| Author | Message | ||
     Bob uk Unregistered guest Posted From: 94.197.122.84 |
I have mispelt it I think. This acid is nasty nasty stuff it painlessly burns into flesh and eats calcium and the only cure is amputation. It is a precursor to PTFE Teflon and ETFE fluon which is a stronger version of Teflon. Both of which are used in cars especially insulation on electrics. So when in car bone yards looking for buried treasure don't touch burnt out cars because there could be nasty hydrofluric acid from heat decomposed wiring insulation. Scary stuff. Telfon frying pans if heated to over 260c will give off hydrofluric acid fumes this will kill caged birds in seconds. And lung damage to humans. Most cooking oils give off smoke before 200c. (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 1464 Registered: 4-2003 |
Hi Bob, Have fixed spelling. Yes, this is a very dangerous chemical and precautions during handling and use must be followed to the letter. I regularly made and used descaling solutions containing this acid during my career after compulsory safety training which included having to view some very graphic images of Hydrofluoric Acid burns. Wikipedia has the following information on the health and safety aspects of this acid which I am quoting below as it is extremely important especially the burning of materials where this acid is present in the products of combustion: "In addition to being a highly corrosive liquid, hydrofluoric acid is also a contact poison. It should therefore be handled with extreme care, using protective equipment and safety precautions beyond those used with other mineral acids. Owing to its low acid dissociation constant, HF as a neutral lipid-soluble molecule penetrates tissue more rapidly than typical mineral acids. Because of the ability of hydrofluoric acid to penetrate tissue, poisoning can occur readily through exposure of skin or eyes, or when inhaled or swallowed. Symptoms of exposure to hydrofluoric acid may not be immediately evident, and this can provide false reassurance to victims, causing them to delay medical treatment. HF interferes with nerve function, meaning that burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury. Once absorbed into blood through the skin, it reacts with blood calcium and may cause cardiac arrest. Burns with areas larger than 160 cm2 (25 square inches) have the potential to cause serious systemic toxicity from interference with blood and tissue calcium levels. In the body, hydrofluoric acid reacts with the ubiquitous biologically important ions Ca2+ and Mg2+. Formation of insoluble calcium fluoride is proposed as the etiology for both precipitous fall in serum calcium and the severe pain associated with tissue toxicity. In some cases, exposures can lead to hypocalcemia. Thus, hydrofluoric acid exposure is often treated with calcium gluconate, a source of Ca2+ that sequesters the fluoride ions. HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel or special rinsing solutions. However, because it is absorbed, medical treatment is necessary; rinsing off is not enough. Intra-arterial infusions of calcium chloride have also shown great effectiveness in treating burns. Hydrogen fluoride is generated upon combustion of many fluorine-containing compounds such as products containing Viton and polytetrafluoroethylene (Teflon) parts. Hydrofluorocarbons in automatic fire suppression systems can release hydrogen fluoride at high temperatures, and this has led to deaths from acute respiratory failure in military personnel when a rocket-propelled grenade hit the fire suppression system in their vehicle." A very hazardous chemical which must be treated with the utmost respect and care at all times. | ||
| Jan Forrest Grand Master Username: got_one Post Number: 651 Registered: 1-2008 |
On another forum one contributor advised the use of hydroflouric acid to remove white (?calcium?) deposits from brickwork! I countered with citric acid due to the lower risk of flesh damage, greater ease of handling and the fact that, in low concentrations, is even edible. | ||
| Bob uk Unregistered guest Posted From: 94.197.122.86 |
Weirdly hydroflouric acid is edible in trace amounts. I guess when foodstuffs are analyzed to the nth degree all sorts of stuff is found. Bananas have potassium for example. Which why vitamin freaks poison themselves by believing that if potassium is good for you there eat lots and it must be even better. Alcohol is good for you in moderation but too much pickles your liver. PTFE has a good story behind it. A guy a DuPont was trying to make refrigerant which is measured by weight and he noticed that an empty pressure vessel weighed more than it should so he hacksawed it open and found a waxy white stuff. DuPont said PTFE Teflon is to date their best invention.1938. The other result was R12 air con stuff. GM and DuPont are sort of entwined together. Air con compressor oil is another DuPont GM collaboration. What a great story. I like stuff like this. Quite a few inventions don't work then a totally unrelated invention like Teflon makes another invention work. Fluon ETFE was invented by Ashi Glass. Hydroflouric dissolves glass and they where mucking around with glass and the acid and invented Fluon. (1950s) Fluon is low wear and very low friction and has a three fold elastic limit. Making a good stuff for hydraulic dynamic seals. That are impervious to any and all oils such as mineral and glycol. The aero hydraulic lads use a lot of fluon stuff. (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 1465 Registered: 4-2003 |
