Metokote Corp (original) (raw)

Low Cost Wet Abrasive Blast Process for Lead Paint Removal

1996

TRIDENT Refit Facility (TRF) has worked closely with vendors and local regulators to develop a wet abrasive blast paint removal process. This work was initiated when dry abrasive blast operations in their drydock were shut down due to the associated air emission requirements. This action directly affected the command's ability to accomplish its fundamental mission to refit ballistic missile submarines. TRF identified two vendors to help resolve the problem. The first vendor had developed a new system for wet abrasive blast. Introduced in the European market in 1984, the TORBO blast system was brought to the United States in 1992 when it was presented at a national conference of the Steel Structures Painting Council. It is used by Departments of Transportation in many states in the process of preserving bridges. The second vendor had developed an abrasive additive, Blastox, which reacts with the lead paint chips to create a waste product that can be designated as nonhazardous. The wet abrasive blast process developed was first used on the USS MICHIGAN (SSBN 727) hull. It is now routinely used whenever exterior hull paint removal is required. The most important outcome of this process development is that it will permit TRF to pursue work packages involving hull paint removal into the indefinite future.

Blast cleaning standards: Cutting through the confusion?

Proceedings of ACA Conference Paper 13, 2012

The cleanliness of a prepared surface is perhaps the most important factor determining a the durability of a subsequent protective coating system. Standards for surface cleanliness have been available for over fifty years, but there is still confusion regarding definitions, relation between pictorial and written standards and how the standards developed in North America (Joint SSPC/NACE standards) relate to the ISO standards used in the rest of the world. Moreover, with the arrival of power tools that can produce a level of surface cleanliness similar if not equal to levels achievable by abrasive blasting, it is worth reviewing these standards. This paper looks at the various standards and levels of blast cleaning, what they really describe and how they differ from one another. Computer image analysis is used to assess cleanliness levels of the near white (very thorough) level and finds that the ISO and Joint standard levels overlap. Finally, an attempt has been made to simplify and standardise cleanliness levels, incorporating current standards.

BRISTLE BLASTING SURFACE PREPARATION METHOD FOR MAINTENANCE

It has been generally recognised that the best method of surface preparation in maintenance situations allowed by either regulation or situation is either grit blasting or even UHP (ultra-high pressure hydroblasting). Hand tool and power tool preparation has always been regarded as methods which will afford poorer surface preparation standards and therefore reduced lifetime of the maintenance coating. However, a new power tool equipment has been introduced which is portable and achieves cleanliness and surface profile approaching that which is obtainable by blasting cleaning equipment. This paper details this method of preparation and the performance comparison of various standard maintenance products across various accelerated test methods.

The Importance and Measurement of Anchor Pattern from Blast Cleaning

18th International Corrosion Congress Proceedings, 2011

Surface profile or anchor pattern is a measure of the roughness of a blast cleaned surface. It is normally specified for protective coating systems and measured as part of quality control activities. This paper looks at surface profile, why it is important and discuses the various methods and standards used for its measurement. The common belief that profile is important because provide locking or keying of a coating, or provides an increase in surface area is questioned, suggesting its ability to restrain shear stresses during drying, curing and exposure is more important. The paper concentrates on the main methods used for field testing, namely comparators, depth micrometer, replica tape and DFT gauge, looking at ease of use, accuracy and applicability to commonly specified profile ranges for protective coating systems. The replica tape is recommended as it is least subjective, provides reasonably accurate measurements in typical required ranges and provides a permanent record. However, it must be used correctly for optimum results.

Effect of blast cleaning parameters on corrosion of brass parts

Multidiscipline Modeling in Materials and Structures, 2012

PurposeThe purpose of this present work is to investigate how different parameters of the blast cleaning process affect properties and quality of brass parts surface. It aims to study the following process variables: particle abrasive shape: (spherical (S) and angular (G) shot), particle abrasive size (S170, G40 and G50) and the impact velocity (40 m/s, 60 m/s and 80 m/s).Design/methodology/approachAn experimental approach based on three testing methods is used to quantify the analysis of particulate contaminants on substrates surfaces. These methods are: SEM, BSEM and EDXA plots from SEM imaging.FindingsThe results obtained clearly show that the particle embedment decreases with decreasing of the size of angular abrasive. An increase in the embedment could be noted as impact velocity increased. It was also found that the angular abrasives have delivered a contamination level higher than that delivered by spherical abrasives. Furthermore, it was demonstrated that the abrasive debris...

Effectiveness of implant surface debridement using particle beams at differing air pressures

Clinical and Experimental Dental Research

Because implant surface decontamination is challenging, air powder abrasive systems have been suggested as an alternative debridement method. This in vitro study investigated the effectiveness of different powder formulations and air pressures in cleaning implant surfaces and the extent of surface damage. A validated ink model of implant biofilm was used. Sterile 4.1 × 10 mm Grade 4 titanium implants were coated in a blue indelible ink to form a uniform, visually detectable biofilm-like layer over the implant threads and mounted into a bone replica material with bony defects to approximate peri-implantitis. Air powder abrasive treatments were undertaken using glycine, sodium bicarbonate, or calcium carbonate powder at air pressures of 25, 35, 45, and 55 psi. Digital macro photographs of the threads were stitched to give composite images of the threads, so the amount of ink remaining could be quantified as the residual area and expressed as a percentage. Implant surfaces were also examined with scanning electron microscopy to grade the surface changes. No treatment cleaned all the surface of the threads. The powders were ranked in order of decreasing effectiveness and decreasing surface change into the same sequence of calcium carbonate followed by sodium bicarbonate followed by glycine. Higher air pressure improved cleaning and increased surface change, with a plateau effect evident. All powders caused some level of surface alteration, with rounding of surface projections most evident. With air powder abrasive systems, there is a trade-off between cleaning efficacy and surface damage. Using this laboratory model, sodium bicarbonate and calcium carbonate powders were the most effective for surface cleaning when used at air pressures as low as 25 psi.