Sciencemadness Discussion Board

Trying to Acquire HF

raphanus - 3-2-2025 at 00:22

Hi All,

I am trying to acquire HF for home semiconductor fabrication. Are there any suppliers worth looking into beyond simply Aldrich or Home Depot?

For me, Sigma-Aldrich is a big hassle since I will need to acquire it through a lab and Home Depot HF is too low concentration. 48% concentration will be ideal.

Maui3 - 3-2-2025 at 00:28

You can buy HF at home depot?!

raphanus - 3-2-2025 at 00:45

Quote: Originally posted by Maui3  
You can buy HF at home depot?!


only as rust remover at <1% concentration. Huge mark up too.

Keras - 3-2-2025 at 01:48

If you’re in the EU, you can try your luck at limac.lv. I have a bottle of 1L of 60% HF coming from him. Never opened it so far. I keep it safe for maybe later use.

6dthjd1 - 3-2-2025 at 02:10

mario840 might still be shipping chemicals

Sulaiman - 3-2-2025 at 02:19

HF is not only hazardous to use, it is a hazard to store or dispose of as well.
HF escapes enclosures even easier than HCl does
(HF vapours seem to rust steel less than HCl vapours,
but nearby glass will develop an ugly irremovable bloom of rainbow colours)
HF is very corrosive to living tissue, but worse, it is HIGHLY toxic.
You MUST prepare suitable ppe, working environment and antidote. (not cheap)
If possible, avoid HF.
(I believe that there are alternatives)

Could you generate and use HF in-situ?, eg H2SO4 + CaF2

Keras - 3-2-2025 at 04:18

Using concentrated sulphuric acid with calcium fluoride at 250 °C will generate gaseous HF. Tell me in what vessel you’re going to make and handle this…

[Edited on 3-2-2025 by Keras]

bnull - 3-2-2025 at 05:13

Quote: Originally posted by raphanus  
I am trying to acquire HF for home semiconductor fabrication.

Could you please expand on this? From the things I saw in college and elsewhere, it is not so simple and straightforward as, say, decorative glass etching.

Eleutheria - 3-2-2025 at 05:47

Local glassblowers might have HF, if there’s any around you. I once met up with a scientific glassblower at his shop and after I told him I was a chemist he asked me if I wanted to buy any HF from him.

Deathunter88 - 3-2-2025 at 08:05

Walmart has 48% HF for sale right now actually, I ordered some the other week and it arrived in a few days no problem.

https://www.walmart.com/ip/Hydrofluoric-Acid-48-I-HF-solutio...

I would order it soon, these things pop up and get taken down all the time.

teodor - 3-2-2025 at 12:02

As Sulaiman mentioned it is not easy to store. Every few weeks you can find some liquid outside the bottle. The normal practice is a double container.
But the liquid itself is dangerous without any obvious warnings of the danger. It can easily kill or cripple.

raphanus - 3-2-2025 at 12:19

Quote: Originally posted by Sulaiman  
HF is not only hazardous to use, it is a hazard to store or dispose of as well.
HF escapes enclosures even easier than HCl does
(HF vapours seem to rust steel less than HCl vapours,
but nearby glass will develop an ugly irremovable bloom of rainbow colours)
HF is very corrosive to living tissue, but worse, it is HIGHLY toxic.
You MUST prepare suitable ppe, working environment and antidote. (not cheap)
If possible, avoid HF.
(I believe that there are alternatives)

Could you generate and use HF in-situ?, eg H2SO4 + CaF2

Thanks for the concern! I appreciate your attention to safety. I am in the process of acquiring a polypropylene ductless fume hood for the fumigation concerns. I am also considering to modifying it to a ducted hood for extra safety. Generation in-situ is undesirable because it is another source of contamination.
Quote: Originally posted by Keras  
If you’re in the EU, you can try your luck at limac.lv. I have a bottle of 1L of 60% HF coming from him. Never opened it so far. I keep it safe for maybe later use.

