Just in case anyone can help, I think it's worth asking if anyone else
has experienced what iron sulphate can wreak on a wooden floor!

I was in the kitchen yesterday transferring the contents of a packet of
iron sulphate powder to an old biscuit tin (the tin's good for giving
the "powder" a good long shake and breaking down the lumps), but while
putting the cardboard box into the rubbish bin a few of grains fell out
of the lining of the packet and onto the floor.

I now realize I should have quickly sucked these up with a vacuum
cleaner. But unfortunately that's not what I did. I reached for a damp
cloth and wiped the grains up.

Several hours later I saw that there was a dark splodge of about 2 feet
square in the middle of the floor! Some of the grains must have
instantly dissolved in the dampness of the cloth, producing an acidic
solution which I then rubbed around the patch to clear up remaining
grains.

Went online and found that the powder that rhododendrons so adore, is
also used professionally to stain wooden floors a dark greyish shade!

The only remedies I've been able to find online have been:

- apply white vinegar, wait five minutes, rub, then rinse off

- apply lemon juice, wait five minutes, rub, then rinse off

- apply oxalic acid (!), wait, rub, and rinse

- and if these don't work, then resign yourself to removing the varnish
and sanding the wood.

Apparently iron sulphate will penetrate through varnish!


So far, I've applied white vinegar but there's been no miraculous
removal of the grey stains, unfortunately. Still to try the lemon
juice. Don't know whether it's worth purchasing some oxalic acid. May
just go for the misery of sanding and revarnishing.


Does anyone know of any other remedy for this problem - other than never
letting iron sulphate loose inside the house again. The only reason it
was indoors is that a whole packet can turns to a solid lump if kept in
an outdoor shed (in the damp).


Eddy.

On 25/07/2012 15:11, Eddy wrote:
Just in case anyone can help, I think it's worth asking if anyone else
has experienced what iron sulphate can wreak on a wooden floor!

I was in the kitchen yesterday transferring the contents of a packet of
iron sulphate powder to an old biscuit tin (the tin's good for giving
the "powder" a good long shake and breaking down the lumps), but while
putting the cardboard box into the rubbish bin a few of grains fell out
of the lining of the packet and onto the floor.

I now realize I should have quickly sucked these up with a vacuum
cleaner. But unfortunately that's not what I did. I reached for a damp
cloth and wiped the grains up.

Several hours later I saw that there was a dark splodge of about 2 feet
square in the middle of the floor! Some of the grains must have
instantly dissolved in the dampness of the cloth, producing an acidic
solution which I then rubbed around the patch to clear up remaining
grains.

Went online and found that the powder that rhododendrons so adore, is
also used professionally to stain wooden floors a dark greyish shade!

The only remedies I've been able to find online have been:

- apply white vinegar, wait five minutes, rub, then rinse off

Vinegar almost certainly will not hack it at all.

- apply lemon juice, wait five minutes, rub, then rinse off

Lemon juice or better citric acid might.
The fruit acid will with a bit of luck reduce the iron(III) tanin
complex to soluble iron(II) salt which you must then remove. You must
get the stuff mopped up once it fades and not spread it to adjacent
areas or you will have a bigger area affected.

The fruit acid make the complex pale but oxygen in the air will cause
any remaining iron in the wood to darken again later.

- apply oxalic acid (!), wait, rub, and rinse

Same only a much more aggressive fruit acid.
Try rhubarb leaves if you have any.

If you are out of luck you chase the stain deeper into the wood.

- and if these don't work, then resign yourself to removing the varnish
and sanding the wood.

Apparently iron sulphate will penetrate through varnish!

The iron binds with the tannins in the wood and the reaction is the
basis of blue-black iron oak gall ink of old.

http://en.wikipedia.org/wiki/Iron_gall_ink


So far, I've applied white vinegar but there's been no miraculous
removal of the grey stains, unfortunately. Still to try the lemon
juice. Don't know whether it's worth purchasing some oxalic acid. May
just go for the misery of sanding and revarnishing.

It may already have gone some way into the wood too.

