Author Topic: should I paint a Rainwise rain funnel?  (Read 1556 times)

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Offline DaleReid

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should I paint a Rainwise rain funnel?
« on: March 30, 2023, 04:20:08 PM »
While I have my LR Rainwise sensor package down from its mount, I  have been cleaning it, checking for nests, critters and such. and while cleaning the rain catcher funnel began to think that all the rest of the stuff is white, but the collector is black, or mostly black fading a bit with sun over the years.

I know that the temperature and humidity sensors are just a few inches away, and just above the funnel. 

I got wondering if it would help to give at least the outside of the funnel a bit of a white coating with a outdoor spray enamel which would match the color and finish of the rest of the sensor/solar panel housing.

It might make it cooler, and therefore less likely to raise the temperature of the sensor just below the wind vane propeller assembly.

I could also paint the inside, at least down to a few inches away from the drain hole and screen, since during the summer the sun will hit that area too.

Has anyone done this?  Were there regrets?  Is there a reason to NOT do this that I've not thought of?
Dale
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Offline CW2274

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Re: should I paint a Rainwise rain funnel?
« Reply #1 on: March 30, 2023, 06:30:20 PM »
I suggest caution here. With at least Sensirion sensors, they say VOC can be detrimental to the sensor. They even specify which kind of glue to use with the SF2 cap. I suppose if you let the VOC's dissipate, you may be okay. Personally, I'd at least find A VOC 'friendly' paint if you go this route.

Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #2 on: March 30, 2023, 07:35:21 PM »
Good point.  I won't be placing the sensor back on the post for awhile, so I could paint the cone, removed from the unit, and let it stand for a week or two, or if we ever get warm temperatures and sunshine to bake it a bit, the outgassing should be done in awhile.

Thoughts?  Dale
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Offline CW2274

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Re: should I paint a Rainwise rain funnel?
« Reply #3 on: March 30, 2023, 07:38:43 PM »
I think you'll be okay, however, I hold harmless... ;)

Offline vreihen

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Re: should I paint a Rainwise rain funnel?
« Reply #4 on: March 30, 2023, 08:43:43 PM »
Playing Devil's Advocate, both Rainwise and Davis use black rain gauges.  Could there be a technical reason, like solar heat to melt snow in the winter?????
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Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #5 on: March 31, 2023, 10:02:07 AM »
vreihen:
I noticed that, and Peet Bros have those little egg shaped low resolution ones that are black.
But Texas Electronics weather stuff has gold anodized funnels and white collector bases, and many, like Young have a black collector and white bases, but High Sierra and similar have all white.
I guess i'll have to experiment, but I know black is definitely hotter.  The very early Rainwise were green, with an aluminum collar which was so shiny that I have had summer sun get concentrated by the curve and melted the plastic once. 

There may be no right answer.  I'd just like to have a black object nearly the size of a bowling ball in hot summer sun not as close to the temperature sensor.  After all people go to great lengths for aspirated temp sensors, to get true ambient temps.
Thanks.  Dale
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Offline mcrossley

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Re: should I paint a Rainwise rain funnel?
« Reply #6 on: March 31, 2023, 11:26:34 AM »
Another thought, the Davis black rain cone warms and causes a convection current drawing ambient air over the temp sensor below?
Mark

Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #7 on: March 31, 2023, 12:25:06 PM »
mcrossley:  The rain collector is below the temp/humidity, so warm air would rise to heat the sensor. 

I have two of these, so I may do one and not the the other. 

Dale
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Offline TheBushPilot

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Re: should I paint a Rainwise rain funnel?
« Reply #8 on: April 01, 2023, 12:07:48 PM »
Dale,

It's an inherently good idea. I don't think the color of gauge matters much when most commercial grade instruments often provide a self heating option. Of course that isn't the case here. Not to mention those gauges are located in far proximity to the temperature/relative humidity probe(s). My concern with painting the cylinder white is the reflectance from the surface of the gauge. I don't like the RainWise configuration for that reason. Big black mass right under next to the T/RH sensor is pretty poor placement. Unlike the Davis stations with the gauge placement above the radiation shield. I don't know what the implications of a highly reflective surface next to the radiation shield are. Not that the black gauge is any better, but at the very least the light is absorbed.

Making it white is certainly something you could try, of course following the advice of others regarding paint off-gassing.

