Techniques for repairing and restoring wrought ironwork

Basic Principles of Restoration

Understand the concept of minimum intervention in restoration. Aim to preserve as much original material as possible, restoring only what is absolutely necessary.
Learn about the importance of reversibility. Any changes made should ideally be undoable, allowing future restoration if required.
Recognise when replacement of parts may be necessary. This should be done with a similar material to the original and crafted in the same style and technique.
Understand the ethical considerations within restoration and the concept of honesty. Modern interventions should be identifiable upon close inspection to authenticate historic work.

Begin any restoration project with a detailed inspection and assessment of the ironwork. This should include structural integrity, surface condition and any previous restoration efforts.
Consider the level and type of corrosion present. Identify any active rusting, surface pits or structural weakening of the iron.
Determine the climatic and environmental factors affecting the ironwork. Exposure to weather, wind direction, pollution or sprinkler systems can contribute to the corrosion.
Assess any paint layers and coatings. These might bear significant historical information and should whenever possible be documented before stripping.

Understand different cleaning methods like hand cleaning, abrasive blasting, and chemical cleaning. Choose the most appropriate method based on ironwork’s condition.
Be aware of potential damage from aggressive cleaning. Over-cleaning can lead to unnecessary loss of original material.
Use the gentlest method possible to remove corrosion and protect historic surface details.

Know how to re-forge broken elements in the same style, using traditional techniques to replicate the original.
Learn to replace heavily corroded parts with newly crafted items. Match the style and finish of the original whenever possible.
Master patching techniques for non-structural rusted areas, using as similar material to the original as possible.
Acquire skills in multiple joining techniques such as riveting, welding, or bolting according to the original ironwork.

Learn to appropriately protect ironwork using paint systems, either oil-based or modern industrial coatings. These not only enhance appearance but also prevent further corrosion.
Understand the value of historic polychrome paint schemes and replicate them where possible based on traces found during inspection.
Master the use of patinas. They can give a historic appearance when repairing or replacing elements.
Learn about hot-dip galvanizing. It can offer enhanced protection for outdoor ironwork, but it may be too invasive for certain historic pieces.
Understand the effect of waxing, oiling and lacquering, typically for indoor or low corrosion risk items. These traditional finishes are less durable, but they maintain the original texture and appearance of the ironwork.