see what i am talking about.

Thank you again for your time and expertise. I will update the posts as we work through the trouble shooting process.

View attachment 71576
The machine sander with 1500 just seems to float in the surface and does not make much slurry like a cured panel.

 

[MattyJ]

View attachment 71577

65 Shelby Hertz rental that we are prepping for a photo shoot for Hemmings later this week.

 

[TMQ]

Seen this many times while working in a body shop.

It usually happens when body shop "dry" sand clear coats is stead of wet sanding. They use DA with sand paper to get panels flat for rotary work.
The issue (my thoughts) is that the sand paper gets loaded up with knobs of soft clear coats in the sandpaper. Then they get harden and act like large pieces of 80 grit and cut pig tails---the same pattern in DA movements.

Then you have pig tails in clear coats....

I tend to not try to remove all the tails---I'm never sure how deep they go into the clear coat. If rotary wasn't able to get them out, I think they are too deep. You might be able to wet sand them down enough to take them all out and buff to final finish. Me....I wouldn't bet on it...

Tom

 

[TMQ]

Check with painter that did the sanding. They might tell you how much more you can sand down the clear.

The painter at the shop I worked at---does dry sanding all the time. And then he rotary finishes the paint. From time to time he'll mess up. He just then turn around, pushes car back into the booth and repaints the car again.

That IS WHY I tell people to get the paint people to sand down and buff the paint. Then I'll refine and correct paint at the final stages.

Tom

 

[Mike PhillipsMike Phillips is verified member.]

First, here's the full sizer version of your picture,


Pig tails look BAD!

Quick question Matt,


Tom brought up DRY SANDING - I didn't think to ask you over the phone if all the sanding is being done dry or wet?

I assumed both the hand sanding and the machine sanding are done wet?

 

[TMQ]

To add, I’ve seen it done both ways—-DA dry and DA wet.

In both cases, sanding paper loads up quickly and they wait too long before switching out the paper-causing pig tails.


Sent from my iPhone using Tapatalk

 

[98CayenneTA]

To add, I’ve seen it done both ways—-DA dry and DA wet.

In both cases, sanding paper loads up quickly and they wait too long before switching out the paper-causing pig tails.


Sent from my iPhone using Tapatalk

This is a big cause, jammed up paper and not working clean enough.

Another thing is, unlike da polishing during a paint correction with compounds and polishes... try to keep the pad rotation to a minimum and see if that helps. No pad rotation would be just fine.

 

[Mike PhillipsMike Phillips is verified member.]

Just to add...


I don't do any dry sanding. I don't like the dust mess and I don't want to have to wear a respirator. Too much dust for my taste.


So knowing all my sanding is wet, be it by hand or be it by machine, I've NEVER seen this much pig tailing with my work. Never.

I do change out discs as needed. I try to squeeze as much use out of every disc I use simply because my parents taught me not to be wasteful. So I try to be a good steward with all of Autogeek's resources.

The last car I machine sanded was a 1970 340 Charger R/T with DIP or Dirt in Paint. I machine sanded twice, once with 3M Trizact #3000 followed by 3M Trizact #5000. Zero Pig Tails.



Machine sanded with 3M Trizact

Final results

And I would say after compounding out sanding marks, the paint was on the Medium/Hard side of the Paint Hardness Spectrum. Definitely not soft. Also just to note, this is a 20 year old basecoat/clearcoat paint job.




Assuming Matt is swapping out sanding discs and above all - working clean, that is clean car, clean shop, clean sanding lube, clean everything, it's my hunch the problem is the paint is too soft. This is why I suggested the shop call in the Paint Rep and have him do some investigating into the paint process.

Instead of trying to fix the problem at the sanding and polishing step - first investigate upstream and make sure there's not a problem in the painting step.


It's one thing if you're going to paint, sand and buff a care ONE TIME. It's another thing if it's a running business or a running process. The process needs to be looked at and if something is amiss then fix it where it's at, don't band-aide it downstream.


Again - I've never experienced pig tails that look like this.

 

[2black1s]

While this post doesn't directly address the "pigtails", here's some of my general thoughts on sanding and polishing fresh paint. Some of these same comments, I have expressed previously in other similar threads.

