Hello, all. FWIW, this is my first post since registering. I've been a detailing fanatic since the mid-'70's.
JB in Irvine- As I've been using boar's hair brushes for about 20 years and am currently using my second generation of ones from Griot's, I feel qualified to comment.
I have tried pretty much every cleaning method and device out there, and I usually choose to use the brushes, primarily for ease of use and the free-rinsing qualities that you mentioned. I generally have NO marring problems with them most of the time (even when inspected with an illuminated magnifier), but they DO occasionally mar cars that have VERY soft paint (e.g., softer than on a C5, they didn't mar that) and/or cars that get too dirty between washes (so dirty that most ANY method could cause marring) and/or if I get careless. So, all in all, they work well for me. BUT, a non-autopian friend of mine who uses the same brushes DOES get marring/minor swirls, frequently, on a car that has good, hard paint (I've washed it w/o problems using the brushes).
A lot of it depends on technique. (You probably already know all the following but anyhow..) As with mits, Use LOTS of high-lubricity wash solution- keep the brush saturated. Use front-to-back strokes. Don't press hard- barely bend tips of the bristles. Think of it as "lightly whisking" the dirt off the finish as opposed to "scrubbing" it off. Rinse the brush THOROUGHLY and FREQUENTLY, as often as after every swipe if need be (the dirt travels up the bristles some, but it doesn't get enmeshed in them as with a mit- good for rinsing, bad for marring). Clean out and refill your rinse bucket as needed. And if the car's VERY dirty, don't try to get it all off with the first, or even second, pass.
The brushes last a long time (years of weekly washes) with little/no care, but inspect the flagged ends of the bristles for wear- they WILL mar if/when the tips wear past a certain point. BUT, inspect them very carefully before use! I've had to return ones with bristles contaminated with the adhesive used to set them into the handle. BTW, the smaller, paintbrush-style ones are great for nooks and crannies but their wood handles aren't as forgiving as plastic. The ones for wheels also work well IF the wheels aren't too dirty or too delicately finished (the marring issue again). The longer handled one is good for not-too-dirty undercarriages (to my surprise, I prefer the short handled one for wheels- better leverage/control). Yes, they're sorta expensive, but with Griot's you really do get 100% boar's hair (this has been debated here and I got Griot's unconditional assurance about it).
Hope this was helpful. Gee, looong first post
