Why do they paint 2-inch pool pipes black? (just repaired with 2" white PVC)
Brent
flat black?
On Friday, I put a new pool pump motor in but forgot to open all the Jandy
valves so the pipes overheated, expanded, and blew up in places (a 1.5 HP
motor is strong!).
Anyway, my 2 inch outside diameter PVC pipe from Home Depot earlier today
now stands off as bright white while the rest of the pipes re painted flat
black.
No big deal but I was wondering WHY they paint the PVC pool pipes black and
if it's a good enough reason for me to follow suit on my 2-foot section of
repair pipes.
The three reasons I can think of don't seem to hold water:
- heat retention? (c'mon ... how much heat will black retain over white on
a few pipes that are in the open sun?)
- sunlight damage? (maybe ... but then why don't they just sell pool pipes
that have paint on them already)
- asthetics? (c'mon ... can black matter versus white)
Any other reason for the flat black pool pipe paint?
DD_BobK
Paint is for UV protection of the white PVC (not sunlight resistant).
btw, pre-painted PVC would be a PITA to solvent weld
Could you clarify this sentence?
>>>>>>>> "On Friday, I put a new pool pump motor in but forgot to open all the Jandy
valves so the pipes overheated, expanded, and blew up in places (a 1.5
HP
motor is strong!). " <<<<<<<<
What caused what to overheat? Did the system have water in it?
The horsepower of the pump is pretty much meaningless with respect to
"blowing up" pipes.
It's the amount of head (pressure) generated that stresses the piping.
A 1.5 hp pump / motor can either deliver high flow / low head or low
flow / high head or something in between; depends on the pump
design / curve.
Most pool pumps would be hard pressed to get anywhere near the
allowable maximum pressure for PVC piping.
cheers
Bob
mm
<beemd...@Use-Author-Supplied-Address.invalid> wrote:
>I'm curious why they paint all the white 2-inch PVC pool pump area pipes
>flat black?
So they won't explode. Haven't you learned that by now?
>
>On Friday, I put a new pool pump motor in but forgot to open all the Jandy
>valves so the pipes overheated, expanded, and blew up in places (a 1.5 HP
>motor is strong!).
>
>Anyway, my 2 inch outside diameter PVC pipe from Home Depot earlier today
>now stands off as bright white while the rest of the pipes re painted flat
>black.
Oh, never mind.
RBM
"Brent" <beemd...@Use-Author-Supplied-Address.invalid> wrote in message
news:e3de02510245b8d4...@tioat.net...
The pipes are probably not U.V. protected, so they'd deteriorate from the
sun without a covering over them
Steve Barker
The paint is to protect the PVC from the UV of the sun. White paint,
(or green or red or blue) would work just as well.
George
Black pigments are the most effective UV absorbers.
Bob F
A pump running with no flow through heats up the water in it quickly due to the
internal friction. The pipe gets warm and softens. The pressure blows it out.
SMS
Sunlight damage.
Thanks, you reminded me to go paint the replacement pipes I used when I
replaced my pool pump.
JIMMIE
You got it, Protect them from UV radiation.
Brent
> A pump running with no flow through heats up the water in it quickly due to the
> internal friction. The pipe gets warm and softens. The pressure blows it out.
That's exactly what happened!
The pump ran but couldn't push any water past the shutoff (the jandy
shutoff leaked profusely but not enough).
Then the threads must have softened and the pipes heated up because a
post-mortem analysis showed the threaded pipes melted in a V shape (hard to
explain) such that they just blew right out of the motor.
When I tried to connect 2" OD PVC to the cut edge of the pipe run, I found
that the 2 inches had swelled greatly (almost a sixteenth of an inch or so
... way more than can be sanded).
So I just cut off MORE pipe (no big deal); but I was wondering about the
paint.
Brent
>> The paint is to protect the PVC from the UV of the sun. White paint, (or
>> green or red or blue) would work just as well.
>
> Black pigments are the most effective UV absorbers.
I wonder why they don't just sell black PVC 2" OD pipe then???
Even at Leslies' Pool Supply, they're white.
Everyone seems to just paint them.
It's cheap and easy; but I was just wondering why we don't just start out
with UV-resistant PVC pipe???
Bob F
> On Mon, 19 Apr 2010 09:14:44 -0400, George wrote:
>
>>> The paint is to protect the PVC from the UV of the sun. White
>>> paint, (or green or red or blue) would work just as well.
>>
>> Black pigments are the most effective UV absorbers.
>
> I wonder why they don't just sell black PVC 2" OD pipe then???
