How do you make an archery arm guard?

Answer 1

In reality they are quite cheap to purchase, but you can have your own leather bracer made if you wish to.

A decent arm brace is about half the length to the full length of your forearm, and is a wide as two thirds of the circumference of your forearm (you don't need exact measurements).

Traditional Archery bracers are nearly always made of tanned leather, and have some kind of elastic or non elastic attachment to your arm in the forms of leather string, shoelace, or other equivalent going through symmetrical holes in the bracer around your arm.

Remember that a bracer does not need to be of a very complex design, so long as it matcheds the features mentioned above. Many modern style bracers use plastic or thick material such as nylon instead of leather, but they have the same kind of effect at the cost of aesthetics (how good it looks).