Video: Stencil Application with Vapor Abrasive Blasting


By Eric Rennerfeldt, Graco Inc.

Curb Masters, a specialty concrete contractor, was recently tasked with improving the aesthetics of the pedestrianized Nicollet Mall area in downtown Minneapolis. Nicollet Mall spans 12 blocks in the heart of downtown, and is a popular shopping and dining district. The area is currently undergoing a complete redesign as part of a $50 million project known as ‘Minneapolis Big Build.’

Curb Masters is using Graco’s EcoQuip Vapor Abrasive blaster to create a variety of intricate stencil designs onto the pedestrian sidewalks of the Nicollet Mall area. Although the City of Minneapolis did not specify equipment for this project, Curb Masters wanted to minimize dust emissions out of consideration for the many pedestrians that work and live in, as well as visit, the area. Because the EcoQuip Vapor Abrasive blasting equipment suppresses up to 92 percent more dust than dry blasting and requires little containment, passersby have been able to watch the stenciling process throughout.

“Blasting in a busy pedestrian area downtown meant we needed an option that would reduce dust as much as possible while we were blasting,” said Mark Callies, vice president, Curb Masters. “EcoQuip helped minimize the dust, allowing us to reduce the impact on pedestrians by requiring very little containment. Also, typical clean-up was greatly reduced.”

The stencils were produced via CAD software by the New York-based design agency managing the project for the City of Minneapolis. On-site workers placed each of the stencils – which resembled a large jigsaw puzzle – onto the pavement and lightly blasted with glass bead media until the design was ingrained in the sidewalk’s surface. Because glass bead is softer than garnet and crushed glass blasting media, it was an optimal choice for creating the design while preserving the integrity of the pavement. In addition, glass bead media is typically made from recycled material and is safe for the environment.

The urban landscape artist who designed the entire 12-block sequence used three types of stencil across a 150,000-square-foot stretch of sidewalk. Starting with the outer-most blocks on both sides of the 12-block area, a leaf pattern was used in the ‘Woods’ zone, named for its many large trees. The next three blocks inward on both sides, called the ‘Groves’ area, featured a branch stencil to represent the transition from trees to a more urban setting. Finally, a beautiful basket-weave stencil was chosen for the ‘Center Core’ downtown area to complement the decorative artwork on display there.

Curb Masters’ work on this project is slated for completion in the fall of 2017. One benefit of using the EcoQuip skid unit has been the reduced amount of clean-up needed, as there has been far less dust than there would have been with sandblasting. Minimal dust has also allowed the team to use smaller shields in lieu of total containment.

*Claims or positions expressed by sponsoring authors do not necessarily reflect the views of TPC, PaintSquare or its editors. EcoQuip® and Vapor Abrasive® are trademarks of Graco Inc.

Eric Rennerfeldt, Graco Inc.

Eric Rennerfeldt, product manager of Protective Coatings and Surface Preparation Equipment, has been with Graco for 19 years and has experience with various fluid handling systems, with an emphasis on plural-component spray equipment for protective coatings and vapor abrasive blast equipment for surface preparation. He has a bachelor’s degree in mechanical engineering from the University of Minnesota.