Phosphoric Acid Availablity?

[Metropolitan]

Another topic touched on the subject of flux for soldering brass. I don't get on with the silly little pill bottles of flux sold by model shops. They are expensive and far too small.

 

Is it possible to buy neatish phosphoric acid by the litre anywhere these days in order for me to make up my own flux in sufficient bulk to be able to slop the stuff on with abandon without breaking the bank?

 

None of my local chemists sell or can get hold of it anymore and the only source I've found on the web sells it only in 25 litre barrels!

[beast66606]

John,

 

google took < 1s to find

 

http://www.reagent.co.uk/chemicals/phosphoric-acid-lrg-1-7-sg.html

 

(for example)

 

Be careful with it, it's not the nicest of materials.

[bertiedog]

Although expensive in a branded bottle, a little phosphoric flux goes a long way. Larger wholesale chemists will supply Phosphoric acid, but minimum quantity will be an issue.

 

If you want you can try Citric acid, (lemon juice), the powder is widely available from Chemists, and brewers supplies, make up with warm distilled water till no more powder will dissolve, and this is the stock solution, dilute up to 50:50 for use. You can play about with dilution to suit your work.

 

The neat stock solution will clean brass, especially if warmed up slightly. It will also remove silver soldering flux from brass and clean copper.

 

You can also try a mix of acetic acid powder,(vinegar), (again powder to saturated solution, dilute 50:50), mixed one third with Citric acid, and to about 500ml add just a couple of drops of pure detergent (or Soft Soap BP), to act as a wetting agent.(Pure detergent is photographic wetting agent etc) Washing up liquid seems to work OK, just do not put too much in, just a couple of drops)

 

The advantage of these acids is that they are all food grade additives and are a bit safer than sulphuric acid etc., used as killed spirits,(like Bakers fluid), which is acid with zinc dissolved in it..... But handle with care anyway, with all acids make up with gloves, and eye protection, and mark bottles very clearly, and store with care away from children.

 

 

Stephen.

[chrisf]

Phosphoric acid may be found in cola - frightening thought - or in rust remover, Jenolite being one trade name.

 

Chris

[bertiedog]

Try Ebay, Phosphoric acid is freely available in smaller packs, from 100ml up wards.

Use phosphoric Acid as the search, for instance :-

http://shop.ebay.co....-All-Categories

 

Don't use the PH adjusting solutions for hydroponics they may have other chemicals added.

[PhilH]

If you know anybody in the water supply industry in a lot of areas with households with lead pipes 75% solution is used in frighteningly large amounts to make the mild disinfectant mix known as tap water.

 

Obviously if you do get hold of this it has to be let down to around 18% to use as flu x.

[bertiedog]

Odd chemicals are often used with food, most varieties of Olives are inedible without treatment with Caustic Soda, (a lye bath), or other alkaline salt baths, and German Pretzel bread is bathed in Caustic Soda before baking to get the caramel brown crust.........

[craigwelsh]

What is the best container to store made up solutions in by the way as my original bottle from Fourtrack models (now sold by LondonRoadModels) @ 12% has dissolved the thread on its plastic lid where i've clearly leaked some on it... The jar itself is glass.

[Metropolitan]

John,

 

google took < 1s to find

 

http://www.reagent.c...lrg-1-7-sg.html

 

(for example)

 

Be careful with it, it's not the nicest of materials.

 

 

Thanks beast! Much appreciated. Ordered.

 

I've a notion to mix some with an medical aqueous cream. The sort of thing folk have for exema.

[Horsetan]

Phosphoric acid may be found in cola - frightening thought .....

 

Yes, my teeth bore the damage, which is why I have not drunk the stuff for over a decade.

[Pugsley]

I've a notion to mix some with an medical aqueous cream. The sort of thing folk have for exema.

Just make sure you don't get it mixed up with the Vaseline

[halfwit]

When I asked in my local chemist a few weeks back I was told that they used to be able to get it but the supplier charged about 20 quid for a courier to deliver making it uneconomical.

[Jol Wilkinson]

What is the best container to store made up solutions in by the way as my original bottle from Fourtrack models (now sold by LondonRoadModels) @ 12% has dissolved the thread on its plastic lid where i've clearly leaked some on it... The jar itself is glass.

 

Craig,

 

it is the other way around. LRM used to supply it to FourTrack, as well as to their own customers.

 

I've always had mine from LRM, and haven't had that problem with the bottles. I decant mine, a little at a time, into one of those small jam containers supplied in hotels at breakfast time, to provide a much more stable container. Even with their metal lids they last several years, and then only get replaced out because they have a bit of corrosion on the outside of the lid.

