Waterproof is a binary concept...

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Waterproof is a binary concept...

 

So, the roof on the back side of my house has a couple of "V" angles, and the snow and ice builds up.

A couple of years ago the roof leaked, and the main family room need a new roof, new sofa, new carpet...

 

I put a heater cord on the roof and wanted an outdoor thermostat to turn it on and off.

No use running the heater cord on the roof, to melt the snow and ice, when it was warm enough that the heater wasn't needed.

 

It was a bit of a quickie, "weekend" project, and my goal use to use up a few of my old through hole components, as more involved projects are all SMD these days.

This was a quickie DS18B20 digital sensor, relay, LCD for fun, and a Tiny.  Not much too it.

 

The project has worked fine for the past three Winters.

 

I went to go plug it in for the Winter and was dismayed to find that my Water-Tight, Weatherproof case wasn't so water tight after all.

 

Mechanical aspects of project design, and cases, have never been something I've excelled at.

 

Darn.

 

Fortunately, I dried it all out and it works fine.

But I'll have to put it inside of a protective enclosure outside.

 

Photos:

Original project, nearing completion.

Shot of roof, with heater cord melting snow, shot through a screen.

Three year's, post install:  Not looking so good...

 

JC

 

 

 

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Very good to see those practical projects of yours.

Glad it was recovered.

 

Is there a gasket between the case's two halves in the third photo?

Reason : an IP68 rated case has one (thanks, for your post lead to a search)

 

An aluminum case's seal may survive longer but would need remote data I/O.

Likewise with fiberglass-in-polycarbonate (IP67)

 

 

 

 

 

"Dare to be naïve." - Buckminster Fuller

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Ahhh... the old "cool down and suck in moist air" problem.

 

Ross McKenzie ValuSoft Melbourne Australia

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Needs a bag of dessicant and/or a breather

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Your LCD obviously didn't like it - it's telling you to F Off :)

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You didn't mention the IP rating of the Water-Tight, Weatherproof case you chose. I'm guessing you used what was "to hand". From the photo it doesn't look like IP very much at all.

 

Ha Ha! Actually you already have the a solution there. Just include a length of the heater tape INSIDE the waterproof box. (Oh and perhaps a cheapo RH sensor to turn it on}

 

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Perhaps if you deployed it in a bag of rice it would help!  q:-)

 

 

 

Click Link: Get Free Stock: Retire early! PM for strategy

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Hmm, I use (almost) the same enclosure in my product. It is rated IP-65. The gasket is a bit "weak" and is prone to improper installation. I don't like that. But, I did not realize that it could be that bad. Will warn customers because it does need to be opened every few months to replace batteries :=(

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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I would not use any box with a clear lid out doors as the sun will bake the insides during the day and when it cools at night you will get condensation.

Use an opaque box and as stated above add a desiccant pack you can change when it's opened. 

You could always fill the box with Nitrogen or Argon! 

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

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ki0bk wrote:
You could always fill the box with Nitrogen or Argon!
Coat its innards with NeverWet.

NeverWet

Super Hydrophobic Products

Waterproof Coating

http://www.neverwet.com/

 

"Dare to be naïve." - Buckminster Fuller

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it's telling you to F Off

Still laughing over that!

I appreciate the feedback!

 

The case does have a rubber (?) gasket, and it was well seated when originally closed up.

It was a PacTec enclosure, but they don't list the model any more.

 

The power cord squish-the-cord-tight pass through ports were suppose to have a (rubber?) gasket, also.

I omitted those as they didn't come with the connector, and I never placed another $0.50 order for them...  (lessons learned).

The gaskets go between the pass through and the case; the hole for the cord clamps circumferentially down very snuggly around the cord.

 

I hear what Jim is saving about the clear case.

It was an IP.something rated case, (IIRC), I purchased a few of them a few years ago.

 

The original project, years ago, holds an outdoor temp / RH sensor, but it is in a relatively waterproof location, out of the rain and sleet and snow.

 

This case was indeed a "spare", in the parts bin, as suspected above.

 

The clear cover was specifically for the first project, to see its internally mounted LCD.

That project had an internal temp sensor and small (power resistor) heater, to keep the interior warm when the temp is well below freezing.

That, actually, was to keep the cheap RF link happy and on frequency, and the micro on frequency for the USART to RF link.

 

Kartman, you mentioned a breather hole.

I'll have to try to read up on that.

