For immersion the use range is 17 – 20 % or 1 part emulsifier to 4 parts water. The concentration is controlled by using a brix refractometer and a concentration chart. For spray applications the concentration is kept below 5 %. In immersion applications the penetrant covered part is given a quick water wash and then immersed into the gently agitated emulsifier from 30 seconds to 2 minutes depending upon the part surface roughness. The part is removed and washed. The pre-rinse step may be omitted for the spray application method of the emulsifier.