Light Diffusing Window Blinds Made From Multi-wall Plates



Introduction: Light Diffusing Window Blinds Made From Multi-wall Plates

About: Scientist working in in-vitro diagnostics industry. Playing with all types of sensor as a spare time hobby. Aiming for simple and inexpensive tools and projects for STEM, with a bit of science and a bit of sil…

This instructable is part of the "Stick it!" contest. While I am not using any glue in here, suction caps are a central part of the project, and the blinds are sticked directly to the windows.

So if you like the idea and the instructable, please give it your vote!
Thanks, H.


I am living at the third floor of a 90-year old building with a listed façade. While they had done a good job renovating house and flat, there is one basic problem: the windows have no blinds or shutters to keep the sun out, and we are not allowed to add any.

For the larger part of the year, this is not a problem. As we are living in Northern Germany, we usually appreciate any ray of light that finds its way into your flat. But for a short term in summer, when temperatures are starting to reach the 30°C+ range, the sunlight is heating up the flat even further and we would like to keep it outside.

The problem: I am not a friend of curtains, as mentioned we can't place any permanent devices outside of the windows and anything inside the room that absorbs the sunlight would heat it up.

So I was looking for a solution that:

  • blocks a good part of the sunlight before it enters the room
  • diffuses the light, so the rooms do not become dark
  • is a non-permanent, flexible solution, that can be installed or removed rapidly and without mayor efforts
  • does not require any modifications at the outside walls or the windows
  • can withstand rain and heavy winds
  • is lightweight, as it must not place any risk of harm to persons or cars, given it may hit them if blown away
  • is not too expensive
  • is simple to build
  • is not too ugly, neither from the inside nor from the outside
  • should be adjustable to any usual sizes or forms of windows
  • is generally applicable

The solution described below does fulfill all requirements mentioned above.

I am using of a special type of plastic plates that are looking a bit like cardboard and are called multi-wall sheets. The ones I am using are made of translucent polypropylene. So they do transmit light, but it will be strongly diffused, partially reflected. The material is light but strong and can withstand rain and sun.

Even though the plates will block a good part of the incoming sunlight, the room will even get brighter with a soft light, as the plates are diffusing the light, illuminating the room.

In addition to the plates you just need suction cups with a screw at their end, knurled nuts and washers, a sharp knife and a 4 mm drill.

Just cut the sheets to the right size, drill holes at the desired positions, place the suction caps and fix them with washers and nuts, place the unit on a cleaned glass surface on the outside of your window and press the suction caps to fix. Done. More details and images on this are described in a later step of the instructable.

Make sure to use enough suction caps. I would suggest to use at least six for a larger window, and one for every 30 - 50 cm. So far I just have tested the construct on our relatively small and segmented windows, but it should work for larger windows as well. The largest plate size I can get at the place I am buying them is 2 x 1 meter, which should be sufficient even for balcony glass doors.

Step 1: Other Uses, and Some Modifications to the Basic Concept

  • The layout might be usable for applications as well. Here a some ideas:
  • You might use it to block the view though any window or glass plate, temporarily or permanently, without the need to drill or glue something.
  • All those that do not like their view through the window may place an translucent image on the in-side of the plates. Woods or beaches for the one, city views for the other, as you like it.
  • Or just use colored foils to illuminate your room in soothing green, cooling blue, stimulating red, all rainbow colors, and so on.
  • I have not tested this so far, but at least in theory, it might be an effective solution to limit energy losses through windows in winter, as the multi-wall plates seem to be a good isolator. Place them on the inside of the windows. Using M4 spacers, you may even stack multiple layers of multi-wall plates.
  • Might be usable for greenhouses or similar applications. Either to block the sun or to omit direct illumination of the plants by sunlight, or as a flexible insulation tool (see above) in winter.
  • I am having an additional idea for a nice modification, but will have a look on this in early autumn and report then.

Step 2: Materials Used

Polypropylene multi-wall sheets, 3 mm, translucent.
I got mine from Modulor, Berlin, where they offering them in several sizes.
A 2x1 m plate is 13.40 Euro, a 50 x 100 cm plate 4.60 Euro.
The material is often used for architectural model building.

40 mm suction caps with threaded screw.
Available at Modulor or via Amazon. At Modulor they are 0.60 Euro each, or 17.90 Euro for a set of 50.

Knurled nuts M4, Nylon.
Modulor or Amazon. At Modulor they are 0,30 Euro each or 7.90 Euro for a set of 50.
I used the white nylon ones, as I read comments that the clear polycarbonate ones do become brittle if exposed to sunlight for a longer time.

M4 Washers.
I used 4.3 x 15 mm ones. You may find them at the next hardware shop, at about 3 cent each.
They are not absolutely required, but helpful and cheap.

So total cost will be in the range of 20 Euro for a double casement window.

Tools: Cutter knife, 4 mm drill.

Step 3: Preparation and Assembly

  • Measure the area of the glass to be covered and calculate the required size of the plate(s). Be aware that the sheet will be about 1 cm away from the glass surface.
  • Using a whiteboard maker or similar pen, draw the cutting lines on the multi-wall sheet(s).
  • Cut the sheets at the indicated lines. you may use a cutter knife, a jigsaw or a hot wire.
    The material is rather soft, so cutting is very easy.
    Take care not to cut the good parquet floor or the carpets, but place a hard material or a piece of wood below the plate.
  • Draw the points where you like to place the suction cups. Given you use 40 mm suction cups, the distance from the borders should be at least 20 mm. But I would recommend to add at least 5 mm, better more.
  • Drill the holes with a 4 mm drill. Don't drill a hole in the floor, place a piece of wood below the sheet.
  • Place a washer on the suction cup's screw. Put the screw through the drilled hole.
    Place another washer on the screw, put the knurled nut on the screw and fix the suction cup to the plate.
  • As above for all suction cups.
  • Clean the window. It should be as clean as possible, as the suction cups will stick better then. So clean it even if it may not look dirty.
  • Place the sheet on the outside of the window. Use one of the long sides to align sheet and window.
  • Press the suction cups to the glass. First do for two of them, check alignment, correct if required, then fix the rest.
  • Done.

    The concept and material was tested last summer for several weeks, without any drawbacks. So far we had no severe winds coming from the side. But using six suction cups per plate, the plates a sticking very well to the windows.

    To remove the plates, use some tool to let air under the suction cups, but take care not to damage them. You may have to remove the plate first.

    Please let me know if you had made any improvements or mayor modifications, or you have any questions or remarks.
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