Does anyone know of any other remedy for this problem - other than never
letting iron sulphate loose inside the house again. The only reason it
was indoors is that a whole packet can turns to a solid lump if kept in
an outdoor shed (in the damp).

Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

--
Regards,
Martin Brown

On 25/07/2012 15:37, Martin Brown wrote:
On 25/07/2012 15:11, Eddy wrote:
Just in case anyone can help, I think it's worth asking if anyone else
has experienced what iron sulphate can wreak on a wooden floor!

I was in the kitchen yesterday transferring the contents of a packet of
iron sulphate powder to an old biscuit tin (the tin's good for giving
the "powder" a good long shake and breaking down the lumps), but while
putting the cardboard box into the rubbish bin a few of grains fell out
of the lining of the packet and onto the floor.

I now realize I should have quickly sucked these up with a vacuum
cleaner. But unfortunately that's not what I did. I reached for a damp
cloth and wiped the grains up.

Several hours later I saw that there was a dark splodge of about 2 feet
square in the middle of the floor! Some of the grains must have
instantly dissolved in the dampness of the cloth, producing an acidic
solution which I then rubbed around the patch to clear up remaining
grains.

Went online and found that the powder that rhododendrons so adore, is
also used professionally to stain wooden floors a dark greyish shade!

The only remedies I've been able to find online have been:

- apply white vinegar, wait five minutes, rub, then rinse off

Vinegar almost certainly will not hack it at all.

- apply lemon juice, wait five minutes, rub, then rinse off

Lemon juice or better citric acid might.
The fruit acid will with a bit of luck reduce the iron(III) tanin
complex to soluble iron(II) salt which you must then remove. You must
get the stuff mopped up once it fades and not spread it to adjacent
areas or you will have a bigger area affected.

The fruit acid make the complex pale but oxygen in the air will cause
any remaining iron in the wood to darken again later.

- apply oxalic acid (!), wait, rub, and rinse

Same only a much more aggressive fruit acid.
Try rhubarb leaves if you have any.

If you are out of luck you chase the stain deeper into the wood.

- and if these don't work, then resign yourself to removing the varnish
and sanding the wood.

Apparently iron sulphate will penetrate through varnish!

The iron binds with the tannins in the wood and the reaction is the
basis of blue-black iron oak gall ink of old.

http://en.wikipedia.org/wiki/Iron_gall_ink


So far, I've applied white vinegar but there's been no miraculous
removal of the grey stains, unfortunately. Still to try the lemon
juice. Don't know whether it's worth purchasing some oxalic acid. May
just go for the misery of sanding and revarnishing.

It may already have gone some way into the wood too.

Does anyone know of any other remedy for this problem - other than never
letting iron sulphate loose inside the house again. The only reason it
was indoors is that a whole packet can turns to a solid lump if kept in
an outdoor shed (in the damp).

Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

I don't think there's any chemical reaction with softwoods (pine etc),
but hardwoods are a different matter.
If and when acid doesn't work, it can't hurt to try alkali. Try some
washing soda on a small patch, or even bicarbonate of soda

On 25/07/2012 15:57, stuart noble wrote:
On 25/07/2012 15:37, Martin Brown wrote:

Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

I don't think there's any chemical reaction with softwoods (pine etc),
but hardwoods are a different matter.

There is a lot less tannins in softwoods so they tolerate it much
better. But there will still be some rust orange ironstain with no
tannins although it may not be obvious on wood it marks grey concrete.

If and when acid doesn't work, it can't hurt to try alkali. Try some
washing soda on a small patch, or even bicarbonate of soda

No good. Iron carbonates are insoluble. The only chance is a reducing
agent with a soluble iron salt - most fruit acids will do.

--
Regards,
Martin Brown

On 25/07/2012 16:20, Martin Brown wrote:
On 25/07/2012 15:57, stuart noble wrote:
On 25/07/2012 15:37, Martin Brown wrote:

Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

I don't think there's any chemical reaction with softwoods (pine etc),
but hardwoods are a different matter.

There is a lot less tannins in softwoods so they tolerate it much
better. But there will still be some rust orange ironstain with no
tannins although it may not be obvious on wood it marks grey concrete.

