Wiki: Acid

More input incorporated, thanks primarily to Spamlet....

==Precautions== Most acids used in DIY are high risk chemicals. Several precautions are advisable with many acids. These don't all apply to vinegar & citric acid.

  • Due to the potentially high risk involved, labels should be read and advice followed
  • When diluting, never add water to acid, always add acid to water, and stir promptly. Diluting is sometimes highly exothermic, and should be done a bit at a time, wearing safety specs and stopping if it gets hot. If done the wrong way (putting water into acid) the result can even progress to explosion sometimes. Exploding boiling acid is not an essential nutrient.
  • Never mix concentrated acid with alkali, or acid with concentrated alkali.
  • If you mix dilute acid and alkali (to render them safe enough for disposal), do so gradually, stirring, and stop if it gets hot.
  • Some acids used in DIY eat through skin rapidly. Wear suitable gloves
  • When holding the bottle, do so by the label area, so any unnoticed runs are on the back where you're not holding it. Rinsing the bottle exterior after use is a good precaution with hostile acids.
  • Don't mix acid with bleach, the resulting chlorine is toxic enough to kill.
  • Don't mix acid with alkalis, excess heat is generated, and boiling spitting acid isn't a good idea.
  • Some acids plus metal can generate hydrogen, which is explosive above 4% concentration.
  • Suitable gloves & eye protection are sensible for some of the acids. Gloves can be inflated and put under water to check for holes, wise if you're handling the nastier acids.
  • Full face visor should be used for the more hostile acids, and is a good thing for other acids.
  • In case of skin contact with all but the mild acids, wash for 10 minutes to minimise burning, chemical reaction & contamination. In case of eye contact, wash for at least 10 minutes and seek medical help promptly. Use the correct neutraliser for HF.
  • Have a suitable neutraliser available.
** For small amounts this can be baking soda or washing soda ** When handling bulk acids a garden hose is more effective. ** For hydroluoric acid, specific neutralisers are needed
  • Have eyewash equipment available. If you need to use it, time is pretty important.
  • When carrying bulk acid or hostile acids, hold them in a sturdy container away from you. This avoids you getting drenched and maybe killed if you drop the container or it breaks.
  • Plastic bottles can degrade over time. Keep out of sunlight, and use the older ones first. When buying, plastic containers with weathered looking labels might have been sitting out in the sun for years.
  • Store powerful acids at floor level to reduce risk of breakage.

==Sulphuric Acid== [[image:H2SO4 98% 4170-3.JPG|right|200px]] A strong acid, sulphuric acid has many names, including vitriol, glover acid, tower acid, fertiliser acid, chamber acid, battery acid, dipping acid, mattling acid, electrolyte acid.

Uses

  • Eats organic materials rapidly. Eats paper etc in seconds.
  • Good for unblocking drains where the blockage is organic
  • Rapidly eats the paper content in toilet blockages, which caustic soda doesn't.
  • Density of 1.84 means it sinks to the bottom of blockages.
  • Lead acid batteries use pure sulphuric acid of around 4M or 30%. Less pure drain cleaning acid is not usable for batteries.
  • Strong desiccant, but attacks most materials people want to dry
  • Reaction with sugar produces carbon
  • Demos of conc sulphuric burning paper, sugar etc can catch fire, boil, and spit acid
  • Reaction of dilute H2SO4 with hot copper produces copper sulphate, a mould inhibiting antimicrobial.
  • Reaction with zinc produces zinc sulphate, a mould inhibiting antimicrobial.

Risks

  • 98% sulphuric acid drain unblocker is probably the most dangerous of the acids used in DIY. Put a drop on paper for a demo.
  • Dangerous to skin & eyes
  • Destroys cement joints in ceramic pipes
  • Toxic
  • Concentrated sulphuric acid can react violently with water
  • In work situations all use of sulphuric acid must be assessed under the COSHH regulations.
  • Take proper care to keep sulphuric away from kids, the results can be nasty
  • Wipe down batteries after filling them with acid
  • Best wear clothing of little value when handling lead acid batteries.
  • Don't heat concentrated sulphuric acid, the risks increase excessively
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    MSDS]

Purchase

  • Upto 98% sulphuric acid is available as drain unblocker.

