May 17, 2011



Have you ever asked yourself, “Do I really need to use genuine Graco o-rings and repair parts for my spray gun?” The answer can be found by considering how good you are at gun rebuilds and how much time and resources are spent on these repairs. Of course, the answer is, if we’re not spraying they’re not paying.


I am often asked why Graco o-rings are so expensive and if Fusion® grease really needs to be used. The answer is very simple. All o-rings used throughout Graco Fusion spray guns are made from a unique fluoroelastomer material designed and tested to withstand temperatures higher than experienced in the field. Tests are also conducted to ensure that the parts withstand harsh chemicals and most cleaning solvents.


This applies not only to o-rings that come in contact with the chemical, but also to all o-rings in the air section as well. Remember, if you experience gun crossover, the air section of the gun will be exposed to chemical as well. Gun crossover is an occurrence associated with the processing of moisture sensitive materials like ISO (A-side component in foam). It is a challenge to spray two-component materials without having pressure imbalances from restrictions caused by material crystallization or contamination. If one of the chemicals drops to zero pressure due to a restriction, and the other side is at process pressure, say 1200 psi, then the higher pressure side will cross over to the other side, resulting in a material reaction outside of the mix chamber. The expanding foam then backs into all unintended areas, including the air section. Graco is one of the few manufacturers that uses high quality o-rings throughout the gun including the air section and not just the fluid exposed section.


Sure, one could take the time to find competitive o-rings at the local hardware store; however solvent may cause the o-ring to swell. You could also order Viton® o-rings from an industrial supply house and save a little money. However, there is no guarantee that o-rings produced by companies other than Graco will stand up nearly as well. And while our Fusion grease looks like others, the true difference is in the production process. Fusion grease has near zero moisture content as to not react with moisture sensitive material such as isocyanate. This reduces gun rebuilds and offers a more consistent spray pattern for a longer time.


Based on my experience, rebuilding spray guns rarely increases productivity. In fact, rebuilding spray guns decreases productivity dramatically. Ultimately, each of us wants our applicators applying product on the job site so we can get a return on our hourly wages. The spray gun is where rubber meets the road, and requires extra care.


I recently retired from the volunteer fire department after 23 years. As a veteran, I had the privilege to share my perceived wisdom with the new recruits. I would always ask them what the most valuable equipment is in the entire fire department inventory. Of course, they always select the shiny fire truck.


However, just before entering the live fire training, I get to be really smart and explain that the breathing apparatus and hose nozzle is the correct answer. The mask becomes obvious when super-heated steam descends from ceiling. The hose nozzle applicator less so, until the spray pattern is distorted or interrupted and the environment gets even more hostile at a very rapid pace. I am not comparing a well-functioning spray gun to a fire nozzle in importance. What I am saying is that I never left the station after using the fire hose line without conducting a thorough check on the nozzle. In addition, I never would use replacement parts that did not meet the same standards that I did. Overall, I can only suggest that everyone uses genuine Graco parts. Graco enjoys the most professional distributor network in the industry. Based on my interactions with them, I know their standards are the same as ours when it comes to high quality parts. There is no substitute for the genuine article and a business owner can usually be convinced that there is no profit in repairing a spray gun when we need them the most.


So as I often told my fellow firefighters, don’t get burned. Insist on a higher standard.


By Barry Taft, Graco Technical Support