So you have a high quality spray booth but keep finding dirt and dust in your paintwork. The solution is usually not as complicated as you might think. These tips will help you to prevent dirt in your spray booth and hopefully save you the headache of having to retouch paint jobs.
It is estimated that up to 80% of dirt in any environment where paint is being applied, is taken into the area by foot fall and the wheels from trucks, karts and trolleys. Along with this, movement can be the cause and this can be as simple as people movement causing the shedding of dry skin and hair. It can also be through mechanical movement such as fans, paint skids and jigs, as well as vehicle/skid lifting and storage equipment. Some dirt in the environment cannot be seen with the human eye but movement creates air flow, which in turn pushes the particles around and they can collide making larger sized dirt particles.
The use of contamination control matting along with other clean room type products such as shoe covers and other appropriate PPE, along with products that have been designed and developed to trap air borne particulate like tacky mesh, dirt trap, booth films and coatings as well as interior/exterior fan covers.
Fibres play another key factor in contamination of paint, this can be coming from the use of PPE products, as well as work wear. Other producers of fibres are wiping products; most paint shops use sealer wipes, tack wipes, solvent wipes, micro fibre wipes, as well as general purpose wiping products used for hand wiping and robot covers.
There are a wide range of low lint products such as coveralls, gloves and technical wiping products that are both non-woven and polyester as well as a very good quality robot cover either fitted or tube type that is supplied cut and heat sealed.
At the start of the paint process namely degreasing, phosphate and electrocoat dipping, it is really important to have good filtration, as there can be a wide range of particulate and other contaminants being taken in from press and weld, body in white, dirt from the chemicals/paints and again the movement of carriers. Some companies use standard needle felt filtration, these may have a particle size of 25 micron, but these types of filter will typically have a nominal efficiency of around 60-70%, which means 30-40% of particulate that is bigger than 25 micron could remain in the tank and transfer to the body.
We always recommend using high quality filtration media that has a nominal efficiency above 90%. They can also filter out oils, there are excellent 9,300 gauss rare earth magnets available for attracting & holding onto the metal particulate.
Another cause of dirt in paint can be the sanding debris from the use of hand sanders and machine sanders. This can be a problem particularly when sanding debris gets into doors, boot and bonnet channels because these areas are not cleaned as thoroughly as ‘A’ surfaces, they can often be left behind, which can force the dirt out from doors and channels onto the wet painted surface when the body goes into the turbulent air ovens.
There are a wide range of abrasives available such as the Mirka Abranet range that can be used by hand and machine, they offer excellent extraction qualities along with pneumatic and electric extraction units. We are also able to offer atex machinery that is used when you sand potentially hazardous materials such as aluminum, we believe it is more efficient to use suction guns rather than airlines to blow dirt away, as this makes sure you do not generate more static and to ensure that any dirt that is in the atmosphere is kept on the ground. There are also dry fog systems that suppress dirt by keeping it low to the ground, as well as cooling the atmosphere, eliminating the need for cooling fans.
As you can see preventing dust and dirt in your spray booth just takes a bit of careful planning and following a regimented process before you start spraying.