==Hydrochloric Acid== [[image:HCl 34% 4168-3.jpg|right|200px]]

  • A strong acid
  • Also known as spirits of salt, muriatic acid

Uses

  • Eats cement & lime
  • Cleans cement off bricks etc - but not off cement products
  • Can also be used to descale ceramics, but it can discolour otherwise unnoticeable surface cracking
  • 18% hydrochoric acid is used industrially to clean steel before coating ('pickling'). Spent pickling solution is sometimes then used as ferrous chloride.

Risks

  • 34% HCl produces choking fumes and mist
  • HCl is highly corrosive to skin, eyes, lungs etc, and toxic. Inhalation of too much of the fumes can cause death
  • In case of skin contact, wash for 10-15 minutes. In case of eye contact, wash for 10-15 minutes, lifting both upper & lower eyelids regularly, and seek medical advice without delay.
  • Incompatible with many substances
  • Destroys cement joints in ceramic pipes
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    MSDS]

Purchase

  • Sold as brick acid, drain unblocker, and is a component of many patio cleaners.
  • Available upto 34%

==Chromic Acid== Not normally used by DIYers, but occasionally used for extreme ceramic sink cleaning. Its exceptionally effective, but very toxic and should be avoided entirely.

  • Can set fire to organic materials like paper and skin.
  • Disposal creates serious problems, contaminating land and food crops.

==Hydrofluoric acid== A high risk acid that causes particularly bad burns, life threatening poisoning on contact and extreme pain

  • Only used in tiny quantities in diy, typically in little glass etching pens.

Uses:

  • Used to etch glass. A vibrating scribe or [[die grinder]] are safer methods.
  • Also used in commerce to clean greenhouses, but don't.

Risks:

  • Extremely corrosive
  • A contact poison. Poisoning can occur readily through exposure of skin or eyes, or when inhaled or swallowed.
  • HF penetrates tissue more quickly than typical acids
  • Symptoms of HF poisoning can be delayed
  • 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 25 square inches (160 cm2) have the potential to cause serious systemic toxicity from interference with blood and tissue calcium levels.
  • Poisoning causes severe pain
  • HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel or special rinsing solutions.
  • In case of skin contact, medical treatment is necessary, rinsing off is not enough. In some cases, amputation may be required.
  • Hydrogen fluoride is generated by burning fluorine-containing compounds such as some synthetic rubber, Viton, polytetrafluoroethylene (Teflon)
  • Occasionally people have needed amputation after handling burnt car parts.

==Sulphamic Acid== Also known as sulfamic acid, amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid

Uses

  • Used to descale heat exchangers in heating systems
  • Descale and clean metals and ceramics
  • A component in some household descalers & denture tablets

Risks

  • Lower risk than hydrochloric & sulphuric acids
  • Solubility in water is moderate, limiting solution strength

Purchase

  • Fernox DS-3 contains sulphamic acid, inhibitors, indicators & surfactant.

==Phospohoric Acid== Uses

  • Used as rust remover. Turns rust into a stable black ferric phosphate. Often used as a gel preparation to enable it to cling to surfaces at all angles.
  • Phospohoric acid is used as a food additive, E338.
  • Sometimes used to remove limescale and cement stains.
  • Sometimes used as a soldering flux
  • Used commercially as a nutrient for irrigated glasshouse crops

Risks:

  • Don't permit contact with bleach, ammonia or metals
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    Safety data]

Purchase

  • Sold in preparations known as rust convertor, rust remover, rust killer, naval jelly.

==Acetic Acid== [[image:Acetic acid 4159-4.JPG|right|200px]]

  • Also known as ethanoic acid, acetyl hydroxide (AcOH), hydrogen acetate (HAc), ethylic acid, methanecarboxylic acid
  • Concentrated acetic acid is called glacial acetic acid. It freezes at 16C.
  • Acetic acid has a characteristic powerful vinegary smell.

