We have several types of O-rings. First off, Viton is a registered trademark of DuPont™. Number 2: I hear often about the Graco "double Viton o-rings". There is no such thing as a double Viton o-ring. Viton is available in several blends, so all Viton o-rings are not the same.
I have been known to claim ours as triple Viton with a Kryptonite coating, but its to make the point understood. Everyone claims to have a Viton ring and the overwhelming majority are from China and they are not a DuPont Viton ring any more than any cola is a Coke.
Most of our o-rings are Certified DuPont Viton rings and we are issued batch numbers for the rings we purchase and sell to you. The rings that see fluid are a specific blend of Viton, while our SPF Blue Rings are a different blend and are superior to the OEM product.
The rings that only see air are another blend that is less expensive, but all they should see is air and the need for an expensive o-ring to handle air is not required at 120psi. We offer the SPF Blue Rings in some sizes that see air, but we don't recommend spending high dollars when you don't need to.Solvents, by design, dry and dissolve product.
I have some people say that the OEM rep's claim that solvents "condition" the o-rings. This is somewhat true - they condition them to fail so you have to buy more. The solvents dry out the natural lubricant and elasticity in the o-ring. This is why after time, the o-ring will break when you try to remove it.
To properly seal when exposed to pressure, the ring is forced down into the o-ring groove and swells out with the pressure to form a seal between the 2 surfaces. With contaminate in the o-ring groove, the o-ring will "blow out". If the o-ring looses its elasticity it doesn't seal but will roll or break.
REMOVE the rings to properly clean your gun parts. You don't save any time trying to clean your gun and leaving all the o-rings intact any more than showering with your clothes on to save time getting dressed. For you die hard guys that demand a solvent proof o-ring - use the SPF Blue Ring. It will not swell in solvent. We offer the SPF Blue Ring in all whetted sizes - those on the check valve, on the side cartridge and the trigger spool.
Even the OEM manual states not to use CU6, Dynasolve and NMP to flush your gun. Why do you think that is?Personally, all I use is our standard o-ring kit. I don't use the SPF Blue Rings. I rebuild the gun only when it gives me trouble and replace all the rings in the front end section at that time.
I rarely touch the rings in the handle and only replaced the large white ring on the front cap after 2 years and a bit of guilt about it. It never made sense to me to be on a $10,000 job and break down because I wanted to save a couple bucks on an o-ring.