When you’re painting 55,000 little squares in 30 colors along a busy, four-lane bridge over the Rio Grande, you might expect some complications.
You just don’t necessarily expect them in that big beige swath in the middle.
Bob’s Painting (left); City of Albuquerque (right)
|The 55,000 colored squares went great. The big patch of tan epoxy was another story.|
But that’s where Albuquerque’s year-old $112,000 painting job failed.
Making it right—which everyone has—took a little doing. But persistence and collaboration pay off, especially when bad things happen to good coatings.
Public Art Challenge
The problem involved the city’s famed Montaño Bridge, built in 1997, which for 14 years has sported an 800-yard-long mural by Albuquerque artist Dave Dekker as part of the city’s renowned public arts program.
Bob’s Painting Inc., a prominent local painting contractor, was originally selected to work with Dekker to bring the mural to life on what was then a two-lane bridge with no vehicular traffic.
The art-deco-type design features tens of thousands of neatly arrayed red, blue and green squares that taper off into a sporadic sprinkling on a solid tan background.
Bob’s, which boasts “there is nothing we cannot paint,” recreated the work on the bridge using two-part automotive paint, including metallic hues.
Fast-forward to the summer of 2011, when the mural on the bridge—now four lanes and carrying heavy daily motor traffic—was finally set to get a much-needed facelift. Every square would be repainted and a clear sealer sprayed over all.
Again, the city turned to Bob’s, which still had all of the original patterns and color records, said Sherri Brueggeman, who heads the Public Arts Program.
|After more than a decade, traffic and time had taken a toll on the mural.|
Bob’s, in turn, also had the same paint supplier, Bond Paint Co., a veteran local company.
The city, contractor and supplier all worked together to revive the mural, using as many of the original materials as possible and triple-checking data sheets for new formulations. Automotive paint was again used for the colors and a tan epoxy for the background.
Something went wrong anyway.
‘Flaking Off, Almost in Sheets’
A few months after the mural was repainted, the clear coat began to peel and disintegrate. Flakes of coating were flying off the bridge as traffic whizzed past.
“The clear coat they had put on was not sticking to the color coat, and it was really flaking off, almost in sheets,” said Brueggeman.
Bob’s, which had guaranteed the job for 10 years, was also perplexed, said Chris Herman, who oversaw the project for the painting company.
Putting their heads together, the painter and supplier determined that all of the colors were adhering well to the substrate, and that the clear coat was adhering to the automotive paint.
It was the clear coat over the epoxy where things fell apart.
Although the product was approved for application over epoxy, “it just didn’t work out,” said Herman.
What Went Wrong…
After considerable testing, Bob's and Bond agreed on a new two-part urethane to clear-coat the epoxy. Bond replaced the material and even chipped in toward the labor for the redo, said Herman.
Bob’s then pressure-washed the failed sealer, cleaned every square inch with a denatured alcohol, and brushed and rolled out the new coat.
It took a crew of eight painters four weekend days to do the work.
…And What Went Right
The new coating is holding well, and city officials are thrilled with the contractor's and supplier’s responsiveness to the problem.
City of Albuquerque / Flickr
|Two-part automotive paint in 30 colors was used for the squares.|
All good--but what went wrong? No one is quite sure. Theories include a batch error or a formulation tweak that withered the coating in the brutal New Mexico summer sun.
“The epoxy got chalky from the sun and made the sealer pop off of it,” Herman thinks.
But he adds: “They honestly still don’t know what happened.”