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Drum & Rotary vs Shot or Water for Surface-Prep Work

Drum & Rotary vs. Shot or Water for Surface-Prep Work

Water, shot, or sand blasting are common surface-prep methods for (1) removing binders, or (2) preparing existing surfaces for the application of new coatings. Although water and shot blasting are popular for surface-prep work, they may not be the best tools for preparing pavement or flooring surfaces.

Consideration must be given to health and environmental costs whenever these tools are selected and used. 

Not only is clean water is required for water blasting, but when this high-pressure water is mixed with the binders in the surface, it can drive these toxins in and contaminate ground water. Steel shot becomes FOD on airfields, and can be difficult to contain on uneven surfaces. Workers that are exposed to respirable crystalline silica through sandblasting must wear protective gear, as well as protect others in the job vicinity.  

What are the alternative to water and shot that can obtain the correct CSP or SP surface profile on concrete or asphalt surfaces?

This article examines the use of new drum-style or rotary-style mechanical eradication equipment versus traditional blasting equipment on Airports, Highways, Bridges, Residential, Factory floors, roads, steel hulls, decks and tanks. The drum and rotary style surfacers, together with the right cutter tooling and application process, can leave the final surface in an ideal profile and sound condition for any new coating, binder or overlay application. These machines when combined with HEPA dust extractors are a cost-effective and reliable alternative surface prep method to blasting.

Airport Applications:

Traditionally, water, sand and shot-blasting are processes used for surface preparation. Now, professional contractors are using drum-style scarifiers and rotary-style erasers with new cutter removal tools and application processes to replace expensive blasters, and are able to reduce the cost while improving surface profile textures and safety appearance.

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Surface Texturing

A SMITH scarifier, outfitted with a fine Flail-it removal drum assembly – and operating in the cutter-impact-zone consistently, called SMITHing – provides the right frictional properties by enhancing surface texture to promote smoother landings and take-offs. SMITHing with the right SP1 to SP10 surface profile prior to applying durable coatings on a clean, dry, sound surface will promote longer coating life at less cost than another surface preparation process.

Stripe Removal

To prevent sharp-edge ghost lines or grooving of surfaces, a traditional drum-style scarifier may only be used to remove thick markings without the cutters contacting the underlying substrate. Any remaining thin coatings are then removed using a rotary eraser to leave a bevel-edge surface finish which prevents deep surface scarring and water pooling. Multiple shallow-cut passes work best when working on undulating surfaces when markings are applied at carious thicknesses. The use of dry removal applications with dust collection vacuum systems allows for re-striping to occur immediately after the removal process.

Rubber Removal

Traditionally, water and shot blasting can be effective in removing rubber and other contaminants from runway touchdown locations. In many cases, removing contaminants with a combination of a drum-style scarifier outfitted with Strip-it or Finish-it cutters in a fine or medium set-up pattern, depending upon rubber thickness, will improve the surface frictional properties, as well as reduce application costs vs. traditional applications.

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Bridge and Highway Applications:

Professional contractors are now using a variety of drum-style scarifiers and rotary-style erasers outfitted with new cutter removal tools while operating using new corrective processes to replace expensive blasters on bridge and highway applications for surface preparation requirements.

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Surface Preparation

The use of a SMITH skid-attachment combination scarifiers/planers/shavers can be used to surface prep, while reducing the effect of micro-cracking when the surfaces are prepared in multiple steps. Using a variety of cutter drums, from planing, milling, and scarification to diamond shaving, the surface can be prepared without weakening the structure, which could lead to failures due to freeze-thaw cycles and shearing traffic cycles and loads. Using the SMITHing process, while removing correctly in the ‘cutter impact zone,’ reduces prep costs and micro-fracturing for safer, lasting bridges and highways.

Road Regeneration and Rubber Removal

Instead of shot, sand or water-blasting or as an initial step prior to blasting, the use of rotary and drum-style mechanical eradicators is known to be highly effective when cleaning and improving the macro and micro surface imperfections. These applications help to prolong the life of bridges and roadway surfaces, with minimal traffic disruption and cost.

Stripe Removal

To prevent sharp-edge ‘ghost’ lines or grooved surfaces, a traditional drum-style scarifier may only be used to remove thick markings without the cutters contacting the underlying substrate. Any remaining thin coatings are then removed using a rotary eraser, leaving a bevel-edge surface finish which prevents deep surface scarring and water pooling.   Multiple shallow-cut passes work best on undulating surfaces when markings are applied at various thicknesses. The use of dry removal applications with dust-collection vacuum systems allows for re-striping to occur immediately.

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Residential Concrete Applications:

Surface preparation can now be cost-effective when residential applications start SMITHing with drum and rotary style eradicators, instead of expensive shot-blasting equipment. All SMITH equipment is shrouded with dust collection ports so dust can be collected during the process for a cleaner, safer job site.

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Decorative Cuts

Decorative score cuts and artificial grout lines can enhance stained floors. Traditionally, a single blade is used to make the very shallow cutting depths, under 1 1/4″. A SMITH drum-style scarifier outfitted with stacked diamond blades (up to 15″ wide) can be used for a more precise and architecturally improved applications. Add a vacuum system and it’s all dust-free!

