Mill finish
As cut. Edges are sharp.
StandardIncluded
Material guide
Nine metals. One is right for your part.
10 grades in stock0.9 – 20.0 mm3000 × 1500 mm bed1000 × 1000 mm priced online48 h on anything we don’t hold
Which material?
Three questions. We’ll narrow it to three metals.
A starting point, not a specification.
Recommended
indoor · cost first · painted — 5 of 10 grades fit
Mild Steel S275JRBest value. Needs paint or powder coat outdoors.Indoor excellentCost excellentPaint excellent100%Zintec Zinc-coated mildPre-galvanised. Paint-ready, mild indoor corrosion resistance.Indoor goodCost goodPaint excellent85%Aluminium 5251 / 5083A third of the weight of steel. Marine-friendly, non-magnetic.Indoor goodCost marginalPaint good62%
Ruled out: Corten — you'd be painting over the only reason to buy it · Stainless 304 Brushed — you'd be painting over the only reason to buy it · Stainless 304 Mirror — you'd be painting over the only reason to buy it · Brass — a premium metal, never the value answer · Copper — a premium metal, never the value answer
Side by side
Every grade we hold, on one line each.
| Typical uses | ||||||||
|---|---|---|---|---|---|---|---|---|
| Aluminium | 5251 / 5083 | 2,700 | 1.0 – 15.0 mm · 11 sizes | Slow | Very good, TIG or MIG | Very good in 5251 | Enclosures, van racking, boat fittings | |
| Brass | CZ108 | 8,500 | 0.9 – 5.0 mm · 7 sizes | Slowest | Braze or solder | Excellent | Signage, letterplates, interior detail | |
| Copper | C101 | 8,960 | 0.9 – 3.0 mm · 5 sizes | Slowest | Braze or solder | Excellent | Splashbacks, roofing detail, busbar | |
| Corten | S355J0WP | 7,850 | 1.5 – 10.0 mm · 8 sizes | Fastest | Very good, matched wire | Very good | Screens, planters, cladding, signage | |
| Mild Steel | S275JR | 7,850 | 0.9 – 20.0 mm · 14 sizes | Fastest | Excellent | Excellent | Brackets, base plates, frames, jigs | |
| Stainless 304 | Mill finish | 8,000 | 0.9 – 12.0 mm · 11 sizes | Moderate | Excellent, TIG | Very good, work hardens | Kitchens, splashbacks, handrail, trim | |
| Stainless 304 Brushed | 240-grit one face | 8,000 | 0.9 – 6.0 mm · 8 sizes | Moderate | Good, protect the face | Very good | Shopfitting, appliance fronts, lift panels | |
| Stainless 304 Mirror | BA / No.8 | 8,000 | 0.9 – 3.0 mm · 5 sizes | Moderate | Possible, repolish after | Good, marks easily | Retail, backlit signage, feature panels | |
| Stainless 316 | Marine grade | 8,000 | 1.2 – 10.0 mm · 9 sizes | Moderate | Excellent, TIG | Very good, work hardens | Marine fittings, pool plant, coastal rail | |
| Zintec | Zinc-coated mild | 7,850 | 0.9 – 3.0 mm · 6 sizes | Fastest | Good, extract fume | Excellent | Enclosures, trunking, panels, ducting |
Cut cost is a band, not a rate: copper is slower on the bed than mild steel, and the gap is in the price of the part. Put your own geometry through the Builder for the figure.
GradeS275JR
01 · Structural steel
Mild steel
Cheapest per kilo. Welds, folds, and rusts bare.
Density7,850 kg/m³
Yield275 N/mm²
Expansion12 µm/m·K
MagneticYes
SuppliedMill scale, light oil
CorrosionSurface rust in days
Material costLowest
Cut speedFastest
Thicknesses14 SIZES · MM
0.91.21.52.02.53.04.05.06.08.010.012.015.020.0
Good for
- Painted or powder-coated parts
- Welded frames and brackets
- Thick plate to 20 mm
Avoid when
- Left outside bare
- Food or wash-down
- Weight is the driver
Working with mild steel
Mill scale is transit protection, not a coating. Paint within 48 hours of cutting.
WORKED EXAMPLE · 200 × 200 mm plate, 3.0 mm, one off, mill finish — 0.94 kg each · priced live in the Builder
GradeZinc-coated mild
02 · Pre-galvanised
Zintec
Mild steel under a zinc skin. Paint sticks without blasting.
Density7,850 kg/m³
Yield≈ 220 N/mm²
CoatingElectro-zinc, both faces
Expansion12 µm/m·K
MagneticYes
SuppliedDull grey, faint spangle
CorrosionYears indoors, 1–2 outside
Material costLowest
Cut speedFastest
Thicknesses6 SIZES · MM
0.91.21.52.02.53.0
Good for
- Enclosures, trunking, cable tray
- Parts going straight to spray
- Folded sheet, high volume
Avoid when
- Structural — 3 mm maximum
- Welded and left bare
- Outdoors, long term
Working with Zintec
Zinc burns back 10–15 mm each side of a weld. Every cut edge is bare steel.
