What Steel Thickness for a Low Poly Metal Sculpture? 0.8, 1.5 and 3 mm Compared
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The short answer. Riveted designs: 0,8–1 mm. Welded designs: 1,5–2 mm. Large outdoor pieces: 2,5–3 mm. Thickness follows how you join the panels and where the piece will stand — not which animal you picked. Everything below is why, and what breaks if you get it wrong.
This is the question that arrives just before someone spends money, and it is almost never answered properly. Search it and you get supplier gauge charts, forum threads about car panels, and calculators that assume you are building a bracket. None of them know that you are folding a hundred small triangles into an animal.
So here is the answer for this specific job, from the drawings we actually sell.
The three ranges, side by side
| Build type | Thickness | Why this range | Typical piece |
|---|---|---|---|
| Riveted | 0,8–1 mm | Thin enough to fold the tabs by hand and drill cleanly for a pop rivet | Wall heads, shelf pieces, flat-pack gift kits |
| Welded | 1,5–2 mm | Holds its shape under the heat of a weld; thin enough to still cut fast | Indoor statement pieces, lobby and restaurant work |
| Large outdoor | 2,5–3 mm | Resists wind load and knocks, and leaves corrosion allowance | Garden, forecourt, entrance and street-scale installations |
Notice what is not in that table: the animal. A deer and a lion at the same size in the same place take the same sheet. The design does not change the material — the joining method and the location do.
Why riveted designs use 0.8–1 mm
A riveted build has no heat in it. Every joint is mechanical: you bend a tab, line it up against the next panel, and set a pop rivet through two pre-cut holes. That imposes two limits.
You have to be able to fold the tab. Not in a press — in your hands, or over a bench edge with a pair of grips. At 0,8 mm mild or galvanised steel that is comfortable. At 1 mm it is firm but fine. At 1,5 mm you are fighting the material on every one of a hundred folds, and your angles drift, which shows up as gaps in the finished facets.
The rivet has to grip. Our riveted files are drawn around 3,2 mm, 3,5 mm or 4 mm rivets depending on the design, and a standard pop rivet has a grip range — the total material thickness it can clamp. Two layers of 1 mm sheet is 2 mm of grip, which sits comfortably in range. Two layers of 2 mm is 4 mm, and now you are buying long-grip rivets and the head is no longer sitting flat against the facet.
This is the whole reason the riveted range exists: it is the one that finishes without a welder, a press or a workshop. We wrote up why rivet templates finish fastest if you want the timeline. Going heavier than 1 mm quietly removes every advantage you bought it for.
Why welded designs use 1.5–2 mm
Weld the same 0,8 mm sheet and the problem inverts. Thin steel does not tolerate a MIG arc: you blow through, the panel distorts as it cools, and the facet that was flat is now oil-canned. You can weld 1 mm if you are good and patient with TIG, but you should not have to be good to assemble a template.
1,5 mm is the working floor. It takes a tack without burning through, it stays flat while the rest of the piece goes together, and it grinds back to an invisible seam.
2 mm is for anything with a span. A wall-mounted head at 1,5 mm is rigid because it is small and shallow. Stretch the same geometry to 800 or 900 mm and unsupported panels start to flex when you press on them. 2 mm buys that back.
If you are still deciding between the two methods entirely, we put real costs and learning curves side by side.
Why large outdoor pieces go to 2.5–3 mm
Outdoors, three forces show up that a living room never applies.
- Wind. A low poly animal is a collection of flat planes, which is another way of saying it is a sail. A 2 metre piece catches real load, and the load lands on the seams.
- Contact. Garden pieces get brushed by mowers, leaned on, climbed on by children, reversed into. A 1,5 mm facet dents from a knock that 3 mm shrugs off.
- Corrosion allowance. Rust does not care about your finish forever. On 1 mm sheet, losing a few tenths of a millimetre is a structural event. On 3 mm it is cosmetic for years.
This is why the step is to 2,5–3 mm and not to 2 mm. It is not a small increase in strength — stiffness climbs much faster than thickness does, so going from 1,5 mm to 3 mm makes a panel roughly eight times stiffer against bending, not twice.
The largest piece built from our drawings so far is a 6 metre sculpture. At that scale the thickness question stops being about the design and becomes an engineering one — talk to us before you cut. Every file can be rescaled, but the material has to scale with it.
What actually goes wrong if you pick the wrong one
| Mistake | What you will see |
|---|---|
| Welding 0,8 mm | Burn-through on the first tack; warped, wavy facets that no amount of grinding fixes |
| Riveting 2 mm | Tabs you cannot fold cleanly, drifting fold angles, rivet heads standing proud, visible gaps at the joints |
| 1,5 mm on a large outdoor piece | Looks perfect on day one; dents, flexes at the seams and starts to lean after a windy winter |
| 3 mm on a 370 mm wall head | Cutting cost up, folding now needs a press, and the finished piece is heavy enough to need serious wall fixings — for no visual gain |
| Cutting a thickness the drawing was not compensated for | The one below. This is the expensive one. |
The one nobody warns you about: bend allowance
This is the part that separates a flat pattern that assembles from one that does not.