I understand the desire to sand and polish paint as early as possible after painting to help with productivity, but that has never been my recommended process.

Whenever I did my "top notch" paint jobs I would always wait at least 60 days before sanding and polishing. This gives the paint (and primer surfacers) the necessary time to fully "shrink-up" and harden before polishing and that results in a more permanent finish. Many times when a new paint job is sanded and polished within days of painting, the initial results can be stunning, but a few months down the road the paint's finish and gloss level will have diminished slightly. This is a natural phenomenon as the paint cures and is referenced in other threads as paint "hold-out" or paint "die-back".

All of my final sanding is done by hand. I would never use a DA (or any machine) for final sanding. I don't care how good you or anyone professes to be using a machine for final sanding, you will always have better control and precision by hand. And when you're doing the final sanding on a "perfect" paint job, isn't that what you're looking for - absolute precision?

And then, hard rubber blocks are another no-go as a primary tool for final sanding in my book. My final sanding is primarily done with a soft rubber or sponge pad that can follow the contours of the surface being sanded. This is because there are really no perfectly flat panels and even if there were, with the final sanding you are only trying to level the paint's texture, nothing more. All other straightening and flattening should have been done before the paint was ever applied.

Now I completely understand that every paint job is not the "perfect" paint job and as such compromises are made and accepted. Sanding and polishing "too early" is one of those compromises. I've certainly done it.

 

[Mike PhillipsMike Phillips is verified member.]

I was hoping you would see this thread and chime-in. I know I always appreciate your input. :xyxthumbs:

I understand the desire to sand and polish paint as early as possible after painting to help with productivity, but that has never been my recommended process.

Just to add for everyone that will read this into the future.

There's a difference between the type of work done at a collision shop and a custom paint shop or restoration shop. At most collision shops, if they are a successful business, cars are coming in, getting fixed and then leaving. They are at the shop for days, not months. For custom work, there's more time allotted for the work and the car can remain at the shop for extended time - or be brought back.

I just want to share that there are reasons why some cars are painted, sanded and buffed in days or a week or two while others cars have the luxury of having more time for the work to be done.

Whenever I did my "top notch" paint jobs I would always wait at least 60 days before sanding and polishing. This gives the paint (and primer surfacers) the necessary time to fully "shrink-up" and harden before polishing and that results in a more permanent finish.

Many times when a new paint job is sanded and polished within days of painting, the initial results can be stunning, but a few months down the road the paint's finish and gloss level will have diminished slightly. This is a natural phenomenon as the paint cures and is referenced in other threads as paint "hold-out" or paint "die-back".

I'm so glad you shared the above. I completely agree with the above process. If a car can be left along for weeks or even months before sanding and buffing the end results will look better and look better longer due to the reasons 2black1s shared above.

I also want to share a WORD I learned from a painter friend of mine that is the word he uses to describe what happens to paint as it continues to dry and cure after painting.

Shift


Once when talking to him I asked him how long he likes to wait after spraying a car before he sands and buffs the paint and his answer was he likes to 3-4 weeks to give the paint time to SHIFT.

The word SHIFT in this context means not only to fully dry, cure and harden, but also time for any solvents to evaporate out-of and off-of the paint. It also means for the paint to MOVE or SHIFT until it's happy. And this means that as the paint is drying, it's going to shrink and shrink means MOVE or shift.

Body panels are also going to expand and contract as temperatures rise and fall and all these things, the curing, drying, expanding and contracting affects the paint in the first few weeks (or months), until the paint reaches a point where it's done shifting and it settles into it's permanent location and also permanent STATE of being.

Then it's time to sand and buff.


Love that word - shift.

And of course, depending upon the shop and the project - not everyone or every car has the luxury of just sitting around a body shop for weeks or months for the paint to shift before the technicians sand and buff and that's why for a lot of "Daily Drivers", any fresh paint work that is going to be sanded and buffed is often times sanded and buffed within days of popping out of the paint booth instead of months.

As a new wrecked car arrives at a collision shop - another must leave - most shops only have so much real-estate to park cars.



Thanks for chiming in 2black1s - I wish I could remember everyone's real name.


