QUOTE(rick 918-S @ Jul 25 2017, 04:56 AM)
My point was that in order for primitive materials to work on the modern thin HSLA materials you would need to provide a 36 grit scratch in order for the product to ever have a change to bond. Of course this is not possible. Hence the introduction of etch primers. My point was this is a problem with changing products and the EPA regulations.
I started out using DuPont Dulux-Centari-and lacquer based paint in the 70's
I opened my shop in 1979 and sold it off in the early 90's so I was in business during the evolution of materials. We repaired lots of GM delamination issues for a local dealer. My guys used to peel the upper panels with razor blades. The factory sealer stayed in place. The issue was the ability for the low VOC base coat applied at the factory to create a chemical bond before flashing. So I was in business during the time this product line was in development. End user.
The fact is there are many issues that will cause this problem. Could be what I described and what you described in combination.
QUOTE(Wdunster @ Jul 25 2017, 06:50 AM)
Great insight but not accurate. Sorry, please don't take offense. I normally don't get too involved with these conversations but this isn't correct. 36 grit sandpaper hasn't been recommended to use on any of the modern metals or especially the metal or fiberglass used on an RV. It will destroy the substrate. Typically on all the delamination issues we have seen over the years (dodge, ford, Chevy, now Honda) is due to the lack of material. When the suns uv Penetrates through the clear with to low of UV protection (either due to cheap clear with out uv protection or too little clear) it will degrade the base color (which is happening here) or the base is even applied too thin and allows the ecoat to degrade and release the base and clear. Manufacturers skimp as do companies that have an RV to paint in order to save material costs. Premium Clears today even with the VOC law changes are leaps and bounds better than they were before the changes. Agreed this isn't an easy fix but with the right person doing it there may be a chance to rescue some of the colors.
B
QUOTE(rick 918-S @ Jul 24 2017, 09:59 PM)
The EPA forced safer paint product with less VOC ( Volatile Organic Compounds) This caused many issues from the assembly line to the refinish industry. The manufactures in high production were seeing the delamination of the base coat from the sealer and in some production lines the clear from the base coat.
We saw the beginning of this as early as the 80's when Honda came out with HLSA. (high Tensile Strength Low Alloy Steel) All steel is porous to an extent. The thinner, lighter steel has tightly packed molecules. Conventional lacquer based primer was not hot enough to create a bond to the steel.
To continue with this type of product you would need a 36 grit scratch to lock the product onto the metal. The industry came out with etch primers to solve this problem. Acid etch to the steel and soft dried finish to hold the primers.
Here's the layman's explanation. The VOC's in the Solvents used to mix the color and thin the paint should create enough chemical bond to lock one layer to the other.
In your case the base flashed off hard. Likely, partially from too long of a drying time for the base. It is likely the base should have been lightly scuffed to allow a tooth for the clear. With metallic paint we would use a mid coat adhesion promoter. Kind of like the etch primers but a clear product that would slightly soften the base and allow a chemical bond to take place. The secondary issue is likely the clear coat used was unable the create a chemical bond due to low VOC's.
The Repair? There are a couple ways to do it. Careful soda blasting could remove the loose clear on the upper surfaces. Mask and cover the lower parts that have a good bond and re-clear the affected areas.
Strip it all off and start over.
I was in the industry back in the 80's to mid 2000's (BASF and then a TPO substrate supplier where I tested all OEM paints on various materials, including our own). While you've both got valid points, Wdunster's explanation fits here. The reason those cars in the 80's were delaminating was because the OEM's were chintzing out on the basecoat film builds, allowing UV light to penetrate to the primer layer and degrade that product. Nowadays (even 20 years ago like this RV, OEM paints were very good. But 20 years is a long time for a paint to survive on a horizontal panel, even if the clear was applied in a timely manner over the base and with the correct film build. Most aftermarket paints don't have the same UV package as the OEM supplied paint (UV stabilizers are expensive!). So you've got all these possibilities here. The base could've been left too long before clear was applied (no clear biting into the basecoat), the clear was applied too thin (not the correct film build), the possibility that this was an lower quality paint that didn't have a great UV package and it's 20 years old.
Even the best UV packages have a finite lifespan. You might be able to have someone repair that, but I've never seen it done. But there's bound to be a great paint guy out there that can pull it off and make it look acceptable. Trouble is finding that guy...