If and when acid doesn't work, it can't hurt to try alkali. Try some
washing soda on a small patch, or even bicarbonate of soda

No good. Iron carbonates are insoluble. The only chance is a reducing
agent with a soluble iron salt - most fruit acids will do.


I'm sure you're right, but I have a distant memory from my wood
finishing days of alkali at least changing the colour to a more yellow hue.

On 25/07/2012 16:46, stuart noble wrote:
On 25/07/2012 16:20, Martin Brown wrote:
On 25/07/2012 15:57, stuart noble wrote:
On 25/07/2012 15:37, Martin Brown wrote:

Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

I don't think there's any chemical reaction with softwoods (pine etc),
but hardwoods are a different matter.

There is a lot less tannins in softwoods so they tolerate it much
better. But there will still be some rust orange ironstain with no
tannins although it may not be obvious on wood it marks grey concrete.

If and when acid doesn't work, it can't hurt to try alkali. Try some
washing soda on a small patch, or even bicarbonate of soda

No good. Iron carbonates are insoluble. The only chance is a reducing
agent with a soluble iron salt - most fruit acids will do.

I'm sure you're right, but I have a distant memory from my wood
finishing days of alkali at least changing the colour to a more yellow hue.

Actually that rings a vague distant bell, but I think that for it to
work the alkali has to be pure household ammonia solution.

--
Regards,
Martin Brown

On Wednesday, 25 July 2012 15:37:35 UTC+1, Martin Brown wrote:
Lawn sand will also wreck concrete paths the same way with iron stains.
There should be a warning on the side of the packet about spills.

Many years ago I worked in an old fashioned seed/garden shop where we mixed our own lawn sand - after those sessions our teeth would be black for many days.

Rod

"Martin Brown" wrote in message
...
On 25/07/2012 16:46, stuart noble wrote:
On 25/07/2012 16:20, Martin Brown wrote:
On 25/07/2012 15:57, stuart noble wrote:
On 25/07/2012 15:37, Martin Brown wrote:

Lawn sand will also wreck concrete paths the same way with iron
stains.
There should be a warning on the side of the packet about spills.

I don't think there's any chemical reaction with softwoods (pine etc),
but hardwoods are a different matter.

There is a lot less tannins in softwoods so they tolerate it much
better. But there will still be some rust orange ironstain with no
tannins although it may not be obvious on wood it marks grey concrete.

If and when acid doesn't work, it can't hurt to try alkali. Try some
washing soda on a small patch, or even bicarbonate of soda

No good. Iron carbonates are insoluble. The only chance is a reducing
agent with a soluble iron salt - most fruit acids will do.

I'm sure you're right, but I have a distant memory from my wood
finishing days of alkali at least changing the colour to a more yellow
hue.

Actually that rings a vague distant bell, but I think that for it to work
the alkali has to be pure household ammonia solution.

Pee on the floor?
Pete C

Pete C wrote:
Pee on the floor?

Human urine? Are you serious? If you are, I'd definitely try it.

Chris Hogg, the accidental staining is against the grain, and across
several planks, rather than with the planks, so one would have to
blacken the whole floor to hide the streaks. Anyway, we want our nice
oak floor back!

Martin Brown, thanks for the warning to mop up well after using lemon
juice. Will try the juice tomorrow. Thanks for the rhubarb leaves tip.

Yes, there should be a clear warning on the sides of packs of iron
sulphate.

Thanks people.

Eddy.

On 25/07/2012 22:00, Eddy wrote:
Pete C wrote:
Pee on the floor?

Human urine? Are you serious? If you are, I'd definitely try it.

Chris Hogg, the accidental staining is against the grain, and across
several planks, rather than with the planks, so one would have to
blacken the whole floor to hide the streaks. Anyway, we want our nice
oak floor back!

Martin Brown, thanks for the warning to mop up well after using lemon
juice. Will try the juice tomorrow. Thanks for the rhubarb leaves tip.