Uses

  • Vinegar is primarily dilute acetic acid, typically around 4-8%
  • Vinegar cleans copper, copper alloys, brass, bronze - the runoff is toxic
  • Diluted vinegar cleans glass & helps avoid smearing
  • Glacial acetic acid is used to remove warts & verrucas, and the dilute acid for ear infections.
  • Acetic acid makes copper acetate, a pigment and fungicide.
  • Sometimes used with other acids as a descaler
  • Food additive E260

Risks

  • Acetic acid is corrosive, and at high strengths highly flammable.
  • Overexposure to the fumes can cause difficulty breathing. This can easily happen at room temperature.
  • Consequences of exposure can be delayed for a few hours.
  • Fumes above 39C can be explosive
  • Latex gloves don't protect against acetic acid, use nitrile ruber gloves.
  • THe acetic acid in most silicone sealant can sometimes cause mild burns if left on the skin.
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    Safety info]

==Citric Acid==

  • A weak edible acid

Uses

  • Citric acid is a widely used food additive, E330
  • Descaler for appliances that can't take more effective acids, eg kettles, washing machines etc.
  • 6% can remove scale without rubbing
  • Salt enhances the descaling action of citric to an extent.
  • People use anything from 2%-20% as a scale tackling bathroom cleaner.
  • Appliance descalers in supermarkets are usually citric acid based, with or without another acid and corrosion inhibitor. Not a cheap way to buy the stuff.
** A stainless steel swarf scourer in a kettle prevents limescale, and is easier to use
  • Citric acid can often substitute for lemon juice in recipes

Purchase

  • Citric acid is sold as a bagged food additive in some foreign food supermarkets, or less cheaply in small boxes at pharmacies (much used by addicts).
  • Irritant to skin & eyes. In case of eye contact, wash well for 10 minutes and seek medical assistance
  • Corrodes copper, zinc, aluminium and their alloys
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    MSDS]

==See Also==

  • [[Detergent]]

[[Category:Cleaning]] [[Category:Chemicals]]

Reply to
Tabby
Loading thread data ...

In message , Tabby writes

Getting closer

Also used for descaling heat exchangers

e.g.

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as is HCl

which Kamco sell as HD (HyDrochloric)

phosphoric acid is also dangerous in the same way as HF, it attacks the bones, but its effect is less pronounced

Reply to
geoff

Not promptly: continuously. Decant the quantity of acid you want to use, ideally into a measuring beaker or jug of pyrex or polythene. Then pour from the jug or beaker carefully into the larger volume of water stirring all the time with a glass rod or polythene spoon or spatula. Wash the utensils immediately in a good volume of water nearby so that you do not put them down and leave a pool of acid to stick your elbow in later. If you wear clothes you will soon appreciate why.

Diluting is sometimes highly exothermic, and should

Store them in double containment. Many smaller quantities will come in their own unbreakable outer plastic drum (very handy afterwards for things like stone polishing but I digress). If yours doesn't, cut the top off a suitable polythene container and stand the bottle in that. Then if you do happen to kick or drop something on it, your acid is still contained, and it won't swoosh across the floor and set fire to your car, lawnmower, shoes, etc.

No: wash down with a hose outside: you do not want any acid soaked rags around. Put back in the car when it is dry.

Every 10C rise in temperature approximately doubles the rate of a chemical reaction: thus boiling H2SO4 *BP337C* is unspeakably dangerous!

[Really we should be leaving all this to the real Wiki people:
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*
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MSDS] > > Purchase
Reply to
Spamlet

A bit late now, but I'm interested to read this. I once had a Chevette catch fire when a tissue got caught on the exhaust manifold. Unfortunately the first thing to burn through was the bonnet catch so even when I had begged a fire extinguisher from a nearby shop I still couldn't get at the fire, until it dawned on me I could spray it from below. Brave, but stupid, with melted battery and rubber dripping down all over the place. It did take a long time for my hands to heal, perhaps, now I know why. At the time I had visions of the big explosions one sees on TV, so was in a bit of a hurry to put it out. The fire brigade arrived just as I'd finished putting it out, but wrenched up the bonnet and gave it a good squirt anyway.

