There seems to be a huge problem i have noticed recently when restoring digital prints on powder coated aluminum. First of all, I am located around Phoenix, Arizona, and it is probably an issue that has to do with the extreme amounts of sunshine we get.
Over the summer we needed to re-do our 50' long roof sign that was all digital print with laminate, due to the laminate turning black across the sign after a few years facing south. The sign panels were standard white dibond panels. Vinyl was Oracal with oracal laminate.
In the process of removing the old cracked brittle vinyl, I noticed that almost everywhere on the print that no ink was printed on the vinyl (all the white letters) that the powdercoating on the panels was bubbled. To the point that it looked as if a blow torch hit the backside and super heated it. The areas where color was, especially the dark areas were not affected. So when all vinyl was removed, i could see exactly where the white letters were, because the powdercoating was gone in the shape of the letters. I really didnt think much more of it. I sanded, primed, and repainted all panels and put the new decal on, and put back up.
A couple days ago, a customer brought a trailer to me that another shop had done. What first seemed questionable was it was maroon and dark blue lettering, nothing fancy, but had all been printed, laminated and cut to shape of letters. The logo was a maroon mountain with white letters inside. My thought is why not use maroon vinyl, reverse cut the letters and let the white of the trailer be the letters. Nope, it was white vinyl with laminate. As i started removing the burned vinyl, i noticed the same thing as my sign. All the white areas had the powder coating destroyed.
This seemed totally against what i knew of the temperature of light vs dark in the sun. In fact i checked the paint on my black truck vs a friends white truck one day. Mine was 141° vs his at 122°.
My conclusion is this......since black soaks up the sun, and white reflects, the laminate over the white areas were having much more UV rays going through it. They were bouncing off the white and back out through it again. To test my theory, i took our laser temp gun, installed a new battery and checked light vs dark on the old vinyl, and a new piece i placed on the trailer too. These are the readings off the back door of trailer facing west into the sun.
Old printed vinyl:
maroon 125.2°
White area: 126.6°
New printed vinyl:
Black area: 130.0°
White area: 122.3°
Although i wasnt comparing same colors, it does appear that with age, the white areas are actually putting off more heat. The new vinyl was as i would have expected. I was shocked at the old print.
But this is just a warning of something ive noticed just this year only on powder coated aluminum, and nothing else. I will have to definately warn customers of this, because it totally damages the paint, to where a body shop is needed to fix the damage.
Over the summer we needed to re-do our 50' long roof sign that was all digital print with laminate, due to the laminate turning black across the sign after a few years facing south. The sign panels were standard white dibond panels. Vinyl was Oracal with oracal laminate.
In the process of removing the old cracked brittle vinyl, I noticed that almost everywhere on the print that no ink was printed on the vinyl (all the white letters) that the powdercoating on the panels was bubbled. To the point that it looked as if a blow torch hit the backside and super heated it. The areas where color was, especially the dark areas were not affected. So when all vinyl was removed, i could see exactly where the white letters were, because the powdercoating was gone in the shape of the letters. I really didnt think much more of it. I sanded, primed, and repainted all panels and put the new decal on, and put back up.
A couple days ago, a customer brought a trailer to me that another shop had done. What first seemed questionable was it was maroon and dark blue lettering, nothing fancy, but had all been printed, laminated and cut to shape of letters. The logo was a maroon mountain with white letters inside. My thought is why not use maroon vinyl, reverse cut the letters and let the white of the trailer be the letters. Nope, it was white vinyl with laminate. As i started removing the burned vinyl, i noticed the same thing as my sign. All the white areas had the powder coating destroyed.
This seemed totally against what i knew of the temperature of light vs dark in the sun. In fact i checked the paint on my black truck vs a friends white truck one day. Mine was 141° vs his at 122°.
My conclusion is this......since black soaks up the sun, and white reflects, the laminate over the white areas were having much more UV rays going through it. They were bouncing off the white and back out through it again. To test my theory, i took our laser temp gun, installed a new battery and checked light vs dark on the old vinyl, and a new piece i placed on the trailer too. These are the readings off the back door of trailer facing west into the sun.
Old printed vinyl:
maroon 125.2°
White area: 126.6°
New printed vinyl:
Black area: 130.0°
White area: 122.3°
Although i wasnt comparing same colors, it does appear that with age, the white areas are actually putting off more heat. The new vinyl was as i would have expected. I was shocked at the old print.
But this is just a warning of something ive noticed just this year only on powder coated aluminum, and nothing else. I will have to definately warn customers of this, because it totally damages the paint, to where a body shop is needed to fix the damage.
