why orange peel exists...

Setec Astronomy said:
I believe there are some difficulties in getting various panel materials, as I mentioned, to have a uniform surface finish, as compared to the old days when everything was steel and stamped in the same manner. Today you might have a variety of materials produced in a variety of ways. I believe they improved the galvanized finish, but it may not meet that Class A (?) finish that they used to get. Some of the "defects" could also be flaking of the zinc during the forming process.
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Interesting. Each metal part starts out as a roll of steel, that gets stamped in a press. I've never experienced "flaking of the zinc" during the "forming process". Are you referring to the stamping of each sheetmetal part? Those parts are still e-coated & bathed to clean/cover/protect the bare surface before the vehicle goes into the paint station at the plant. Then they get refinished, so I still don't understand the "defect" part that OP is hiding over all those other layers & processes?



Setec Astronomy said:
Just as a point of reference, and I know you have toured auto plants as well, but the factory setting is much different than in a body shop. In the shop if they get a panel that has a surface finish that doesn't match, they can do something about it, rework it in some manner...that just isn't going to happen on the assembly line.
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Well, their different in respect to everything up to the actual coating & spraying of the panel (e-coat vs. corrosion protection/primer/sealer). Both applications still "can do something about it". Whether it's sanding for excessive OP, dust or runs, they all get done regularly in both environments. I'd have to say the OEM level is actually more critical of the final finish and how uniform it has to be. The body shop's biggest defect fear is probably color matching and straight body work (prior to refinish).



Seems like you & I always go round and round with these OP discussions...:)

I still plan on contacting my trainer @ Spies Hecker about the whole OP & durability thing from the past discussion.:think:
 
David Fermani said:
Interesting. Each metal part starts out as a roll of steel, that gets stamped in a press. I've never experienced "flaking of the zinc" during the "forming process". Are you referring to the stamping of each sheetmetal part? Those parts are still e-coated & bathed to clean/cover/protect the bare surface before the vehicle goes into the paint station at the plant. Then they get refinished, so I still don't understand the "defect" part that OP is hiding over all those other layers & processes?
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I don't know what to tell you, I used to read the auto industry mags 20 years ago and I distinctly remember them reporting that double-sided galvanized panels were unable to be used because the surface finish was unsatisfactory. This was at the beginning of the use of galvanized steel in auto body construction, IIRC correctly there were some welding issues as well. Again, I'm not talking about defects but about the texture of the surface, certainly you're aware that zinc galvanize makes steel less smooth, and that fiber reinforced plastics can have a texture to the surface due to the reinforcement material.



I don't know about e-coat but certainly other electroless and electroplating processes that I have hands-on experience with will not fill any surface textures, only follow and telegraph them (with the exception of corners and blind holes into which the plating may not throw evenly in the case of electoplating processes).



EDIT: Here's a quote from a report on the 2001 NAIAS: "One of the obstacles standing in the way of this technology is the continuing inability to produce cost-effective thermoplastic panels with a consistent Class A surface. For a vehicle like the Wrangler, this could be a disadvantage, as most buyers use this vehicle as everyday transportation, and expect a glossy surface. A limited-edition vehicle, however, could follow the lead of the Willys by using the matte finish to distinguish it from its lesser brethren. This would eliminate the need for a $350-million paint plant, cut costs, reduce pollution, but fall well below the 100,000 unit per year level this technology can support." from this site: Feature Article - Detroit's Suicide (Door) MACHINES - 03/01
 
So answer me this...



If OP exists in the paint layer, and then ClearCoat is applied on top of it...



When people talk about sanding out the OP, aren't they going to remove a good bit of CC to get the surface smooth?
 
hooked said:
...If OP exists in the paint layer, and then ClearCoat is applied on top of it...
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OEM base coats lay down with very little or no OP. Of course, the have no gloss or environmental resistance either. They’re formulated to be part of a multi-stage system.





hooked said:
...When people talk about sanding out the OP, aren't they going to remove a good bit of CC to get the surface smooth?
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Yes. That's why it's not recommended for thin OEM finishes. Some people do it and get away with it. That doesn’t make it a good idea for everyone.





PC.
 
OP generally refers to what is on the exterior surface. While the base coat may have OP on it, the clearcoat on it is going to fill in the texture and have OP of its own.



Removing OP, just like wetsanding, polishing, compounding, etc. are all going to reduce the paint thickness.
 
truzoom said:
While the base coat may have OP on it, the clearcoat on it is going to fill in the texture and have OP of its own.
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If their's OP in the base, the final finish will look worse. The clear will accentuate it. PC's totally right, most OP is mostly in the clear, not really the base. I'm sure if you cranked down your air pressure and hardened it fat, you'd get tons of craters. :nono
 
MorBid,



I was asked this question on another forum, and I did not know the answer. Your explanation is articulate and your solution is extremely helpful.



I would like to ask your permission to copy and paste your reply to the E60forum.org. Please let me know if you will consent to the use of your message, and if you want me to acknowledge you as the source or not.



Thanks in advance!
 
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