This is a little design project of mine that is very easy. All you need is a PETE soda or drink bottle of a desirable shape with a screw top, and even then the design can be tinkered with to include most any bottle.

The results of this project can be stunning or commonplace, it just depends on what kind of bottle is used.

Note: these glasses are not recommended for use with hot liquids. The plastic is a thermoplastic, which means that it can deform, melt, or release chemicals or particles into the air or your drink. Please use them only with cold drinks. These are also alcohol-safe.

Extensive research has been done on the reuse of plastic bottles. This research has found that PETE (Plastic number 1) bottles do not pose a health risk to be reused, as long as they were originally intended for food products, and are in good clean condition. Just don't put hot liquids in them or leave them in the sun for extended periods, as the solar radiation can break down the plastic. Any leaching of chemicals into contained liquids has been found to be negligible, far below the levels of water quality safety standards. Furthermore, all these tests were conducted on liquids that had been in the bottle for an extended period, and since the outcome of this project is a cup of one sort or another, the liquid probably will only be in the cup for a few hours max. Sodas, soft drinks, and alcohols are all sold in PETE plastic bottles, so there is no risk in using them again. Once the cup has been in solid use for a year or so it might be a good idea to replace it, but normal use is not an issue.

Tl;Dr: it is safe to reuse PETE plastic bottles because science says so.

Step 1: Materials

-PETE (plastic #1) beverage bottle of your choice- there are some cool bottles out there, shop around! You can even mix and match different bottle parts around to make more unique cups.

Step 2: Tools

Hot glue gun and glue, you can also use epoxy, whatever works.
knife, scissors, or other fairly precise bottle-demolition tool.
very fine grit sandpaper or a piece of metal that can be heated.
Sink and soap for washing.

Step 3: Clean It Up

Clean your bottle well with soap and warm water, you don't want any residue or germs left on it!

Step 4: Cut Cup

Look at your bottle and decide where you want to cut it- the size and style is up to you.

Using your knife or scissors, cut the bottle in half where you want. Most soda bottles have a design that commonly includes a diameter somewhere on it, so you can follow that to get a clean cut. Go slow and use a sharp blade, you want the cut as clean as possible with no burrs.

Step 5: Smooth Rim

Now, that cut edge will be the rim of your glass, and you don't want a sharp or jagged edge to put your lips on. There are two ways to smooth it.

Sandpaper- use fine grit sandpaper to smooth the edge, use finer and finer grains until it is smooth enough for you.

Heat- get a hot surface such as a stovetop, hotplate, griddle, etc. put a flat piece of scrap metal on it and heat it up.Make sure the metal is flat and clean, and that you won't ever use it for food. It doesn't need to get hot, 250 degrees F is about all you need. Once the metal is heated up, put the cut edge down on it levelly for just a second. This will melt the cut surface smooth. If you do it for too long or have the surface too hot, the plastic may stick to the metal or the edge of the plastic may curve inward and ruin the edge. It helps to do a few practice pieces first.

You may want to heat the plastic outside or in a very well ventilated area, but since the plastic should only be hot for a second and it is barely melted, and at such a low temperature, doing this inside is an acceptable risk. If you can smell it, do it with ventilation.

Step 6: Cut Base

Flip the remaining chunk of bottle over and cut off the bottom. Bottles vary, so bottoms vary. Cut it down to where it is of a desirable size and sits flat.

Step 7: Scratch and Glue

Use some sand paper or a knife to scratch up the top of the bottle, and the part of the base you are gluing to. This will make your glue adhere much better.

Glue it! It helps to use a tiny dot of glue at first just to tack it in place and make sure it is level at first, then come along and reinforce it with more glue once everything looks good.

Keep any and all glue and glue residue out of the inside of the cup, the majority of glue isn't food safe and you will have to restart.

Step 8: Decorate, Clean, Drink!

You can attach more bottle parts to your cup to give it whatever kind of look or features you desire. Handles, garnish holders, straw holes, whatever you see fit.

Once you are done building and decorating, wash the bottle again with warm soapy water to get workshop residue off it.

Drink from it!

These are lightweight, recyclable, pretty indestructible, and always start conversations.

I make these all the time, so a gallery will begin to develop on this step. User builds will also be put here.

There are all kinds of ways you can turn PETE bottles into cups, brainstorm and make some!