>
> Even at Leslies' Pool Supply, they're white.
Maybe they don't want to confuse PVC with ABS?
Brent
> I wondered about this myself. Is the OP sure the original pipes
> weren't ABS?
We have LOTS of sun here. All day sun.
I'm not sure if it's ABS or PVC for all the pipes, but the pipes I bought
at Home Deport say they are PVC.
What made me wonder about the black versus white was I needed a fitting and
I grabbed one that was black through and through. I mixed it in with the
white fittings and then painted the white ones.
I wonder (based on the ABS question) if that one black fitting was ABS
while the rest (the white ones) are PVC?
That makes me wonder: What's the difference from a practical standpoint for
outdoor 12-hours-a-day-in-the-sun 2-inch OD pool water pipes between black
ABS and white-painted-black PVC pipe?
Note: Leslies pool supply sold only the white PVC so maybe I should have
asked the teenager behind the counter but I didn't think of it when I was
there.
Steve B
lasts a little longer.
Brent
> If you cut the end and it is black in the middle, it is ABS.
> That is what the solar contractors use.
> Pool contractors use PVC for the regular pool plumbing.
Given that, ALL the pipes I cut were white on the inside (with purple glue
at the seams).
A single 4-inch-long sleev-like fitting I grabbed out of the miriad of
various elbow-like fittings I bought at the hardware store was black all
the way through as I had to cut it to fit.
So, given that black is ABS and white is PVC, my pool plumbing is currently
99% (white) PVC with that single fitting of (black) ABS that I used without
knowing the difference.
Now that I realize I've mixed ABS with PVC ... I wonder ... does it matter
that I have ABS accidentally mixed in with mostly PVC (painted black)?
Brent
>> Even at Leslies' Pool Supply, they're white.
> Maybe they don't want to confuse PVC with ABS?
I think I found a clue why I need to use (white) PVC and not (black) ABS
pipe fittings in the high-pressure side of my pool plumbing! :(
http://www.swimming-pool-repair.net/plumbing.html
"ABS is not pressure rated for applications such as a pool plumbing sytstem
and an ABS pool system will be likely to develop leak problems
prematurely."
Also ...
"ABS pipe can be identified by its black color and the yellow glue used to
fuse the fittings to the pipe. PVC is generally white and should have a
wall thicknes of 40mm commonly refered to as schedule 40."
Since I used the "blue" glue, I wonder if it will make a difference with my
single accidental ABS fitting???
Brent
> What caused what to overheat? Did the system have water in it?
> The horsepower of the pump is pretty much meaningless with respect to
> "blowing up" pipes.
> It's the amount of head (pressure) generated that stresses the piping.
Hi Bob,
To clarify, I'm not really sure if the 220 Volt 1.5 HP motor horsepower
mattered but what I saw was a two-inch wide stream of water shooting
straight up in the air about fifteen feet!
It was like a rocket ship was taking off when the pipes heated up so much
that the threads gave way on the fitting comeing up vertically from the
motor impeller on the pressure side of the pump. Kaboom!
Afterward, when I cut the pipe and put new parts in, for a good foot or so,
the 2 inch OD white PVC pipe was way larger than 2 inches on the outside
such that no fitting would fit.
I was very confused because otherwise the very thick (shedule 40 at least!)
PVC pipe didn't seem to be any standard. Finally I realized the heat
expanded the pipe so much that it was no longer 2 inches in outside
diameter.
I simply cut away all the bad pipe but had to go into my spares box and
accidentally pulled out a black ABS fitting and glued that in.
Unfortunately, I now know that the black ABS pipe isn't pressure rated so
it's going to be a weak link (where were you when I needed you ... :-)
I'm not really sure WHY a pump that has plenty of water with nowhere to go
heats things up ...
Maybe the water bashing back and forth at high speed, going around in
circle after circle after circle after circle heats it up because even the
basket on the inboard side of the pool pump was melted and had to be
replaced.
SOMETHING about the water having nowhere to go made it get hot as hell
there until the system blew up!
LM
> What's the difference from a practical standpoint for
> outdoor 12-hours-a-day-in-the-sun 2-inch OD pool water pipes
> between black ABS and white-painted-black PVC pipe?
"The Effects of Ultraviolet Radiation on PVC Pipe"
http://www.uni-bell.org/pubs/uni-tr-5.pdf
Summarized by the PVC Pipe Association here:
http://www.uni-bell.org/faq.html
Further summarized by yours truly below:
Q: What effect does ultraviolet exposure have on PVC pipe?