I did think about not sealing the case, to let it breath, but then I figured I'd have ants and bees and what not crawling around inside the box, if I didn't have a good enough mesh / sponge to block the bugs.

 

 

I didn't add a desiccant pack.  Truth be know there was far too much water in the case for that to have helped / solved the issue.

If I had managed to have a better seal to begin with, then that would no doubt have been very beneficial.

 

I'll have to have a look at "Never Wet".  I wasn't familiar with such a product.

 

The nice things about my projects is that a "Factory Recall" generally involves one device...  Which I then label a "Prototype"!  smiley

 

JC

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ki0bk wrote:
You could always fill the box with Nitrogen or Argon!
Make a brick of it

logo

MG Chemicals

8322 - Optically Clear Epoxy

http://www.mgchemicals.com/products/potting-compounds/epoxy-potting-compounds/8322-optically-clear-epoxy

 

"Dare to be naïve." - Buckminster Fuller

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The case may have an IP rating, but that goes out the window when you put holes in it! If there were no gaskets on the cable glands, then that was not helping the situation. It also helps if you put then in the right way. Unfortunately, it is difficult to get a hermetic seal, so with changes in temperature, exchange of air takes place. Air has water vapour and that can change phase depending on temperature to give you condensation. A breather is a hole with a semi-permeable membrane like Gore-tex to allow the exchange of air. These are good if you have a sizeable volume of air as they remove the potential pressure differential. For small volumes of air, sealing the box is probably the best solution and some dessicant to clean up the rest.
In the middle east these issues are common as we had enclosures outside that had a few litres of volume. The internal temperature would reach 70C in the day, then drop down to 20C in the evening. Rinse and repeat each day. We would use breathers, heaters and dessicant to keep the insides happy. The heaters were used to keep the internal air above dewpoint in the evenings.
Sometimes the 'heaters' were just a 25 or 50W metal jacket resistor mounted on the aluminium backplate and the resistance chosen to give us 10-20C above ambient. For small volumes, this is only a couple of Watts.

Last Edited: Sat. Jan 21, 2017 - 11:24 PM
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If it's warmed up to ? 60C in the sun and then there come a thunder shower  that cool it down to 20C in seconds with water everywhere there will come water in sooner or later.

 

I guess it depends of the climate but here is better with a drain pipe so the box can breath, and it should have a cover to it can't be warmed up by the sun.

 

 

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Go for the root cause, increase the pitch of the roof. :). But no electronics fun with that.

It all starts with a mental vision.

Last Edited: Sun. Jan 22, 2017 - 01:53 AM
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It also helps if you put then in the right way.

blush

 

JC 

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I thought that the heater cables designed for roofs had  built in sensors.  I was wrong. They do sell various thermostat options, but the reviews on all of the ones that I saw were not impressive ( 3 starts on average). So your DIY solution is probably the best.  Hope you can solve your waterproofing issue.

 

hj

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Sparrow - I was in Qatar many years ago when it rained - everyone around me was in awe of the rain. Then i realised it doesn't rain there often. As for shields - we had those, but we couldn't shield fully as there were lcds and operators that needed to be accesable. It's also hard to escape the ambient air temperature of 40+C

Last Edited: Sun. Jan 22, 2017 - 11:29 AM
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It rained 3 times in the 5 years that I was in Saudi Arabia. With no drainage system in Jeddah then these events became floods.

 

I was involved in tendering for the public transport bus system in Oman.  Shields were a problem because of the need for passengers to have access to keyboards, displays and ticket issuing devices. Very unpleasant temperatures and sand storms so automated access panels were also needed. We didn't win the job and were thankful for small mercies.

Ross McKenzie ValuSoft Melbourne Australia

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Just got a report from users of my accelerometers in the Amazon rain forest. They put two desiccant bags in each one. They have been dry inside after a year. Now, they are never IN running water and rarely subject to direct rain being some 20m up tree trunks. So, I am really suspicious of the wire entries on DocJC's hardware. My boxes are ALMOST identical to his and use the same gasket system with transparent lids.

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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One thing to consider when have cables enter an enclosure is water migrating along the outside of the cable. When the enclosure is mounted vertically, the entries should be at the bottom so gravity works in your favour.
Jim, the dessicant bags are most likely doing their job. The ones i used to use would change colour when they were done.

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I used 1 pound bags of desiccant in my drifting buoys with an internal volume of about 30 litres.

