Cleaning your spray equipment efficiently requires the use of the correct solvent. Selecting the right solvent for clean up requires that several factors be taken into consideration: types of coating to be flushed, cost of cleaning solvent and which solvent may be used to allow your company to comply with regulatory requirements. The following list of solvents are recommended for each type of coating material listed.

 

These solvents will flush out their respective category of coatings with the least amount of solvent consumed. Therefore, the total amount of flushing solvent used on an annual basis should be taken into consideration when calculating your equipment flushing and cleaning costs. Cheap cleaning solvents that are blended with low cost co-solvents may be lower in cost on a per gallon basis; however, these solvents may require much higher amounts of cleaning solvent to perform the same level of clean up. Therefore, the annual cost of solvent may actually be higher than using a higher grade of cleaning material. Do not forget to calculate the cost of solvent waste removal when figuring your annual costs for clean up. We recommend using the best solvent cleaning blend that cuts the type of material you are spraying the most efficiently and provides the lowest flushing and cleaning costs. Consult with your solvent supplier to analyze the best blend of solvents to meet your cleaning requirements.

 

Local and national environmental regulations will also factor into the best solvent cleaning solution for your facility. Where regulatory codes restrict the most ideal blend of solvents, acetone will need to be used to replace hydrocarbons that are restricted in your area. Acetone is a non-regulated material and will allow you to use this type of cleaning solvent without being concerned that it is listed on the Hazardous Air Pollutant (HAP) list. If you are required to use acetone for cleaning purposes, keep in mind that for most solvent based materials, the solubility of acetone for most materials is not the best type of cleaning material and does not flush most types of coating efficiently. Therefore, acetone will require a longer flush-out cycle and a larger volume of solvent to perform the same level of clean-out as the preferred type of solvent would for the type of coating you are spraying.

 

For water-based materials, a mixture of two parts water and one part EB Glycol/Butyl cellusolve will provide an excellent clean up solution for your water base application equipment.

 

At the end of each day, we recommend removing and cleaning both he air cap and fluid nozzles of the gun. Before unscrewing and removing the fluid nozzle from the end of the gun, be sure to remove the gun needle or trigger the gun to the fully open position to remove the tension of the fluid needle on the fluid nozzle. This will prevent bending or damaging the needle during the removal of the fluid nozzle. The interior and exterior surfaces of the gun should be cleaned with a nylon brush and the appropriate cleaning solvent. To prevent severe damage to the gun and air cap, never use a stainless steel or brass bristle brush. As a best practice standard for effective clean up, we recommend using the nylon brush, a tip cleaning needle, and compressed air to remove all debris and to dry the parts free of cleaning solvent before reassembling. Hold the parts up to a light source to check all fluid and air passageways to ensure that they are free of debris and fully open. At this point, the fluid nozzle should be replaced on the end of the gun. Air caps and tips can be set aside or mounted back onto the gun.

 

Soaking gun tips and air caps in cleaning solvent until the next use is NOT recommended. Cleaning solvents can corrode tips and air caps, and any material that hasn’t been removed can continue to harden in the solvent and build up in the material air passageways and will be harder to remove after long term use.

 

For proper clean up procedure for pumps and pressure pots, we recommend using enough solvent to flush through the equipment in order to completely purge the coating material from the equipment. At this point, we also recommend allowing the system to pull air into the pump and into the fluid lines before continuing to flush with cleaning solvent. This procedure will allow the pressure system to pass the air through delivery system to provide an “air chop” to more effectively purge the system. The system should be flushed with enough solvent until the solvent flows clean and does not feel tacky when touched.

As a final system clean-out step, we recommend increasing the fluid pressure on the system to the maximum rated pressure for your equipment.  This will force solvent under pressure into the “dead zones” of the fluid delivery system. All interior areas of the pumping system and hoses will stay wet and prevent paint hardening within the equipment. Make sure all safety devices on the gun are activated to prevent operator injury from accidentally triggering the gun under high pressure solvent. As a final step, wipe down the exterior of the equipment and hoses with a clean rag and solvent to ensure that no hardened material builds up on the equipment. This will also prevent contamination from material flaking off of the equipment when next used.

 

Thorough, consistent cleaning of your equipment takes time and effort. However, every good spray operator understands the joy and benefit of coming into work knowing that the spray gun will work properly and trouble-free. The importance of proper cleaning at the end of the day prevents problems from occurring the next day, causing hold ups in production and wasted time and effort on the part of all concerned.