Burn Through or Existing Damage?

[Aaron@P2PQD]

Hi Guys,

             Looking for some professional opinions here as I'm not sure what to make of this. I'm polishing a Red Holden GTO and have come across a problem. Hoping someone can confirm or deny my suspicions.

 

So, I'm using the Flex 3401 VRG with Adams Paint Correcting and Adam's Paint Finishing with Orange Microfiber and White foam. I have done 4 passes on microfiber and there are still some scratches but nothing major. When doing pass number 5 on White foam the below damage occured. The damage occured instantly and at first I thought I had dropped a blob of polish from the pad into the panel gap. At first I thought it was strikethrough and my heart sank as the person who owns this car loves it immensly and has trusted me to prep it for show.

 

Upon further inspection though, I'm not so sure the damage is entirely my fault. Here's the data to help

 

- Car was resprayed about 3 months ago

- Car has 140 Micron of paint fairly consistently across all panels

- Car has burn marks from previous respray/rotary buffer

- I had done 5 passes in total which lead me to believe I had burnt through (still quite likely)

- Area of burn through has 97 micron or 3.3mil according to my gauge

- Area I polished has 104 micron left

 

Data that doesn't add up

- Area of burn through shows no hazing around immediate area or at all

- No paint transfer on White foam

- No paint transfer on Revive & Blue applicator

- Scratch looks shiny, not Matte

- Still alot of paint left on area, Although I do understand that this is no indication of the clear coat thickness

- Scratch has sharp edges like something has dragged it at some point

- I wipe down after every pass, I would have noticed hazing and stopped immediately

- I don't apply alot of downward force when polishing, I would say no more than 2kg of pressure

- Damage happened immediately, Not progressively

 

After taking this into consideration, I'm actually beginning to wonder if the car had a previous touch up and I was unlucky enough to take the touch up off with the buffer, However I am willing to accept that there is every likelyhood I just straight up went too hard. We were chasing perfect for this particular car and I will admit I was pushing the limits to achieve it, I did think 100 micron would leave me with a safety margin though as most cars I have polished have had less than this to begin with. A professional opinion would be greatly appreciated at this stage, I have stopped the correction until I can get hold of the customer but I would like to pinpoint the cause so I can learn from this experience.

 

Pics

Edited January 7, 2015 by titanium_jerk

[Chris@Adams]

From the pic it looks like it's not on the edge it looks like its inside a little. Is this correct? If this is the case it may have been a touch up..

[Aaron@P2PQD]

Yeah Chris, It is slightly inside the corner of the panel

[Sizzle Chest]

It does appear to be a scratch/gouge that possibly was repaired.  You said that the car was resprayed 3 mo's ago?  The whole car was shot?

[Aaron@P2PQD]

Hi Scott, It's had a few over it's lifetime but the front end is the most recent. The roof is the only factory paint left on it and weirdly it measures very similar to the resprayed panels. I know the respray was an insurance job and the gapping isn't pretty. The car has had a supercharger and cam fitted since the respray also so maybe something happened then and it got touched up, I might be reading too much into it though.

 

The other thing I'm finding odd is the amount of clear coming off from a cut, With this same combo on Jap cars and soft blacks I usually see no more than 4 microns a pass. This is averaging 10 which is worrying to say the least.

[Ricky Bobby]

Since its on the panel edge, and paint is thinnest on the edges, its possible it was removed.

 

What doesnt add up to me is why on the White foam which is a really soft polishing pad that the "burn through occurred", and not on the more aggressive MF pad.

 

Also it could easily have been a touch up and there is no paint to transfer because you may have just agitated it enough to leave the surface.

 

Either way, I don't really think its your fault because you have done your due diligence with paint measurement, you mentioned the car has had several resprays and rotary buffer sessions as well.  Has that panel been resprayed?  If so, I'd say its shoddy body shop work because if they did a good job the paint wouldn't be coming off like that.  Looks like primer to me that I'm looking at.

[Aaron@P2PQD]

The other thing I'm finding weird is that I'm getting no paint transfer. If I was getting paint transfer I could pretty safely say I just f'ed up but as I'm not seeing any I'm not so sure. Although, Does that rule still apply when looking at primer?

[Aaron@P2PQD]

Thanks Jason, I literally watched it appear in front of my eyes which is why I initially thought maybe I had a build up of polish on the pad which had deposited itself in the panel gap. I'm 100% certain it didn't occur earlier as I wipe down after each pass to asses which pad/polish to use for the next

[Ricky Bobby]

Just because you didnt get paint transfer on the pad doesn't mean that its not paint that is removed.

 

The vibration/polishing action of the machine probably loosened/removed the shoddy touchup paint or portion of paint in a "chunk" and it probably fell in between the panels somewhere.  Pop the hood or open the door (not sure which panel it is), you may find the chunk of paint laying somewhere close lol.

[Aaron@P2PQD]

No luck I'm afraid, I even went through my microfiber to see if there was any evidence of it in there. If it is a touch up it's an odd place for it. I find it odd that I wouldn't have seen this on the previous wipe down or during claying but maybe I did just go through and not notice until I went to the white pad

[Team Adam's]

If you hit the entire car 4x with microfiber its highly unlikely you would've seen any significant transfer, it would've been a small amount each time. It would've been virtually impossible to know it was happening until it was too late.

 

It is beyond the edge a little, but it its possible if you were crossing that gap frequently that the fingers of the microfiber were sweeping that edge with pretty decent frequency. On both factory and respray that kind of area is going to be significantly thinner than the rest of the car... unfortunately its possible that you did strike thru an already thin area, but its equally possible it was a poor touchup too. Really hard to say with a resprayed vehicle though without knowing how/what the shop did. Even has the potential to be bad prep work - which would also be common in areas like that.

 

FWIW - that would also be categorized as strike through, not a burn.

 

EDIT - don't suppose you have access to a paint thickness gauge so you can get some thickness readings? Would be very worthwhile to get a reading of a center panel, then a few readings in the jambs to get a feeling for how thin it was sprayed on the edges.

[Aaron@P2PQD]

Thanks Dylan,

Have taken more thorough thickness measurements across the repainted panels and I think I just got unlucky. Bonnet (05 GTO) scoops measure 4.35 mil on one side and 5.35 mil, Hood seems to vary between as low as 3 mil and as high as 6. Just measured the fender in micron and the top corner (where I went through) is as low as 97 but get's as thick as 600 micron as you move forward and down the panel. 

 

I think at this stage I'm leaning towards it being a poor respray, And me trying to cut too heavily to remove the swirling. None of the swirls I was chasing were deep enough to catch a nail so I thought I was pretty safe chasing 95%, Evidently it shows you can never excercise too much caution.

[Aaron@P2PQD]

Well, To follow up on this I spoke to the customer today and he contacted the panel shop as he knew them rather well. The panel shop said they believed it was damage that occurred while fitting the hood and did touch it up, They have offered to repaint the panel for him free of charge. I offered to shoulder some of the expense but they didn't think it was necessary. I still think I could have been more careful and definately should have excercised more caution.