A: Not much but enough to warrant a thin coat of opaque paint!
Modulus of Elasticity = unchanged after two years of sun
Tensile Strength = unchanged after two years of sun
Impact Strength = reduced drastically (by 75%) after two years of sun
Structural Integrity = unchanged after two years of sun
Pressure Capacity unchanged after two years of sun
The loss of impact strength stopped deteriorating as soon as the pipes were
protected by the sun so it's directly related to the UV radiation.
Luckily, the presence of an opaque surface between the sun and the pipe
prevents UV degradation, since UV radiation will not penetrate thin shields
such as paint coatings or wrappings or burial.
Why black? What's more opaque than black? Electrical PVC outdoor pipe is
gray. Go figure.
PS: I heard some paint won't stick to PVC so maybe you need special PVC
paint?
Elmo
> maybe you need special PVC paint?
http://www.pvcworkshop.com/painting.htm
How to Paint Your PVC Pipe Projects
Quote
"I've had the best success with the Krylon™ Fusion brand that’s formulated
for plastic and PVC."
JIMMIE
> On Mon, 19 Apr 2010 18:30:23 -0700, "Steve B"
>
> <deserttrave...@dishynail.net> wrote:
> >Painting black reduces the absorption of UVA, B, and C so that the pipe
> >lasts a little longer.
>
> around here with well pipes, water softeners pressure tanks etc, that
> have been in the sun for 30 years without breaking so I do think the
> UV thing may be overstated a bit.
> Sure if you back over one with your car it will break but it isn't
> just going to spontaneously shatter.
I took out some PVC pipe that had been exposed to the sun for about 7
years. It was still doing its job but it was brittle as heck.
Jimmie
JimT
"Brent" <beemd...@Use-Author-Supplied-Address.invalid> wrote in message
If it makes any difference mine are all still white. I don't remember seeing
any that were painted any color. That's weird that it blew up. I had my
waste valve closed one time and tried to back wash. I didn't have it on long
so it didn't do anything. I'm glad you said something because I never would
of imagined that could happen. I'll bet your motor seal goes out soon if it
isn't gone already.
I'm always afraid I'm going to do something stupid like that.
DD_BobK
LM-
Super reply!
My landscape guy used white PVC (not sunlight resistance & unpainted)
for an above manifold but placed such that it got very little direct
sunlight.
After about 25 years, a narrow strip of plywood (3/4"x 3.5" x 96")
that I Ieft on the patio cover blew off and hit one of the brass anti-
siphon valves.
The PVC on the pressure side broke and I repaired with the grey
PVC........ too lazy to rebuild the whole manifold in sunlight
resistant PVC or copper.
Maybe it'll last another 25 years? :)
cheers
Bob
Oren
wrote:
>Sunlight damage.
>
>Thanks, you reminded me to go paint the replacement pipes I used when I
>replaced my pool pump.
(Mohave Desert)
Okay I had to go look. My pool pump pipes are gray. Spears brand
fitting, 2" PVC 1. Looked up gray pipe, it is SCH 80. My pipe stated
SCH 40. So, I scraped it with my razor blade. Sure enough, the pipe
is white. Looking further I found the blue glue. Some of the glue,
painted gray looks like it is special - but not so. All this time I
figgered it was gray pipe...
The supply lines for the solar panels are SCH 40, PVC1 painted a
desert tan/sand color (eye appeal). Obvious the installer for the
solar used a aerosol spray can. I can see some over spray on the gray.
A suggested paint for Lasco was to use a water base, white latex.?
Brent
> Okay I had to go look. My pool pump pipes are gray.
> I scraped it with my razor blade.
> Sure enough, the pipe is white.
Thanks for that information.
It's wonderful to finally understand what is going on.
Schedule 40 PVC is 40mm thick and the gray is for UV protection.
I think the riddle of the painted pipes has been solved! :)
FLATSHIPP'N-N-HANDLING 99CENT N/R S/H25$ NO PAYPAL
no do not paint ! reason for black paint 2 much beer, attemtp to hide
pluming.
reason not to paint . ease of repair.
never walk away after a repair , prime the pump and wait to see that
every thing is flowing WITH NO LEAKS and the filter preasure is
OK .you can turn pump on and off on and off and watch the pump as you
do this (my trick) see leaks ? fix them.... remember a clean poool is
a safer pool.... POOLPUMPREPAIRGUY .IN SUNNY LONGWOOD FLORIDA . where
the pool is always open, come on in the water is just fine.. Jay