Not in the EU.
Quote: Originally posted by Deathunter88  
Walmart has 48% HF for sale right now actually, I ordered some the other week and it arrived in a few days no problem.
[...]

What an interesting seller! Never would've thought Walmart would come up. Thanks for the tip. I am currently looking at the seller's own site. I'm seeing listing for 3.8 liters of 48% HF for ~$90 shipped. Is it too good to be true? That is 6x cheaper than Sigma without shipping!

Deathunter88 - 3-2-2025 at 12:34

Quote: Originally posted by raphanus  
Quote: Originally posted by Sulaiman  
HF is not only hazardous to use, it is a hazard to store or dispose of as well.
HF escapes enclosures even easier than HCl does
(HF vapours seem to rust steel less than HCl vapours,
but nearby glass will develop an ugly irremovable bloom of rainbow colours)
HF is very corrosive to living tissue, but worse, it is HIGHLY toxic.
You MUST prepare suitable ppe, working environment and antidote. (not cheap)
If possible, avoid HF.
(I believe that there are alternatives)

Could you generate and use HF in-situ?, eg H2SO4 + CaF2

Thanks for the concern! I appreciate your attention to safety. I am in the process of acquiring a polypropylene ductless fume hood for the fumigation concerns. I am also considering to modifying it to a ducted hood for extra safety. Generation in-situ is undesirable because it is another source of contamination.
Quote: Originally posted by Keras  
If you’re in the EU, you can try your luck at limac.lv. I have a bottle of 1L of 60% HF coming from him. Never opened it so far. I keep it safe for maybe later use.

Not in the EU.
Quote: Originally posted by Deathunter88  
Walmart has 48% HF for sale right now actually, I ordered some the other week and it arrived in a few days no problem.
[...]

What an interesting seller! Never would've thought Walmart would come up. Thanks for the tip. I am currently looking at the seller's own site. I'm seeing listing for 3.8 liters of 48% HF for ~$90 shipped. Is it too good to be true? That is 6x cheaper than Sigma without shipping!


It's legit, like I said I ordered some and it arrived within a week. Also, Sigma is not a good source for price comparisons, especially for industrial chemicals.

chempyre235 - 3-2-2025 at 12:51

One more thing to note. Make EXTRA certain that you have all the appropriate PPE for working with HF, including calcium gluconate. Here is an SM thread which addresses HF safety. If you haven't worked with this acid before, I'd highly recommend reading it first. I also seem to remember an SM member distilling homemade HF, who also had some good safety recommendations, but I couldn't find the thread.

Good luck, and stay safe!

Rainwater - 3-2-2025 at 13:00

Quote: Originally posted by raphanus  
Hi All,

I am trying to acquire HF for home semiconductor fabrication.

Look into ammonium bifluoride as an enchant.
Its cheap,
clean,
"Less" toxic,
easy to store
and in solution, will etch doped silicon but not many if the photo resists.

metalresearcher - 3-2-2025 at 13:14

Indeed, playing with HF and fluorine in general is extremely dangerous. I don't want to have it.
There is a reason that there were "fluorine martyrs" under the 19th century scientists trying to isolate F2.
https://en.wikipedia.org/wiki/Fluorine#Isolation

raphanus - 3-2-2025 at 20:23

Ok. Thank you all. I will be doing more research about this before proceeding.

MrDoctor - 3-2-2025 at 22:45

Quote: Originally posted by Rainwater  
Quote: Originally posted by raphanus  
Hi All,

I am trying to acquire HF for home semiconductor fabrication.

Look into ammonium bifluoride as an enchant.
Its cheap,
clean,
"Less" toxic,
easy to store
and in solution, will etch doped silicon but not many if the photo resists.


its illegal here now but i found two bottles of that at the ole antique store, its used as anti-slip for swimming pool tiles, i guess the idea is you pour it over fresh new glazed tiles and it etches the crap out of them, making them nice and grippy.