Hi Bob, I would be very surprised if Hydrofluoric Acid was an additive in foods however there are chemical compounds containing fluorine that are naturally present or specifically added to water, food and used in products for human use. I expect these are the sources of fluorides present in chemical analysis results. The best known of these would be Stannous [Tin] Fluoride and the cheaper Sodium Fluoride used in toothpaste to minimise tooth decay. A number of different Sodium Fluoride compounds are used for drinking water fluoridation to minimise tooth decay. Many foods also contain various fluoride compounds e.g. black tea, wine, lamb and carrots to name a few. The safe daily limit for fluoride consumption by an adult is 10 milligrams [mg]. P.S. Good news for us in the Southern Hemisphere is the recently reported reduction in the size of the hole in the Ozone layer over Antartica formed by chlorofluorocarbon pollutants released into the atmosphere by human activity destroying the naturally formed ozone layer in the atmosphere that protects us from ultraviolet light rays known to cause skin cancer. This reduction follows the banning of these compounds extensively used in the air conditioning industry [R12 refrigerant was a particularly potent contributor] and the reduction of the amount in the atmosphere as the chlorofluorocarbons already present degrade over time. | ||
| Randy Roberson Grand Master Username: wascator Post Number: 305 Registered: 5-2009 |
muriatic acid is commonly used to clean fresh brickwork. Hydroflouric is superbad stuff. We use a solution of hot water and citric acid to pickle (clean) new piping for engine lube oil systems. It can also clean cooling systems. The DuPont-GM association resulted from the DuPonts being major investors in GM's early years. JJ Raskob, DuPont treasurer, met WC Durant, thought there was opportunity, bought 500 shares in 1914 and persuaded PS DuPont to buy 2000. PS stepped in to settle in internal struggle for control of GM during WW1 or thereabouts, was elected chairman. Fascinating story. | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 1541 Registered: 4-2003 |
Randy/Thank you for that bit of history - I must consult Mr Google for the details. Meanwhile I recall somwhere 40 years ago peering into the stripped engine block of my first RR a 51 Dawn. The water passages were incredably crudded with rust which explained why when the Lady up front spotted a hill in front of us the temperature rose. I was advised to use a propriety cleaner which used, I believe, citric acid as the active agent. It was an interesting task undertaken by someone who had nightmares about dissolved engines - me! I remember well-greasing the exposed machined surfaces and warming the block while it soaked. The end of the story was a block probably cleaner than when new! What would one use now on cast iron? Later I found that early bottle washing plants used the citric stuff to clean there machinery which inevitably rusted. | ||
| Bob uk Unregistered guest Posted From: 94.197.122.72 |
Dave, I think I must mean fluorides in General as trace elements in food. I see the connection between Teflon and R12. These chemicals in the environment are not good. They have been altered by methods that don't happen naturally. They are impossible to get rid of them once released. In the UK the government take these chemicals very seriously. Scrap yards who burn old wiring to get the insulation off get closed down. R134a is not as good as R12 but does the job well enough for the UK. R12 is difficult to get here but any good aircon place can fit R134a along with a special oil plus new drier. Mine is R12 and is weak, needs a service which is £100 so not too bad. According to the BBC carbon in the atmosphere has risen. I personally am not entirely convinced about carbon and global warming. There's something missing in the theory. Our green party is asking for the UK to reduce carbon by 10% which because UK contribution to global carbon is 2% it means 0.2%. Recently a field near us flooded and the local greens were citing abnormal weather patterns but the field flooded about ten years ago and has a history of flooding. (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 1466 Registered: 4-2003 |
