Finishing Starts at the Forge

There is a temptation, especially when you are new to the craft, to treat finishing as the last ten minutes of a job — a quick scrub, a wipe of wax, and out the door. In practice the finish begins the moment you take the workpiece out of the fire. Every hammer blow that you leave visible, every brush mark you decide to keep, will be amplified by whatever you put on top of it. A finish is not a disguise. It is a lens.

Good finishing does three jobs at once: it protects the steel from rust, it deepens the natural colour and texture of forged metal, and it tells the viewer where to look. The same simple hook can look like a factory pressing or a piece of handwork depending on how its surface has been treated. What follows are the techniques I reach for most often, and the small details that separate a finish that lasts from one that disappoints within a season.

Brushing and Surface Preparation

Before anything goes on the metal, the metal has to be clean and consistent. Fire scale and mill scale are the enemy of a good finish: they flake, they hold moisture, and they will not take wax or oil evenly. A wire wheel on an angle grinder or bench grinder will strip scale quickly, but it also leaves a very uniform, slightly sterile scratch pattern. On decorative work I often stop short of that and use a hand-held card file or a stiff hand brush to keep some of the fire's character.

A few practical points:

• Match the brush to the metal. A steel wire wheel cuts aggressively and brightens the surface; a brass wire brush is gentler and leaves a warmer, slightly gilded tone that suits traditional ironwork beautifully.
• Work with the form, not against it. Brush along the length of a taper or scroll so the scratches follow the lines your hammer established.
• Degrease last. Wipe down with a solvent such as acetone or methylated spirits and let it flash off before applying any finish. Oils from your hands will cause patchy waxing.
• Decide about scale before you start. Some pieces — fire tools, garden structures, architectural ironwork — are better left with a lightly brushed fire-scale finish, which is durable and honest. Others want to be taken back to bright steel.

Waxing: The Blacksmith's Standby

Wax is the finish most smiths learn first, and for good reason. It is forgiving, it smells wonderful, and it can be applied straight onto hot metal. The classic approach is to warm the piece until it is hot enough that water sizzles and dances on the surface — roughly 150 to 200°C — then rub on a wax and oil blend with a rag or a stiff brush. The wax melts, flows into the pits and hammer marks, and the oil carries it into the tighter detail.

A simple shop blend is a handful of beeswax melted into boiled linseed oil, with a little turpentine to thin it. Applied hot, it gives a deep, satin, dark-brown sheen that flatters forged texture. Let it cool, then buff off the excess with a clean cloth. For indoor pieces such as candle holders, door handles and furniture, a thin coat of a hard microcrystalline wax over the top adds gloss and fingerprint resistance without looking plastic. Never leave a thick, tacky layer — it attracts dust and looks grubby within weeks.

Oils for a Softer Sheen

Where wax gives depth, oil gives a drier, more matt appearance that suits rustic and garden work. Boiled linseed oil is the traditional choice; it cures rather than simply drying, building a thin, slightly amber film. Warm the metal first — not scorching, just comfortably hot to the touch — and apply thin coats with a rag, wiping off the surplus after twenty minutes. Two or three coats, spaced a day apart, will outlast a single heavy one by a wide margin.

Tung oil behaves similarly but cures harder and with less yellowing, which is useful on pieces where you want the steel colour to stay cool and grey. A word of caution that bears repeating: rags soaked in linseed or tung oil can self-heat and catch fire. Lay them flat outdoors to dry, or drop them in a bucket of water. It is not a myth, and it has caught out plenty of careful makers.

Patination and Colour

Not every piece should be black or bright. Heat itself is one of the finest colourists available to a smith: run a polished surface through the tempering colours — straw, bronze, violet, then a lovely peacock blue — and quench at exactly the shade you want. It is a nervous business on a large piece, because the colours chase each other quickly, but on small fittings it is unmatched.

Chemical patination broadens the palette further. A cupric nitrate solution brushed onto warmed steel and gently heated will bloom into rich browns and russets; liver of sulphur gives deep, slightly iridescent blacks on copper and bronze; and a cold blue solution produces a gunmetal grey that takes wax beautifully. Always work outside or with extraction, wear gloves and eye protection, and neutralise thoroughly before finishing. Whatever colour you build, seal it. An unsealed patina will keep developing, and not always in the direction you wanted.

Choosing and Living With the Finish

Match the finish to the life the piece will lead. Indoors and handled daily: wax over a brushed or blued surface. Outdoors and rained on: a cooked-on oil finish, or wax renewed each season. Near the coast, where salt air eats steel for breakfast, be generous with both and accept that maintenance is part of ownership.

Tell your customer what you have used and how to look after it — a paragraph on a card is worth more than any guarantee. Most hand-forged finishes improve with attention, deepening and settling over the years. That is the quiet pleasure of the craft: the piece you finish today will keep changing in someone's hands long after it leaves your workshop.