Working notes
What we see on the mill floor
Short pieces written after a claim, a rejected lot or a question that keeps coming back from buyers. No product pitches — the useful part is the mechanism, not the catalogue.
What Third-Party Inspection Covers, and What It Misses
A clean eighteen-page report, and the plate arrives under-thickness. Nothing was falsified. The scope asked a different question.
2026-10-31 · Read →
Stainless Steel Grades Explained: 200, 300 and 400 Series
The number tells you the alloy family — austenitic, ferritic or duplex — and the family, not the exact grade, decides most jobs.
2026-10-31 · Read →
Seamless vs Welded Stainless Steel Pipe: Which to Specify
Seamless is not better — it is rated higher for pressure and costs 20–60% more. Most buyers pay the premium without ever needing the extra rating.
2026-10-31 · Read →
Stainless Steel Surface Finishes: 2B, BA, No.4, Hairline, 8K
The finish is a measurable surface roughness, not decoration. The designation varies by mill — the Ra number is what you can actually hold someone to.
2026-10-31 · Read →
Incoterms for Aluminum: FOB, CIF and DAP Compared
CIF obliges the seller to insure the cargo. The cover required happens to exclude handling damage and condensation, which is most of what goes wrong.
2026-10-31 · Read →
304 vs 316L Stainless Steel: Which Grade to Specify
316L is 304 with molybdenum added and carbon pulled down. The difference is one number — PREN — that decides everything in chloride service.
2026-10-31 · Read →
How Many Tonnes Fit: Container Loading for Aluminum
Aluminium fills a container by weight, not volume. Why a 40-foot box often moves less metal than two 20-foot ones.
2026-10-31 · Read →
Aluminum Sheet Standard Sizes and Thicknesses
The sizes that are stocked, the 6 mm sheet-to-plate line, and why a 7075 sheet in a 6061 size means a mill order and a longer lead time.
2026-10-31 · Read →
Aluminum Density and Specific Gravity by Alloy
Aluminum is sold by weight, specified by dimensions. The density table by alloy that turns a millimetre into a kilogram, from 1050 to 7075.
2026-10-31 · Read →
Chemical Composition Limits: ASTM vs EN vs GB
The first line of a mill certificate, and the one place a buyer can check a claim against a public number. Composition limits for the common grades.
2026-10-31 · Read →
What to Put in an Export Packing Specification
Ask three suppliers what seaworthy packing means and you get three answers. None of them is a specification you can inspect.
2026-10-31 · Read →
Mechanical Properties of Common Aluminum Grades
What you are really comparing is a handful of numbers. Tensile, yield and elongation for the grades buyers order, at their working temper.
2026-10-31 · Read →
Aluminum Coil: ID, OD, Weight and Length Calculation
A coil is a ring of wound strip. The formula that turns OD and ID into weight and footage, and the 1-3% correction for winding tension.
2026-10-31 · Read →
Aluminum Weight per Square Meter: Table by Thickness
Aluminum weighs about 2.70 kg per square metre per millimetre of thickness. The table by thickness and alloy, and the formula that checks any order.
2026-10-31 · Read →
Aluminum Gauge to mm Chart (B&S Scale)
Aluminum gauge is not steel gauge. The B&S chart from 8 to 28 gauge, with millimetres and tolerance bands, and the rule that prevents ordering mistakes.
2026-10-31 · Read →
Aluminum Sheet Thickness Tolerance: ASTM B209 vs EN 485
The tolerance depends on thickness and width. The matrix for ASTM B209, EN 485 and GB/T 3880, and the three questions that check any quote.
2026-10-31 · Read →
8011 vs 1235: Foil Alloy for Packaging and Battery
8011 is the strong iron-bearing foil for packaging; 1235 is the pure formable foil for capacitors and batteries. Pinhole count decides the lot.
2026-10-31 · Read →
Theoretical or Actual Weight: What You Are Actually Paying For
The packing list says 20,000 kg. Your weighbridge says 20,180 kg. Nobody erred, and the gap is where a quiet argument starts.
2026-10-31 · Read →
3105 vs 3003: Roofing and Cladding Selection
3003 is the general roofing workhorse; 3105 is the stiffer pre-painted coil grade for longer spans. The coating usually decides.
2026-10-31 · Read →
6063 vs 6061: Extrusion Alloy or Machining Alloy
6063 is the extrusion alloy, 6061 is the strength alloy. The choice is shape and finish against a 40% strength gap.
2026-10-31 · Read →
5754 vs 5052: Automotive Sheet Selection
5754 is Europe's version of 5052. The choice is decided by the standard on the drawing, not by any performance gap.
2026-10-31 · Read →
1050 vs 1060 vs 1100: Purity, Conductivity and Price
1050 and 1060 differ by 0.1% purity. 1100 adds copper for strength at the cost of conductivity. None of them is a strength grade.
2026-10-31 · Read →
6061 vs 7075 Aluminum: Strength, Machining and Cost
6061 is the workhorse, 7075 is the specialist. The 75% strength gap is real, and it comes with two strings attached.
2026-10-31 · Read →
3003 vs 5052 Aluminum: Formability Against Corrosion
3003 forms more easily and costs less; 5052 is stronger and resists salt. The deciding variable is almost always the environment.
2026-10-31 · Read →
5052 vs 5083 Aluminum: Which Marine Grade to Specify
5083 is the hull, 5052 is everything bolted or formed onto it. The difference is one property that never shows up in a tensile table.
2026-10-31 · Read →
Tread Plate Thickness: Base Metal vs Overall, and Why Orders Go Wrong
A caliper over the bars reads 6.5 mm, one on the flats reads 5.8 mm, and both are right. The order named a word that means two measurements.
2026-10-31 · Read →
How to Read an Aluminum Mill Test Certificate, Field by Field
Most buyers check the alloy and the tensile figure. The fields that decide whether the document is worth anything are further down the page.
2026-10-31 · Read →
How to Write an Aluminum RFQ: The 11 Fields That Avoid Requotes
Four days for a price, then three more rounds to fix it. Each missing field is one round trip. Eleven lines that end the loop.
2026-10-31 · Read →
How to Check a Chinese Aluminum Supplier Before You Send a Deposit
Price first, checks later is why deposits go wrong. Seven things to verify in two days — no factory visit required.
2026-10-31 · Read →
6061-T6 or 6082-T6: Choose by Process, Not by Data Sheet
The data sheets match. Anodized color, thick-section strength and cycle time do not. Where each grade actually wins.
2026-10-31 · Read →
What Lands in Your Yard: Six Costs Between FOB and Your Door
A worked example: a $2.85/kg FOB quote that lands at $3.19/kg, and the three costs nobody puts on an invoice.
2026-10-31 · Read →
Why Aluminum Arrives Damaged — and the Packaging That Prevents It
Three of the four common failures are decided before the container is sealed. What to specify, and how to keep the claim alive.
2026-10-31 · Read →