Oxalic Acid

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neil
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Post by neil » Sat Oct 09, 2004 9:17 pm

I've got some really nasty waterstains on the sole boards of the Tideway, I was wondering about using Oxalic Acid to remove them.

Now, I've never used Oxalic acid before so I need some advice if its a good idea and what how to use it safely (also need to know where to buy it)

I know it will remove the staining as Kevin used it to great effect on the Dragon mast but will it noticiably bleach the mahogany surrounding the water staining?

regards

Neil
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jonathanR
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Post by jonathanR » Sun Oct 10, 2004 9:17 pm

I used this stuff to get rid of iron stains to my mahogany N12.

I got it in crystal form and made up saturated solutions and painted it on to the affected timber. When the stains were gone I neutralised it or dissolved it away with fresh clean water.

I had a problem getting it, though. Chemists seemed to think I was mass poisoner. I got it from a chemist who knew me professionally and thought I was sound chap.

It was a bit hit and miss but wonder if acetic acid from a DIY wine shop or white vinegar would have done just as well. I hear some people use brown sauce as an acid cleaner and its apparently great to use on tarnished silver! What it does to ones' insides when liberally applied to the ubiquitous bacon sarny makes me wince.

Oh by the way do not test its strength using the tongue test - take my word for it, its strong.


Regards

Jonathan

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Ed
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Post by Ed » Sun Oct 10, 2004 11:58 pm

Gosh.....well now is where we want a searchable archive for the old forum.....as this subject has come up at least twice before....normally with tons and tons of dire warnings about the very real dangers of working with a pretty formidable poison such as this.

For what it is worth....I have never had much luck with Oxalic Acid....but I know that others have. Problem for me was trying to keep the bleaching action just on the stained wood. If you are not careful, you can end up faded dark bits.....and even more faded light bits....and well it just all looks like a mess.

I have some limited sucsess with some of the much less dangerous wood cleaners.....the Neutrol one....and another sold at boat jumbles.....but even they are pretty wicked stuff....and you still have the problems of what do you bleach and what not.....and if not, how do you prevent it going where you don't want it.

But I remember from last time that there are those that reckon its brill.

cheers

eib
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Rupert
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Post by Rupert » Mon Oct 11, 2004 8:59 am

Does Dec Rens still exist? It was a ready made oxalic acid cleaner. Seem to remember it having a limited good effect on stains, and it didn't do much bad to the surrounding area. There were some jobs (on ply I seem to remember, but it is 13 years ago) where it did nothing but get the wood wet.
Rupert

chris
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Post by chris » Mon Oct 11, 2004 9:46 am

http://www.mailspeedmarine.com
sell ''deks net - trol'' which claims to clean weathering and restore orininal colour, says it's non bleaching. I've not used it but have used Dek rens before. - don't know if it's the same. I have got some oxalic if you can't get hold of any. I find it does work - mostly. and have used it restoring antique instruments without disaster. If it does bleach the wood colour out, which it shouldn't, oil should bring that back.
Rustins do an actual wood bleach in two parts. That WILL lighten the timber colour but should lighten any black satin. (they have a website).
Not sure that any of these chemicals do the timber much good though. Certainly needs neutralising.
Eco friendly alternative... leave the marks there and call it a 'Patina'. In the antique world if you remove the patina you chop xx,xxx pounds off the value!

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Post by Garry R » Mon Oct 11, 2004 1:59 pm

There is stuff called Stains away which is for removing rust on textiles - excellent for rust stains on sails - HOWEVER - when you read the ingredients it turns out to be 15% oxalic acid and being in the chemistry business there is no problem with me getting the dry stuff and make it up myself. As for the hazards written on the jar - a bit of common sense and rubber gloves required and if necessary wear goggles or sunspecs to avoid splashes. Label the jar well if you are going to keep it or flush it down the lavatory when you are finished - loads of dilution is all that is required for most of the acids. Rhubarb leaves are full of oxalic acid and we don't get a health warning on those!! Safety Instructions while necessary for first time users are usually over the top and also boil down to common sense in my view are designed for the complete idiots - most of those who sail will have been drowned already!!

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Post by alan williams » Mon Oct 11, 2004 4:33 pm

Wrote about Oxalic Acid before. Gary I also work in a Lab. Warnings are not to be taken lightly. Oxalic Acid is a poison if taken orally and results in a very painful death. Heat breaks it down which is why uncooked rhubarb is poisonous. Enough said. Chemical is a listed poison hence reason why chemists careful about selling it. Neil contact me if you want some, carry it in the lab. I will give you all the H&S details. Gary I'm also a Qualified in Laboratory and Industrial H&S.

Cheers Al Williams

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Post by Garry R » Mon Oct 11, 2004 4:42 pm

I agree completely Al but provided that the sensible precautions are taken (as suggested) there is nothing to be frightened about. I am on our H & S Committee here too but if you were concerned to the point of paranoia on every warning you wouldn't get out of bed in the morning!!! Motto - read the instructions, don't be cavalier and be safe.

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neil
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Post by neil » Mon Oct 11, 2004 6:50 pm

OK, thanks for the replies.

I'll take you up on your offer Al - and I promise not to eat it.
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Ed
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Post by Ed » Mon Oct 11, 2004 9:13 pm

Ah.....yes.....now I remember the thread last time....

eib
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stu
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Post by stu » Mon Oct 11, 2004 10:10 pm

I know it's not a perfect system as you can only search the titles of each thread but if you want to try and find a topic on the old forum you could always use the Edit - Find (on this page) function in IE. I used it to find an old thread about removing sail numbers and the residual glue. Really must investigate a proper archive of the old forum and make it searchable too ? :D
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