Im still trying to figure out how i can make silver fluoride with it without having to distill HF

hedgeberg - 3-2-2025 at 23:09

Oh, jesus christ, uh, don't??? Mess with HF? If you can possibly avoid it? I used to work in semiconductor cleanrooms, and so much of the safety training was focused around how not to die in a space that contained HF -- not even how to handle it, just how to stay safe in the event of inadvertant exposure.

What you need to understand is that it doesn't react significantly with skin or the lining of your lungs, so people exposed to HF often don't realize for several hours after initial contact, but the fluoride ions will preferentially go after your bones. If you ever look up pictures of people who have been exposed to HF, it's pretty god damn horrifying. If you absolutely must deal with HF, make absolutely sure you've got some kind of full-body protective clothing that is rated for HF, probably make sure you're not working on any kind of reactive flooring, get a face shield, and possibly most importantly, since I don't know if this was mentioned in other threads, make sure to get your hands on a calcium donor gel syringe. We had to keep that stuff around and accessible in industry. The point of the donor gel syringe is that, in the event of HF exposure, you can inject it into the exposure site to give sacrificial material for the fluoride to attack instead of your bones. Be warned, if you ever need to inject that stuff, it is supposedly excruciatingly painful, and you are advised to not take any painkillers because the pain is supposedly how you know whether or not there's still any free fluorine in your system.

I'm sure a certain amount of my fear on this is industry rumor that we used to share around in an attempt to put the fear of god into us, but I've seen enough to know I wouldn't personally risk having HF around me. It's not as bad as a nerve agent or anything, but it's up there.

MrDoctor - 4-2-2025 at 00:13

fortunately i only need less than a gram, to form some AgGa nanoparticles, but yeah, im with you there.

That being said if its so deadly why is it present in 0.1% as rim polish?

teodor - 4-2-2025 at 01:31

Obviously the amount matters.
But we are talking about the bottle of 48% HF. Which should be used and stored somehow for a long period of time or disposed. I have one. After 3 months in my garage I found the HF eated through the bottle and everything around was wet. I used the second plastic box so it was possible to limit and clean the mess. Woelen gave me a better bottle (the original one was from some reputable chemical supplier, but still) and I decanted it but next day the bottom of the new bottle was wet. This is what you also can expect and you should be prepared.
If you need small quantities it is better to have small bottles for everyday usage, and if you plan to use HF often some spills will happen just because the probability of them is not zero. You need a proper technique of working with it and limiting the amout and the area.

For working with the original bottle use 2 pairs of gloves. Nitrile and sick gloves above it. Wash hands if you see the liquid on gloves. Never sit and keep the body position such a way that you will not get the liquid on yourself if the bottle turns over. Protect as much of your body as you can with something you can quickly discard out in case of contamination.
For everyday usage use small bottles and plastic pippetes. Don't use thick gloves because you need accurate movenings. Nitrile ones should be enough if you can imeediately wash or dispose them. But some people recommend 2 pairs, I am not sure what is the reason. Also I am not sure at which rate HF fumes can penetrate nitrille but doesn't keep your hands above the liquid for long period, also you can discover this by yourself. Use long sleeves to protect the other part of your hands which are inside a fume hood.
Use a tray under your working area or on the bottom of your hood to prevent spills going outside.

The density of HF is bigger than air. In small quantities it just forms mist with water vapours but if you expect gaseous fluorides in your process make sure your hood has air intake not only from the top but also from the bottom. This is the job of the back wall in any professional fume hood. For designing your own you need an to have an air flow meter.

Also, when people say to use CaF2 for generation in-situ they obviously don't mean distilling it.


[Edited on 4-2-2025 by teodor]

chempyre235 - 4-2-2025 at 09:29

IIRC, the innermost pair of gloves is supposed to be coated with calcium gluconate gel, to act as a neutralizing barrier to any HF that makes it through the outer glove.

teodor - 4-2-2025 at 11:00

Quote: Originally posted by chempyre235  
IIRC, the innermost pair of gloves is supposed to be coated with calcium gluconate gel, to act as a neutralizing barrier to any HF that makes it through the outer glove.


