richardh10
Active member
When you have cleaned off the oxalic acid that you have used on the deck, does the residue that is washed into the sea cause any damage?
Thanks
Thanks
Oxalic acid
- Thread starter richardh10
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Fimacca
Active member
I would have thought so !
Tim Good
Well-known member
I don’t know the answer but it is an organic compound found in citrus, spinach and others. It’s not a synthetic long tailed polymer. But clearly the stuff we buy is high concentrated.
A google search shows a statement from the US National Organics Board stating:
“Since oxalic acid is naturally occurring in the environment as well as in honey, and its use has little to no negative environmental impact, its use is not considered damaging to the ecosystem”
A google search shows a statement from the US National Organics Board stating:
“Since oxalic acid is naturally occurring in the environment as well as in honey, and its use has little to no negative environmental impact, its use is not considered damaging to the ecosystem”
awol
Well-known member
Why are you using oxalic acid on your decks - Boracol or Patio Magic are better at removing algae. Rust stains would be an excuse, I suppose.
geem
Well-known member
Sandy
Well-known member
It is a natural compound and can be found in rhubarb.
arcot
Member
GHA
Well-known member
from chatgpt, often a better place to ask than in here ( or in addition to) ...
"how harmful is oxalic acid if wash into the sea
Oxalic acid is a naturally occurring organic compound found in many plants and vegetables. In small amounts, it is not harmful to humans or the environment. However, if a significant amount of oxalic acid is washed into the sea, it can be harmful to marine life.
Oxalic acid is a chelating agent, which means it binds to minerals and metals in the water. This can lead to a reduction in the availability of essential nutrients for marine organisms, which can affect their growth and survival.
In addition, high concentrations of oxalic acid can lower the pH of seawater, which can be harmful to marine organisms that are sensitive to changes in pH. This can disrupt the balance of marine ecosystems and lead to the decline of certain species.
Overall, while small amounts of oxalic acid are not likely to cause significant harm to the environment, large amounts can have negative impacts on marine life and should be avoided if possible."
"how harmful is oxalic acid if wash into the sea
Oxalic acid is a naturally occurring organic compound found in many plants and vegetables. In small amounts, it is not harmful to humans or the environment. However, if a significant amount of oxalic acid is washed into the sea, it can be harmful to marine life.
Oxalic acid is a chelating agent, which means it binds to minerals and metals in the water. This can lead to a reduction in the availability of essential nutrients for marine organisms, which can affect their growth and survival.
In addition, high concentrations of oxalic acid can lower the pH of seawater, which can be harmful to marine organisms that are sensitive to changes in pH. This can disrupt the balance of marine ecosystems and lead to the decline of certain species.
Overall, while small amounts of oxalic acid are not likely to cause significant harm to the environment, large amounts can have negative impacts on marine life and should be avoided if possible."
Ian_Rob
Well-known member
Does this really explain anything? Torrential rainfall lowers the acidity. Torrential rainfall off an acidic moor raises it. Torrential rainfall off an area of limestone lowers it? What conceivable dosage of oxalic acid would be required to affect the pH to the point where it negatively impacts on marine life?
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GHA
Well-known member
far more than the other replies so far
Asking again -
What conceivable dosage of oxalic acid would be required to affect the pH to the point where it negatively impacts on marine life?
Oxalic acid is a weak organic acid with a pKa of 1.3 and is found naturally in many foods. It is also used in various industrial applications such as cleaning agents, metal polishing, and as a reducing agent in photography.
The amount of oxalic acid required to negatively impact marine life depends on various factors such as the pH of the water, the buffering capacity of the water, the species of marine life present, and the duration of exposure.
In general, the pH of seawater ranges from 7.5 to 8.4, and marine life has adapted to survive in this range. However, if the pH drops significantly outside of this range, it can have detrimental effects on marine life. For example, if the pH drops below 7.0, it can cause physiological stress and even death in some marine organisms.
The amount of oxalic acid required to lower the pH of seawater to levels harmful to marine life would depend on the amount of buffering capacity in the water. Buffering capacity refers to the ability of the water to resist changes in pH when an acid or base is added. Seawater has a high buffering capacity, which means that it can resist changes in pH even when an acid is added.
In general, adding a small amount of oxalic acid to seawater would not have a significant effect on pH or marine life. However, if a large amount of oxalic acid is added, it could potentially lower the pH to levels harmful to marine life.
It is important to note that intentionally adding oxalic acid to seawater, or any other substance for that matter, is not recommended as it can have negative impacts on the marine ecosystem.
https://chat.openai.com/chat
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Stemar
Well-known member
I could see a LOT (several kilos) of oxalic acid doing harm in a locked marina, but most places in the UK, the management changes the water twice a day so unless everybody in the area is going mad with it, it'll be diluted to vanishing point before it can do any damage
coopec
N/A
Has your deck never been varnished/treated before?
I use Sikkens Cetol on my timber work. I was going to use Oxalic acid but since it was cetolled 2+ years ago I just followed their directions.
1. Please provide step by step instructions on how to clean and revive outdoor decking. Where should you start? How should you prep (ie sweep and remove dirt, cobwebs and leaves)?
1. Sweep away dust, cobwebs, leaves and bird droppings.
2. Using a hard-bristle brush, scrub the deck with a mild detergent solution to remove embedded dirt, grease and grime. Rinse with fresh water.
3. Once the deck is completely dry, apply two to three coats of the timber coating last used on the deck
I use Sikkens Cetol on my timber work. I was going to use Oxalic acid but since it was cetolled 2+ years ago I just followed their directions.
