paint imperfections

[Saundra Mahon]

While detailing my son's new 2002 sport trac, we noticed small white fractures almost like animal hair on the hood especially and on the truck bed. There had been evidence of about 3 hits of hail damage, could this have caused these fractures in the paint and is there any concern that it will eventually chip off and look horrible?

Thanks

Saundra

 

[Yardsale]

Depends on whether the hail corresponds to the fracture areas.



The paint and clear-coat are old and there could be some age-related discolorization. How does the paint on the roof look?

 

[Bo Loo]

I have the same issue. Doubt it's hail related - I live in FL and have had no hail damage.

 

[Saundra Mahon]

Thanks for the responses, I will check the roof today. Now that I think about it the tail gate has the same thing and it has no hail damage.

 

[Mark K 2]

Here's what the black paint looks like on my 2001 Job 2 Sport Trac. It started doing this a few years ago. The surface is smooth, as if the damage is to the underlying paint, not the clear coat. These are pictures of the edge of hood. Sorry about the bright sun, but bright light makes the cracks show up better. I live in Wisconsin and the truck has never been in a hail storm and has been stored in a garage its whole life.



[Broken External Image]:



[Broken External Image]:

 

[Saundra Mahon]

You probable have a better camera than I do. Mine looks like cat hair.

 

[Mark K 2]

I used my obsolete cell phone camera.

 

[Yardsale]

 

[Gavin Allan]

CRAZING



Crazing describes small cracks that appear in the finish. Generally, these cracks are quite numerous and have random axis, resembling a dry lake bed. They are akin to the crazing seen in pottery glazes.



Crazing is caused when two materials bonded together expand or contract at different rates causing lateral surface forces greater than the strength of bond. The expansion and contraction can be caused by thermal, chemical, or mechanical forces. Crazing can appear at any adhesion interface including that between substrate and primer, between primer and basecoat, or between basecoat and clear coat.



It is often easy to determine which adhesion point cracks and whether or not the cause is thermal. If it is thermal related, as usually is the case, it is often easy to determine the conditions under which the crazing occurs, e.g. which stage of heating or cooling. Usually, thermally induced crazing is controllable, either by less abrupt temperature changes or by using materials with more closely matched coefficient of expansions.

 

[csamuels]

In the body shop industry we call it "checking"

The checking may even be in the factory primer/sealer

Another cause is if someone has already re-painted the panel and the film build is thick (i.e. over 10mils, one mil is about the thickness of a piece of scotch tape)

The only real cure I know of is to mechanically, or chemically remove the clear coat, base color, sealer, and primer, (know in the old days as stripping to bare metal) then go back with an epoxy primer, sealer, base color, & clear coat.

Just sanding and re-spraying may cover it up for a period of time, but the new paint will sink into the old cracks and reappear??.