dropper bottles

[annettegascoigne]

Hi All,
Probably been discussed before but...
The plastic droppers (orange ones) that we use on our 25ml brown bottles for class sets of chemicals are doing my head in. They do not last and become discoloured.
I have tried to source better ones than the science supply stores with some success - and they were black which was a better colour - but now I cannot get them.

Please tell me your solutions/other ideas. Should I change entirely to a different type of bottle? When they just need a few drops I am not sure that anything else will be as good?

Thanks.

[Pm706Narrogin]

When we had to do our big update to GHS labels a few years back, we got funding from the school and decided to upgrade our droppers at the same time.

We got some black ones from Perth Scientific to put on chemicals that stain like iodine, silver nitrate, potassium permanganate and food colouring. They're black neoprene rubber and I haven't had to replace one in the three years they've been on the bottles. See if you can find a supplier of them local to you.

How often are you having to replace the other ones? A few of my newer red rubber ones have discoloured but I've only had maybe a dozen degrade in the last 3 years and all of them are in with the corrosives

[RosalieL]

I bought white screw caps and have those on the chemicals that degrade the rubber teats (eg anything above 0.1M acids) for storage on the shelf and switch over to droppers when they get sent out for classes. It does add to the work load a bit but I'm in a small school so we only have one set of 10 of each. If I'm short on time, I send out 3ml disposable pipettes with them instead of the screw on droppers.

[annettegascoigne]

Thank you for your ideas. I would like to get my hands on the black neoprene droppers. I will keep searching for a supplier.
I've been buying the red (orange?) ones from MTA. It's hard to say exactly how long they last I just seem to be having to replace/clean/throw out regularly as they deteriorate into the solutions. The white screw caps are a good idea.

[Pm706Narrogin]

Do you have a proper corrosives storage cabinet or are your corrosives segregated on their own shelves in your chem store?

I haven't noticed a lot of our teats degrading since I last changed them 3 years ago but we just have them on segregated shelves. I wonder if the extra space allows for better airflow and venting of any vapours

Funnily enough the ones I had to replace were on the acetic acid but they're also on the shelves closest to the back wall and I suspect the airflow from the extraction fan isn't as good there. I have no other explanation for how they needed doing but the HCl and sulfuric in the next two columns have been fine

[annettegascoigne]

The dropper bottle solutions are just segregated on their own shelves. Funny sometimes what does and doesn't agree with them.
I think I have found black ones from a soap supply store on line. If anyone in NSW knows where to buy these from a science supply store please let me know.
I am tempted to buy them from Perth!

[bigmack]

At my old school , we always had the glass dripper bottles with Red rubber teats . I tried Black Silicone rubber ones and they were great for most things but totally useless for acids . Would disintegrate in about 6 months .

At my new school , we had a mix of about 5 different stuhl style droppers . It was a nightmare matching lids and bottles . And the space they tool up was ridiculous.

We had a few 30ml bottles that looked good so I ended up buying a 100x 30ml twist top droppers for all our precipitation chemicals .( From Ebay ) These are all 0.1mol/L . They are all holding up very well .
( second and third pics in link below)
https://www.chemtalk.com.au/viewtopic.p ... 392#p51392

Never again will I go back to dropper bottles with teats .

[LabbieSeth]

I bought white screw caps and have those on the chemicals that degrade the rubber teats (eg anything above 0.1M acids) for storage on the shelf and switch over to droppers when they get sent out for classes. It does add to the work load a bit but I'm in a small school so we only have one set of 10 of each. If I'm short on time, I send out 3ml disposable pipettes with them instead of the screw on droppers.

Where did you buy the white screw caps from Rosalie? I started looking for them earlier this week as I had the same idea of storing with caps and adding droppers as they go out to class

[Marama T]

I reckon I'm gonna go bigmack's way. I'm tired of buggering about replacing teats.

[RosalieL]

I bought white screw caps and have those on the chemicals that degrade the rubber teats (eg anything above 0.1M acids) for storage on the shelf and switch over to droppers when they get sent out for classes. It does add to the work load a bit but I'm in a small school so we only have one set of 10 of each. If I'm short on time, I send out 3ml disposable pipettes with them instead of the screw on droppers.

Where did you buy the white screw caps from Rosalie? I started looking for them earlier this week as I had the same idea of storing with caps and adding droppers as they go out to class

I've just checked back through my emails and I think it was SSA (Science Supply Australia) item number 2450 Description Cap white PP 24mm plain and they were 15c each in 2023.

[Anna Z]

Yep, Science Supply. We also put caps on ours when not in use and then swap to the droppers.