[mrennie]

Hello,

Looking for some help troubleshooting why I am getting pigtails when doing my cut and buff process.

I am sure it is the 2000 grit dry stage that is doing this.

My process is:

-wet sand out the trash and orange peel with 1000 grit on a soft block

-wet sand out the 1000 grit scratches with 1500 grit on a soft block

-dry sand out the 1500 grit scratches with 2000 grit 3M purple finishing discs mounted on a 3M interface pad, with 6" orbital sander (3/8" throw)

-wet sand the 2000 grit with 3000 grit 3m trizact on an interface pad

-wetsand the 3000 grit with 8000 trizact on an interface pad

-buff


What is happening is that when I start dry sanding with the 2000 grit, I can see pigtails once in a while and some are so deep (far deeper than 2000 grit) I need to go back with 1000 or 1500 grit and wet sand again to get them out. I am using fresh discs and sanding with the pad flat against the panel. Have tried wiping the discs off with a clean microfiber tower after each few passes and that doesn't make any difference.

Also seems like they only occur in one direction, i.e., when sanding the door side to side and up and down, there are no pigtails in the horizontal or front to back plane, but there are in the up and down or vertical plane.

Thanks!

[nytrainer]

Obviously there must be some dirt, etc getting between the surface and the sandpaper. Can even be previous grit flecks of clear that are hanging around the area or crap in water bucket, etc. I’ve found blowing off the panel as if you’re you’re painting the first coat (sometimes using tack rag) between grit stages help to get the small stuff that’s easy to miss.
I also think 3/8 throw is a bit much once your getting to the fine grits. I use a 3/32 da for the fine grits (1000 and up).
I’ve had that problem before too. I used guide coat on a problem panel one time that worked for me. For example I sand with 1000 then guide coat (powdered) then sand with 1200 (checking for pigtails from the 1000 grit) then reapply and sand with 1500 (looking for 1200 grit pigtails) etc. By the way I’m using dry discs from 1000 and up (Eagle abrasives)
Keeping your panel, clothes and polishing area reasonably clean will alleviate most of the pigtail problems

[mrennie]

OK thanks for the feedback.

I'm hand sanding the 1000 and 1500 as it is my first cut and buff and I am scared to cut through if I used the orbital on lower grits.

This is the only palm orbital I own, actually bought it specifically for the 3M Trizact discs and their documents recommend a 3/16" throw, but perhaps the dry discs work better with 3/32" throw.

I think I have area reasonably clean, but perhaps it is 1000 or 1500 grit left over that I can't see. I have been wiping panel with soapy water spray and microfiber cloth followed by air for this step, but will move to alcohol/water mix and new cloth as I have been doing between and after Trizact discs to see if that helps.

[nytrainer]

I had a Hutchins water bug for years but got tired of wet, cold shoes lol. I changed over to dry some years ago and actually use Eagle abrasives in 400-2500 and their Buflex up to k-3000 (equivalent to 4000j.
Because the 3/32 is not aggressive like a 3/16 throw I don’t worry about sand through from 1000 grit and up.

[mrennie]

Oops (don't go by memory!)... I am actually using a 3/16" throw orbital (as recommended for the Trizact discs), the short throw sander of the same model was 3/32".

[78w72]

those pig tails swirls usually happen from the paper getting clogged up. do you see little spots built up on the paper when they happen? chances are thats the reason & if so, when that starts it means the paper is done or that it needs to be wiped off along with the panel of any dust created by sanding.

i usually start with 1000 if heavy orange peel or 1500 dry on a DA after knocking down any dirt nibs or runs/high spots of clear. starting dry with 1500 on a DA wont cut through if you are careful & keep it moving with lighter pressure & not too high of rpm & if there is a good 3 coat minimum of clear, if its thinner just be extra careful especially around edges or body lines. doing it wet in those grits by hand is just creating extra work IMO, but nothing wrong with that if you want.

i then move to 2000 wet on the DA keeping a good flow of water to wash away the sanding residue, a spray gun like for windex works good & wipe down the panel every couple minutes to see where youre at on knocking down the peel. then when its 99% smooth move to the 3000 trizak pad. then buff with a good compound like 3M perfect-it on a wool pad, ive never really felt the need to use the foam pads & final polishing on most colors, after a good wax they look like glass & im never going for 100% perfect show quality shine.

but again, check the paper when those pigtails start to show up, i have also found the brand of paper makes a big difference in how long they last or how fast the pig tails will show up, cheap paper is not always worth the small savings when it comes to things like that. one other trick i do when the paper isnt totally done but is getting some build up & causing pigtails is to use a dull razor blade on a small scraper to lightly scrape off those small spots that get built up on the paper, will let you get a couple more minutes of use out of it.

