Rinsing off Oxalic Acid

Highndry said:
What precautions do I need to take regarding the Oxalic/wallpaper paste mix as I rinse it off my topsides? Is it a case of as long as it's diluted enough, it's safe?
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Oxalic acid is present naturally in some plants (Rhubarb leaves are full of it - that's why they are poisonous). So I don't think the Oxalic acid presents any environmental problems. The mould killer in the wallpaper paste might be a different matter, though.

I used Oxalic acid solution (no wallpaper paste) on woodwork from my boat, and just rinsed it off in the garden. The lawn where I did it hasn't taken any harm!

Of course, you need to keep it off yourself.
 
AntarcticPilot said:
Oxalic acid is present naturally in some plants (Rhubarb leaves are full of it - that's why they are poisonous). So I don't think the Oxalic acid presents any environmental problems. The mould killer in the wallpaper paste might be a different matter, though.

I used Oxalic acid solution (no wallpaper paste) on woodwork from my boat, and just rinsed it off in the garden. The lawn where I did it hasn't taken any harm!

Of course, you need to keep it off yourself.
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I'll maybe do it without the paste then.

Thanks for the help.
 
Highndry said:
I'll maybe do it without the paste then.

Thanks for the help.
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the paste is to stop it from running off vertical surfaces before it has had any effect.
presumably AntartcticPilot could apply it flat to his woodwork if he was at liberty to rinse it in the garden, so he wouldn't have needed it.
 
chewi said:
the paste is to stop it from running off vertical surfaces before it has had any effect.
presumably AntartcticPilot could apply it flat to his woodwork if he was at liberty to rinse it in the garden, so he wouldn't have needed it.
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It had been taken back to bare wood, so the solution was absorbed into the surface. I was removing dark stains from wood, for which Oxalic acid is brilliant stuff. I did have some of it horizontal, but it wan't necessary; the solution soaked into the wood.

Just a thought - you could thicken the mixture with flour, which would avoid the fungicidal nasties in wallpaper paste.
 
I'm doing the GRP 'white' topsides of my Medina so most of it is a horizontal surface. The vertical surfaces - hull - are being polished out by a chap from the local bodyshop so I can probably get away without the paste.
 
Be Very Wary !

When preparing to paint my grp boats' topsides I read the 709 paint instructions ' wash down with water ' so foolishly thought it must be mild stuff.

Then I washed off the boat with a hose, the stuff running down my bare arms.

Within a few minutes my arms were burning badly, I rushed to the club loo and washed them under the tap but it didn't seem to help, it felt like it was burnining straight through to the bone, I was in big trouble !

I was very lucky that Pat, an ex Hospital Matron, was handy and knew what to do with Alkaline burns.

I had to fill a basin and immerse my fore-arms for 40 minutes, that did the trick.

I hate to think of the stuff getting in my eyes...

Be very careful with Oxalic Acid.

Andy
 
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Oxalic acid is not an alkali Seajet - its what it says, an acid. It must be that you used a strong solution and had sensitive skin. I have washed off the topsides of my boat with a sponge and a weak oxalic acid solution without gloves - not a clever approach or one I would recommend but I had forgotten the rubber gloves. When using anything like that its sense to wear goggles.
 
Bosun,

whatever it is, keep clear of it ! The advice about keeping burns immersed ( 40 minutes ) seems good, though I'd imagine only goggles can save eyes.

Andy
 
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Seajet said:
Be Very Wary !

SNIP

Be very careful with Oxalic Acid.

Andy
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Yes. Although I think it is environmentally OK, it is nasty stuff. You can get severe skin irritation and/or burns and it is pretty toxic stuff, with about half a gram being the lowest recorded lethal dose. It can be absorbed through the skin, so skin contact is not just painful, but also can poison you. Death is from kidney failure, which probably isn't a good way to go either.
 
I've never used rubber gloves for oxalic acid and have never had any adverse effects. I think really, unless you are a right mucky bugger you are unlikely to get enough on you, of sufficient concentration to do yourself any harm. I usually use it by mixing it into hot water until it stops dissolving and then slap it on with a paint brush. I only use it for getting the stains out of wood though. I've no experience with trying to clean gelcoat with it.
 
AntarcticPilot said:
Yes. Although I think it is environmentally OK, it is nasty stuff. You can get severe skin irritation and/or burns and it is pretty toxic stuff, with about half a gram being the lowest recorded lethal dose. It can be absorbed through the skin, so skin contact is not just painful, but also can poison you. Death is from kidney failure, which probably isn't a good way to go either.
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600mg /kg ! That is equivalent to 50 g for a typical 13 stone yachtie
 
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Woodlouse said:
I've never used rubber gloves for oxalic acid and have never had any adverse effects. I think really, unless you are a right mucky bugger you are unlikely to get enough on you, of sufficient concentration to do yourself any harm. I usually use it by mixing it into hot water until it stops dissolving and then slap it on with a paint brush. I only use it for getting the stains out of wood though. I've no experience with trying to clean gelcoat with it.
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I think Woodlouse must use a very weak mixture, but in any form it's best not to mess around with the stuff, bad news for breathing it in or being burnt by it - also if using it warn any passers by and don't let it spray on nearby boats, let alone people or their pets.
 
Reactions to Oxalic Acid

Woodlouse said:
I've never used rubber gloves for oxalic acid and have never had any adverse effects. I think really, unless you are a right mucky bugger you are unlikely to get enough on you, of sufficient concentration to do yourself any harm. I usually use it by mixing it into hot water until it stops dissolving and then slap it on with a paint brush. I only use it for getting the stains out of wood though. I've no experience with trying to clean gelcoat with it.
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It must obviously be that some peoples skin reacts differently to different acids,etc. I have used strongest oxalic solutions for years, always wear vinyl gloves, seriously avoid getting it near mouth. But have had this stuff on my arms and hands a few times with no affect. I use it carefully and wash off hands at end of job. I treat it with respect but never had a reaction.
 
Seashoreman said:
It must obviously be that some peoples skin reacts differently to different acids,etc. I have used strongest oxalic solutions for years, always wear vinyl gloves, seriously avoid getting it near mouth. But have had this stuff on my arms and hands a few times with no affect. I use it carefully and wash off hands at end of job. I treat it with respect but never had a reaction.
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+1
Mixed a cupful of saturated solution yesterday to treat some rust stains on deck, found I'd forgotten to bring gloves or a paintbrush, put it on with a bit of rag in hand, hosed hand off a few minutes later. Not dead yet. I usually wear gloves, but have spilled/splashed it on skin before. If it is not washed off fairly promptly I have had mild stinging on bare arms - skin there softer than my hands.
 
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