Ross McKenzie ValuSoft Melbourne Australia

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ka7ehk wrote:
Just got a report from users of my accelerometers in the Amazon rain forest.

 

So how fast do the trees run???

 

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

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Are there ents in the Amazon?

 

Ross McKenzie ValuSoft Melbourne Australia

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Is the Amazon cloud above the Amazon rain forest?

back on topic - was the fuse holder IP rated? 

 

Last Edited: Tue. Jan 24, 2017 - 01:31 AM
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 was the fuse holder IP rated? 

Not home this week.

In class all week to try and keep up with all the rapid changes taking place in my main job...

 

Anyway, I don't have access to my files, parts list, and the data sheet for the fuse holder.

 

That said, I believe it was weatherproof, IIRC.  Rubber gasket on the case, and a spring loaded cap with a rubber gasket.

 

I'll have to check it next week.

 

I had never even considered that as a possible source of moisture entry...

It makes good sense to consider it, (consider any opening in the case!), I just hadn't really given it a lot of thought until lately.

 

JC

 

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I don't suppose you could just move the case indoors?

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Well, still need the temp sensor outdoors, unless I redo the project to IOT methodologies, 8266 and pull in local weather.

Lots more possible failures with that approach than a simple outdoor temp sensor.

 

The output, a switched 120 VAC Mains, is also outdoors.  So again would have to trade a dry indoor uC box for a hole through the wall.

 

Wife doesn't like seeing me walking around the house with a drill in my hands.

 

JC

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The cause of ice dams is heat from the attic melting snow.  The melt water runs to the eaves and freezes.  If you can prevent this heating, you can prevent the ice dams.  You need adequate attic ventilation and adequate heat insulation at the attic floor.   

 

If done right it will also cut the cost of heating the house. 

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Here's a few ideas for protecting your project in a wet environment:

 

   In addition to the gasket, use a silicone sealant (Link) on the outside where the lid mates with the box.

 

   Use a Silicone Conformal Coating (Link) on the boards inside the box to protect from any moisture that does get inside.

 

   Use polyurethane foam (Link) to fill the inside of the enclosure. 

   This will minimize the amount of moisture that can get inside the box from any leaks that persist.

 

 

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DocJC wrote:
... unless I redo the project to IOT methodologies, 8266 and ...
The follow-on to ESP8266 is ESP32.

ESP32 can reach to -40C.

SparkFun ESP32 Thing is a new arrival at Mouser.

Off-the-shelf, Olimex has a complete ESP8266 (ESP8266, relay, Li-po charger, box)

ESP32 are also in Pycom WiPy (Wi-Fi, Python) on a module for -40C .. 85C

DocJC wrote:
Lots more possible failures with that approach than a simple outdoor temp sensor.
Concur


http://platformio.org/platforms/espressif32

http://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf (page 33)

via

http://www.espressif.com/en/products/hardware/esp32/resources

http://www.mouser.com/new/sparkfun/sparkfun-things/

https://www.olimex.com/Products/IoT/ESP8266-EVB-BAT-BOX/open-source-hardware

https://www.pycom.io/wp-content/uploads/2016/11/wipySpecsheetFinal.pdf

 

Edit : Pycom

 

"Dare to be naïve." - Buckminster Fuller

Last Edited: Wed. Jan 25, 2017 - 01:53 AM
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Once your box is cleaned and dry, can you mount it under the eves where it will not be in direct sun light and protected from direct contact with water? 

 

Jim

 

Click Link: Get Free Stock: Retire early! PM for strategy

share.robinhood.com/jamesc3274

 

 

 

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Hi everyone,

 

I appreciate all of the feedback, and guidance for improving the design.

 

When the roof leak occurred, a few years ago, the roofer put "ice guard (?) " under the shingles.

IIRC it was a foil sheeting of some sort, now part of the building code, but wasn't when the house was built.

 

The house had the shingles replaced last year, and as part of that process, we added a ridgeline vent to help improve the attic ventilation.

 

I like the suggestions, and links, for improving the waterproofing of the box.

Pretty soon I'll be able to qualify it similar to watches and submarines!

 

Regarding repositioning, there is a rear deck on the house, and the box sat under the deck, on the ground.

I will probably try to put it in a box, under the deck, (out of the sun light and away from direct rainfall), and up off the ground.

Probably should have done that the first time!

 

JC

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DocJC wrote:
Regarding repositioning, there is a rear deck on the house, and the box sat under the deck, on the ground.
(dot the Is, cross the Ts)

Is/was the box in a circuit with a GFCI?

