Blocking a Felt Hat

Measure around the head just above the ears, where the hat will sit. Add 10 mm for the ribbon that goes inside the band. That figure is the crown block size you need.

A plain cone hood gives a crown and a narrow brim at most. A capeline carries a wide brim already. Pick by the brim you want — you cannot add felt later.

Hold the felt up to a light. Thin patches show through as bright spots and will stretch first and tear. Position any thin area where it will be cut away or hidden under the band.

Hold the felt in steam, moving constantly, for 2 to 3 minutes until it is limp and floppy right through. Thorough steaming is the whole job. Steam must penetrate every interlocking fibre — under-steamed felt will not hold its shape and will be weaker when dry.

Push the softened cone down over the crown block, working with flat palms from the top down. Pull evenly all round — pulling harder on one side sets a permanent lopsided crown.

Tie a blocking cord tightly into the groove at the base of the crown block. This fixes the headline and stops the felt creeping back up as it dries.

Steam any wrinkle again locally and stroke it outward toward the brim with the heel of your hand. Never pinch a wrinkle flat — that sets a crease you cannot remove.

Push blocking pins through the felt into the block just below the cord, at 30 mm intervals all the way round. Angle them downward so tension pulls them tighter, not out.

Slide the brim block up under the surplus felt, steam the brim area again, and stretch it flat and even out to the rim. Pin it down all round.

Leave it on the block to dry completely at room temperature — overnight at minimum, 24 hours in humid weather. Removing a damp hat undoes everything; the felt relaxes straight back toward the cone it used to be.

With the hat still pinned, run a marker at a fixed distance from the crown all the way round, then cut on that line with sharp shears. Cutting off the block guarantees an uneven brim.

Lay millinery wire along the brim edge, overlap the ends by 40 mm, and stitch it down with a blanket stitch. The wire is what holds a brim shape against gravity and weather.

Stitch grosgrain ribbon inside the headline with small stitches that do not show outside. The sweatband is what makes the hat comfortable and what takes the wear.

Felt is older than weaving. Matted wool needs no loom — only fibre, moisture, heat and agitation. Wool fibres are covered in microscopic scales; work them together wet and warm and the scales interlock and ratchet, and the mat never comes apart. That makes felt one of the oldest textiles humans have, and it is why a felt hat can be one continuous piece with no seam anywhere.

Why steam and not just water. Steam carries far more energy than hot water at the same temperature and penetrates the mat faster and more evenly. It swells and relaxes the fibre scales so they slide instead of gripping — which is exactly the opposite of the felting process that made the material. When the hat dries, the scales lock again in the new shape. Milliners have kept steaming rather than soaking for a reason: the search literature is blunt that steaming is the old way and works best.

The block is the pattern. There is no paper pattern in blocking. The wooden block is the design, which is why milliners accumulate and guard collections of blocks, and why block-makers were a specialist trade. A hat shape going out of fashion meant a block going idle for thirty years — and blocks were kept, because fashion returns.

Stiffener. Commercial hoods and capelines arrive pre-stiffened, traditionally with shellac, which is what lets the blocked shape hold. Some milliners add more stiffener for a crisper result; a common modern workshop substitute is a 50/50 mix of PVA and water, chosen because it does not dry to a white film. Both are legitimate; the shellac route is the historical one.

The hatter's disease — and why this blueprint is safe. Historic fur felting, not wool, used mercury nitrate to make animal fur mat properly. The mercury poisoned generations of hatters, causing the tremors and neurological damage behind the phrase "mad as a hatter". That process is long abandoned and it is not this one: wool felts through mechanical agitation alone and needs no mercury or any other toxic agent. The history is worth knowing precisely because the modern craft carries none of it.