Materials, sizes and what it costs

Nothing here is exotic. A piece of board, a box of nails, a spool of sewing thread and a hammer. The details that matter are the ones that stop the piece failing halfway through.

The board

What	Number	Why
Thickness	12 mm minimum, 18 mm if using 30 mm nails	5 mm board causes nail failure under tension; 1 cm is the practical floor
Material	Plywood or MDF	Avoid particleboard — nails do not hold in it
Size	Cut it about 5 cm larger than the nail ring	You need somewhere to hold it and somewhere to hang it
Finish	Two or three thin coats of white, 12 h between coats	Contrast is the whole game; matte beats gloss

A few thousand lines pull surprisingly hard. Thin wooden rings have been reported to distort “into a pringles shape” under 3,000-plus lines, so if you want a hoop rather than a solid board, over-build it.

Popular real-world builds: a 39 cm IKEA lazy-susan disc painted matte white; a 60 × 60 cm paulownia board at 18 mm for 30 mm nails; a 80 cm laminated hoop on 12 mm MDF. The original Vrellis pieces used a 71 cm aluminium rim.

The nails

• Size: 1.2 to 1.6 mm shank, 20 to 30 mm long. Escutcheon pins and panel pins both work. Never go below about 10 mm of length.
• Protrusion: somewhere between 5 mm and 12 mm above the surface. Sources disagree; what everyone agrees on is that consistency matters more than the number. Uneven nail heights make the thread ride up and slip off.
• Count: buy about 10% more than the design calls for. You will bend some.
• Heads: small heads or none. A wide head catches the thread on the way past.

A depth stop makes the whole job faster and better: wrap a strip of tape around the nail at your target depth, or clamp a block of the right height beside it. Check your spacing every 20 to 30 nails against the printed template rather than at the end.

The thread

This is where most first attempts go wrong: people reach for embroidery floss or crochet cotton, and it is far too thick.

• Use sewing thread, 100 to 150 dtex (roughly Tex 10 to 15, or 0.10 to 0.15 mm). 100 dtex gives finer detail; 150 dtex is the comfortable default.
• Polyester or a cotton-poly core spun is stronger than pure cotton at these thicknesses.
• Black on white is the classic and the highest contrast. White on a matte black board also works — the studio has an invert switch for it.

How much

A useful rule: the mean chord across a circular board is about 0.64 × the board width. So:

thread length ≈ 0.64 × board width × number of lines, plus about 8% for the wraps around each nail.

For a 53 cm board with 2,600 lines that comes to roughly 900 m. The studio calculates the exact figure from your actual solved sequence rather than the rule of thumb.

For reference points from finished pieces: 1 to 2 km for 3,000 to 4,000 passes on a 71 cm board; 2.3 km for 3,844 lines on an 80 cm board; 1,543 m for 3,000 lines on 0.8 m.

What to buy

A 1,000 m spool of Gütermann Sew-All (Tkt 100, Tex 30) is easy to find but on the thick side. A serger cone — Maxi-Lock at Tex 27, 3,000 yd — is better value and closer to the right weight. Either way, buy more than you think: joining thread mid-piece is possible with a tiny knot but nobody enjoys it.

Tools

• Hammer, and pliers for holding nails you would rather not hold with fingers.
• A long ruler and a craft knife for the template.
• A printer, or a print shop and a USB stick.
• Optionally a pin vice for pilot holes in hardwood.

Rough budget

Board, nails and thread for a 50 cm portrait land in the region of the cost of a takeaway meal. The expensive input is time: 3 to 6 hours of winding for a mid-size piece, plus an evening of hammering and a day of waiting for paint.

Sources

Board and nail numbers are drawn from Johannes Haupt’s build notes, the Hackaday knit-portrait project, Embroidery Hooping’s portrait basics, and Good Strings’ nail guide. Thread lengths come from Vrellis, Michel’s Hackaday build and christiansiegel/knitter.