When sheet metal is folded, the outside of the bend stretches and the inside compresses. The material does not simply pivot around a corner — it takes up length. So a flat pattern is not the finished shape unrolled; it is the finished shape unrolled and then corrected for how much material the folds will consume. That correction is called the bend allowance, and it is calculated for a specific thickness.
Cut a drawing compensated for 1 mm out of 2 mm sheet and every fold eats more material than the drawing expected. Individually the error is a fraction of a millimetre. Across forty panels it compounds into facets that no longer meet, tabs that fall short of their holes, and a nose that does not close.
The piece does not fail dramatically. It just never quite comes together, and most people blame the file.
So: the thickness is not a preference. It is part of the drawing. If you want a different thickness, ask for the file to be redrawn for it — get in touch and say what you are cutting. Rescaling and re-compensating is routine work; guessing at the bench is not.
Want to test this cheaply before you commit? That is exactly what the €30 Eagle Head is for. It is a 370 mm welded wall head in 1,5–2 mm sheet, the lowest-priced file we sell, and it costs less than the steel you would waste proving the point the hard way. Cut it, fold it, and you will know within an evening whether our compensation matches your machine and your press. Every other file in the catalogue is drawn to the same standard.
What thickness does to your weight, cost and cutting time
Steel weighs about 7,85 kg per square metre per millimetre of thickness. That gives you an exact figure to plan with:
| Thickness | Weight per m² | Cutting | Folding |
|---|---|---|---|
| 0,8 mm | 6,3 kg | Fast; hand tools work — snips, nibbler, jigsaw | By hand |
| 1 mm | 7,9 kg | Fast; hand tools still work | By hand, firmly |
| 1,5 mm | 11,8 kg | Laser or plasma; angle grinder for straight cuts | Bench edge or press |
| 2 mm | 15,7 kg | Laser or plasma | Press |
| 3 mm | 23,6 kg | Laser or plasma, noticeably slower per metre | Press brake, no alternative |
Two things fall out of that table. First, weight is the hidden cost of going thick — it changes your wall fixings, your delivery, and whether one person can lift the finished piece. Second, 0,8–1 mm is the only range you can cut with tools you probably already own, which is the argument in cutting sheet metal at home without a plasma cutter. From 1,5 mm upward you are sending the DXF to a shop, and that is fine — most makers do.
Stainless, mild steel or galvanised?
Thickness first, alloy second — but the alloy shifts the ranges slightly.
- Mild steel — the default. Cheapest, folds most predictably, welds easily. Needs a finish if it lives outside.
- Stainless — stiffer and springier than mild steel at the same thickness, so it fights you a little more on the fold and springs back a degree or two. Beautiful mirrored finish, no coating needed. Our riveted files suit it well at 0,8–1 mm.
- Galvanised — good value for riveted outdoor work since the coating does the corrosion job. Do not weld it without serious extraction: heating the zinc coating produces fumes you do not want to breathe.
For a riveted outdoor piece, galvanised at 1 mm is often a smarter answer than going thicker in mild steel.
Frequently asked questions
What is the single most common thickness? 1,5 mm. It covers most welded indoor work, which is the largest part of the catalogue.
Can I rivet 1,5 mm if I have a press? You can fold it, yes. But check your rivet grip range before you buy the sheet — two layers of 1,5 mm is 3 mm of grip, and the standard rivets our files are drawn around may not reach. It is a workable choice, not a free one.
Can I weld 1 mm to save money? With TIG and a steady hand, yes. With MIG, expect burn-through. The saving is a few euros of steel against a real risk of scrapping the panel — rarely worth it.
Does the thickness change if I scale the file up? Yes, and this is the one people miss. Thickness scales with size, and the flat pattern has to be re-compensated for the new thickness. Contact us before you rescale.
Is 3 mm the maximum? For our designs, in practice yes. Beyond 3 mm the folds need larger radii, the bend allowance changes substantially, and a low poly facet starts to read as clumsy rather than crisp. Large pieces get their strength from internal framing, not from ever-thicker skin.
What about aluminium? It works for riveted builds at 1–1,5 mm — aluminium is softer, so you go slightly thicker than you would in steel for the same stiffness. It is light, which helps for hanging pieces. It is not a welding option unless you have TIG and aluminium experience.
My local supplier sells by gauge, not mm. What do I ask for? Ask for the millimetre figure and let them convert — gauge numbers differ between standards and the mismatch is exactly how people end up with the wrong sheet. 0,8 mm, 1 mm, 1,5 mm, 2 mm and 3 mm are all standard stock sizes across Europe.
Where to go from here
Pick your joining method first, then your location, and the thickness is decided for you. Riveted and indoors: 0,8–1 mm. Welded and indoors: 1,5–2 mm. Large and outdoors: 2,5–3 mm.
Every file we sell states the range it was drawn for, on the product page. Browse the riveted templates if you have no welder, the welded templates if you do, or the full catalogue — files start at €30 and download instantly, with the nested DXF, every fold angle in degrees and the numbered assembly order.
Never cut one of our drawings before? Start with the €30 Eagle Head and settle the question for the price of a takeaway. New to the whole process? The step-by-step build guide walks through cutting, deburring, folding and assembly in order, and this one helps you pick the right design for your setup.