Traditionally the blasting and painting of ship block sections has been conducted in the open air in ship yard dock sides using expendable abrasives and open spray painting. Obviously there are many draw backs to this process. Firstly the production rate is always unstable as the blasting and painting process is always at the mercy of the weather. During periods of inclement weather it is impossible to blast or paint due to rain and high humdity levels. In tropical regions this can be a major problem as the rainy season can last for weeks and bring production to a stand still. The other issue is with environmental pollution. Blasting with expendable abrasives and unconfined spray painting both release large amounts of polluting chemicals, dusts and pollutants into the environment.

With increasingly strict envirnonmental regulations, and with the introduction of new IMO regulations for production of double skin hull vessels, the requirements for surface preparation and protective coating application have changed. Aside from the above regulations and pollution issues open blast and painting is not the best way to achieve productivity and quality work.

With the installation of a Blastechnik ship block combination blasting and painting facilities it is more economical than ever to move surface preparation and painting operations inside into an environmentally friendly climate controlled atmosphere where blasting and painting can be conducted around the clock 365 days a year without being at the mercy of the weather or producing vast amounts of pollution. Blasting and painting inside a climate controlled facility will result in higher productivity, higher quality work and substantial cost savings.

Another key advantage and cost saving benefit of moving the blasting process to inside a blasting chamber is the choice of abrasive that is able to be used. Instead of using thousands of tonnes of expendable abrasives, and consequentally having thousands of tonnes of waste to dispose of, the blasting abrasive of choice is now steel grit (DuraGrit). With the correct recycling equipment this abrasive is able to be recycled hundreds of times. As the abrasive is so durable, the breakdown rate is extremely low (=0.5kg/m2), resulting in a fraction of the waste being generated and needing to be disposed of when compared to expendable abrasives.

One of the major issues that arises during the processing of ship block sections, or other very large steel fabrications, is the problem of flash rusting of the part after blasting and prior to painting. The Blastechnik blastroom is able to maintain relative humidity levels at 50% RH during blasting and clean up. With a relative humidity level of just 50% RH the risk of flash rusting is almost completely eliminated, providing ample time between blasting and painting. During spray painting the relative humidity level is maintained at 75% RH. Most painting specifications require spray painting to be carried out with a relative humidity level no greater than 80-85% RH.