Surface preparation is the single most important factor in avoiding rust and flaking paint when renovating and repainting wrought iron railings, gates and mild steel ironwork, so it's worth getting it right the first time.
This is the way I Remove rust and strip old paint from metal railings.
Using a wire brush or preferably a drill with wire brush attachment is the best way to remove rust and flaking paint when renovating iron work. This method of removing rust takes longer than sand-blasting, but will completely remove all the rust and loose paint from your wrought iron railings and gates.
It is important to use good quality wire brush attachments or you will waste time replacing the cheap ones. Believe me, you get what you pay for!
The wire brush attachments needed are a cup shape, a large rotary wire brush and a 25mm wire end brush to get to the ornamental bits.
The kit featured here, available from amazon has all the drill attachments you will need.
Use a wire brush to remove the rust and flaking paint. Then, use a good paint stripper to strip the paint from the iron work. Next brush on a rust converter to convert the rust back to iron. You can use either a metallic undercoat and top coats or use Hammerite type Metal paints, which don't need an undercoat and are hard wearing, to repaint the gates and railings. If you are not a dab hand at painting, make sure to cover the area under the metalwork.
Rust starts deep inside metal, gradually eating its way through the metal weakening it. Once it starts you will need a product to not only stop it from getting worse, but to stop it dead. This metal paint does just that. It leaves a hammered metal finish. Protects for up to 8 years and can be painted straight onto any rusted metal surface without primer.
Using rust converter paints.
Hammerite type products convert rust to metal and leaves a protective film that protects against future rust
easier because once the loose rust and flaky paint has been removed and the metalwork has been cleaned, there is no need for further wire brushing or sanding.
If you use a rust converter paint, providing you have removed all the loose rust, it isn't necessary to remove all signs of rust.
Sand-blasting is the quickest way (but not the cheapest) to remove old paint and rust from metal work and gives a smooth finish. It is ideal for renovation of ornamental wrought ironwork. Sand blasters can be hired from the larger tool hire companies or you can remove the gate or railings and take them to a specialist.
The cheapest way, if you are renovating a lot of metal work is to purchase a sandblaster.
To stop the rust and paint from blowing all over the patio, place a plywood board behind the railings and a ground sheet under it. You might be able to recycle some of the sand too.
The structural use of Wrought Iron in building dates back to early history. Wrought iron is stronger than the more brittle cast iron. Relegating cast iron to an ornamental role, wrought iron door furniture has been around sinse Roman times.
Our main use for wrought iron, however is in the manufacture of long lasting and sometimes ornamental wrought
iron gates and railings. The wrought iron railings in Westminster Abbey date from the thirteenth century, displaying all the characteristics, which we have come to know as 'wrought
There are wrought iron railings in Westminster Abbey dating from the thirteenth century, which, in essence display all the characteristics, which we have come to know as 'wrought ironwork'. The great age of British ironwork "the English style" started at the end of the seventeenth century building on the French fashion for the Baroque style in gates and railings which was sweeping the country houses of Britain.
Owing to the cost of forging wrought iron, each piece is made by hand, while castings could be repeated in the 10s of 000s once the mold had been made, ornamental ironwork was mainly made of cast iron. Mild steel cheap because of its ability to be mass produced gradually brought about the decline in wrought iron, and the craft skills associated with it.
Puddled wrought Iron has been available in limited supply for the blacksmiths of Britain who kept the skills and craft going and we are seeing a steadily increasing demand in recent times.
Before the Romans came, Britons were noted for their iron jewelry; an expensive metal in literal terms, for the time and labour expended to make even a small cinder of iron. Early wrought iron was made in the fire from ore and charcoal. The heat was sufficient for the charcoal to reduce the iron oxide to iron, but not to melt it. As a result the silicate slags were included, not refined away as we might do now, but entrained in the fibrous structure of the material. For this reason, the old irons have lasted for hundreds of years. Iron may corrode, but not its coating of silicate slags.
However little survives because wrought iron may be repeatedly recycled and benefits from reworking. Scrap could be bundled, heated until it glowed white hot, and forged again by hammering into a solid mass to produce an iron of a higher quality.
The earliest surviving architectural ironwork in this country is probably Norman, such as the portcullis, "ex solido ferro" at Raby Castle and barred treasury windows as at Canterbury Cathedral. Doors too were often strongly bound with iron, frequently of a decorative nature, such as the famous example of Stillingfleet Church, illustrated above. Dating from c1145, it has only recently been renewed. The original is conserved within the security of the church.
From the exquisite precision of the locksmith and the armorer, to the prosaic work of the mender of ploughs and the shoer of horses, the art of the blacksmith developed. Little of this early architectural ironwork is typical. The catch of a door or the bar of a window for example, were more or less ornamented according to the whim of the smith and as today, the available budget. Familiar types emerged, such as the Suffolk latch, and various forms of hinges. Frequently inventive, often crude, but always fashioned in accordance with the nature of the iron.
With the introduction of blast furnaces in the 15th century the availability of wrought iron increased. Craftsmanship reached new heights in the period of Great English Ironwork which started in 1690 or thereabouts with the arrival of a Belgian, Jean Tijou. Some of the finest examples of the period include his own work, such as the screens at Hampton Court, and the work of his disciples such as Thomas Bakewell's garden arbour now known as the 'Birdcage' at Melbourne Hall (1707 - 1711), William Edney's St. Mary Redcliffe gates (c1710), and the Davies Brothers' gates at Chirk Castle (1715 - 1721).