Reason : I've tripped these on outer wall outside outlets (cut an extension cord with a trimmer (doh!), rainwater onto a battery tender)

 

"Dare to be naïve." - Buckminster Fuller

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Boy Howdy! It would be such a simple thing to just buy a commercial product like THIS

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Someguy22 wrote:

Boy Howdy! It would be such a simple thing to just buy a commercial product like THIS

 

But I bet Jay would say "Where is the fun in that?"

 

Ross McKenzie ValuSoft Melbourne Australia

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Where's the fun in that?

JC

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Regarding the GFI, there are a couple of outdoor outlets and they are all on GFI'd circuits.

Don't want to electrocuted a squirrel!

JC

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Yeah mouth to mouth on a squirrel might not be the best taste sensation...

 

Ross McKenzie ValuSoft Melbourne Australia

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It would probably be nuts...

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ESP32 are also in Pycom WiPy (Wi-Fi, Python) on a module for -40C .. 85C

A new arrival at Adafruit :

Pycom Universal IP67 Case for Pycom boards ID: 3690 - $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits

For a better sense of it, skip the pictures, watch the video, and listen to Limor's description.

Early in that video, Limor stated that Adafruit's Feather boards are a fit for that case.

 

"Dare to be naïve." - Buckminster Fuller

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Thank you for the pointer to the case.

 

I'd have to re-spin the board, but that would be OK as I've learned a lot about water proofing since that first project.

 

Truth be known I need to get the roof wires working for this current Winter, and I didn't have time to re-do the above project.

So I broke down and purchased a commercial thermostat / Mains switch.

 

It lasted about two months, (Nov and Dec), and failed when the real Winter weather hit.

My unit lasted a lot longer than that!

 

Sigh.

 

So many projects, so little time to work on them.

 

JC 

 

Edit: Typo

Last Edited: Sat. Feb 16, 2019 - 06:00 AM
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If function is more important than looks I prefer to use simpe PVC pipes as outdoor enclosures.

It's about the cheapest you can find and you can add a screw on "inspection" lid on one end with a rubber seal.

These are 100%  air and water tight and can easily resist atmosferic pressure differentials without leaking.

https://duckduckgo.com/?q=pvc+pipe+screw+on+end+cap&iar=images&iax=images&ia=images

 

If you want to go fancy and add a breather, you can glue on a knee of a smaller diameter and add a piece of bicycle inner tube or other flexible material.

PVC is easily glueable (Is that French?)

About breaters... Just found a picture of a flexible end cap for PVC pipes among the many pictures from the link above:

But these may or may not have enough flexibility to compensate for normal atmospheric air expansions, depending on the length of the PVC pipe.

 

 

On a sidenote:

Has anyone reading this ever tried to use polyurethane based floor varnish as conformal coating?

Doing magic with a USD 7 Logic Analyser: https://www.avrfreaks.net/comment/2421756#comment-2421756

Bunch of old projects with AVR's: http://www.hoevendesign.com

Last Edited: Sat. Feb 16, 2019 - 02:05 PM
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Apart from the waterproof enclosures, I do not really understand:

 

DocJC wrote:
I put a heater cord on the roof and wanted an outdoor thermostat to turn it on and off.

 

Temperature is not a good indication "for snow on the roof", and even if there is snow on the roof, it just adds to the roof insulation, and as long it's less than half a meter or so it's weight should not be a problem either.

 

 

Another side note:

How do those heater cables work?

Is the end normally shorted?

If so, you can put a  diode parralel to a resistive temperature sensor on the end and fully pot it.

Then you only have the heater cable and the temperature sensor on the roof and everything else can be put in a dry place.

 

 

 

Doing magic with a USD 7 Logic Analyser: https://www.avrfreaks.net/comment/2421756#comment-2421756

Bunch of old projects with AVR's: http://www.hoevendesign.com

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The issue is the back side of the house has a couple small roof segments a different angles / directions.

It undergoes some freeze / thaw cycles, and ice can build up / work under the shingles.

A few years ago we had a roof leak from this, trashed the ceiling, some furniture, the carpet...

 

Re-roofed that section with "ice guard" under the lower few feet of shingles, IIRC.

 

With the heater cord one eliminates both the snow, and more importantly the ice.

 

I have a large roof, but only this one small section is wired for heat.

 

JC