:)

I afraid in 10 years people will not be able to nottice irony in your post.

Just to make my post more meaningful, I'd like to notice that in the mid of 20th century in his book about solvents (describing anhydrous HF system as well) Ludwig Audrieth wrote (citing from my memory): "Some of solvents mentioned in this book are quite toxic substances. But things like that should never stop real scientist to investigate those solvents."

How much in the opinion was changed. I would not say safety is not important, but for scientists of pre- mid 20 century era science and questioning the nature was always much much more important.


[Edited on 4-2-2025 by teodor]

Dr.Bob - 4-2-2025 at 17:40

There's no irony in the post, that is a good way to protect against HF leaks.

I worked with HF in a few different ways, and hated it, as the PPE is awkward, the tolerance for errors is low, and disposing of it was a mess. Had to neutralize small amounts with K2CO3 which makes KF and a large mess. Somehow I always got to do the dirty jobs at several different places of employment.

hedgeberg - 4-2-2025 at 23:32

Quote: Originally posted by MrDoctor  
fortunately i only need less than a gram, to form some AgGa nanoparticles, but yeah, im with you there.

That being said if its so deadly why is it present in 0.1% as rim polish?


We live in a society or something. Insert your meme of choice. As an undergrad I worked with a solution called "nickelex" intended for plating nickel onto silicates without an electrolytic process, and it contained 1% concentration, and we were ok to work with it unsupervised with relatively minimal PPE. However, 1% was about the limit of what was deemed "safe" -- if we wanted to go stronger we'd need to use one of the university's all-teflon wetbenches in the cleanroom and take a specialized course. .1 molar HCl isn't going to hurt you, 10 molar HCl will sting if it gets on you. It's always a question of concentration and dose at the end of the day.

Safety is a personal decision. How you choose to evaluate your risk threshold is your decision and we all take potentially lethal risks every day just by being alive. That being said, HF is considered a "particularly hazardous substance" by most of the industrial world, because even if, like with all other risks, you can minimize harm, it's a lot easier to screw up if you're not exceptionally careful. Accidents can and will happen, and I'd personally rather not walk around with a loaded gun pointed at my foot. Even the best home chemists make mistakes sometimes. If you can get away with very low concentrations for your project, you should probably do so.

WGTR - 5-2-2025 at 07:39

Long term, if you want to play around with etching a variety of substrates, I would suggest building or buying an old plasma etcher. SF6 is one fluorine-containing feed gas that is used for etching silicon. The advantage of plasma etching in this case is that SF6 is pretty inert, and the reactive species are minimal and generated in-situ under low pressure. Plasma etching is also a very clean process.

https://afm.oxinst.com/learning/view/article/fast-smooth-etc...

I have an old plasma etcher (probably 1980’s-90’s vintage) in the lab along with several bottled gasses such as SF6, oxygen, CHCl3, N2, and 1-2 others. You can use one material as an etching mask for a silicon etch, then switch gasses and remove the mask afterwards, without attacking the silicon. Very cool stuff.

As for concentrated HF, I have used it 1-2 times, under extreme duress and with excessive amounts of PPE. I avoid it much like I avoid chromic acid.

[Edited on 25-02-05 by WGTR]

MrDoctor - 7-2-2025 at 19:32

Quote: Originally posted by hedgeberg  

If you can get away with very low concentrations for your project, you should probably do so.

thankfully that is the case, unless im mistaken, HF in solution should react with silver carbonate at any concentration. so i just have to find a nice safe way to transfer that HF into water. I think i should probably do up a thread of my own for this tho rather than intrude into someone elses, since i technically dont need HF, its just in my limited understanding HF is the only clear choice i can see.