Cow Muck
The application of cow manure and lime can help prevent soot staining due to a combination of factors:
Physical Barrier: The organic matter in the manure, including hair and fibres, can create a physical barrier that helps to prevent soot particles from penetrating the plaster.
Chemical Reaction: The alkaline nature of lime plaster can react with acidic components in soot, neutralizing them and reducing their staining potential. The cow muck also contains humic acid and tannins both of which are chelating agents. Organic components in cow muck might also have adsorptive properties for certain types of staining molecules. Complex organic polymers and humic substances can have various functional groups that can bind to soot components through van der Waals forces, hydrophobic interactions, and other mechanisms, further trapping them within the cow muck coating.
Sealing Properties: The oils and fats in manure can help to seal the pores of the plaster, further reducing the penetration of soot particles. This reduces the pore size so that oils and tars created by the chimney exhaust fumes cannot pass through.
It's important to note that fresh cow manure should be used, as it contains the most effective components. The manure should be well-mixed into the lime plaster to ensure even distribution.
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Quicklime : Cow Muck
Used hot or cold and harled on.
Can be used thicker to act as a daub coat to save time and it will adhere to most substrates well enough to be used as a primer. for mixed substrates to control suction.
Naturally keyed so no need to scratch or beat back.
Well reinforced with natural fibres.
Can be used as an additive for lime plaster to improve its qualities and ease of use. Not for external use in this manner as it's a biodegradable material.
WARNING
The ammonia smell you're experiencing when applying lime plaster to soot is due to a chemical reaction between the alkaline lime and the acidic components in the soot. Soot often contains nitrogen-based compounds, which, when mixed with the alkaline lime, can release ammonia gas.
This reaction is more pronounced when the soot is wet, as the water helps to facilitate the chemical reaction. Additionally, the heat generated during the setting of the lime plaster can also accelerate the reaction, leading to a stronger ammonia smell.
To reduce the ammonia smell, you can try the following:
Ensure the soot is dry and remove as much as possible: Before applying the lime plaster, make sure the soot is completely dry. This will minimize the amount of water available for the chemical reaction.
Ventilate the area: Good ventilation can help to dissipate the ammonia gas. Leave if you need to.
Wear protective equipment: Ammonia gas can be irritating to the eyes, nose, and throat. It's important to wear protective equipment, such as a mask and gloves, when working with lime plaster and soot.