WORKED EXAMPLE · 200 × 200 mm plate, 1.5 mm, one off, mill finish — 0.47 kg each · priced live in the Builder
GradeS355J0WP
03 · Weathering steel
Corten
Rusts once, then stops. Never painted.
Density7,850 kg/m³
Yield355 N/mm²
Expansion12 µm/m·K
MagneticYes
SuppliedBright rolled, no patina
Full patina6–18 months outdoors
CorrosionSelf-arresting oxide layer
Material costLow
Cut speedFastest
Thicknesses8 SIZES · MM
1.52.03.04.05.06.08.010.0
Good for
- Screens, planters, cut signage
- Outdoor pieces never repainted
- Structural outdoors — 355 yield
Avoid when
- Within a mile of sea
- Runoff onto pale paving
- Permanently wet, or buried
Working with Corten
The patina needs a wet/dry cycle. Year one bleeds orange onto whatever sits below.
WORKED EXAMPLE · 200 × 200 mm plate, 3.0 mm, one off, mill finish — 0.94 kg each · priced live in the Builder
GradeMill finish
04 · Austenitic stainless
Stainless steel 304 & 316
Never rusts, never painted. 304 inland, 316 near the sea.
304 · inland
Density8,000 kg/m³
Proof stress≈ 210 N/mm²
CorrosionExcellent inland
Material costMid-range
Thicknesses11 SIZES · MM
0.91.21.52.03.04.05.06.08.010.012.0
316 · coastal
Density8,000 kg/m³
Proof stress≈ 220 N/mm²
CorrosionMo-bearing, salt tolerant
Material costHigh
Thicknesses9 SIZES · MM
1.21.52.03.04.05.06.08.010.0
Expansion17.3 µm/m·K
MagneticNo
Supplied2B mill finish, both faces
Food safeYes — EC 1935/2004
Cut speedModerate
Good for
- Kitchens, wash-down, brewery plant
- Handrail, never maintained
- 316: coastal rail, pool plant
Avoid when
- Budget leads — a premium metal
- 304 near salt
- Big unsupported flat panels
Working with stainless
Within sight of the sea, or on a gritted road? Specify 316 and A4 fixings throughout. Slightly magnetic after heavy forming.
WORKED EXAMPLE · 200 × 200 mm plate, 2.0 mm, one off, mill finish — 0.64 kg each · priced live in the Builder
Grade240-grit one face
05 · Finished stainless
Stainless 304 brushed
Grained at the mill, so every part in the batch matches.
Density8,000 kg/m³
Proof stress≈ 210 N/mm²
Expansion17.3 µm/m·K
MagneticNo
SuppliedGrain one way, PVC film
CorrosionAs 304 — inland
Food safeYes, film removed
Material costMid-range
Cut speedModerate
Thicknesses8 SIZES · MM
0.91.21.52.03.04.05.06.0
Good for
- Shopfitting, appliance fronts, kick plates
- Cut signage and lettering
- Sets that must match
Avoid when
- Folds across the grain
- Welding the show face
- Above 6 mm — unstocked
Working with brushed 304
Folds across the grain won't match at a corner. Above 6 mm we grain plain 304 instead.
WORKED EXAMPLE · 200 × 200 mm plate, 1.5 mm, one off, mill finish — 0.48 kg each · priced live in the Builder
GradeBA / No.8
06 · Finished stainless
Stainless 304 mirror
A true reflective polish. Shows every fingerprint.
Density8,000 kg/m³
Proof stress≈ 210 N/mm²
Expansion17.3 µm/m·K
MagneticNo
SuppliedPolished one face, film on
CorrosionAs 304
Food safeYes, film removed
Material costHigh
Cut speedModerate
Thicknesses5 SIZES · MM
0.91.21.52.03.0
Good for
- Retail interiors, feature panels
- Backlit signage and reflectors
- Lettering off a dark wall
Avoid when
- Public reach, no polishing
- Big flat panels — waviness
- Bolted through the face
Working with mirror 304
It leaves us film-on and should be fitted film-on. A scratch has no invisible repair.
WORKED EXAMPLE · 200 × 200 mm plate, 1.5 mm, one off, mill finish — 0.48 kg each · priced live in the Builder
Grade5251 / 5083
07 · Light alloy
Aluminium
A third the weight of steel. Never rusts, won't take heat.
Density2,700 kg/m³
Yield5251 ≈ 165 · 5083 ≈ 125 N/mm²
Expansion23.8 µm/m·K
MagneticNo
SuppliedMill finish, film 3 mm up
CorrosionSelf-passivating, never rusts
Food safeAnodised or coated only
Material costMid-range
Cut speedSlow
Thicknesses11 SIZES · MM
1.01.52.03.04.05.06.08.010.012.015.0
Good for
- Anything lifted, carried, hinged
- Enclosures and heat sinks
- 5083 for boat fittings
Avoid when
- Above 150 °C
- A weld carries load
- Wet contact with steel
Working with aluminium
Per kilo it looks dear beside mild steel. Per part it usually is not — the same plate weighs 34% as much, so it tends to land near mild and under stainless.
