[Moderator David@stives]

I bought some Hypochlorite tody, when i read the contents, I saw it contained Sodium Hydroxide as well.

I bought this to clean a bitumen coated metal tile roof, now I am a bit worried if this might be a bit too toxic for the job.

What do you think ?

[Blast Away]

Reacting chlorine and sodium hydroxide produces Sodium Hypochlorite:

     Cl2     +       2 NaOH        =           NaOCl             +        NaCl              +    H2O   

Chlorine   Sodium Hydroxide   Sodium Hypochlorite    Sodium Chloride      Water

[Blast Away]

Like I said mate, I'll speak to my supplier.

[Roger Oakley]

I bought some Hypochlorite tody, when i read the contents, I saw it contained Sodium Hydroxide as well.

I bought this to clean a bitumen coated metal tile roof, now I am a bit worried if this might be a bit too toxic for the job.

What do you think ?

Dave

Does the roof have any lead flashing around it? if it does the Hypo will more then likely turn it orange/brown as hypo and lead are not a good mix, so you might want to re-think what you are going to use to clean it with.

[Moderator David@stives]

Lee

Job starts mon morning, but would still like to know, still testing it on stone, it is clearing the algae even at max dilution ir 20:1

Roger

The roof is bitumen type covered metal.

Thanks for the tip

[trevor perry]

sodium hydroxide is otherly known as caustic soda, what dilution rate are you using this at we use it on some stainless steel cleaning but it should definately not be used on lead or aluminium also beware of leaving to dwell on any glass surfaces as this will definately burn the glass, how are you applying this dave if there is any chance of spray being blown onto passers by then do not use it as caustic soda causes severe burns your men need to wear full PPE, if in doubt contact the number on your chemical data sheet

[Moderator David@stives]

Hi trev

I have found another supplier, who sells hypochlorite with nothing else added.

I will just save this batch for other stuff,

Will download a data sheet later

[Moderator David@stives]

This is the stuff they sold me

Sodium hydroxide, Sodium hypochlorite

http://www.tim-gibson.com/products.php?id=25&product_type=1

[Roger Oakley]

And I bet you paid a pretty penny for that Dave.

For what you are trying to clean you should only need 13%-14% Hypo, a 3:1 Mix with water should do you, as I said before if there is a lead flashing it will most prob. turn it brown/orange, you will need to watch your run off as Hypo can and will kill plants- grass etc and do not use near a fish pond. Also watch for wind drift, wear the correct PPE and you should be ok.

[Moderator David@stives]

Hi Rog

I paid about £12.00

I might just use nothing, I am sure it will clean without chemicals, just thought it might speed things up.

I will look out for the lead

[Roger Oakley]

Dave,

So not to expensive to be honest, if that was for 10+ lts.
I had a look at the site but couldn't see a MSDS sheet or info, there most probably, isn't much caustic soda in it, you can use caustic to give Hypo a bit of a boost, it is short lived but does work.  If you are going to use it, follow there mixing details, do a small test area if you can. Good luck.