Engineered by combining the best steel with carbon levels high enough to be called iron. Manufactured to precise standards, quick chilled, then heat treated to produce an incredibly hard blasting material.
The best abrasive for the toughest jobs.
The end result is savings of 10-20% in paint, VOC's, and labor costs. Most importantly, it prevents premature coatings failure. METgrit® Blasting Abrasives have emerged as the product that most effectively meets the technological and environmental demands for steel surface preparation and lead paint removal. METgrit® Blasting Abrasives clean faster, with less dust generation and can be recycled - making surface preparation cleaner, cheaper, and safer while generating hundreds of times less dust and waste than conventional mineral abrasives.
Blast cleaning has been the most effective surface preparation for the past 50 years, and that is unlikely to change in the next 50 years. What is changing is the methodology and materials used for blast cleaning. METgrit® Blasting Abrasives have become the abrasive of choice with its unique irregular and sharp angular shape which enhances blast cleaning efficiency by combining impact with scouring action.
Conventional grit may produce an appearance good to naked eye because of the light refractive properties of the faceted steel anchor pattern, but in fact, could create quality control problems. Conventional grit may cause an inconsistent profile, rogue peaks, embedment or hackles.
Chesapeake's irregularly shaped metallic abrasive particles are specifically engineered to effectively remove paint, rust and mill scale while imparting a consistent, controllable profile free of these problems.
Much has been written about the problems encountered when removing lead-based paints from steel structures. The problems include creating effective containment structures, assuring worker health inside containment, complying with regulations on disposing of lead-contaminated waste, and controlling cost. METgrit® Blasting Abrasives can help with these concerns.
Changes in the Resource Conservation and Recovery Act (RCRA) involving Land Disposal Restrictions (LDRs) have brought about sweeping changes in the methods used to blast clean steel structures. No longer is open blasting permitted for removal of hazardous materials. "Escaping materials that reach the ground and water may constitute illegal disposal and are subject to enforcement action", according to one EPA representative. Because of the changes in federal regulations, as well as those of state and local agencies, the contractor involved in blast cleaning and painting is forced to deal with rapidly evolving technology in order to comply.
One objective of abrasive recycling is to maintain cleanliness of the abrasive. The first step in this process is to develop a method to meter the abrasive flow to the cleaning station. Many systems are now employing some form of mechanical metering system to control the flow of the abrasive., which improves the effectiveness of cleaning.
The function of the cleaning station is to remove all forms of debris from used abrasive. The first step is to remove large trash, such as paint chips or bits of concrete. This is best done with a coarse screen at the point where the abrasive falls into the initial collection/metering system. The trash collection area should be easily accessible because it will require clean-out one or more times a day. After trash removal, the abrasive is fed into a collection bin, then metered into an air-wash system where the abrasive stream is subjected to a series of tumbling air wash cycles. The velocity of the air washing through the cascading abrasive is adjusted to remove dust and fines as completely as possible, leaving only clean sized abrasive to be returned to the blast pot. To summarize, a cleaning station contains a coarse screen to remove trash, a storage hopper, a metering device to provide controlled flow of abrasive, and an air-wash classifier that removes dust and fines.
As a general rule, no more than one percent by weight of non-abrasive material should be present in the recycled abrasive. Daily sampling of the recycled grit is recommended to be certain all systems are working well. The operator should screen working mix samples on a #70 screen and record the weight percent that is coarser and finer than a #70 screen (that is for normal steel blasting, finer blaster requires finer screens). If the weight of the particles passing a #70 screen is greater than one percent of the total screened sample weight, then the operator should check the abrasive cleaning station. Specifically, operators should check the dust collector for plugged filters or bags.