Removing hardened Cement from Metal

[Rufus RoughcutParticipant @rufusroughcut]

Hi Jason
that was not a poke at you at all I just generally think that threader’s around chemicals should be a bit more careful about the options proposed to others

[Speedy Builder5Participant @speedybuilder5]

Re Hydroflouric acid – I read, understand and agree with all the warnings, and so should the rest of us – However, when I was at school in the 50s- 60s, this acid was kept in a glass bottle with a thick layer of wax around the bottle, and kept on the shelf with the other acids. I can only assume that it was a weak mix, but what would HSE say about that these days !!

[jason udallParticipant @jasonudall57142]

I think “HSE” wouldn’t be keen on citric acid

But to be fair its not hse but the individual school that has to “do a risk assessment” on it.
Thus it would often be ruled out for “safety”…

[jason udallParticipant @jasonudall57142]

Re hf.
Just found a “recipe” for cooking it up at home..from 1930

Edited By jason udall on 25/09/2013 09:25:50

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Speedy Builder5 on 25/09/2013 08:40:48:

Re Hydroflouric acid – I read, understand and agree with all the warnings, and so should the rest of us – However, when I was at school in the 50s- 60s, this acid was kept in a glass bottle with a thick layer of wax around the bottle, and kept on the shelf with the other acids. I can only assume that it was a weak mix, but what would HSE say about that these days !!

At our school it was kept in a rubber bottle. I wouldn't think it's a good idea to keep it glass.

Russell.

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by jason udall on 24/09/2013 23:42:25:

Err? Rufus..it was certainly not my intent to trivalise the hazard that HF poses..

I have reread my post ..I do not get where I did that.

I will say again..HF or hydrofluric acid has no place in the hobbists "hands"

any reagent that can pull apart glass I don't want around..

there will be readers who work or have worked with this stuff,,,,,few if any will take handling/use of it lightly…

Edited By jason udall on 24/09/2013 23:43:35

Hi, I first became aware of HF back in 1970 when I started working for my previous employer. The dangers of these sort of substances were not always made fully aware to those on the workshop floor in those days. However, my late elder brother who was already employed by the company as a lab technician in quality control had access to all the data sheets and he told me all about the dangers of these things. luckily for me the use of HF was discontinued in the production plants shortly after I started working there.

Many years later I asked for a small quantity of some HF, which I knew they had in the lab, for my personal use at home for an experiment on some glass. The departmental head in the lab gave me consent to take some off site on two conditions, firstly he had a disclamer drawn up exonerating the company of all liability of any damage to property, injury to any person and disposal of any unused HF or resadues thereof, which I had to read and understand and sign and witnessed by one of the lab technicians (not my late brother as he had left and was deceased by then) and secondly I had to accept and understand when and how to use a special cream in the event that I or anyone else should get HF on thier skin. I also had to asure him that I would be using appropriate PPE and extreme caution while I was using it.

You really do need to know what you are dealing with and all the dangers to yourself, others around you and any damage to the enviorment that HF may cause. I really do agree with Jason that it is not really suitable in hobbyist hands.

Regards Nick.

Edited By Nicholas Farr on 26/09/2013 00:30:32

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