Patent Pending Parameters of use: The cup washer was developed during the use of both open and closed cell foam manufactured by NCFI, Inc. Both of these foam products are designed and developed to be applied at a minimum pressure of 1,000psi. I continue to apply this material with both the cup washer and/or the replacement side seal as needed based on supplies. My preference is the replacement side seal as it is used without the cup washer over the mating face of the steel side seal. These materials are typically ly applied at a slightly higher pressure of 1,100psi 1,200psi 0psi depending on the elevation above the equipment; 2 nd floor, 3 rd floor or attic. This helps maintain pressure in the fluid lines while rising vertically. It has been reported that the cup washer does not hold up well to higher pressures; above 1,300psi. However, it has also been reported that the replacement side seals have been used successfully in the application of polyurea. A static pressure of 2,500psi with a dynamic pressure of 2,200psi +/- has had positive results with no scoring. The versions that are currently available include Graco Fusion AP, Probler P2/Graco Elite P2. The Probler model requires the use of a new side seal housing that replaces the original housing and threads into the housing block. The side seal can be installed with the spring after having been threaded into the mounting block. PMC-AP2 will be available this summer with filter screens of 60 mesh in packs of 20 (June 20125).
Unacceptable gun cleaners would be harsh chemicals like acetone, brake cleaner, carb cleaner, paint thinner, Xylene, Tolene and other such chemicals with the purpose of other than spray foam gun cleaner. This is best for a Glycol-Ether mixture manufactured by Univar or other manufacturers. Since the replacement parts are a copolymer in nature, the above listed cleaners would be detrimental to the integrity of the parts. Copolymer = plastic. When using cup washer with open cell foam: Assemble the wet/fluid end by installing all o-rings and screens. Prior to installing the side seal into the housing, it is necessary to make sure that both the mixing chamber sides and the side seals are polished using 2500 wet/dry paper on a flat polished steel surface. It is best to use a circular pattern while polishing to avoid micro-scratches in one direction which could lead to premature scoring. Complete the side seal assembly and install the cup washer over the side seal mating face. When installing the side seal assembly, hold the housing with the cup washer on top. Position the gun over the housing assembly and insert up into the wet/fluid end until completely seated. Repeat for the other side and complete the assembly and mounting on the hose manifold. Shutting down at the end of the day: At shut down, when the proportioner is parked, the pressure is below 250 psi. This includes inside the check valve and side seal housings. To prevent the excess pressure from causing the fluid to leak out over night, it is important to drain the pressure from the gun completely by closing off the manifold control valves and activating the gun to dispel the rest of the pressure in the gun. Actuating the trigger once or twice is all that is needed. Allow the foam to react and develop as normal. Drill out the mixing chamber and inject more lithium grease into the grease port until discharge is visible from the outlet. Turn off the air and give an extra squirt of grease into the gun. This will allow the gun to be ready for the next day without having to disassemble or clean the gun. When using cup washers with closed cell foam: Assemble the wet/fluid end by installing all o-rings and screens. Prior to installing the side seal into the housing, it is necessary to make sure that both the mixing chamber sides and the side seals are polished using 2500 wet/dry paper on a flat polished steel surface. It is best to use a circular pattern while polishing to avoid micro-scratches in one direction which could lead to premature scoring. Complete the side seal assembly and install the cup washer over the side seal mating face. When installing the side seal assembly, hold the housing with the cup washer on top. Position the gun over the housing assembly and insert up into the wet/fluid end until completely seated. Repeat for the other side and complete the assembly and mounting on the hose manifold.
Shutting down at the end of the day: At shut down, when the proportioner is parked, the pressure is below 250 psi. This includes inside the check valve and side seal housings. If there is more than one job in a single day, follow the shut down and grease injection for open cell foam. When arriving at the next location, follow standard start-up and heating procedures. When shutting down for the end of the day, the gun can be left assembled and mounted on the hose. If you choose to disassemble the wet/fluid end, this includes removing the o-rings and cup washers. Place o-rings and cup washers onto a clean shop towel and spray with gun cleaner as outlined above in Parameters of use. wipe off excess chemicals and cleaner. Wrap in clean shop towel and rinse thoroughly with water to prevent the gun cleaner from softening the o-rings or cup washers. Leave the soft parts to rest over night. Use a spray bottle to spray the hard parts including the check valves, screens, metal side seals and housings. Used compressed air to remove residual foam chemicals from the parts, place the parts on a clean towel and re-spray with gun cleaner. Wrap the towel up with the parts inside and place in a plastic bag overnight. A zip type bag will work well for this. In the morning or the next day, use compressed air to blow off any material that is still on the metal parts. If needed, a soft brass plumbers brush can be used to brush off any excess build-up. Wipe off the o-rings and cup washers, and assemble as normal. Inspect the mixing chamber for any signs of scoring. It may be necessary to lightly polish the sides of the mixing chamber, but discoloration from the cup washer is normal. Inspect the mating face of the cup washer for scoring. You may notice a small mark from the center to the outside, this is normal, and can be polished out with 2500 wet/dry paper. Place the cup washer on the side seal to provide a flat surface pressing inside the cup washer. After polishing, the side seal and cup washer can be installed into the side seal housing and assemble the gun as outlined above. The above listed procedures can be accomplished in about 15 minutes at the end of the day and the beginning of the next production day. These insure a clog free, score free gun for a full day of production. Greasing Requirements: When using open cell foam, a pattern change does not appear as quickly as with closed cell foam. Approximately every 20 minutes, it may be necessary to drill the mixing chamber. If it is not necessary to drill the chamber, it is advised to do it anyway, and give another shot of grease into the wet/fluid end assembly to prevent residual fluid from crystallizing with the lithium grease, which is what causes the scoring to begin with. There is no such thing as too much grease!
When using closed cell foam, the spray pattern change is more visible and should be drilled as needed. Once the mixing chamber is drilled, give another shot of grease into the wet/fluid end assembly to prevent residual fluid from crystallizing with the lithium grease, which is what causes the scoring to begin with. There is no such thing as too much grease! If you are using a 2020 mixing chamber (000), it is advised that only enough grease be used to lubricate the mixing chamber. This is to avoid clogging the side inlet ports of the mixing chamber. A pair of cup washers can be used from job to job and can last from two three weeks, if the above procedures are used. This can reduce overhead expenses for mixing chambers and side seals by 80% - 85%. The cup washers and these instructions will stop unexpected leaking, which results in increased production on a daily basis.
Side seal mating face with minor scratches from center of inlet port to outer circumference is normal, but indicates that additional polishing of mixing chamber face required. Center opening is inlet port to mixing chamber with the trigger in the on or shoot position. Use 2500 grit paper wet dry paper and a circular motion to polish both side seals and mixing chamber. This is a representation of light wear scratches from the mixing chamber inlet port to the outer edge of the mixing chamber. This also shows stress fractures caused by higher pressures and temperatures. Some foams form at 1,000 pounds per square inch (psi), others form at 1,400 psi. Temperatures can vary from 130 F - 140 F or higher. Polyurea can average between 140 F - 160 F and 2,500 3,000 psi static pressure. Polyurea applicators should check the seals at the end of each day to avoid catastrophic failure due to the increased temperatures and pressures. When the mixing chamber is properly polished, the side seal will look like this without any scoring from the mixing chamber. This also applies to Polyurea, although stress cracks will still occur and should be checked at the end of every day or the beginning of the next day of spraying.