WORKED EXAMPLE · 200 × 200 mm plate, 3.0 mm, one off, mill finish — 0.32 kg each · priced live in the Builder
GradeCZ108
08 · Decorative alloy
Brass
Bought for the colour. Warm gold, going honey-brown unlacquered.
Density8,500 kg/m³
Tensile≈ 340 N/mm² half hard
Expansion19 µm/m·K
MagneticNo
SuppliedBright rolled, minor marks
CorrosionTarnishes warm brown
JoiningBraze or solder, not welded
Material costHighest
Cut speedSlowest
Thicknesses7 SIZES · MM
0.91.21.52.03.04.05.0
Good for
- Signage, letterplates, switch plates
- Small parts that tap
- Clock and instrument work
Avoid when
- Structural — 5 mm maximum
- You intend to paint
- Immersed in seawater
Working with brass
Cold-rolled 63/37. Unlacquered it goes honey-brown within months, which is usually the point.
WORKED EXAMPLE · 200 × 200 mm plate, 2.0 mm, one off, mill finish — 0.68 kg each · priced live in the Builder
GradeC101
09 · Living finish
Copper
Pink, then chocolate, then green. Best conductor on the rack.
Density8,960 kg/m³
Tensile≈ 250 N/mm² half hard
Expansion17 µm/m·K
MagneticNo
Conductivity100% IACS
SuppliedBright rolled, already oxidising
CorrosionDarkens, then verdigris
Material costHighest
Cut speedSlowest
Thicknesses5 SIZES · MM
0.91.21.52.03.0
Good for
- Splashbacks, bar tops, roofing
- Busbar and earthing plates
- Antimicrobial handles, push plates
Avoid when
- You want it bright
- Touching oak or aluminium
- Over 3 mm — unstocked
Working with copper
Brazed or soldered, not welded — and the slowest thing on the bed, because it throws the beam straight back.
WORKED EXAMPLE · 200 × 200 mm plate, 1.5 mm, one off, mill finish — 0.54 kg each · priced live in the Builder
Sheet sizes & stock
What fits on the bed.
You buy the rectangle your part occupies, not a sheet.
Max part3000 × 1500 mm
Max priced online1000 × 1000 mm
Nesting allowanceIncluded
Profile tolerance±0.10 mm
Flatness±1.5 mm per metre
Thickness toleranceEN 10051 / EN 485
| Stock sheet | Size | Area | Mass in 2 mm mild | Held in |
|---|---|---|---|---|
| Standard | 2000 × 1000 mm | 2.00 m² | 31.4 kg | All nine materials |
| Long | 2500 × 1250 mm | 3.13 m² | 49.1 kg | Mild, Zintec, Corten, 304, 316, alu |
| Full bed | 3000 × 1500 mm | 4.50 m² | 70.7 kg | Mild, 304, alu; rest to order |
| Offcut rack | 1250 × 625 mm and down | 0.78 m² | 12.3 kg | Last week's offcuts |
How the sheet is charged
You pay for the bounding rectangle your part occupies, plus an allowance for the skeleton left around it. Both are already inside the figure the Builder shows — there is nothing to add on afterwards.
Offcuts and the skeleton
Offcuts above 300 × 300 mm go on the rack, sold by weight. Ask and we’ll strap your skeleton to the pallet.
Parts over 1000 × 1000 mm
Still cut — the Builder passes them to us for a manual check. Over 3000 × 1500 mm we split the part and tell you where.
Finishes
How it leaves us.
Chosen in the Builder and priced with the part.
Deburred
Edges linished, dross off. Safe to handle.
Per partIn the Builder
Vibro tumbled
Ceramic media. Every edge radiused.
Per partIn the Builder
Brushed 240 grit
A material, not a process. One grain direction.
See 304 brushedMaterial
Mirror polish
Also a material. Film stays on to the door.
See 304 mirrorMaterial
Powder coated
Any RAL. Priced on coated area, both faces.
Per m² coatedIn the Builder
Quoted per job: zinc plating, galvanising, anodising, vapour blasting, patination.
Material questions
The six we’re asked every week.
Will mild steel rust?
Yes — within days outdoors, hours if wet. Paint within 48 hours, or move to Zintec, Corten or stainless.
Which stainless should I use near the coast?
316 — its 2–3% molybdenum resists chloride pitting. 304 tea-stains in its first coastal winter. Use A4 fixings.
Can you cut galvanised sheet?
Zintec, yes. Hot-dip, no — it attacks the optics. We cut mild and send the assembly out to be dipped. Allow 10 working days.
Do you supply material certificates?
Yes — EN 10204 3.1, priced per batch. Ask at order time; afterwards means a recut. We’re ISO 9001.
Can I supply my own material?
Yes. Flat, clean, dry, 30 mm spare edge. Cutting and setup only — a good deal less than supply-and-cut. Send 10% spare; we can’t warrant it.
What’s the minimum thickness for a tapped hole?
One thread diameter: M4 wants 4 mm, M6 wants 6 mm. Thinner, use a clinch nut. We tap to M12 — the Builder prices it per hole.
Still deciding? Send the drawing and we’ll price it in three materials.
No sales call.
Or call 01234 567 890 and ask for the cutting office.