When you live on a students budget you want to spend as little as possible on rent.

In Germany the concept of dormitory isn't as common as in the US, most students here live in the city center in "shared apartment communities". That's how I lived the last few years and I'm pretty happy with my housing situation. I found a nice and inexpensive room in an apartment I share with two other students. The only downside to my room is the not-so-splendid-view: the row of houses on the opposite side of the street is awfully close and it feels like the neighbors can count the peas in my soup...

Since I'm not a fan of net curtains I used another way to establish some privacy - I "frosted" my windows in an easy (and easy removable) way. This method is pretty cost-effective (less than 50 cents per window) and it can be beautified in many ways.

I learned about this glass frosting technique from one of my flat mates. He does this curtain replacement methode since years, and I also used it now for more than two years with no troubles at all.

BTW It isn't such a crazy or very fresh idea to use milk products for painting - check out these wikipedia articles about casein paint and milk paint ;)

Step 1:

This is a real students budget project, basically all you need is a cup of plain low fat yogurt and a sponge.

To speed up the process a paint roller will come in handy. But if you are on a tight budget and don't own a paint roller you can also use a dish-washing sponge.

If you want to cover just a part of your window it's helpful to use adhesive tape to determine the area to be painted and to get a clean finish. If you prefer to cover the whole window you won't need it.

You actually don't need huge amounts of yogurt, I think I ended up using about half a cup for the window I did for this instructable...

Surprisingly the yogurt adheres very well with the glass and doesn't roll off at all.

Step 2:

All you have to do is to distribute the yogurt on the window.

Please note: You have to paint the side of the window that faces your room - don't do this method on the outside! The rain would wash away your curtains...

The easiest and quickest way is to use an spongy paint roller, saturate it with yogurt and apply it gently to the window. It took me about less than five minutes to do my window. It is really easy.

If you use a simple sponge it will take a little longer, but the result will be the same. Just dab the yogurt soaked sponge on the window in a steady motion.

When done applying just wait for the yogurt to dry. It depends on the temperature and humidity how long it takes to dry. I did my window on a warm and sunny day and it was dry in about 15 minutes.

As you can tell from picture no.5 the yogurt "paint" becomes more opaque when it's dry.

While the yogurt is drying you may recognize a slightly creamery like smell in your room - but as soon it's dry this slight smell will be gone.

Step 3:

If you want to cover the window just partially like I did, I recommend using adhesive tape as guidance lines.

Just determine the area you want to cover and mark it with two long strips of tape.

Then cover the area with yogurt, covering the tape partially as well. If you accidentally dabbed across the tape just take a piece of fabric or tissue and remove the yogurt while still wet.

When you finished applying the yogurt - remove the tape and you'll end up with a crisp outline.

Step 4: Beautification Options - 1

There are several ways to add designs to the yogurt curtain, some of them you have to prepare before you apply the yogurt:

Adhesive foil reserving method:

You can use adhesive foil (I used adhesive foil which is originally made to cover books) and create stickers with an exacto knife. Apply those stickers to your window before you dab it with yogurt. When you carefully remove the stickers later you'll get a nice and crisp negative shape of your sticker. (I tested this method on an old glass of a picture frame, thats why you see the wooden table underneath the glass...)

Adhesive tape method:

You can also play around with strips of adhesive tape. The very first time I made a yogurt curtain I placed several stripes of tape in different widths horizontally on my window to obtain a stripy design. You could as well construct several geometric shapes...

Paintbrush method:

You can use a bristle paintbrush to obtain interesting patterns. The last two pictures show the pattern you get by dabbing the paintbrush constantly in a downwards motion. It's worth to experiment a little with different brushes and motions (you can do tests and experiments on old picture frame glasses).

Step 5: Beautification Options - 2

Although the dried yogurt paint sticks well to the surface of the glass - it doesn't bond like glue or real paint.

You can use a sturdy piece of plastic (like a piece of an old credit card) to scratch away parts of the yogurt. That's how I did the instructables robot design on my window.

You can either do a freehand drawing (that's how I made the dinosaur in the last picture) - or use a printed template to get more control over the outcome of the picture. I used Rasterbator to blow up the robot (there's an instructable about how to use the program) and taped the printed sheets together.

Tape your template on the outside glass and you will have nice guidance lines for where to scratch the yogurt away.The credit card scraper is hard enough to scratch the yogurt but doesn't damage the glass. Try not to touch the yogurt surface with your fingertips - the moisture of your skin may "wash away" the yogurt paint...

I really like this method, it gives your picture a drawing-like appearance.

Step 6: Remove the Curtain

If you get bored of your window design or if you move out from your room you can easily remove your yogurt curtain. I just used warm water, a squirt of soap and a dash of ethyl alcohol. You could as well just use warm water and a windex like glass cleaner. Your curtain will be disappeared in no time.

Step 7: Pros and Cons and Variations

I hope this instructable is helpful and prevents you from taping bubble warp to your windows... :)

There are some things to note to this method - as it has it's weak sides too:

I think the yogurt curtain doesn't work well in very humid rooms. So you shouldn't use it in rooms like the bathroom where frequently condensation occurs on the windows. I suspect there's a good chance of growing mold on your curtains in such a humid environment. Though I want to point out: I lived now more than two years with my milky window curtains in a multi-functional sleeping-working-living room and there occurred absolutely no signs of mold or critters (also no smell). So for "regular" room situations it's absolutely suitable.

In general the yogurt paint connects very well to the glass and doesn't brittle or dust away over time - but the yogurt surface is relatively sensitive to touching (At the last picture of step 5 you may recognize some traces of fingertips - when I did the drawing of the dinosaur I wasn't really careful and touched the glass a lot...)

If you you are looking for a more of a long term solution you probably should go with this instructable: https://www.instructables.com/id/Faux-Stained-Glas... In this instructable acrylic paint is used - This may give you a more permanent curtain which is less sensitive to the touch - but you will have to use a blade to get rid of the paint...

Btw: the yogurt-window-frosting-method is not only useful for strange housing situations, you could also use it to frost the windows of a glass cabinet or a glass door if you want them temporarily opaque.

And another idea for a variation (I haven't tried yet) is to use watercolor or food color mixed with the yogurt. I suspect you could make colorful yogurt curtains this way....