[MUSLCAH]

How fresh is your clear ? Did you forget to activate it ?…..and those dust nibs should be cut with a hard block…a soft block just rounds them off. Has the surface seen some 70 degree temps …you know to cross- Link. And your wasting time and money with 8000 sanding….unless your using that **** 3M compound .

[tjs72lemans]

I'm no pro, but when I've cut and buffed, I did it all by hand. A body man friend I was in the MN Nat'l Guard with loaned me his DA and said it's much faster. I was too afraid to mess up what I knew I could time consumingly do by hand. I also feel anything finer than 3000 grit is a waste of time.

[HoovDaddy]

I'm 69 and still do them by hand up to 3000. Im a non-profit so time doesn't matter. Minimizes errors.

[HoovDaddy]

Sandpaper should not load up on fully cured clear. Just my opinion. Compound on a wool pad should remove those marks, instead of sanding more.

[400 4spd.]

Why am I getting pigtail scratches with orbital sander during cut & buff?

Somewhere in your process you must be getting some grit on the paper.
Swirls or marks on top of the clear is the paper loading up with paint material.

[mrennie]

Originally Posted by 78w72

those pig tails swirls usually happen from the paper getting clogged up. do you see little spots built up on the paper when they happen? chances are thats the reason & if so, when that starts it means the paper is done or that it needs to be wiped off along with the panel of any dust created by sanding.

That might be it. I have noticed those little spot and you are right, they don't show up right away but more when the paper is closer to used up. The 2000 grit 3M discs I am using are a white colour and I am somewhat surprised how quickly the white wears off (I am assuming that is the abrasive), but as soon as it starts to wear I do see those spots show up. They are fairly easy to just wipe off so I will watch closer to that. I am wiping off the panel after each few sanding passes.


Thank you very much.

[mrennie]

Originally Posted by MUSLCAH

How fresh is your clear ? Did you forget to activate it ?…..and those dust nibs should be cut with a hard block…a soft block just rounds them off. Has the surface seen some 70 degree temps …you know to cross- Link. And your wasting time and money with 8000 sanding….unless your using that **** 3M compound .

It is single stage, no clear. Painted in September of 2020 and left at 70*F for several months before starting any paint correction. Unfortunately this is the slowest restoration possible as I am determined to do it all myself and life keeps interfering with my plans.

Regarding the 8000 grit Trizact, yes, I am using that "****" 3M compound as you refer to it but it requires it to be used LOL. I am a guy that follows instructions, I find that helps me be successful when doing something new. I know you and a few others suggested a compound (can't remember the name right now) that works well for you but it was not available here and they would not ship to Canada when I cut and buffed the body in December 2020 so I am using what I have available to me which is mostly 3M products. This is the only car I will probably ever paint so I am trying to do a decent job without buying lots of different products I will never finish using.

I am happy so far

P.S. The ripples in the picture with me and the mask are not in the paint, they are the reflection of the plastic sheet I stapled to the ceiling to keep dust out.

[MUSLCAH]

Looks great to me…..I use the wet 2000 and 3000 and don’t get any sludge in the paper…but makes a mess if not careful. My body shop materials rep..gave me some Dry sanding paper in 2000 and 3000 to try….it worked well without gumming up. I like to hand block the first cut …wether it be 600 ..800…1000… depending on the amount of material Iam sanding …old school traits never leave

[dhutton]

I have tried just about everything out there. I found 1500 Trizact to be complete garbage.

Here is my current method. 3/16 DA on about half speed for all grits.

1000 Eagle yellow film dry.
1500 Tolecut dry
2500 Buflex dry
8000 Trizact wet

ACA 3D 500 on a black wool pad
ACC 520 on foam

This is hands down the fastest easiest system I have tried. I use a fair number of discs. You can do the 1500 and 2500 wet if you want to extend disc life. I try to minimize wet sanding. Use an interface pad. Tape your edges.

Don