On 2/28/2016 2:00 PM, wrote:
On Sun, 28 Feb 2016 09:44:29 -0700, Don Y
wrote:

On 2/27/2016 11:18 AM, Frank wrote:
On 2/27/2016 12:37 PM, Don Y wrote:
On 2/27/2016 10:07 AM, Frank wrote:
On 2/27/2016 11:46 AM, Don Y wrote:
On 2/27/2016 8:03 AM, SeaNymph wrote:
On 2/26/2016 6:56 PM, Don Y wrote:
The sun is brutal, here. Anything outdoors fades in short order.

For things like the house, it's no big deal -- the colors chosen
"fade well" (unlike some stronger color choices) and the whole
building fades at the same time (no "shadow lines").

But, smaller things with more vibrant colors really wash out quickly.
E.g., all of the knobs (is that the right word?) on our hose bibbs
have virtually no color left to them. If they'd HAD none to start
with, it wouldn't be noticeable. But, as it is, they just have
ghostly suggestions of past glory!

Are certain (types of) paints better at holding their color?

Is it something you could paint with an acrylic paint? Acrylic paint
is very
resistant to all manner of things.

I'd have to aerosol-ize it, but I can do that (paint sprayer).
What;s the problem with "spray enamel"?


For small stuff, acrylic paints come in spray cans.
Reputable companies test their products for outdoor weather-ability.
I've seem devices like a Weather-Ometer for accelerated testing and
have also
seen test panels exposed to weather for years.

http://atlas-mts.com/products/product-detail/pid/226/

Lots of products, like your hose bibs are probably not tested for
weather-ability and plastics can fail more rapidly than the pigment they

I think this is a die-cast "knob" that is enameled prior to sale.
It certainly doesn't *feel* plastic (I can try a flame test on one)

contain. These things are not painted but the pigment is dispersed in
the
plastic but weathered surface may frost over from the polymer
degrading and hid
the color.

Again, I'm pretty sure this is a chunk of metal underneath a thin
coat of paint/enamel. I can also test that -- chip away at it to
expose the underlying material (if any).

Could be painted metal. If so, I would look for an acrylic paint for outdoor
use. Fading of color depends on light stability of the color.

(sigh) And I was *at* The Paint Store just yesterday! Crap. Too many
"issues" to keep track of with too little grey matter...

Pigments from metal oxides or salts generally hold up better than colors from
dyes but cans would probably not tell you what is in it. You could probably
look up stability for different colors. Black that comes from carbon and white
from titanium dioxide should hold up best. Iron oxide reds probably so too.

"Knobs" in question *were* red. But, who knows what the pigment
source was (when you buy a bibb, they're probably assuming you're not
interested in where the color originated!)

OTOH, there really aren't many color choices available. Hence the desire
to learn what to look for in a *chosen* paint...
Most of them are powder coated, likely with an epoxy thermosetting
(the cheapest type and not really recommended for outdoor use) powder
that fades quickly and weathers pootly. Acrylic and Flouropolimer
thermosetting are the best thermosetting - and Nylon is the most
common thermoplastic.

The commercially available knobs are generally red (for hot water)
blue (for cold water) , yellow (for natural gas or non-potable water)
and Green (potable water-common for external irrigation etc)

Yes, and they also tend not to be very interchangeable. E.g.,
gas valves tend to be "stops"; you don't turn the gas on "just
a little". So, ball valves. OTOH, if you expect the valve
to do metering, then a ball valve will fail in short order!

[The style of knobs on each varies based on the valve style;
have a look!]

My first thought was just to buy "replacement" *knobs* of
particular colors. But, different valve stems, manufacturers,
etc.

E.g., I selected large "knobs" as small knobs seem to be harder for
aging hands to grasp (it's unlikely that I will be getting YOUNGER!).
As well as some other mechanical constraints dictated by the locations
of each, mounting style, etc.

Rather than add all those criteria to a wish list -- with ZERO
chance of finding "assorted colors" AND those constraints,
I simply found something that addresses the mechanical
constraints (I can *change* a COLOR, but not a casting!).

Now I'm stuck with that color changing aspect of the problem...