S

Is it? The real Wiki:

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reports on inconclusive tests of people drinking loads of Coke and Pepsi, which is not quite in the danger league. However, conc phosphoric acid in its various forms is still not to be toyed with.

We really should give the 'real Wiki' link for each acid: they are very good. S

Reply to
Spamlet

Incidentally, while wee are on the subject: I have got an interesting paper on the uses of urine somewhere...

S
Reply to
Spamlet

lol, could make a novel wiki article. Or would that be taking the wiki? Why not start a thread for it,cleaning is just about within diy.

NT

Reply to
Tabby

Cleaning is well within d-i-y, but only in the sense that it's useful to know that kettle descaler can be used for things other than kettles. In depth detail as to how you might kill yourself with hydrofluoric serves no purpose IMO.

Reply to
stuart noble

Sorry, should have snipped a bit more!

I meant sulphuric.

Reply to
The Medway Handyman

Sorry, should have snipped a bit more!

I meant sulphuric.

Reply to
The Medway Handyman

Some of the confusion comes from the way we tend to label acids as 'corrosive: causes burns', and alkalis as 'caustic: causes burns'...

The negative log gets you a nice round figure for one particular ion instead of having to quote for H+ *&* OH-, but it is by no means an easy concept to explain.

Let's have a go...

You could just say that: "Extremes of acidity or alkalinity are highly reactive and can cause serious burns": but how to indicate just how reactive they are? A useful way to make a scale of reactivity is to imagine a series of concentrations where each step is ten times stronger than the last. Such is the pH scale.

[You can think, similarly when you are heating solutions: a 10C rise in temperature approximately doubles the rate of reaction.]

The 'H' in pH stands for hydrogen ion (H+). Positive ions like H+, are reactive atoms from which an electron has been removed: this is what *makes* them reactive in solution: they 'want' to get their electrons back, from other substances, to become neutral again. The more concentrated these ions are, the more strongly they will be able to attract electrons back and the more vigorous the reaction will be. The pH scale *only* deals with the concentration of the H+ ion: the concentration of the chemicals that will produce a solution of a particular pH varies with the chemical, so speaking of Strong Acid, is not the same as speaking of concentrated acid.

When the chemist says Strong acid, he means that it is a substance that forms these H+ ions easily *in water*. Water is what is termed a 'polar' solvent, because its molecules are arranged such that the O atom has a bigger attraction for the molecule's electrons than the two H atoms. This makes each molecule like a little magnet with slightly positive poles at the H end, and slightly negative poles at the O end. This is what makes water such a good solvent: its slightly charged molecules can surround ions like H+ and keep them free in solution to make them available for chemical reactions.

Each step in the pH scale from 7 down to 1 indicates a tenfold increase in strength in the *acid* direction, with pH1 being ten million times as H+ ion concentrated as pH7. Each step in the scale from pH7 up to pH14 indicates a tenfold increase in the *alkaline* direction, with pH14 being ten million times stronger than pH7. [This may seem an awkward way of looking at things, but it saves having to have separate scales for H+ and its counterpart, OH-. For the DIYer it might have been more intuitive to call it a pOH scale, so then we would have a scale where the numbers went up with the concentration instead of down, but we are stuck with it I'm afraid!]

The concentration of the H+ ion is not directly related to the concentration of the acid that produces it. Weak acids with a capital W do not so readily form H+ ions in water, and so can still have a moderate pH even when quite concentrated. Solubility is also important: HCl is a gas that won't dissolve in water to give highly concentrated solutions, whereas H2SO4 will concentrate almost to treacle like consistency, and is so attracted to water that the pure acid is only found in space. In concentrated form it is extremely dangerous, but, because it is so lacking in the water the H+ ion needs to become mobilised, the term pH is no longer much use to indicate just how dangerous it is. Remember, the pH only refers to the concentration of H+ : not of the acid itself.

