←back to thread

896 points tux3 | 2 comments | | HN request time: 0s | source
Show context
sevensor ◴[] No.43547977[source]
I TAd a semiconductor fabrication lab class 20-odd years ago. Mostly it was about making sure the students had the absolute fear of God put into them about working with HF, but there was also a bit at the end where you actually got to do a voltage sweep and characterize your transistor. If in fact you had made a transistor rather than a needlessly complicated resistor. The other TAs and I passed this paper around and thought it was just hilarious.
replies(1): >>43549188 #
dvh ◴[] No.43549188[source]
And then there are Etsy moms making frosted shot glass
replies(2): >>43550734 #>>43553033 #
sevensor ◴[] No.43550734[source]
I would make them reread the MSDS.
replies(1): >>43552739 #
kragen ◴[] No.43552739[source]
I've seen an MSDS for sodium chloride USP that recommends against use in food, and says that you should wash your skin with abundant water for 15 minutes if you contact it and seek immediate medical attention if it gets in your eyes (after, of course, spending 15 minutes in the eyewash station). It also warns you to keep it away from sources of ignition, that it should not be released into the environment, and that you should not handle it without gloves and face protection.

Here, this is the first sodium chloride MSDS I googled up: https://www.fishersci.com/store/msds?partNumber=S64010&produ...

replies(1): >>43553338 #
throwanem ◴[] No.43553338[source]
Fortunately, HF is as safe as NaCl. Or so I take you to suggest, this otherwise totally failing to follow from anything anyone has said...
replies(1): >>43553765 #
kragen ◴[] No.43553765[source]
Sevensor said they would like to make Etsy moms using HF to frost shot glasses reread the MSDS for HF. This would only benefit them if MSDSes were reliable guides to the risks of working with different materials. Unfortunately, as evidenced by my example, they are not. Therefore, the Etsy moms, having reread the MSDS, might reasonably dismiss the information contained in it, unfortunately failing to protect themselves against the very real dangers it poses. Furthermore, given the astounding lack of thought evident in the NaCl MSDS, it is reasonable to guess that many MSDSes you find for HF will propose "safety" measures that are actually counterproductive, such as wearing gloves.

I thought all of this was obvious from my comment.

replies(2): >>43553885 #>>43554941 #
sevensor ◴[] No.43554941[source]
You don’t wear gloves when you work with HF? You are banned from my lab. 8 mil nitrile. Always check for cracks and pinholes before use.
replies(2): >>43555024 #>>43563179 #
pedvide ◴[] No.43555024[source]
Part of my PhD involved lots of fluoride synthesis using HF. I always used gloves (changing them very frequently). My advisor never used them for the following reason: if a droplet of HF lands on your glove you won't notice, but HF will go through the glove. If it lands on your bare hand chances are you'll notice it and wash them immediately. I could never follow his advise, but I did change gloves pretty much every step in the synthesis just in case.
replies(1): >>43555825 #
1. sevensor ◴[] No.43555825[source]
I’m definitely in the frequent glove change camp. And PSA for anyone reading this, latex gloves are worse than useless for protection against HF. But hopefully anybody working with HF already knows that.
replies(1): >>43563328 #
2. kragen ◴[] No.43563328[source]
The MSDS at https://www.nano.pitt.edu/sites/default/files/MSDS/Acids/Hyd... doesn't specifically mention to avoid latex, so it wouldn't be a useful source of information on this point. One of the four times that it mentions gloves, it does specifically specify "neoprene" (not latex nitrile), and the other three times, it doesn't say anything. Even though neoprene is strongly HF-resistant, rereading the MSDS is probably going to be worse than useless to the Etsy moms.