Important information to consider when using wet electrostatic spray equipment.
From many years Spraytrain.com have provided training for operators using electrostatic spray equipment. The training provided helps operators to maximise transfer efficiency and reduce waste. There are many things to think about from a safety and efficiency point of view when using electrostatics.
Earthing: – Earthing is very important for safety and efficiency. The following items should be earthed when using wet electrostatic spray equipment: –
- The items being sprayed
- The spray gun
- The operator (usually through the spray gun handle)
- Any items in the spray area that could receive a charge
- Paint and solvent containers
- Note! Do not use plastic containers
Electrostatics are usually purchased to increase transfer efficiency and reduce waste. Electrostatics will only work if the items to be spray are earthed correctly. Items that are not earthed will become “charged”. This means they will accept the coating being sprayed for a short time, but will then reject the coating once the item becomes “charged”. The time it takes for the item to be charged will be proportional to its mass. For example a large item such as a skip will take longer to be “charged up” than small items weighing a few ounces. If the operators are are getting covered in overspray while spraying electrostatically it is usually due to the item not being earthed correctly. The reason for this is the coating is going to the best earth.
Earthing and static discharge: – The above item explains that items that are not earthed become “charged up”. The limit of charge that an item can accept is proportional to its mass. The limit of charge is usually referred to as its “capacitance”. The dangers of large items being charged up to their capacitance is that they will produce a “hot spark” if they discharge to earth. A “hot spark” is capable of igniting solvent gasses in the spray area.
Would you need to earth all the above if you were not using electrostatics? The answer is yes you would need to ensure everything is earthed if you are spraying and not electrostatics and using solvent based coatings.
If you want to know more about electrostatics see our website.