When pre-made hat bases just won't do, it's time to get blocking! Hand blocking your own sinamay bases is easy to do, opens up a whole new world of customisation and can even be done without specialist equipment. So let's begin!



-Sinamay Fabric

-1.2mm Millinery Wire

-Wire Joining Ferrules


-UHU Glue

-Straw Stiffener


Tools & Equipment:


-Wire Cutters


-Hat Block

-Cling Film

-Straight Pins

-Blocking Pins


-Millinery Needles

-Empty Jar & Paintbrush

-Spray Bottle for Water

Not Essential But Nice:

-Tea Towel (to wipe up messes)

-Tape Measure





Step 1: Prepare Hat Block

Sinamay is a sticky business, so we want to protect our wooden hat blocks with 2 layers of cling film. This will protect it from moisture, dye transferring and will help to ease the sinamay off the block when it's dry. We like using a piece of oilcloth fabric to protect our work surfaces as well. 


Step 2: Cut Out Sinamay

Sinamay fabric can vary in thickness, weight and opaqueness. For thinner, sheer handwoven sinamay you will need three layers to make a sturdy hat base. Our sinamay is a nice thick weight so we will be using two layers to make a small pillbox fascinator. Cut a piece of fabric big enough to fold up and over the sides of your block. For additional layers, use your first piece as a template, ensuring that you match up the grains of the sinamay.


Step 3: Wet Your Sinamay


Most sinamay fabrics have a built in sizing agent that helps sinamay retain it's shape, so it's really important that we keep this sizing by not over wetting our sinamay. We are going to block all of our layers of sinamay at once, so start slowly by spraying a fine mist with a water bottle on the front and back of your fabric sandwich. Over wetting your sinamay can also make the dye bleed out of it, so use caution! Your fabric will begin to soften up and should start to become more supple when the water is absorbed. When your layers have become nice and buttery your ready for the next step. 

Step 4: Block Your Fabric

Ensuring once more that your layers are all on the same grain, place your sinamay sandwich on the table with the grains running straight from left to right and up & down. We will start by pinning 'on the straight' at 12 o'clock, 6 o'clock, 3 'oclock then 9 o'clock, tightly pulling the fabric taught at each edge and inserting in the pin to keep in place. If your block has an indented crease your pins will go there. We are using a basic wooden disc so will be putting them on the outer edge. 

Now that you have your 4 key pins in place, it's time to add more. Working in between your previous pins, insert more using the same clockwork principles of working directly across from the last pin you inserted. Pull tightly, smoothing out gathers as you pin. Your goal is to work out any visible lumps, bumps and creases from your fabric.

Keep adding pins as necessary, making sure the grain of your sinamay has not slipped and that your fabric remains suitably wet to work with. After inserting several pins, you may find that you can take out even more slack from the sinamay so don't be afraid to unpin, tug and re-insert your pins until you have a totally smooth surface free of unwanted bulk.

Step 5: Dry & Stiffen

After letting your fabric completely dry on the block, we need to make it stiff so it holds it's shape. If you have a very crisp shape with flat surfaces feel free to take a mini iron to it to take out any unwanted bumps whilst still on the block. For our stiffener we are using a spirit based straw stiffener here, but a watered down PVA glue solution will work just as well - a 1:3 ratio (1 part PVA, 3 parts water) tends to work well.

 Using a standard paintbrush, paint 2-3 thin layers of stiffener onto your piece, thoroughly drying between each layer. Don't go heavy handed with the stiffener here - glooping it on can result in your piece fusing to the hat block or a window pane effect in between sinamay strands.

Step 6: De-Block & Cut

When your sinamay has completely dried from stiffening (usually overnight), it's time to take your piece off the block! Before we do that we will want to mark out our wire line with chalk. Your wire line will usually follow the crease where you inserted your pins. Our simple pillbox shape has no crease on the underside of the block so we will mark a line at it's bottom edge.

Removing your sinamay from the block can be nerve wracking affair, but if your piece has been sufficiently blocked and stiffened it will remarkably remember it's shape, even after you have given it a little tug. Sometimes gently getting in-between the block and the fabric with your fingers followed by a quick rip off the shape works best. Think of ripping off a delicate plaster!

After you have pulled your fabric from the block, cut approximately 5mm away from your wire line to remove excess fabric.

Step 7: Wire It Up

Wiring up the edge of your hat makes sure it maintains it's shape and also allows for a sturdy base to attach your fittings. Cut a piece of millinery wire to fit the chalk line of your piece, dab the raw ends into UHU glue and insert into the wire ferrule. Squeeze ferrule with pliers to secure.


Place wire into piece, pinning the 5mm fabric excess over the wire to encapsulating it. After pinned into place, use a double thread to sew into place using a 'wire stitch' (similar to a blanket stitch). 

Step 8: Finishing

Now your shape is complete you can decide how you want to finish it! From here you can insert a lining, add a curved petersham ribbon or cover your wired edge in sinamay bias. 

Liked our tutorial? Head over to Instagram and tag us @petershams to show us your hats! 

xoxo Petershams