A knight costume is a suit of armour that can be worn over a loose tunic and trousers or leggings. Making armour for knights was a labour-intensive and very expensive activity, as each piece of armour had to be tailored to the body of the knight, or else it might prove dangerous in battle. Nowadays, metal suits of armour are in short supply, so make your own lightweight knights armour from cardboard -- it won't protect you in battle, but it will get you all the best-dressed prizes at fancy dress parties.
Measure the circumference of the paddling helmet, or a similar, peak-free helmet that fits the designated wearer of the knight's costume. Draw a line to this length on a piece of butcher's paper.
Draw two parallel straight lines on either side of this line, five inches away. In the centre of the lines, draw on the design for the face of the helmet, using the central line as the reference point of the brow, with the bottom line the point where the helmet ends near the neck, and the top line the top of the helmet. You can simple draw an arch, or add a nose plate in the centre -- its up to you. Cut out the butcher's paper template and transfer it to the cardboard.
Trace around the paper template onto the cardboard, then cut around the outline with a utility knife. Wrap the cardboard around the helmet, positioning where the middle line would be around the rim of the helmet. Glue in place with hot glue. Cut out a circle that matches the size of the top of the helmet, and glue that on top.
Trace a rectangle, roughly the size of the wearer's chest, onto butcher's paper. Cut out and trace this template twice onto cardboard, for the breastplate and back plate of the armour. Cut out two more rectangles, around three inches wide by six inches long for the connecting plates of the shoulders.
Lay the chest plate and breastplate flat on a work surface, around four inches apart at the top. Place the two connecting plates between the breastplate and back plate. They should be an inch in from either side, with an inch overlapping on each end. Glue in place with hot glue.
Cut two pieces of cardboard long enough to span from the wrist to just before the elbow, and wide enough to go around 3/4 of the arm of the wearer. Repeat for the calves, thighs and upper arms.
Paint all the components of the knight's costume in the desired shade. Silver, gold or bronze are good choices. Cut 32 strips of fabric to one inch wide and ten inches long.
Hot glue the fabric strips onto each end of the upper and lower arm covers and the upper and lower leg covers. These are the ties for attaching the armour to the body.
Make a hole with a utility knife or scissors through the cardboard and fabric where they are attached. Push a split pin into the hole, ensuring the head of the pin is on the outside of the cardboard. Open the legs of the pin to attach it firmly to the cardboard. This helps to securely fasten the cloth ties to the cardboard, as well as giving the appearance of riveted metal.
Insert three split pins on either end of the shoulder plates where they attach to the breast and back plates to give the same appearance of rivets. Put the body armour on first, then the legs, arms and lastly, the helmet.
Paint a crest, like a rampant lion or a unicorn onto the breast plate.