ok, this was a quick little project you can do with a metre/yard of vinyl, cardboard and foam.
for the gauntlet, you need:
hot glue (i'll explain why you need this in a sec)
for the blade, you need
a craft knife (prefably supidly sharp)
silver spray paint
Step 1: Gauntlet.
so to start the gauntlet, cut a 5 by X (the length of your wrist to elbow) square in the vinyl and cut it out, make sure it fits around your arm comfortably because i don't want to have people's lawyers trying to sue me because it was too tight and cut off your blood circulation to your forearm. if it's too wide, just cut it back a few centimetres, then try it again, once you have your perfect fit, add velcro to either side to attach it to your arm.
the armour plates:
for this, i had a template to make these from, i should have provided it on this instructable somewhere, but you're gonna take your cardboard and mark around the armour pieces and then with a craft knife, cut them out. Again, i'm not at fault if you injure yourself with the craft knife.
the belt details.
make three 5X1 strips from the vinyl and hot glue them to the gauntlet BEFORE attaching the armour plates, this way, it looks cooler and more authentic.
also, make some space to attach the hidden blade with velcro.
once all that's done, find where you want the armour plates attached and stick them down with velcro.
Step 2: Hidden Blade
ok, this is possibly the easiest but most complex part of the build, you need a craft knife, foam and hot glue.
what i did was grab the stormthecastle.com's hidden blade template and tweaked it a little.
i made everything thinner and the blade box sides shorter.
i halfed the size of the blade in width
halfed the size of the box top and bottom in width
halfed the size of the blade box sides by half in height
i looked at how they came together and put it together with hot glue.
the next step was to paint it up in silver, so you'll have to do that first before hot glue.
lastly, attach it to your gauntlet.