Weather station radiation shield  

Re: Weather station radiation shield

Could you use self adhesive aluminium foil to cover the Plastic, and provide IR and UV shielding.

otherwise consider blue filament to absorb the IR...
(problem there is it may pass Ultraviolet light. )
a red layer would tend to absorb Ultraviolet light.
both would diminish white light...

regards Joan

Re: Weather station radiation shield

Emissivity is one of the issues for IR - need to check with the plastic manufacturers to get a good idea how the material performs. Also, something reflecting one color means nothing for a different band where it may be entirely transparent. This all depends on the dyes and pigments used. A good white PLA with plenty of titanium dioxide pigment may do well.

ps: you want something that doesn't absorb IR - instead, you want something that reflects IR.

Re: Weather station radiation shield

Or Polycarbonate?

Also, why not try and model one of existing style of designs that is used for an EMR cover? Indeed there are already stl files out there based on these types.

Re: Weather station radiation shield

How about gluing aluminium foil on it?

Re: Weather station radiation shield

Stainless Steel tape is more expensive but will have A longer life than foil
https://smile.amazon.com/gp/slredirect/picassoRedirect.html/ref=pa_sp_atf_aps_sr_pg1_1?ie=UTF8&adId=A02226999DO08ZTQ5HR1&url=https%3A%2F%2Fsmile.amazon.com%2FSilver-Temperature-Stainless-Acrylic-Adhesive%2Fdp%2FB00L48YNKK%2Fref%3Dsr_1_1_sspa%3Fie%3DUTF8%26qid%3D1545086695%26sr%3D8-1-spons%26keywords%3Dstainless%2Bsteel%2Btape%26psc%3D1&qualifier=1545086695&id=4913917361162135&widgetName=sp_atf

Or make it out of SS sheet steel...

But let's take a step back And look at your whole project.

Over and over I am reminded of the old saying " To a man with a hammer everything looks like a Nail."
in our case our 3D printer makes us look at every project in terms of "what can we print that will do this"

I used to dO the same thing with my machine tools and my house is full of stuff that would have been more practical for me to have bought down at the hardware store or to have made them out of wood.

The trick is to look at any project with "what should each part of it be made out of"

Re: Weather station radiation shield

Hello,
I am trying to print a radiation shield for my meteorological project. The purpose of the radiation shield is to absorb all the radiation from the sun and provide shade for the temperature sensor, so that it can give precise measurements. I need to achieve the following:

ASA. Outdoor, UV proof, Pretty well ideal for this application.

Re: Weather station radiation shield

Most plastics will survive outdoor conditions (mainly sun exposure) better with a good quick spray paint. If you don't want to spray it avoid 'virgin' plastics without pigment as the pigment tends to reflect or absorb UV rays and therefore saves the plastic from taking the 'impact'

Having said that, I agree with martin above in that you may find something easy lying around or at your local hardware shop for cheap. Although I clearly understand the appeal of printing anything and everything because you can 😆

Could you share some photo's of your interesting project? Would be interesting too to see how the shields you printed failed

Re: Weather station radiation shield

Thank you for the great ideas! I tried Aluminium tape with ABS and it works great. Now I am waiting for the ASA fillament to arrive. Maybe I would consider a colorless cover paint. I will test it under UVC light for a couple of days to see it there is much difference.
Of course I need to test the shield properly, before making the decision this is the best solution to the problem. Sadly it is winter, so not much sun. 🙂
I will post pictures when we have a prototype.

Re: Weather station radiation shield

I was thinking about the use of the aluminium foil for light proofing and I realized this is not the way in the long run for many reasons. Then I was thinking about the possibilities of the technology and I realized there could be another way. But I am still new to 3d printing and it would be interesting to read your thought on the subject.
So basically the idea is that white filament is the perfect color, especially made from ASA, but will require quite a big thickness to be light proof, which would drive the price and the weight too high. On the other hand I tested black PETG and it is absolutely impenetrable to light. Obviously the problem with black filament is that it requires a layer of white paint on top of it.
Than I was thinking about printer with dual extruders and Prusa's MMU 2.0. Would it be possible to print a part with white 2 layers of white fillament on the outside and the inside and between them a layer of black filament?

This way the part will be white on the outside and opaque. The materials will bind together perfectly, because they are the same, only the colors will differ. What do you think? Is it possible with the MMU or would I need a printer with 2 extruders? Which slicer would I need to use to program this behavior?

Re: Weather station radiation shield

An MMU will do that. However, I think you'll only need around 4-5mm thickness to knock out most/all of the light.

How about you just print off a few small sections of various thicknesses and see what's needed.

Re: Weather station radiation shield

How do I split an object into multiple STL files, so that I can print it the way I want? We are using Fusion 360.

Re: Weather station radiation shield

I made this in 123D design.

Black part is inset in white part.
Saved both parts. As STL.

Loaded both parts at same time into slic3r pe edition. Chose mmuv1 allocated the white to extruder 1 and the black to extruder 4. Sliced at .35 layer height and printed.

Be aware that wall thicknesses above 2mm are likely to cause infill. Which will reduce their light absorption significantly. The back wall of the white part. Is 3mm and is showing infill

Regards Joan

Re: Weather station radiation shield

It's a common misbelief that colored or even black items block specific wavelengths of light. This is especially true as the light drifts into infrared. At these lower frequencies, the emissivity of the material can have as much or more effect than transmission on thermal absorption and re-radiation properties. An example is polished metal that gets hot in sun light, even though it reflects visible light rather well.

Re: Weather station radiation shield

I was playing with the concept today. Just printed a test piece with the MultiColor options, with manual fillament change. This is the result. It looks quite well. The tickness is 2.4mm, each layer is 0.8 mm thick. The material is PLA.

We will order the MMU 2.0 and we will test the performance of the radiation shield with that of our professional weather station.

Re: Weather station radiation shield

Another thing I was thinking about was would it be possible to print the outside with ASA and the middle black and inner white layer with PETG? Good quality ASA is something st twice as expensive as PRUSA PETG.

Re: Weather station radiation shield

What range of light are you trying to keep from hitting the sensors? If you are trying to keep "heat" from building up, you need a low e layer. Plastic color will have no effect - and while a black layer inside white layers might make it optically darker - it will do nothing for reducing interior temps.

If you are serious about keeping the innards cool, you should apply something like this to the exterior of the cover:
https://www.solec.org/lomit-radiant-barrier-coating/3482-2/

Re: Weather station radiation shield

We are going to do 2 tests in the comming few weeks to determine which is the best way to do this.
The first test would be to put 3 pieces from PLA, PETG and ASA under UVC lamp for a month and see how the change.
The other one would involve testing the different models we have under an infrared lamp such as this one.
We will report as soon as we have done the tests.

Re: Weather station radiation shield

You should test with a source that approximates solar radiation at 1500w/m^2 black body. You could drop the energy by known latitude if you're going to be in the far north. Without knowing what radiated energy levels you are testing with you really aren't learning anything. Better to just stick the thing outside under real sun and see what happens.

Re: Weather station radiation shield

If you use the same heat source you can replicate the test over and over again. The idea is to see how fast and how much the temperature inside rises when there is a source of heat nearby. The slower it goes up the better the protection.