Sciencemadness Discussion Board

How to safely open HDPE bottles with cap inserts.?

Sulaiman - 18-10-2024 at 23:27

Most liquids that I receive are in HDPE bottles with this type of cap and insert.
IMG_20241019_145124.jpg - 56kB
They mostly seal well, but opening them has presented a couple of hazards:

Internal vapour pressure can POP the insert out when the cap is unscrewed.
Not necessarily immediately, sometimes there is a delay,
...A wet insert and little drops of liquid travel in the general direction of my face.
(So I remove the cap with an old cloth covering the cap and top of bottle)

I pull the inserts out using a fingernail, so I often get small quantities of liquid on my finger.
Gloves can be punctured between my fingernail and the bottle/insert gap.
(This is my main concern)

Anyone got a tip/trick/tool that they can suggest. ?

I wear eye protection (almost) always,
unless staining, toxic or hazardous chemicals are in use, I work without gloves

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paulll - 19-10-2024 at 00:05

Maybe look up, "spudger," on ebay or the like? Sold dirt-cheap as pry tools for electronics, but perfect for the job, as long as whatever you're opening is compatible with nylon. They're commonly in steel, too, but a bit more hit-and-miss as to whether you're getting a pry-tool, or a butter-knife...

Precipitates - 19-10-2024 at 05:44

An old small knife - but yeah they can be annoying at times

jackchem2001 - 19-10-2024 at 16:14

This will not help with chemicals you are receiving, but the pressure buildup in storage is because if you add the liquid, cap, and store immediately, the liquid will not be in equilibrium with its vapour in the container and so will vapourise over time until this equilibrium is reached. To fix this, I recommend adding the liquid, loosely capping the container, shaking, venting etc (like a separatory funnel) until there is no sign of pressure buildup (air has now been displaced by the vapour of the liquid). Adding the liquid while hot and doing this process would pull a vacuum which I assume could be helpful for storing volatile materials. Note that this will not stop pressure buildup for materials that decompose into gases during storage (e.g. HNO3).