I use it full strength without issue even on blacks ...
Never had a issue with FK425 on ANY color steaking,but I always follow up my initial wipe with a second. :dunno:
I used the FK 425 matched with the Woobies. Very happy with the results. However, I also tried my free sample of WG Spritz Seal... really liked this stuff over a freshly buffed second application of WG 3.0.
from what the folks on the AG hotline told me, the streaking is a rare but known occurance. Only happens with some finishes. For me, it was on Monaco Blue metallic paint that had WGDGPS topped with SSII.
It wasn't an amount issue, it would happen even if I lightly misted a good MF and wiped. It was like it flashed immediately with the first wipe, and those spots wouldn't buff out. Left dark streaks. The dillution did help, but didn't completely eliminate it.
It wasn't a temperature issue - would happen when the car was warm or cold, in the garage or out. Anywhere between 50 and 80 degrees. I suspect it may have been a combination of the surface and the humidity. It was that random. who knows, maybe I got a batch that had too much polymer boost in it
But I am pretty sure mine was a rare occurance, as it didn't happen 1) all the time, 2) on my other (Black Obsidian) SUV, or 3) on 2 other vehicles I detailed, or 4) consistently under any one situation (i.e. application method, temp, amount, etc).
It was just really frustrating because I liked the finish the product leaves so well, I kept trying to use it and then would have to rewash the areas if it did happen. At times, before I called AG, I was very tempted to throw the still-almost-full gallon into the trash and be done with it.
So I'm not knocking FK425 - just be aware that it can do this, and if it does, try dilution. Odds are you won't need to, based on the thread where I was looking for help. But some folks have had the same problem with it I did.