We normally make solutions of chemicals with water as the solvent. Everyone knows that the 'formula' of water is H2O, but if you want to imagine a bit more about pH, it is better to think of it as 'HOH'. This is a neutral structure in which the electrons are shared between the three atoms, though, as above, the O attracts them more strongly than the H, so it could be said to behave like a little magnet. Despite its general stability, in a volume of water containing billions of these molecules, a small percentage break up into ions: the H+ that we have already seen, has its counterpart in the negative OH- ion. This ion still has the electron attached which has been 'lost' by H to make the H+ ion. So, in the case of the OH- ion, it wants to 'give away' or share its extra electron to become neutral again, and, as in the case of H+, the more concentrated OH- becomes, the more strongly will be reactions, as it seeks to share its extra electron to become neutral again. The fact that water is thus slightly ionised itself allows us to quote a pH for it even when nothing is dissolved in it.

As, in pure water, there are always the same number of H+ ions as OH- ions, it is neutral over all, and should have a pH of 7 but will often be a little lower in practice. Once acids or alkalis are dispersed in the water, the pH changes dramatically as extra H+ or OH- ions are mobilised. Acids are, thus chemicals which break up in water to greatly increase the proportion of H+ ions relative to OH- ions. Alkalis have the opposite effect: increasing the concentration of OH- relative to H+.

Hope this gives a reasonable insight without having to go into the maths. Wikipedia proper will give the full picture, for the mathematically inclined:

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Reply to
Spamlet

Yes.

Reply to
Mark

I have a need to buy a chainsaw for general garden maintenace, small tree felling etc.

I fancy a stihl but which model ?

new or second hand ?

To start with it will be used for 10 -20 hours therafter not a lot

I have a couple of acres

any one care to make a recommendation

help appreciated.

Chris

Reply to
christopher

as big as it needs to be for the bole size you want to cut.

I prefer a little one. Easier to handle, but sometimes its not man enough.

Reply to
The Natural Philosopher

I bought a Stihl MS250 with a 16" bar for 'garden maintenance'.

It probably cost about what I would have had to pay to get some one to do the work that I initially bought it for.

Reply to
Michael Chare

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only sell Husqvarna, but they respect "the German brand" (i.e. Stihl). It's worth reading the "Advice & Info" stuff.

Reply to
Dave Osborne

Stihl are indipensable if you have a large amount of land and use them for long periods. They are well designed and built. If you want one, get one that's an appropriate size for the job in hand. Too large means that it's unwieldy and expensive and potentially dangerous. Too small is also dangerous, that is don't attempt to cut anything that has a diameter greater (or even close to) the length of your saw. If the tip of the saw catches it can kick back and that's not a pleasant experience.

The Stihl MS170 is a really good choice for garden work. It has a 12in blade and that's sufficient for most uses around a garden. It's *not* suitable for felling large trees. About 9-10 inches is the maximum diameter I would tackle with one.

If your use is occasional then I wouldn't sniff at the Husqvarna range. I have one that has been used for pruning olive trees for the last ten years - no problems with it so far. It cost just £90 so it's fine for something that's used just once a year (although it's then used solidly for a month and used to prune > 85 trees and to chop the branches for firewood.)

Reply to
Steve Firth

Bought a 236e from them last year OK outfit to deal with ..

Recommended...

Reply to
tony sayer

Why is this appearing under Wiki Acid?

S
Reply to
Spamlet

Because this line appears in the headers:

References: which is the message id for the first message in the Wiki:Acid thread.

Which in turn means that the OP effectively created a new thread by replying to the Wiki:Acid thread and then changing the subject line and not quoting anything previous. Either that or he *did* start a proper new thread but his posting software got its knickers in a twist.

Reply to
Dave Osborne

Amazing that people are still finding and replying to it!

S
Reply to
Spamlet

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