After softwashing a surface such as a roof, which has a lot of lead flashing, with a sodium hypochlorite product (eg Benz Lightning Cleanze) the sodium hypochlorite may react with the lead and discolour it.
Rinsing prior to softwashing with a sodium hypochlorite product, rinsing during softwashing, and then a final rinse when the softwashing treatment is complete, will go a long way to protect the lead.
Quick tip: When wetting the lead, there is a possibility of diluting the Lightning Cleanze that has just been applied. If this happens just give the surface an extra application by spray or brush. Another way of working is to treat the render below the flashing first, and give Lightning Cleanze some time to activate before wetting the lead.
Of course sometimes rinsing alone just isn't enough.
That's where Benz Oxy Cleanze oxidation removal gel comes in ...
New lead has a whitish/blueish appearance that "dulls down" to the grey colour we are familiar with, eg. the lead flashing on roofs.
Oxy Cleanze will quickly remove oxidation stains on lead flashing caused by natural oxidation and softwashing with sodium hypochlorite.
Quick tip: Modern lead may not be pure and so can discolour over time. Benz Oxy Cleanze will not reverse this form of reaction.
We coated the lead in the photo below with neat Lightning Cleanze and left it for 60 minutes. Then we rinsed and dried it. The temperature was 6 ℃.
In the photo below we applied Oxy Cleanze rust remover by brush and left it to work.
The photo below shows the results after only 30 minutes.
Two hours later we rinsed the Oxy Cleanze gel from the lead.
The results we achieved would be satisfactory for most lead restoration work, e.g. after lead has been cleaned with a sodium hypochlorite based product.
Apply a second coat if needed. In the photo below the far right section was treated a second time. We left this overnight (it was winter and cold – we do not recommended leaving a treated surface overnight during the warmer summer months) and rinsed the oxidation removal gel from the lead.
The photo below shows what it looked like when dry. Notice that the lead looks brighter and more blue/white than the dull grey we are used to seeing on lead flashing. It will gradually "dull down" with age (btw: the change of background colour was due to poor lighting conditions).
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On the property below, one application of Oxy Cleanze was enough to remove the yellow staining caused by softwashing with sodium hypochlorite, along with some ingrained oxidation.
After four hours at 5 ℃ we thoroughly rinsed Oxy Cleanze rust removal gel off the lead flashing with water using a garden hose and some light brushing. The photo below shows the result:
Note: The ingrained oxidation, which had built up over many years, cannot be removed without the repeated use of Oxy Cleanze rust remover, which could cause whitening of the lead .
This may be undesirable in some situations and for some customers. So always inform your customer of the possible results of repeated applications of Oxy Cleanze and allow your customer to make the decision as to whether to go ahead.
Natural weathering will reverse the whitening you can see in the above photo as the lead flashing tarnishes and dulls down.
We hope this information is helpful.
Ben, Leo & Fiona