Disclaimer: this is an involved process not for beginner, it comes from the strange mind of someone has always loved discovering how things are made (lace making aged 9?). A shape made from papier-mâché over a balloon is a more classic approach, but this is comfortable to wear and way more cool! The photo was taken at the end of a long day of wear ;)
if you need a dramatic headpiece for a school play or fancy dress costume here is a step by step guide.
Polystyrene display head
1/2 m panne velvet (I had tonnes left so you may get away with 30cm if you can buy less)
25cm - 1/2 m contrast material
Fake hair - I found cos play wigs are in great colours from around £3
Fat quarter / 25cm lining material in any colour
wire (about 0.4mm thick - ideally cotton covered)
1m woven buckram or heavy weight woven interfacing.
Optional, holographic gold hair extension hair
The pickle is almost ten, and her head measurements are an almost perfect fit for standard polystyrene display head (for adult ladies I have found that a male display head is a better fit, as we all know how small seems to be beautiful when it comes to display models). It is definitely worth taking a measurement! Display heads are available on line from about £2.
Cover the head with cling film then start to layer up with iron on buckram or the heaviest fusible interlining. Get something that is woven then you can use the bias effect to get a lovely smooth edge around the curves of of the head.
I used 10 - 15cm wide bias strips of buckram then ran the strip and the left over corners under the tap briefly before rolling them up and it and popping them into a polybag for about 20 minutes to make it really malleable. Cut another bias strip of a lining material, any only material will do but it will help make a soft barrier so you do not get a mess welded to you display head.
Pin the start of the lining strip at an angle so that when you wrap the strip around the head you do not cover the pins. Pull the strips firmly as you go and you will get a beautifully shaped finish. Once you have a base layer repeat with the first layer of buckram. Once you have a section that you are happy with pin (at an angle) cover with a damp cotton cloth and iron buckram into place. The iron I am using was a cheap steamer iron that I got from Lidl for well under £10 (I put a silicon cover on so I don't need to use an ironing cloth). The left over corners of buckram so are great for covering the crown of the head where the strips don't reach.
The general rule with shaping materials over heads ('blocking' is the millinery term) is think about the compass. Start by securing the main directions, where the fibres of the material are in a straight line (North and South then East and West) then go for the diagonals which have more give due to the bias effect (NE, SW then NW and SE).
I did three layers of buckram and this was beautifully firm. If you have difficulty making the crown section smooth and you have some bits that look as if they will stick up you can just trim away any excess and iron it all flat. A covering layer will make it look neat later. Also you will trim the edges so don't worry if you are covering the ears and forehead unduly.
When finished draw on where you think the edge of the headpiece should be. Once it has dried, ideally overnight, gently prize it off the display stand. A flexible piece of plastic may be needed (for example a ruler to a plastic plant tag). Trim the edge, erring on the side of caution if are not sure as you can always trim back further later. Check to see if the lining has stuck, if necessary a bit of clear glue such as UHU can finish the job neatly. When you are happy withe shape blanket stitch the wire around the edge of the headpiece.
Next draw on the correct shape for the horn. Ours was about 40cm long, so I started by drawing the 40cm line and the arc around the tape measure to make a another 40cm line about 20cm away resulting a narrow pizza slice shape. Draw on an extra 2cm along one long edge and along the bottom arc shape as seam / sticking allowance. Cut in along the bottom arc seam allowance to allow you to fold it outwards to stick onto the head when you are ready.
The next bit is fiddly. You need to roll up the horn into a spike then gently iron it together. I had a paint brush that I covered in a cloth and held it down the inside as I ironed the outside of the buckram to stick it all together.
I stuffed the horn for added stability then I ironed the horn onto the head shape. I cut a few scraps of buckram into strips to act like a type of buckram sellotape to keep it really stable.
Repeat the cutting out steps but this time in the contrast material. Fold over then iron one long edge of the contrast material flat then wrap around the horn. You can pin along the horn, then sew it all together, with an invisible stitch. Here is a link if you are unsure: http://realhousemoms.com/invisible-ladder-stitch/
Next do the same for the ears. Start by cutting out a 15cm radius semi circle of buckram the cut this in half. Cut a 7cm straight line from the outside of the 1/4 circle towards the middle, then fold the straight sides inwards. This is your ear shape. Fold out ear so that the outer third of the circle is folding outwards and you you have a flat bit to iron/ stick onto the head shape and the pointed end you can fold up into an upright position. If you want to take if one step further I sewed some of the wire along the edge of the ear so that I could manipulate the shape a little more.
Following the shape of the ear sew a little triangular shape of velvet with a little contrast material in the centre and pop over the ears.
Take the panne velvet and work out where the horn will fit, trying to keep the grain line of the velvet going from the back of the head directly over the head to the forehead. Make a slightly too small hole for the horn(as the material will stretch and you don't want a gaping hole). Fit the velvet over the head and over the horn. At this point when it is almost in position mark out where the ears fall and carefully cut out the ear holes. Sew velvet to the ears and horn, folding over the edges of the main velvet then pulling over the ears and horn before stitching it all together.
The wig is made up of strips of hair attached to a mesh cap. Unpick or cut the strips of hair off. Sew the strips of hair into place, with a fringe and swooping over to one side with plenty to swish down the back. Once it is done you can be a unicorn hair stylist and trim for effect. I also sewed a little of the main hair over the base of the fringe hair to over up the plastic roots.
Once the mane is in place I trimmed the panne velvet and using the compass theory (first North and South then East and West before other points) I folded over the edge and pinned into the wire at the edge. You can pull the diagonal edges firmly to get a smooth edge that does not look like a shower cap!
As a final indulgence you can take som holographic fake hair and use a darning needle to thread if through the hair and tie it into place.
Result - one very happy unicorn, you can call her Candleberry!