Thread: Hydrofluoric Acid

Nasty stuff. Not can but will cause bone density and brittleness issues by removing calcium from bones and usually death will follow. If using keep on hand a tube of calcium gluconate gel that would need to be applied with in seconds of skin being exposed to, plus will also cause acid burns to the skin. At best if you come into contact with pure hydrofluric acid you could expect to have long term bone damage, likely minimum lose the limb exposed and very high probability of death. Can also lead to cardiac arrest quite rapidly. One of the single most dangerous acids to be used. One of the highlights we had to know when working in labs and while using lab techs had to carry with them.
Used to be used in a lot of laboratories in mineral processing, cleaning other material from gold nuggets and part of the composition of aluminium cleaner. Worked well but is highly dangerous, especially in undiluted form.
Was widely used in aluminium cleaner until about 3 years ago, when it was pretty much banned from this use. It does clean aluminium up nice, but has significant health risks. I think it has now been replaced with an alternate acid. I have some in the shed but it does not work as well.
If you intend using take extreme precautions and PPE.
Also leaving it on for more time than recommended and result in eating away of aluminium and if used on paint work can strip the paint if left on for more than a few seconds.
When in the Pilbara we used to get our fire appliances cleaned once a year with the aluminium cleaner (not pure Hydrofluoric Acid but contained). Would clean the Iron Ore residue off easily so shows how powerful it is. I think the brand we used to use was CT18 and that is the one that changed its composition.

As for Sulfuric acid, if you add water to it it will become exothermic and can explode and or catch fire.

Now having said all that the best way to apply is to use in diluted aluminium cleaner form, can be diluted further as required. We used to use in spray bottle form. Apply in small sections, use a non abrasive pad and wash off quickly, wearing PPE (long rubber gloves, goggles etc). For trays and aluminium chequer apply, brush and hose off quickly. Can be used on paint as well in very diluted form and hosed off quickly.

We used to use concentrated HF in gold mining laboratories.

1. You have to store it in plastic - it will easily eat through glass.

2. Drillers used it to measure the angle of a hole in the ground. Put some HF in a test tube and lower it down the hole on a string to the depth at which you want to measure the angle. Leave it still for about 5 minutes and then pull the test tube back up. There will be an "etch line" at the acid / air interface. By measuring the angle of this etch line against the vertical, you can calculate the angle of the drill hole. If you leave it down there too long, you will only retrieve the top half of the test tube.

3. The only acid that will clean quartz out of gold nuggets. Hydrochloric and nitric will remove most other rock types / impurities, but they will not touch quartz. HF will easily dissolve quartz. (Don't use hydrochloric and nitric together though - the combination in the right proportions is known as "aqua regia" and is the only acid that will dissolve gold).

As others have said, don't get it on any part of your body, nor breathe in the fumes. One of the nastiest chemicals that I've ever worked with. One of the nastiest things about is that many people will not even know that they have got it on their skin - in a lot of cases, it does not burn you straight away like other acids do - it simply resembles water. Once you have realized what is on your skin, it is often too late and some pretty drastic medical action is required.

I've never heard of it used as a cleaning agent for wheels etc so don't know how it would go for that. Personally, I wouldn't touch the stuff - for any purpose.

I have seen it burn straight through a steel hotplate though - an idiot metallurgist I worked with once thought he'd "speed up" the process of dissolving the quartz inclusions out of a gold nugget, so put the nugget in some HF in a glass beaker on a hotplate. While his back was turned, the HF dissolved the bottom of the beaker, spilled onto the hotplate and burnt straight through it. Luckily the benchtop was PVC and it didn't go any further.

I haven't even seen HF around minesite laboratories for years now. The OH&S brigade got it banned on most sites that I know of after a couple of particularly nasty accidents. The only other acid that I've worked with that is about as scary as HF is Perchloric acid. That stuff bursts into flame as soon as it comes into contact with just about any combustible material in the presence of oxygen. A favourite "prank" was to squirt some onto someone's leather work boots and watch the reactions when their boots burst into flame.

My recollection from high school chemistry is that it is one of the few acids that will eat through glass and in concentrated form needs to be kept in an earthenware container.

That aside, the one thing that all of the above posts (including the OP) agree on is that this is nasty stuff. Frankly, I'd put up with black, manky mags rather than expose myself to the possible health risks of HF acid...

From what I have read here....I wouldn't go near the stuff! Just do a bit of hard scrubbing with some baking soda or something. Not worth risking health for a set of mags.

Thanks for the replies fellows, especially you Jerry , I am not concerned about the PPE requirements, I have all that is needed and would use it. My primary concern is whether it will damage the wheels.
Craig, Chemtec Blitz still contains hydrofloric (and sulfuric) acids. Chemtec and Septone are now the same company. CT Blitz and Septone Ali Brite (what I have) are the same product, different labels. CT 18 is a general truck wash, years ago it was very caustic, that's why it worked so well. It was hard on paintwork and after a protracted legal battle with a truck manufacturer, who claimed CT 18 was inducing corrosion causing warranty claims on its products, Chemtec changed the formula.

I'm amazed that these and similar products are so easily available. They're easier to buy than grog, durries or sinus tablets that actually work.

As most of the others have indicated, it is one of the nastiest chemicals you can get, although I suspect the cleaner uses it in very diluted form, so the cleaner is probably not that bad - although I, personally, would not use it under any circumstances.

And the "contradictory" statements in the data sheet are not contradictory - one says it is harmful on the skin, the other says it does not sensitise the skin (perhaps because there is no skin left?). Being harmed and being made more sensitive are two different effects.

John

Originally Posted by BMKal

I haven't even seen HF around minesite laboratories for years now. The OH&S brigade got it banned on most sites that I know of after a couple of particularly nasty accidents. The only other acid that I've worked with that is about as scary as HF is Perchloric acid. That stuff bursts into flame as soon as it comes into contact with just about any combustible material in the presence of oxygen. A favourite "prank" was to squirt some onto someone's leather work boots and watch the reactions when their boots burst into flame.

But does it clean mag wheels though?

Chemtech Blitz contains Phosphoric Acid, not HF. Very different acids.

[ame="http://www.chemtech.net.au/Blitz%20MSDS.pdf"]http://www.chemtech.net.au/Blitz%20MSDS.pdf[/ame]

Septone ALI BRITE contains Sulphuric Acid and Ammonium Biflouride, which dissociates to produce a solution containing a very low strength (0.98%) Hydroflouric Acid.

http://www.septone.com.au/msds/ATA1.htm

Didn't know that Chemtech had changed the formula for CT18 - explains why it doesn't work as well as I remember it. I use CT20 on the D4 - works well and puts a bit of a shine on the paint.

And yes .................... Jerry's response is appropriate.