Trials in the UK have confirmed the advantages of a new grit blast medium made from 100% recycled glass as a method of cleaning steel and preparing metal ready for painting.
The results of the full s…
Trials in the UK have confirmed the advantages of a new grit blast medium made from 100% recycled glass as a method of cleaning steel and preparing metal ready for painting. The results of the full scale test at Dunstons Ship Repairs in Hull, eastern England, announced in April 2006, are part of a wider series of trials commissioned and funded by WRAP (the Waste & Resources Action Programme) and managed by the Shipbuilders & Shiprepairers Association (SSA). Carried out in controlled conditions, the trial compared the performance of recycled glass grit with copper slag, the shipyard“s usual abrasive, in blasting a mooring pontoon. Preparing surfaces by grit blasting is the preferred method in the marine industry as it is often the fastest and most thorough means of removing iron oxides, rust, oil, grease, dirt, old paint and other surface contaminants from vessels prior to making repairs and alterations. Graham Billany, Managing Director at Dunstons, said: “We“ve used copper slag for more than 30 years and while this is a cost effective material we were interested in exploring the potential of recycled glass grit as an environmentally friendly alternative. “We agreed to a full scale trial, after the results of preliminary tests on different steel samples, including man hole covers, rusted cargo hold plates and heavily pitted ballast tanks, proved very encouraging.” In the initial trials, recycled glass demonstrated improvements in productivity over the traditional copper slag of up to 240% and the time taken for blasting was reduced by up to half. The performance of medium grade recycled glass grit supplied by Wolverhampton Abrasives was compared with copper slag using the same blasting equipment. As well as being a more sustainable use of resources, recycled glass grit“s main benefits over conventional blast media are that it is non-toxic, inert and does not cause respiratory or environmental problems. It does not contain crystalline silica or heavy metals and so can be used in public places and environmentally sensitive areas, such as watercourses. Glass grit is also free of chlorides and salts that can corrode clean surfaces so its use delays “gingering“ of steel, and, through spent media being classified as a nuisance dust, rather than hazardous waste, can offer lower disposal costs. In contrast to most conventional abrasives, recycled glass does not have to be imported, meaning shorter delivery times for blasting companies and potential environmental benefits, through less energy being used in transportation. Andy Dawe, Materials Section Manager (Glass) at WRAP, said: “We“ve been aware of the advantages of recycled glass grit in the UK for some time, but our task has been to demonstrate the operational and commercial benefits to the market by funding trials such as these”. “In the USA, glass grit has been proved to effectively clean masonry, renovate equipment and restore woodwork, among other applications”. “We“re delighted the marine industry is recognising the potential of this new medium and hope specifiers and contractors will now use it more widely”. The widespread use of recycled glass will assist the UK in meeting its target under the European Union packaging directive, which says 60% of glass must be recycled by 2008. Preliminary data for 2005 indicates that 50% was achieved. Recycled glass is available manufactured to BSI PAS 102 specifications, setting standards in terms of colour, contamination limits, particle size requirements and appropriate test methods.