I know this isn't the point of the thread but if it were me I would just try to separate the gauge from the sensor suite and be done with it. There isn't really much that can be done to mitigate the effects of an object that close to T/RH sensors, regardless of color. But trying the different color is certainly an option.
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Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #9 on: April 01, 2023, 03:23:36 PM »
BushPilot:
Your idea of separating the gauge from the ISS is one I've been thinking about.  I have this on a peak of the shed, and with arthritis and ear trouble making me less of a mountain goat springing around on the roof to more of leaving my fingerprints in the ladder as I go up from gripping so tightly.

I think that Rainwise had a remote gauge linking to these units as an option, but don't want to cough up any more than I already have invested in them.

I do have several Rainwise 0.01" tippers around here and was thinking of making a remote mount, but I'd still have to to clean it, which it seems I have to do a couple times a year with fall leaves and spring pollen and tree debris from their pollenating. 

I already had used one of those small Molex plugs on a 20 foot wire to run out to another tipper sitting on the deck, and maybe I'll try to find a better place for a rain gauge with no obstructions and go with that.

Good ideas all  around and I thank the participants for their comments.  I'm open to more discussion of course.  Dale
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Offline CW2274

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Re: should I paint a Rainwise rain funnel?
« Reply #10 on: April 01, 2023, 07:07:16 PM »
I've used a RW tipper for a good eight years, remoted away from my VP2 ISS. All of my components are separate, T/H, rain, and wind. Remoting the rain gauge away is without a doubt the way to go, IMHO. Put it where you want. 

Offline TheBushPilot

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Re: should I paint a Rainwise rain funnel?
« Reply #11 on: April 01, 2023, 07:53:52 PM »
Dale,

What does the termination point for the gauge within the station look like? Since getting on a ladder is a concern of yours have you considered putting it at or near ground level? Maybe you could simply wire up an extension cable from the bucket up to the suite on your shed roof. That way maintenance is easy while eliminating any need for wireless connectivity and $$$. Just an idea. :-)
"There is — always — more than one thing influencing anything we are trying to measure." ~ Sherman Fredrickson
"Do it right or don't do it at all."

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Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #12 on: April 01, 2023, 09:02:49 PM »
I had a couple of those waterproof compression type fittings that are common on newer cars, the ones that seal and provide a little pressure inside to keep dust and stuff out.  I am hoping that this will allow me to hard wire it with a detachable way to allow either one to stay in place if the other has to be moved.  I'm working on that this weekend partially because it is nice and I want to be out, but also based on much of the discussion here.  Thanks again, nice thinking.  Dale
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Offline TheBushPilot

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Re: should I paint a Rainwise rain funnel?
« Reply #13 on: April 02, 2023, 12:14:09 AM »
Do share what you end up doing. I look forward to seeing what you come up with.
"There is — always — more than one thing influencing anything we are trying to measure." ~ Sherman Fredrickson
"Do it right or don't do it at all."

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Offline vreihen

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Re: should I paint a Rainwise rain funnel?
« Reply #14 on: April 02, 2023, 08:46:31 AM »
Rainwise does use a ground mount for their standalone tipping bucket rain gauges, so it isn't a crazy idea to extend the cable and mount the gauge near the ground:


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Offline blizzardof78

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Re: should I paint a Rainwise rain funnel?
« Reply #15 on: April 29, 2023, 01:11:51 PM »
Take or leave my following comments which I'm sure you'll ignore being from me, but I owned one of these units for a few years. Had it on the roof right beside the Davis Vantage Vue. Noticed NO difference what-so-ever in the temperature readings. If it ain't broke, don't fix it! Who cares if it's white, black, yellow, whatever color....

Offline DaleReid

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Re: should I paint a Rainwise rain funnel?
« Reply #16 on: April 29, 2023, 02:41:45 PM »
Your real world experience is worth a lot more than speculation.

I did paint one of two that I have.  The one is now bright white, a paint like Rustoleum intended for adherence to plastics. 

After I cleaned them up, I pained one with three light coats of paint until it was well coated.

Since then I've only had a chance to do a few checks, but the rain collector itself was about 23 degrees F cooler in the sun than the identical unpainted black one.

The  mistake I made was not making sure the temp readings off both of the Mark IIIs weren't the same in night time conditions, which is on my to -do list. but the black one was about a degree higher overall during the day. 

If we ever get some sun back, I'll do more careful observations.  And calm conditions will help, since lately we've had nature-provided FARS ventilation to keep things cooled off.

More later, and thank you for the comments, everyone. Dale
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