The change was toward a freer use of beaten sheet metal ornamentation applied to the bars to form baroque leaf-work, swags, masks and all manner of delights. The techniques were no doubt derived from armoury. The material was superb, not only for its ability to accommodate deep, cold, repoussé work, but also for its persistence, for much of what we can see today has weathered nearly 300 years.
To accurately recreate items from the past, we must, even today use materials and methods similar to those used then. Draftsmanship is a thing of the modern age, so too are obsessions with dimensions, symmetry and squareness. The delicate lace work of the Golden Gates at Chatsworth is no worse for the absence of a straight line or a square corner. Built without drawings, held together with thousands of tiny rectangular rivets, all different sizes, filed, no doubt, by a team of complaining apprentices. Not easy to restore, but made infinitely more difficult by the attentions of an arc welder of our own time, in the interest of a former standard of 'restoration'.
The iron of this period is now referred to as charcoal iron, a highly carburised form of iron which was made by constant reworking in the fire. It was even hardenable, unlike the puddled irons of the 19th century, and there is no substitute for it. Only very recently has this iron been made again for the conservation industry. It is available in sheet form.
English Ironwork took its course through the 18th century, from Baroque to Rococo, and into a more austere era of mechanisation.
Cast Iron and the Victorian Age
Cast iron has been known to the Chinese since before Christ, and was in general use in Britain in the 16th century, mainly for items like ordnance, firebacks and cooking pots. It was not until the 18th century that any large scale use in architecture became apparent. The Adam brothers experimented with cast iron. At first it was used as an ornament to wrought ironwork. It was not however until after the foundation of the Carron Ironworks in 1759 that the headlong rush into all things of cast iron began, so familiar to us from the 19th century.
Industrialisation enforced new requirements for design, strength and accuracy. The carefree blacksmith became a technician. Ornamental work too became accurate, made to drawings, and characterised by squareness and symmetry. New industrial methods brought mass produced puddled wrought iron, rolled bars of consistent section, and new sections such as angles and tees, as demanded for the construction of the new iron ships.
19th century ironwork was, however, by no means devoid of fun, as can be seen from the railings of the London Law Courts, the Albert Memorial, Holyrood House, and railway ironwork such as Great Malvern station, as well as from the later glories of art Nouveau and arts and crafts ironwork.
Wrought iron, with its high tensile strength came again to the fore in the Railway Age. Shipbuilding practices of fabricating structures by rivetting together rolled wrought iron sections, came into use in building, particularly in bridge building for the railways. Riveted plate girders and latticework could span greater distances and carry heavier loads than cast iron structures as tragically illustrated by the collapse of the first Tay bridge in 1878. The wrought iron plate girder became the basic device of building. Assembled into a dynamic framework until, in America, buildings which seemed to scrape the sky became possible.
The Emergence of Steel
With its higher carbon content and greater hardness, the value of steel had been recognised since the earliest days of iron making. But it was slow to produce and expensive. In 1856, in an attempt to mass-produce wrought iron and by-pass the established hand puddling process, Henry Bessemer stumbled upon mild steel, an even stronger, more consistent material. The Bessemer process enabled large batch production, and by 1876 mild steel was cheaper than wrought iron, gradually replacing it for structural purposes. However the material was rather more prone to corrosion, and in cases where durability and resistance to weathering were paramount, wrought iron held its own for nearly another century.
The general fall in standards since the War, and the inexorable process whereby everything must be the cheapest, not only did away with the production of wrought iron, but we very nearly lost the art and skills so important to the working of the material.
Over the years technological improvements have made the manufacture and working of ironwork much easier. However for the conservation and replication of old ironwork we should bear in mind that only techniques similar to those extant when the particular piece was originally created will produce a thoroughly accurate replica. If a skill is not exercised it will be forgotten, and with it the ability to create in the manner of the past. The conservation of skills is perhaps just as important as the conservation of the artifacts.
Should the use of modern mild steel in the conservation of wrought iron work be permitted there will also be a tendency to compromise on technique. Mild steel does not for example, lend itself so readily to welding in the fire. Furthermore there is a tendency to use modern, mass-produced sections, which are unlikely to match the imperial dimensions used in the past.
Prior to the 19th century, sections of wrought iron were forged to shape, which gave them a more varied form and surface texture. By comparison restorations in mild steel will appear relatively lifeless and the result will be inconsistent with the texture of the original.
Finally, wrought iron is a material with a proven record of longevity which will prolong the intervals between successive restorations. It is true that its cost is higher but in many cases the cost of the material is small in comparison with the cost of skilled labour, all of which will be lost as the mild steel rusts away.
Wrought iron is currently available for restoration work, primarily through the recycling of old material.
Although sources of early charcoal iron are limited, there are vast quantities of 19th century material available from redundant and demolished structures such as bridges, which can be reforged.
An increase in demand for wrought iron for conservation work could also make the production of charcoal iron viable.
This article is reproduced from past editions of The Building Conservation Directory.