Scratch Removal and Wet Sanding...What Is Up With New Car Paint
Q: Are we the only ones that are getting paint thickness readings that are all over the place?
We had a Ford in this week that had factory paint that measured from 3.9 mils to 6.1 mils. This is not the only one...all of our late models are having this level of varied paint?
Grumpy...any input?
A: First of all, what model,build date (month/year), what assembly plant?
Q: As for the build location and exact build dates, I did not note that info but I will! We are also seeing variances within imports. We had a BMW 5 series in and while the paint was varied, it was not to the degree of the domestics?
Here are a few model samples from the past ten days:
2007/2008 Ford F-150's
2007/2008 Chevy Tahoe's
2008 Cadillac Escalade
Measurements from panel to panel are close matching but compare those measurements on the same vehicle to the doors or roof and they are worlds apart.
On the F-150, the entire back bed was 3.9 - 4.9 and even; meaning that the rear panels were nearly the same side to side yet the doors and front panels on the same truck were from 3.4 - 6.0...and not spotty...very even and to my trained eye it would indicate a factory finish yet has so many odd levels of paint?
A: Sounds like the Fords are from one of the older plants, older paint kitchen.
The "bells" are in need of adjustment.
Same may be at the makes as well.
They are supposed to get two applications of clear on the horizontals, some manufacturers only put one application on vertical panels, while others will do two full clear applications on the entire vehicle.
Some use an "anti-chip primer" on a few of the leading edges, which will show a higher film build.
Another issue is the "base color" of the vehicle, red requiring almost twice as much film build as black, white, etc.
There are many variables, plant age, time of year (as a new model is getting ready to go on line), the plant will not be as vigilant about keeping equipment operating at spec, etc. as the equipment will be completely reset to meet application requirements of the new models.
Or, the new model may be using a new clear, which will require different atomizers on the bells, etc.
The main concern is that the "flats" (hood, trunk,top) are showing at least 4.5 mil film build,(the "edges" may show slightly less) however, overall, these areas are subjected to the most UV exposure and having less than 4.2 mil will usually result in premature clear failure.
Ketch
Is it still safe to assume that the clear is roughly 25% of that total coverage?
A: Total film build has little to do with the life of the paint, as long as there is a good e-coat coverage and a surface primer to block any UV's from penetrating through to the e-coat.
A very small amount of UV's will get through a clearcoat, and if no surface primer, they will reach the e-coat and cause premature delamination of the upper layers. (Ford F series mid to late 80's, GM sedans, pickups, vans, Toyota Tacoma's, Chrysler vans, Neons, etc.)
Then there is the concern with the type and percentage of the extremely expensive UV blockers in the clear.
The clearcoat is what is most important.
1.5 mil is normally acknowledged by the paint manufacturers and their customers,as the minimum amount of clear, and 2 mil is the target for longest life.
Only the very top .5 mil has real density and is where the majority of the all important UV blockers are concentrated.
Total film build is often misunderstood, and is only an "indicator" to knowledgable technicans as to the extent of any previous corrective work that may have been done.
The total film build reading may be influenced, additionally, by what primers are used by a manufacturer.
For years in the 90's, Chrysler applied an additional layer of an anti-chip primer over the surface primer, which was over the e-coat.
This was only done to mid and upper level vehicles, not Neon's, etc.
The film build would read out at 6.5 to 7 mil, however there was still only 1.5 to 2 mil of clear.
Many mid sized GM pickups and SUV's of the late 90's and early 2000's, had a "powder coat" primer used. This would provide a total film build reading of 7.2 to as high as 10 mil. This variance was due to just how high a temperature was being used to flow the powdercoat primer, and some did not compact as much.
Once again, the total reading makes little difference, as these GM's of then and now, still receive 1.5 to 2 mil of clearcoat.
Ketch
Renny
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