The bottles you use when mixing your eLiquid is at the end of the day down to what you prefer, but below I have provided some interesting information to help you make that decision.
My personal preference is the modern chubby gorilla style bottles. The convenience of a wide mouth make for very easy pouring of VG make them my personal first choice. I used what is known as a "Boston Round" in HDPE for a few years and while cheap and convenient to obtain, the mouth of the bottle is a lot more difficult to manage that all important final pour of VG. Keep in mind that while you can try and reuse a plastic bottle in a pinch, they are really only designed for single use.
It is also imperative that the bottles you buy have a child safety cap especially when the contents includes nicotine.
These days we are spoiled by choice of color of your bottles. Brown/Black colored bottles do assist in keeping your eLiquid stabilized over time. Followed by blue then green. Other colors also may assist a little in helping to reduce the degradation of your concoction over time. However using clear or milky translucent bottles is fine.
Simply store your bottles out of the light when not using.
In saying all that, I suggest to only make /store what you intend using up in a 6 month period along with storing your eLiquid in a cool dry place out of direct sunlight mostly, you should find you can use most bottles successfully.
PET Vs HDPE Vs Glass
PET Polyethylene Terephthalate is a strong, lightweight plastic resin and form of polyester that closely resembles glass in clarity and takes colorants well. PET is commonly used in food packaging due to its strong barrier properties against water vapor, dilute acids, gases, oils and alcohols. PET is also shatter-resistant, slightly flexible and easy to recycle. These bottles will wrinkle and I consider them a one time use bottle or for personal storage of liquids if you don’t mind wrinkled bottles. These wrinkles will eventually crack over time. PET is more resistance to leeching of gases such as Oxygen than HDPE bottles.
HDPE has very good stress crack resistance as well as high impact and melt strength. HDPE is appropriate for personal care, beverages, food and chemicals. It lends itself particularly well to blow molding. These bottles are reusable and stand up to a lot of abuse (squeezing). Elmer’s Glue comes in HDPE Bottles.
Glass Glass containers don’t leach potentially harmful chemicals when in contact with food. They are more durable and more reusable than any plastic container. Ever notice how foods you buy in glass bottles taste better? It’s a no brainer, especially for long term storage of your e-juice and base liquids and recipes.
Closures come in all shapes and sizes. Child proof, tamper evident, different linings (seals), dropper type, standard cap closure, spout caps, etc. Determine what specific needs you have and do some research. In my opinion childproof caps should always be used. But in some cases that may not be possible.
Droppers: Pertaining to glass bottles, these are the rubber bulb type dropper caps with the glass tube for dispensing your liquids. These also come in plastic at some sources. They can also be found graduated for measuring the amount of liquid you are dispensing. These come in pointed tips and bulb tips. I say this because when sourcing your bottles you need to make sure you get the pointed tips. If in doubt always ask the supplier. These are readily available with childproof threads.
Spout Caps: These are great for use on your larger bottles of PG, VG, and your Nicotine dispensing bottle at your mixing table. These should not be used as long term storage bottles as they don’t provide the best seal.
Plain Caps: Caps come in all different varieties. Colors, type, seal, etc. The best I have found is a poly cone lined cap. These are by far the cleanest closure and provide the best seal. But I have yet to find any childproof offerings. So be warned if using these types of closures make certain that any harmful liquids are stored well out of a child’s reach.
Dripper Tips: These are the tips used in plastic containers. These come in various shapes and sizes. Some are thicker and rounded at the tip. Some are very slender and more easily fit into the various fill ports on some atty’s. Capella Flavor Drops use the thicker rounded tips. Flavourart uses the long skinny tips. Make sure you are getting the proper tip for your application.
Determining Cap and Thread Size for Various Bottles This is easiest to explain by the professionals. CLICK HERE to view a page describing various threads and how to determine cap size and thread type. The “T” dimension will be the first number of the cap size. The second number will be the number or type of thread. So if the distance across the threads is 28mm, and the thread on the bottle makes one full revolution the cap size will be 28-400. If the thread makes one and a half revolutions the cap size is 28-410.
Sourcing Your Bottles and Closures Below are some links to vendors for various types of bottles and closures. If you have any links you would like added to this list feel free to contact me or post below and I will add them.
Note: I have not ordered from all of these vendors. So I am unaware if they have good shipping practices, customer service, etc.