 

Jol

[shortliner]

Craig,

 

it is the other way around. LRM used to supply it to FourTrack, as well as to their own customers.

 

I've always had mine from LRM, and haven't had that problem with the bottles. I decant mine, a little at a time, into one of those small jam containers supplied in hotels at breakfast time, to provide a much more stable container. Even with their metal lids they last several years, and then only get replaced out because they have a bit of corrosion on the outside of the lid.

 

Jol

Those little jars of jam and mamalade are available in Morrisons - I use them for mustard!

[Jol Wilkinson]

Thanks beast! Much appreciated. Ordered.

 

 

Their order quantity should make about 36 pints at 12%. Keep you going for a couple of weeks

 

Did they recommend/suggest a suitable wetting agent. Purified water is also a good idea for diluting the acid. You could use the water produced by a de-humidifer if you have one.

[PhilH]

I work with the stuff and can confirm that it is nasty, indeed we have to wear full chemical suits, goggles, pvc gloves etc. And for once this is not H&S overkill so please be very careful when handling concentrated forms of it.

 

Safety data sheet

[298]

I get to use it in industrial quantities at work, i'm not sure how much it costs but at nearly £300 per 25 litres, I mush have got through about a hundred grand's worth...

[Metropolitan]

I work with the stuff and can confirm that it is nasty, indeed we have to wear full chemical suits, goggles, pvc gloves etc. And for once this is not H&S overkill so please be very careful when handling concentrated forms of it.

 

Safety data sheet

 

Hi Phil

 

In view of the fact that I'm 53, I smoke and I drink and generally do everything to excess; I think that a few fumes or burns from this acid is unlikely to do me much extra harm! I will not, therefore, be wearing a protective suit when soldering up my next brass kit!

[coachmann]

It is nasty stuff and there is a right way and wrong way of letting it down with water. I store a mixed solution in a brown bottle and pour a small amount of 'working' flux into an ink bottle. Ink bottles are designed to be less easily tipped up. Only trouble is the flux destroys the fabric of plastic/bakelite lids over a time.

[chrisf]

... there is a right way and wrong way of letting it down with water.

 

Indeed. Add acid to water, never water to acid. AW not WA as my late chemistry master explained. I think I've done well to remember that after 51 years!

 

Chris

[PhilH]

Hi Phil

 

In view of the fact that I'm 53, I smoke and I drink and generally do everything to excess; I think that a few fumes or burns from this acid is unlikely to do me much extra harm! I will not, therefore, be wearing a protective suit when soldering up my next brass kit!

 

Let's just hope that you don't get the undiluted stuff in your eyes either then - you won't be making any more kits if you do.

[Major Clanger]

 

I've a notion to mix some with an medical aqueous cream. The sort of thing folk have for exema.

 

So you're going to mix a concentrated acid with a cream of unknown composition.

 

DO YOU REALLY THINK THAT'S A GOOD IDEA??

 

I would hope that being a Chartered Chemist gives me licence to shout on this topic and save people from their (potential) own folly.

[Horsetan]

Someone better give the local undertaker a call. Just in case. Anyone want to open a book on Metropolitan qualifying for this year's Darwin Awards?

[Shamouti Ben Yafo]

Keep an eye wash bottle nearby, at least!

[Kenton]

So you're going to mix a concentrated acid with a cream of unknown composition.

 

DO YOU REALLY THINK THAT'S A GOOD IDEA??

 

I would hope that being a Chartered Chemist gives me licence to shout on this topic and save people from their (potential) own folly.

Perhaps being a "Chartered Chemist" (isn't that the one you pay a fee to use ?)

a better bit of advice would be to explain what the composition of "medical aqueous cream" actually is, what effect mixing phosphoric acid with it will actually have, and if the ultimate product would be of any use whatsoever as a representative flux gel suitable for soldering kits.

 

or does that require a pharmacy qualification?

 

Perhaps a more positive approach and with a little less OTT scaremongering - because I have a feeling that Metropolitan was seriously going to try this anyway, and not on an industrial scale with high volumes of concentrated phosphoric acid but more like on a test tube level and possibly with partially diluted acid.

 

BTW Aqueous Cream BP is a mixture (pbv) of White Soft Paraffin BP (15%) Liquid Paraffin BP (6%) Water (79%) Though some "medical" forms also contain small amounts of other constituents such as antibacterials or preservatives though typically < 0.1%.