Garage Floors

Garage floors can be prepared for epoxy floor coatings using a SMITH diamond shaver, or a fine-finish scarifier to achieve the proper SP3 – SP5 surface profile. The handheld, walk-behind, or self-propelled equipment can also be used to remove cracks and uneven spots, chemical spills, existing grease, oil stains and more, at considerable cost-effectiveness than the use of shot blasters and diamond grinders.

Sidewalk Trippers

Leveling uneven sidewalks is fast, easy, and inexpensive using a SMITH scarifier, outfitted with Flail-it cutters in a coarse or medium setup. While operating in the ‘cutter impact zone,’ float the drum-style equipment in a circular pattern for an anti-slip SP3 – SP5 texture.

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Factory and Warehouse Applications:

Without the right surface preparation equipment, removing tenacious coatings is a difficult and time consuming process. Using SMITH drum and rotary style eradicators is proven to be a much easier and faster removal method than shot-blasters when removing floor coverings, waterproofing membranes and thick coatings.  Selecting the right sized equipment, outfitted cutter drum assembly and using the equipment correctly is key to getting the surface prepared correctly.

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For the hired painting or flooring contractor, the task of getting the surface prepared correctly can be daunting. Especially when there is so much misinformation and equipment choices for managing a wide variety of surface preparation challenges.

The benefit of using just 2 machines – a drum-style scarifier and a rotary eraser or grinder – should be all the equipment a contractor needs to accomplish up to 90% of typical flooring prep work. Having two machines also makes it economical and convenient for the contractor; the contractor would only need to bring an assortment of outfitted cutter-drum assemblies and a HEPA vacuum system to contain dust and debris.

Most applications are on horizontal surfaces. Any application on vertical surfaces (such as walls), the equipment would have to be used with an approved vertical rigging systems to properly profile the surface.

Concrete Surface Grinding

If the job requires a finished, polished surface, a diamond grinder would be the tool of choice. Before you start grinding or polishing concrete, however, the contractor would determine how much concrete materials, coatings, and overlays that would have to be removed, reduced, or leveled prior to the final grinding or polishing step. In these circumstances, professional contractors significantly reduce the amount of finishing time by pre-conditioning the surface with a drum-style scarifier or shaver to remove any coverings and coatings, exposing the aggregate to an SP3 – 4 profile.

Start the concrete grinding process when the surface is within 1/16″ complete. Any surfaces that have to be reduced further can be quickly accomplished with a vertical drum-style scarifier, especially when cleaning, leveling and removing mastics, epoxies, urethane, paint, sealers, coatings, repair materials or overlays. A scarifier outfitted with a fine set-up with milling, finishing, stripping, or flailing cutters can also be used to smooth out uneven surfaces on floors, or to remove leftover glues and mastics after old floor coverings are removed on terrazzo, marble, granite, or decorative concrete applications.

Crack Repair

Proper maintenance of concrete floors often involves crack repairs and spalled surfaces. Cracks in concrete floors are caused by a number of factors, including ground or building movement, unstable subsurfaces, the concrete curing process, poorly placed control joints, heavy traffic or loads, moisture and/or temperature cycles. Specialized handheld or walk-behind crack-chasing and joint clean-out saws can repair most cracks or expansion joints.

Parking and Roof Decks

Scraping blades, PCD discs, or stripping tools can be used to remove adhesives, thick thermoset epoxy, or urethane coatings, thinnest mortars, waterproofing membranes, roofing material, VCT, carpet, marble or ceramic tile, vinyl, wood flooring, rubber and other materials in a variety of applications. The PCD discs can be used in a rotary eraser or grinder to break aways these membrane coatings.

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Steel Applications:

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Ship Decks and Hulls

As part of a routine maintenance schedule for any ship with a nonskid thermoset-type deck coating that must be removed and replaced, the use of a drum-style scarifier (handheld, walk- or ride-on models) outfitted with the right cutters can complete the job faster and at less cost than using shot- or water-blasting methods.

The benefit of using SMITH scarifiers to remove the non-skids and create the right surface profile fast, easy and cost-effectively for coating re-application is the #1 reason a SMITH is selected. In addition to non-skids, the drum-style scarifiers also remove paint and rust, mill scale and marine growth, clean ship decks and offshore platforms.

Storage Tanks

With the use of a vertical rigging system , drum-style scarifiers can prepare storage tanks, ship hulls and other vertical or near-vertical steel surfaces. As the equipment removes and strips away the coatings, it profiles the surface simultaneously in the right SP texture for immediate new coating overlays. A range of surface profiles can be achieved through selection of the correct cutter, spacing pattern, and travel speed.

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Conclusion

Selection of the right rotary and drum style surface preparation equipment with the right tooling and removal method offers the following benefits versus blasting operations, to wit:

  • High productivity rates
  • Reduced manpower and fatigue
  • Reduced maintenance costs vs. shot blasting
  • Requires less manpower and minimizes operator fatigue
  • Dust containment and waste disposal with HEPA vacuum
  • No costly high-pressure water pumps or shot-blast components to buy or maintain
  • No flash rusting since surface is prepared clean and dry
  • No requirement of inventory of shot other than replaceable cutter drums
 
© 2017 SMITH Surface-Prep Solutions - 1610 S. Dixie Highway, Pompano Beach, FL 33060-8913
Toll Free: 1-800-653-9311 | Ph: 954-941-9744 | Fax: 954-545-0348
Specifications and data are subject to change without notice.