Sulphamic Acid - Mix ratio and exposure

superheat6k

superheat6k

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My boat has Cummins engines where the raw water circulates the heat exchanger for fresh water cooling then onto the similar bur smaller gearbox cooler then injects into the exhaust. There is no seawater contact with the engine itself. The main heat exchangers have a considerable build up of hard scale along the lower tubes.

I also wish to thoroughly dose the loo outlet to dissolve any scale build up, although I am careful to always pump thoroughly to wash the piss and poo right through and out.

I have bought a tub of Sulphamic acid and wish to know how much I can mix with water to achieve a powerful, but non damaging dilution for both of these applications.

1 Should I mix it with hot water

2 How many tablespoons of the powder per litre of hot / cold water

3 How long can I leave the solution to soak for, e.g. hours / days and is sulphamic likely to attack any metals or rubber seals / hoses. I will remove the zinc anodes.

4 I appreciate this is an acid so gloves and goggles are necessary and that I must add acid powder to the water and not the other way around, but how lethal is Sulphamic compared with say Sulphuric.

Thanks
 
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Totally different acids. Sulphuric acid is extremely strong in concentrated form. Sulphamic acid is much weaker and is traditionally used for scale removal as it will dissolve carbonate build up but not attack the metals/ceramics used for water systems.

You should be able to Google for concentration but I would try about 20% by weight and see how well that attacks some scale that you can see. If it's effective at that concentration I would stick with it.

Richard
 
superheat6k said:
My boat has Cummins engines where the raw water circulates the heat exchanger for fresh water cooling then onto the similar bur smaller gearbox cooler then injects into the exhaust. There is no seawater contact with the engine itself. The main heat exchangers have a considerable build up of hard scale along the lower tubes.

I also wish to thoroughly dose the loo outlet to dissolve any scale build up, although I am careful to always pump thoroughly to wash the piss and poo right through and out.

I have bought a tub of Sulphamic acid and wish to know how much I can mix with water to achieve a powerful, but non damaging dilution for both of these applications.

1 Should I mix it with hot water

2 How many tablespoons of the powder per litre of hot / cold water

3 How long can I leave the solution to soak for, e.g. hours / days and is sulphuric likely to attack any metals or rubber seals / hoses. I will remove the zinc anodes.

4 I appreciate this is an acid so gloves and goggles are necessary and that I must add acid powder to the water and not the other way around, but how lethal is Sulphamic compared with say Sulphuric.

Thanks
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Sulfamic acid is a weak acid , although much stronger than the organic acids often found in domestic descalers. No comparison with sulfuric acid but I suggest you read a safety data sheet for the full info. http://www.sciencelab.com/msds.php?msdsId=9927286

It is moderately soluble in cold water (a little more than 20% at 20C) but I suggest you dissolve it in hot water and use it while still hot . I'd try around 10%. More for heavy scaling perhaps. Less for light scaling

See the instructions for using Fernox DS3, which is sulfamic acid. In fact if you use DS3 you will benefit from the fact that it contains a colour indicator which will tell you if the acid is all consumed before the scale is all removed.
http://www.fernox.com/files/Fernox/Content/PDF/English/DS3 IT1b leaflet.pdf

It should do the job in hours rather than days .... ( in minutes perhaps if you could keep it warm.)

It should be safe on all the materials in your cooling system, but probably wise to remove the anode, or simply fit a new one when you have finished.

No worries about adding acid to the water or vice versa. That's a vital precaution when diluting sulfuric acid and advisable with other strong acids.
 
RichardS said:
Totally different acids. Sulphuric acid is extremely strong in concentrated form.
Richard
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Sulfuric acid is a strong acid in aqueous solution. Technically when concentrated it is not an acid .
Note also the approved spelling of sulfur and its compounds.
 
VicS said:
Sulfamic acid is a weak acid , although much stronger than the organic acids often found in domestic descalers. No comparison with sulfuric acid but I suggest you read a safety data sheet for the full info. http://www.sciencelab.com/msds.php?msdsId=9927286

It is moderately soluble in cold water (a little more than 20% at 20C) but I suggest you dissolve it in hot water and use it while still hot . I'd try around 10%. More for heavy scaling perhaps. Less for light scaling

See the instructions for using Fernox DS3, which is sulfamic acid. In fact if you use DS3 you will benefit from the fact that it contains a colour indicator which will tell you if the acid is all consumed before the scale is all removed.
http://www.fernox.com/files/Fernox/Content/PDF/English/DS3 IT1b leaflet.pdf

It should do the job in hours rather than days .... ( in minutes perhaps if you could keep it warm.)

It should be safe on all the materials in your cooling system, but probably wise to remove the anode, or simply fit a new one when you have finished.

No worries about adding acid to the water or vice versa. That's a vital precaution when diluting sulfuric acid and advisable with other strong acids.
Click to expand...
Thanks - I was rather hoping you might reply as I know your answer would be thorough. Apologies for the "ph' rather than 'f' in sulfuric and sulfamic. (my spell checker isn't happy though !!!).
 
superheat6k said:
(my spell checker isn't happy though !!!).
Click to expand...

A lot of people aren't

I bet it took a bit over getting over to the non chemistry science staff in schools. The physicists still believe that earth, air , fire and water are the four elements that every thing is made up from.
 
aquaplane said:
Yes. We used to keep suphuric acid above 95% in steel barrels. There are no H+ ions about as there is not enough water to allow the acid to dissociate.
Click to expand...

Ah .... I was obviously a bit too obscure with the use of the roll-eyes thingy. :)

I should add that I am a qualified industrial chemist and had my own personal store of fuming sulphuric acid (98%-ish) at home for many years (as well as HCl, HNO3, NH3 etc) so the properties are well-known to me. :)

Richard
 
But, but - don't fysicists say that theirs is the only proper science and everything else is stamp collecting?
 
RichardS said:
Ah .... I was obviously a bit too obscure with the use of the roll-eyes thingy. :)

I should add that I am a qualified industrial chemist and had my own personal store of fuming sulphuric acid (98%-ish) at home for many years (as well as HCl, HNO3, NH3 etc) so the properties are well-known to me. :)

Richard
Click to expand...

I deduced from another topic that you were a qualified bodger and would normally therefore be found in your hut in the woods making chair legs on your pole lathe
 
nigelmercier said:
When did this come into use in the UK?

Is it to try and stop us making fun of Americans? We will see how they do in their national intelligence test in two weeks.
Click to expand...

FWIW, in additional to Vic's learned explanation, the OED accepts both sulphur and sulfur, whilst pointing out that the latter is correct in "chemistry and other technical uses".

That would be the same Americans who think that making the 'f' sound with the digraph 'ph' is just a little bit perverse when there's a perfectly good letter which will do the job just as well. Noah Webster may have been an unpleasant piece of work, but he had a point.

Incidentally, it was another famous American, Humfry Davy, who first named the metal 'aluminum'. Unccountably, there's a statue of him in Penzance, although his forename has been anglicized on the inscription.

I'll draw no comparisons with the recent UK intelligence test.
 
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I use it quite regularly, dissolve as much as you can in hot water - it works a treat on heat-exchangers - the crystalline form I use, is supposed to be put on neat and washed off.
It's yellow when potent, turns red when exhausted. Buy from any plumbers' merchant.
Saturate solution is about 20% by volume - for the engine heat exchanger I mix up a bucket-full, run it through, catching in another bucket and leaving it to stand 20' between runs. You really need 3 buckets, one @ the raw-water pump, one @ the exhaust and one being mixed.

http://www.fernox.com/files/Safetydatasheets/English/58223_DS-3_2kg_Eng.pdf
 
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