Hi Bill, Up here on the mid-north coast, there is a large group of old machinery enthusiasts, many being retired farmers who put their old machinery in the hay shed and when they retired from the farm, the shed was emptied and their collection of "rusty iron" was shipped with the furniture [much to the wife's dismay] to their retirement home which always included a shed/garage big enough for a workshop where they could bring their old machinery back to life. Every Father's Day, they gather at Macksville for the "Rusty Iron Rally to display their work, marvel at the work of others and watch the tractor pull events. "Rusty Iron" is a very apt description and the first step is to remove the rust from the machinery, this is usually done by soaking the machinery with a solution of molasses and water for a period of time up to 3 months for a heavily corroded item. The molasses removes the rust but does not affect the base iron/steel. Examples of items cleaned by this method can be found searching the web using "rust removal with molasses". Have a look at the winch on the Land Rover Club website: http://www.aulro.com/afvb/projects-tutorials/115028-rust-removal-molasses.html | ||
| Jan Forrest Grand Master Username: got_one Post Number: 652 Registered: 1-2008 |
For those who really need to keep using R12a refrigerant, the British Oxygen Company have a dedicated recycling plant for it in the UK. It can still be obtained in (IIRC) 20 kilo cylinders or larger for refrigeration engineers/servicers to recharge systems that are incompatible with R134a. However many people have found that simply replacing the charging valves followed by a diligent flushing will permit many older systems to soldier on for many years more before a full overhaul becomes necessary. Early refrigeration plants used pure ammonia as the refrigerant before the artificial compounds were discovered. On the ozone depletion front: Originally it wasn't known just how efficient these compounds could be in neutraising O3, so it was assumed that being otherwise so stable, atmospheric losses could eventually lead to them being recovered by the standard fractional distillation that gives us nearly all the other 'natural' compressed gasses such as oxygen, nitrogen, argon, helium, etc, etc. | ||
| Bob uk Unregistered guest Posted From: 94.197.122.74 |
My air con guy said that using nitrogen to flush last or was it first. Anyway the nitrogen absorbs any damp in the system. And also the New drier is smaller. I was hoping to be able to service the old drier but he said it's best to fit a new one. Ammonia is another nasty stuff. I worked for Fairey Hydraulics on Tornado hydraulics in 1974 for 18 months and we used ammonia in the metal treatment department which was a separate building. Which I kept away from because they had cyanide as well. One day they had to evacuate because a bottle of ammonia gas fell over and snapped the head valve off. The guys had snot comming out of their eyes and all went to hospital. They were all ok the following day. They evacuated the building in 20 seconds. I am very careful with chemicals because my knowledge is so rudimentary and the more I learn the more alarmed I get. I reckon that if the truth be known that a lot of older people with various health problems have been unknowingly exposed to hazardous chemicals in their working lives. I think the guy who was in charge of fluorides development was Midgley who also put lead in petrol. He was cited by the USA government as doing a great service to mankind. Untill 50 years later when they discovered lead contamination and a hole in the ozone layer. (Message approved by david_gore) | ||
| Jan Forrest Grand Master Username: got_one Post Number: 653 Registered: 1-2008 |
Thomas Midgley Jr. is accredited with the 'invention' of both tetraethyl lead as well as the first of the CFC's. His last invention didn't work out too well either. It was a harness/lift to permit him to put his own polio damaged body into & out of bed without assistance. Unfortunately on its final use it slipped and strangled him to death. | ||
| Bob uk Unregistered guest Posted From: 94.197.122.76 |
Didn't he do well. I sort of feel sorry for him, but also you have to laugh. Today I was thinking about PTFE in engines (slippery 49) and I did a Google and up turned Ford trucks. The article is from 1992 and Ford is appears teamed up with Briggs And Stratton Lycoming, DuPont and a couple of university and tested a range of additives. I scan read and found that PTFE gets into the combustion chamber and the exhaust gas contain hydroflouric acid which apart from being a health hazard also rots the exhaust and other damage (cat I think) So there you have it, not only are the additive people ripping off they are also damaging cars and people and animals. Unfortunately DuPont tried to stop them but got done under free trade rules. Which the perverts of this engine snake oil have used the ruling to prove the PTFE works in engines which doesn't. Plus the ozone layer maybe. I am going to contact my MP and ultimately try and get the muck banned. (Message approved by david_gore) |