ON second thoughts try the rhubarb leaves on a spare piece of
sacrificial scrap oak first. There is a chance that they contain enough
iron in their own right to cause trouble. They do also contain some
oxalic acid but the iron content might be a nuisance.

Yes, there should be a clear warning on the sides of packs of iron
sulphate.

Oxalic acid is sold as one of the more aggressive boiler descalers.

Salt in vinegar is another recipe that is worth a try. I suggest you
experiment on a scrap piece of oak wood with iron to get a mix that
works rather than inflict trial treatments on the precious floor!

--
Regards,
Martin Brown

On 26/07/2012 10:52, Chris Hogg wrote:
On Wed, 25 Jul 2012 22:00:09 +0100, Eddy
wrote:

Pete C wrote:
Pee on the floor?

Human urine? Are you serious? If you are, I'd definitely try it.

That is urea for the most part. The trick I recall requires ammonia.

Chris Hogg, the accidental staining is against the grain, and across
several planks, rather than with the planks, so one would have to
blacken the whole floor to hide the streaks. Anyway, we want our nice
oak floor back!

Martin Brown, thanks for the warning to mop up well after using lemon
juice. Will try the juice tomorrow. Thanks for the rhubarb leaves tip.

Yes, there should be a clear warning on the sides of packs of iron
sulphate.

Thanks people.

Eddy.

Another suggestion if you're desperate: a combination of hydrogen
peroxide and phosphoric acid in sequence. Reasoning: ferric phosphate
is colourless (white in powder form), but the 'iron sulphate' sold
commercially for garden use is usually a mixture of ferrous and ferric
iron sulphates, so there may well be some ferrous iron still present
in the wood on your floor. The addition of hydrogen peroxide should
oxidise any remaining ferrous iron to the ferric state, and the
phosphoric acid will then bleach it. If you use the phosphoric acid
alone without pre-oxidation, you may get a mixture of ferrous and
ferric phosphates, which is black.

Hydrogen peroxide is available at most high-street chemists, and IIRC
the chemical used for lowering the pH of fish ponds contaminated by
fresh cement is phosphoric acid, and can be obtained in aquarium
shops. Use them in sequence rather than as a mixture. I make no
guarantees though, either that it'll work or that it won't spoil the
surface of your floor. Personally, I think I'd try sandpaper and a
re-varnish first!

Definitely try all of these suggested recipes on a piece of scrap oak
that you have made a controlled iron stain on and leave for a couple of
weeks to see if there are any bad side effects.

You might also want to try looking in the library for a book called
"Henleys 1001 Formulas and Trade Secrets" under cleaning iron stains -
but take what they say with a big pinch of salt and ignore anything
involving mercury or conc. acids!

--
Regards,
Martin Brown

Thanks for your thoughts, Martin.

Yesterday afternoon I got to work on the kitchen floor with a lemon.
Cut it into halves and then rubbed the stained area hard with the two
halves until such time as I had pressed out all the juice by using the
flesh of the lemon to rub the juice into the wood.

After ten minutes, the result was as if a miracle had occurred!

You can imagine our relief ! The beautiful oak floor was back to
pristine condition. No need for sanding.

How wonderful is the humble lemon, eh? Amazing.

24 hours have passed with no darkening of the area on which the iron
sulphate "solution" was smeared, so I'll soon be getting to work with
some floor polish soon. (The lemon has really left the wood "naked".)

So, many thanks for your confirmation, and thanks too to the other
people who replied.

Was Pete C's suggestion that we use urine on the kitchen floor a joke?
It would of course get into the cracks between the planks and eventually
reek. Not nice in a kitchen! Not nice anywhere.


Eddy.



Martin Brown wrote:

Vinegar almost certainly will not hack it at all.

- apply lemon juice, wait five minutes, rub, then rinse off

Lemon juice or better citric acid might.
The fruit acid will with a bit of luck reduce the iron(III) tanin
complex to soluble iron(II) salt which you must then remove. You must
get the stuff mopped up once it fades and not spread it to adjacent
areas or you will have a bigger area affected.

The fruit acid make the complex pale but oxygen in the air will cause
any remaining iron in the wood to darken again later.