KupferwalzLaminoir / Liège

Copper rolling mill / Liège / since 1889

Threemillimetresto a twentieth.

Cast, hot rolled, cold rolled, annealed and cut in one building. One alloy, ten gauges, and a scrap bin that never leaves the site.

The gauges
The interior of a copper rolling mill, a wide sheet of copper running between steel rolls
The cold mill. Eleven passes behind it, four to go.

Ten gauges

Drawn at forty times scale, so the thinnest one is still visible. Anything between them is a special and takes two weeks longer.

  1. 3.00 mmRoofing, standing seam
  2. 2.00 mmRoofing, welts and flashings
  3. 1.50 mmCladding, folded panels
  4. 1.00 mmCladding, cassette
  5. 0.70 mmGutters and rainwater
  6. 0.50 mmRepoussé and spinning
  7. 0.30 mmEngraving plate
  8. 0.20 mmEtching plate
  9. 0.10 mmShim and gasket
  10. 0.05 mmFoil, laminated

Tolerance is ± 3 % of gauge or ± 0.01 mm, whichever is the larger, measured on five points across the width. The measurement travels with the coil.

Copper is the only material in this building that never gets worse. Everything we cut off, drop, reject or take back goes into the next melt, and it comes out exactly as good as the metal that arrived on a lorry.

Kupferwalz has rolled on the Quai des Ardennes since 1889. Forty-one people, one casting bay, a hot mill from 1974 and a cold mill that has been rebuilt twice around its original frame.

We roll one alloy. Everything else about the order — gauge, temper, width, finish — is a setting; the metal never changes.

Five stations

A slab is 180 mm thick when it is cast and 0.05 mm when it leaves. Nothing else happens in between.

  1. 01

    Melt and cast

    Cathode copper and our own returns, melted under charcoal and cast as a slab 180 mm thick1 120 °C
  2. 02

    Hot roll

    Down to 12 mm in eleven passes while the slab is still red, which is the only cheap reduction there is820 °C
  3. 03

    Mill and pickle

    Both faces skimmed, the oxide taken off in acid, and the coil weighed before anything else happensCold
  4. 04

    Cold roll

    The gauge is made here, one pass at a time, with an anneal whenever the metal stops being willingCold
  5. 05

    Anneal and cut

    Softened to temper, levelled, and cut to sheet or slit to strip on the same line450 – 650 °C
A tall coil of rolled copper sheet standing on end on a mill floor
Two point four tonnes, on end, waiting for the slitter.
A stack of cut copper sheets on a pallet seen from a low angle
Cut sheet, 1.0 mm. The gauge is printed on the top one.

Three habits of the mill

All three cost money and all three are the reason anybody buys from a mill this small.

A small rolled copper sheet offcut, slightly curled

I

Gauge is measured, not claimed

Every coil is measured on five points across the width and at both ends, and the sheet goes out with that measurement printed on it, including the one that is at the edge of tolerance.

A short copper billet with sawn ends

II

One alloy, endlessly

Cu-DHP and nothing else. Copper is the only common metal that can be melted back into itself forever without losing anything, so our scrap never leaves the site.

A heavy steel mill roll segment with polished faces

III

The rolls are ours

Ground in the building, to a crown of four hundredths, on a machine bought in 1961. A rolled sheet can be no flatter than the roll that made it.

The specification

Published in full. If a job needs something not on this list, it is a conversation, not a form.

  1. Cu-DHPPhosphorus deoxidised99.90 % Cu minEN 1172Roofing and cladding
  2. Cu-DHPPhosphorus deoxidised99.90 % Cu minEN 1652Sheet, strip, plate
  3. Temper R220Annealed220 MPa minSoftDeep drawing, repoussé
  4. Temper R240Quarter hard240 MPa minHalf softFolded panels
  5. Temper R290Half hard290 MPa minSpringyStanding seam
  6. WidthSlit to order20 – 1 000 mm± 0.5 mmAny gauge
  7. LengthCut to orderUp to 4 000 mm± 2 mmSheet only
  8. Coil weightAs rolled80 – 2 400 kg—Inner Ø 400 or 500
  9. FinishMillAs rolled, bright—Standard
  10. FinishPre-patinatedGreen or brown—Six week lead

Every kilo of copper ever mined is still copper. We are only ever borrowing it and changing its thickness.

Martine Delhaize, melt shop

Where it went

Recent work, with the customer’s permission. Roofs outlive everybody who argued about the budget.

  1. 2026Cathédrale Saint-PaulLiège0.7 mm, 14 tRoof, standing seam
  2. 2025Musée de la BoverieLiège1.0 mm, 6 tCladding, cassette
  3. 2025Rijksmuseum depotAmsterdam0.2 mm, 240 kgEtching plate, cut sheet
  4. 2024StadhuisMaastricht0.7 mm, 9 tRoof and gutters
  5. 2024Atelier VandeputteGhent0.5 mm, 90 kgSpinning blanks
  6. 2023Kasteel van GaasbeekLennik2.0 mm, 3 tRoof, restoration
  7. 2022Grand CurtiusLiège1.5 mm, 11 tCladding, pre-patinated
  8. 2021Basilique Saint-MartinLiège0.7 mm, 17 tRoof, the largest since 1998

Buying from a small mill

Minimum
One sheet over the counter, one coil by lorry. There is no minimum for a restoration.
Lead time
Four weeks from stock gauge, six for pre-patinated, ten for anything unusual.
Offcuts
Sold by weight on Fridays and bought back at the same price whenever you like.
Certificates
EN 10204 3.1 with every despatch, whether or not you ask for it.

Quotations, specials, scrap

Ask for a price

Quai des Ardennes 60, 4020 Liège. The weighbridge is open from six; the office, sensibly, is not. Quotes go out the day after the mill has looked at the schedule.