Mike

 

[Mike PhillipsMike Phillips is verified member.]

My final sanding is primarily done with a soft rubber or sponge pad that can follow the contours of the surface being sanded.

What do you think of these?

The above is a medium soft rubber hand backing pad from Meguiar's.


It fits a half sheet perfectly. I show it because we sell it but I've also been using it since going to work for Meguiar's back in 1987.


Have you ever used one of these?

 

[2black1s]

I was hoping you would see this thread and chime-in. I know I always appreciate your input. :xyxthumbs:

...


Thanks for chiming in 2black1s - I wish I could remember everyone's real name.


Mike

Thanks Mike! John

What do you think of these?

The above is a medium soft rubber hand backing pad from Meguiar's.


It fits a half sheet perfectly. I show it because we sell it but I've also been using it since going to work for Meguiar's back in 1987.


Have you ever used one of these?

I don't recall ever using that exact pad. The ones I use, made by 3M, look nearly identical and from your description they sound very similar too.

 

[Mike PhillipsMike Phillips is verified member.]

Thanks Mike! John

I'll try to lock that into my knower. It's getting a tick full now days.

I don't recall ever using that exact pad.

The ones I use, made by 3M, look nearly identical and from your description they sound very similar too.

There is a similar flexible rubber block from 3M and also a thinner version with holes in it if I remember correctly.

PM me your shipping address and I'll send you one to inspect and test out. Then share your thoughts as I would respect your opinion.

 

[Cosmin]

with older, restore or repaint cars , sometimes i seen a lot of sanding marks , pigtails that were in the prime , or color , and clear coated after... but still visible , just a thought
* if that`s the case is not much to do.

but if on the clear than probably , like was mention before because is a soft paint , also the jump #500-#1000

 

[TMQ]

with older, restore or repaint cars , sometimes i seen a lot of sanding marks , pigtails that were in the prime , or color , and clear coated after... but still visible , just a thought
* if that`s the case is not much to do.

but if on the clear than probably , like was mention before because is a soft paint , also the jump #500-#1000

That's the conundrum...Is it in the clear? Base coat? or in primer?

One thing you can do---wet sand lightly on clear coat. Buff out and there's a bitty change, then you'll know it's in the clear coat and can be taken out.

Tom

 

[2black1s]

with older, restore or repaint cars , sometimes i seen a lot of sanding marks , pigtails that were in the prime , or color , and clear coated after... but still visible , just a thought
* if that`s the case is not much to do.

but if on the clear than probably , like was mention before because is a soft paint , also the jump #500-#1000

That's the conundrum...Is it in the clear? Base coat? or in primer?

One thing you can do---wet sand lightly on clear coat. Buff out and there's a bitty change, then you'll know it's in the clear coat and can be taken out.

Tom

Scratches buried beneath the clear in the color coat are usually pretty obvious to the trained eye and are a totally different type of defect than the one being discussed here.

The primary cause of such defects is from finishing with too course of a sanding prior to applying the primer surfacer and topcoats. In such cases the primer surfacer has to fill-in those sanding scratches. Most primer surfacers will easily fill-in sand scratches if you were to stop at that point. The problem occurs when the topcoat is applied.

The solvents in the topcoat will penetrate the primer surfacer and cause what is known as "sand scratch swelling" of the underlying scratches. You can sand the scratches out but as soon as you apply another coat of the topcoat they will re-appear.

Depending on the severity and the type of paint being applied these scratches may re-appear immediately following the topcoat application, or in less severe instances or with less aggressive paint types the scratches may not show up until the curing (and inherent shrinking) process progresses.

In the case of solid colors these scratches can usually, depending on severity, be sanded and polished out once the paint is fully cured.

That is not the case with metallics with their reflective characteristics. Even when you sand and polish the clear coat as perfectly smooth as possible, the metallic particles will transmit the scratch appearance through the clear coat because of their irregular orientation resulting from the underlying scratches. If this is what you are dealing with, there is no fix short of stripping and repainting.

 

[MattyJ]

Thanks Tom, the pigs are not the big deep ones from dirt but smaller and many.

As far as sanding I am responsible for all sanding and buffing. The painter just sprays his best and says here you go.