1. Please provide step by step instructions on how to clean and revive outdoor decking. Where should you start? How should you prep (ie sweep and remove dirt, cobwebs and leaves)?
1. Sweep away dust, cobwebs, leaves and bird droppings.
2. Using a hard-bristle brush, scrub the deck with a mild detergent solution to remove embedded dirt, grease and grime. Rinse with fresh water.
3. Once the deck is completely dry, apply two to three coats of the timber coating last used on the deck
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thinwater
Well-known member
A. Slightly different function, as you noted.
b. Patio Magic is definitely harmful to the marine environment, which is of interest to the OP. Please read the SDS and use in strict moderation.
Toxicity The quaternary ammonium component is very toxic to aquatic
organisms. After testing in fish, Daphnia, and algae, the lowest
effect was for Daphnia, EC50 0.0058 mg/l. No information is
available on other ingredients. [note that the only active ingredient is 10% BAC and the other ingredient is water]
c. Borate is present in seawater, and unless you go ape, a small amount will do little harm. Borocol is glycol and borate.
coopec
N/A
If you haven't got tannin stains would you still use oxalic acid?
https://forums.whirlpool.net.au/archive/2774469
https://forums.whirlpool.net.au/archive/2774469
Neeves
Well-known member
I find a contradiction here.
1. We all use, or nearly all use, an antifouling to keep our hulls clean for a season (6 months?), a year. We may 'in water' hand scrub, wash, with a sponge to perk up the effect.
2. Some use Coppercoat that is sufficiently toxic that the hulls to which the coating is applied stays clean. Perking up demands abrading to expose more copper - in water - what happens to the waste copper?
Obviously there is no concern of the environmental impact of said coatings to the ecosystem adjacent to your hull. Well there is a concern - but no sensible alternative.
3. There is a concern, this thread, about a 'small' amount, I'm assuming negligible, of oxalic acid to the ecosystem, seawater, near our yacht.
You may not use AF - then your hull is so fouled your diesel consumption increases factorially. Maybe no damage to the hull ecosystem but definitely an impact on atmospheric pollution.
We have a long way to go before there is an antifouling system that has no negative impact on any ecosystem.
We could all dry sail.
Silicone coatings - simply look at the safety gear used when application on a commercial scale - if silicone is so safe why the safety kit? It is suggested some components of silicone coatings may be carcinogens.
Just don't be profligate with the oxalic, spot use seems a good option.
Jonathan
1. We all use, or nearly all use, an antifouling to keep our hulls clean for a season (6 months?), a year. We may 'in water' hand scrub, wash, with a sponge to perk up the effect.
2. Some use Coppercoat that is sufficiently toxic that the hulls to which the coating is applied stays clean. Perking up demands abrading to expose more copper - in water - what happens to the waste copper?
Obviously there is no concern of the environmental impact of said coatings to the ecosystem adjacent to your hull. Well there is a concern - but no sensible alternative.
3. There is a concern, this thread, about a 'small' amount, I'm assuming negligible, of oxalic acid to the ecosystem, seawater, near our yacht.
You may not use AF - then your hull is so fouled your diesel consumption increases factorially. Maybe no damage to the hull ecosystem but definitely an impact on atmospheric pollution.
We have a long way to go before there is an antifouling system that has no negative impact on any ecosystem.
We could all dry sail.
Silicone coatings - simply look at the safety gear used when application on a commercial scale - if silicone is so safe why the safety kit? It is suggested some components of silicone coatings may be carcinogens.
Just don't be profligate with the oxalic, spot use seems a good option.
Jonathan
AngusMcDoon
Well-known member
Yes. It removes rust marks and brown waterline discolouring that affects older GRP boats with light coloured gelcoat where the surface has become slightly porous through age. The OP doesn't say what his deck is made of, but the response on the thread you posted about tannins is relevant only to a particular problem of water ingress damage to wood, so not relevant to most common use of oxalic acid for cleaning purposes.
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AngusMcDoon
Well-known member
Maybe it's not a problem where you sail but in the UK older light coloured GRP boats commonly get brown staining over much of the topsides that oxalic acid removes. It's particularly apparent on boats that sail in murky water like the east coast rivers or the Bristol Channel.
Irish Rover
Well-known member
Very timely thread for me. I've never used oxalic acid for cleaning but my deck needs a thorough cleaning and has some rust stains. If I buy it in powder form how much should I put in a bucket of water and what precautions do I need to take to prevent injury to myself.
Ian_Rob
Well-known member
I use a 12% solution thickened with wall paper paste.
NOTE: That is 12 grams/100ml NOT per 1 litre as my original posting.
NOTE: That is 12 grams/100ml NOT per 1 litre as my original posting.
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Refueler
Well-known member
The proportions OA powder to medium hot water varies depending on who you ask and what YT video you watch.
I tried the low ratio but found it too weak ... 60gr / litre
Some sites say upping the amount of oxalic does not make it stronger .... sorry but I do not agree. I ended up with over 200gr to a litre to get rid of some stains .. but generally I would suggest 100gr to 1 litre of medium hot water.
I also add a small qty of Wallpaper paste to thicken the mix so it stays where you put it.
Safety : Gloves, safety glasses or better is a face shield. Old clothes that cover you well.
Tip : For anyone thinking to do any vertical or near vertical surface and using a long handled brush .... the problem here is the 'goop' tends to run down the handle and onto your gloves etc. Simple solution .... take an empty plastic drinks bottle and cut it so you have a funnel like item left. (The bottom part can be used for mixing stuff). Slide the bottle over the handle with screw top end towards your hands. Tape in place ..... it now provides a means to 'catch' the rundown into the bottle and not onto you.
