I. Core Principles of Stone Maintenance
The core of stone maintenance lies in building a protective barrier, blocking the penetration of water, oil stains and pollutants through chemical protective agents. Protective agents are divided into two categories:
Penetrating protective agent: It penetrates deep into the pores of stone to form an invisible protective layer, suitable for high-porosity stones such as marble and sandstone. For instance, for marble protection, silane/siloxane-based protective agents should be selected, which can reduce water absorption rate by over 70% and effectively prevent alkali efflorescence and water stains.
Surface-type protective agent: Forms a film on the surface of stone and is suitable for low-porosity stones such as quartz stone. For instance, fluorocarbon protective agents can enhance the hydrophobicity of the surface and reduce the adhesion of stains.
Scientific basis: Protective agents can extend the lifespan of stone by reducing its water absorption rate (according to the "Stone Application Care Technology" standard, the water absorption rate after high-quality protection should be ≤0.5%), blocking the migration channels of salt and alkali substances, moisture and pollutants.
Ii. Stone Restoration Technology System
Repair techniques need to be customized based on the type of damage, the characteristics of the stone and environmental conditions. Common techniques include:
Micro-fissure repair
Applicable scenarios: Crack width 0.1-1mm, such as fine cracks on the surface of marble.
Operation process
To clean the cracks: Use a blade to scrape off the residual glue and contaminants. If necessary, clean with hydrogen peroxide.
Filling material: Select marble glue or stone sealing wax with excellent leveling properties and adjust it to match the color of the stone.
Glazing treatment: Use a mixture of VD glazing No. 1 and No. 2, and polish it with a 3M4100# scouring pad to enhance hardness and wear resistance.
Case: During the restoration of a white marble railing in a certain museum, this technique was adopted, which made the cracks invisible to the naked eye after repair and increased the wear resistance by 40%.
Fracture repair
Applicable scenarios: Fracture width 0.2-0.3mm, such as granite step fracture.
Operation process
Clean the gaps: Use an engraving machine to expand the cracks to 2mm to facilitate the penetration of the colloid.
Filling with glue: Inject imported marble glue or crystal glue to ensure that the gaps are fully filled.
Partial renovation: Grind until smooth with a 2000# grinding disc, and then carry out crystallization treatment.
Data support: The shear strength at the fracture site after repair can reach 15MPa, approaching the original stone strength (20MPa).
Hole repair
Classification processing
Small holes (diameter ≤5mm) : Fill with stone repair powder, compact and then grind.
Large holes (diameter >5mm) : Embed crushed stones of the same type, fill with epoxy mortar, and grind after curing.
Effect verification: The color difference ΔE at the hole area after repair is ≤1.5 (in accordance with the CIE Lab color difference standard), meeting the decorative requirements.
Iii. Special Plan for Lesion Treatment
Stone diseases require "targeted treatment". Common diseases and their treatment methods are as follows:
Rust spots
Cause: Oxidation of iron ions inside the stone or contamination by metal fittings.
Governance
Apply rust remover (containing oxalic acid or citric acid, pH value 3-4), and let it stand for 5-10 minutes.
Rinse with clean water and repeat the operation until the rust spots are removed.
Prevention: Before installation, carry out protective treatment on the stone and avoid using iron-containing accessories.
Water spot
Cause: Water retention after wet construction.
Governance
Spray water stain remover (containing penetrating solvent), cover with cling film and let it stand for 24 hours.
After rinsing with clean water, reapply the protective measures.
Case: After the treatment of water stains in the lobby of a certain hotel, the evaporation time of water was shortened from 30 days to 3 days.
Bai Hua
Cause: Salt precipitation leads to the accumulation of white powder on the surface.
Governance
Spray with Baihua remover (containing hydrochloric acid or phosphoric acid, pH value 2-3) and let it stand for 3-5 minutes.
After rinsing with clean water, apply additional protective measures to prevent recurrence.
Data: The recurrence rate of Baihua decreased by 90% after treatment.
Iv. Standardized procedures for daily maintenance
Daily maintenance is the key to extending the lifespan of stone materials and should follow the following norms:
Cleaning frequency
Ground stone: Wipe with a microfiber cloth daily and deeply clean with neutral detergent weekly.
Wall stone: Wipe once every two weeks.
Countertop stone: Wipe with clean water after each use and clean with neutral detergent once a week.
Cleaning taboos
Avoid using acidic (such as toilet cleaner) or alkaline (such as soapy water) cleaners to prevent surface corrosion.
Do not use steel wool balls or hard-bristled brushes to prevent scratches.
Protection period
Natural stone: Apply penetrating protection every 1-2 years.
Artificial stone: Surface protection should be redone every 2 to 3 years.
High-traffic areas (such as the floors of shopping malls) : Reapply protective measures every 6 to 12 months.
V. Principles of Technology Selection and Material Matching
Stone type matching
Marble: Avoid using acidic protective agents to prevent the dissolution of calcium components.
Granite: Anti-oil stain penetrating protective agent is selected to resist oil penetration.
Sandstone: High-permeability protective agents are used to fill the coarse pores.
Environmental adaptability
Outdoor stone: Select UV-resistant protective agents to prevent aging.
Damp environment: Select hydrophobic protective agents to reduce water absorption rate.
Performance requirements for repair materials
Leveling property: Ensure that the surface is smooth and free of unevenness after filling.
Adhesion: The bonding strength with stone substrates is ≥2MPa.
Polishing property: The glossiness difference between the restored stone and the original stone is ≤10%.