Leaf stain in slabs - how to shift?

[Richard Ivy 14]

Until my super duper 200BAR pw arrives from the US, I have to soldier on with my crummy 120 BAR machine.

I cleaned some cheap looking slabs today for a neighbour, but couldn't get rid of what appears to be, pretty sure of it, stains left behind by leaves. (brown/rusty colours).

I think I have read somewhere on TGS about this, but can't find it.

Has anyone a tip on removing these stains?

Thank you.

[Larry B 55]

Concrete stains are typicaly removed with an acid. Try oxalic first and go from there.

[Richard Ivy 14]

Thank you.

I'll go to bed now thinking oxalic acid!

G'night all.

[Jeff 232]

RICHARD, If its leaf or nut stains try straight bleach, just spray it on and the stains with disappear. Its called tannin stains???

[aquabob 14]

RICHARD, If its leaf or nut stains try straight bleach, just spray it on and the stains with disappear. Its called tannin stains???

yep...bleach...i usually apply it wth a pump up sprayer, (straight) which work best and is the most efficient way of spot treating stains. if it is a large area downstreaming or x-jetting would be the fastest way of covering it. the stains will usually come off with a 10:1 application.

[John Orr 206]

Ditto on the bleach, I do it all the time and it works great. Oxalic may work too, but it will lighten all concrete to which it is applied - so you'd need to apply to the whole area.

[wgasa 16]

Tanic acid leaching from decaying foliage.Berry stains are another matter.Clorine is your best & cheapest bet,downstreamed with a surfacant dont worry if it dry's HP wash with or without a surface cleaner & reapply if nessasary.Downstreaming thee same solution your finished prouduct will take care of any swirls & or stains.Pure clorine is best but for a large area the above method saves you 50% of clorine.:USA:

[Aplus 525]

I downstream chlorine, and don't worry about rinsing. Does a great job.

[John T 744]

Yup I downstream chlorine also for stains like that but after a short while I do rinse. You just never know if a kid is going to walk out there barefoot and step on the chlorine laying on the concrete........

[Jeff 232]

Yup I downstream chlorine also for stains like that but after a short while I do rinse. You just never know if a kid is going to walk out there barefoot and step on the chlorine laying on the concrete........

The hell with the kid , he probably needs a good cleaning anyway. LOL only kidding

[PLD 14]

As stated before, chlorine is the ticket...

Why not oxalic? Back to chem101. If you need to breakdown Tannic Acid think alkali (ph+). Need to consume organic material, think oxidizer.

Need a good Ph+ oxidizer? Try 12% NaHClO3 :)

Philip

[Richard Ivy 14]

Sorry I don't understand what this means: 'Need a good Ph+ oxidizer? Try 12% NaHClO3'

Secondly, do you apply oxalic acid dilute in a pump up sprayer?

Thank you.

[Larry B 55]

Glad somebody on here knows enough about concrete. It seems I have been making it overly difficult by using oxalic. Bleaching out those kind of stains would be muh easier than applying oxalic to the entire area with a pump up.

[CCPC 26]

Sorry I don't understand what this means: 'Need a good Ph+ oxidizer? Try 12% NaHClO3'

Secondly, do you apply oxalic acid dilute in a pump up sprayer?

Thank you.

Save the Oxalic for rust stains. Use the bleach/chlorine for the tannin stains.

[Richard Ivy 14]

Tannin caused by leaves?

Rust caused by metal objects resting on the surface?

[CCPC 26]

Tannin caused by leaves?

Rust caused by metal objects resting on the surface?

Tannin caused by: leaves, nuts, acorns, berries, bark, etc.

Rust caused by: metal objects resting on the surface, fertilizer, irrigation system/well water, etc.

[Richard Ivy 14]

Ok, this chlorine you talk of - is this the smae item that goes into swimming pools, or something I buy neat and have to dilute according to my needs?

Sorry if I'm duplicating stuff already covered - I am reading the Chemicals thread at this time, but it takes a while to read and digest.

[Jeff 232]

Ok, this chlorine you talk of - is this the smae item that goes into swimming pools, or something I buy neat and have to dilute according to my needs?

Sorry if I'm duplicating stuff already covered - I am reading the Chemicals thread at this time, but it takes a while to read and digest.

Richard liquid chlorine(pool Chlorine) usually 12.5% or store bought bleach for clothes is around 5-6%.> The above to are used to remove the leaf stain, Also is used for part of house wash mix . 12.5% or bleach is what removes green mold or black mildew on homes etc.

Oxalic acid is used for many different things. Mix at different strengths.

Oxalic is great to remove irrigation rust stains on concrete. It will also brighten concrete alot., best to apply to entire area. Ox also used as a neutralizer & wood brightener after stripping or cleaning wood decks fences etc.

Several ways to apply Oxalic depending on the type of work being done. Pump up Xjet brush etc.

Richard these 2 pictures are of concrete walkways with rust from irrigation system, you clean concrete with pressure washer & surface cleaner, then you apply the oxalic acid. I apply it with a lower GPM machine with an Xjet. Xjt is the nozzle on the end of the gun, with the hose in a bucket of Oxalic.

You can see before and after it makes a huge difference. Thought the pictures might help you understand easier

JL

[Jeff 232]

Richard more pics. This is also irrigation rust stains from sprinklers. On this vinyl fence I used pump up sprayer & oxalic several applications were needed. Oxalic can be used on most any home or building surface with rust. Oxalic isnt always as effective on other kinds of rust but in many cases work or at least lightens other kinds of rust

[Jeff 232]

These pics are before and after using 12.5% house wash. You see the white trim ithas black mildew and some green mold you spray on with Xjet or chem injector and it instantly starts to remove the mildew & mold

My house wash mix is simple 12% & soap spay it on and rinse

[Jeff 232]

Richard, This a picture of me & ?? after drinking very cold American BEER, Just thought Id throw this one in, just so you know its not just all work

Really you need any help just keep asking

Jeff

[Richard Ivy 14]

Thanks Jeff, great help as usual.

Seems that oxalic can be used against almost any discolouration - I've never heard of those rust stains from irrigation. Nasty - like the fence had been smoking!

You know when the underside of gutters gets all dark and grubby with mould (mold??) and algae, could a mix of oxalic deal with it?

I think I would be very concerned about spraying oxalic acid, or any other chem, up into the air where it can go anywhere. Not only this, but can this stuff etch windows?

(glad to see it's not all work work work!)

[Richard Ivy 14]

ALso, when you say '12%', Jeff, what do you mean by this? Is this the name of a product or the ratio of something you create?

[Jeff 232]

Richard mold & mildew BLEACH not oxalic.

JL

[Richard Ivy 14]

Jeff, in that other thread about 'bleach', does this mean chlorine? I'm confused on that one.

Secondly, you say to keep rinsing the windows - question: how much of the guttering would you spray before coming back to rinse? How long before the chems have worked, and crucially, how long before you damage the glass? Assuming you are talking about damaging glass.

[Richard Ivy 14]

What is '12%'? Is this a brand or the quanity of bleach to

water?