I would also suggest foamboard. I use it for most of my props. It is kinda weak when you only have one layer but most decent sized swords are at least maybe 3 layers thick. Still even one layer can last if treaten with care. I know the lightning sword I made for rosabella has some areas that are only one layer thick and they only have minimal damage after 3 or 4 cons , not to mention being shipped by ups and the flight to and from anime expo.
Also foamboard is cheap, lightweight, and extremely easy to work with.
I made a tutorial for the lightning sword awhile ago so ill copy it here for you. I know your making a different sword but the process would be the same. But if you need any help or advice feel free to pm me. I would offer more advice specific to your sword but I don't know what it looks like -_-;;
anyway here is the tutorial I hope it helps
So here is my tutorial on how to make lightning's sword from FFXIII
* foamboard *primer
*gorilla glue *silver spray paint
*boxcutter * red and black acrylic paint
*large paper * projector (optional but its the easiest way to go)
*wax paper (recommended but optional)
*sandpaper * some sort of clear sealer
before i get started with the explaination here is the link to my gallery im having some problems with getting some more detailed pic up right now but in my gallery i have pics through the whole process and their labled as to what part im at (ie. schematics, layers, finished product ...) so please use those for reference
i made the sword out of foamboard (you can get it at the dollar store so its cheap) and i did it all on my own in about 4-5 days and most of that time was bc i messed up the first time and i had to wait for the paint to dry so this prorp is not very time consuming or hard.
ok first get a good image of the side of the sword head on and then if you have a projector use it to make a large projection on the wall of your sword (about 50" for lightning) then trace the image onto paper (you can tape sheets together or use newspaper )
*** note the 50" recommended measurement was made for someone about 5' 4" *** therefore if you feel this size would not be right for your height then you will want to measure the length when you are standing from the groung to your chest and use this for the length of your sword
now cutout your image so that ur left with a full size paper version of your sword (these are ur schematics) **** you can also make schematics by gridding off ur image and paper and drawing by hand or by printing out the large version from ur computer but that can be a lot of ink****
ok once you have your schematic figure out how mant layers you want ( i did 7 for lighting 1 base for the whole sword 2 (1 on each side) inner layers of the sword and all the handle 2 of just the inner handle and 2 of the higher parts of the handle ***** there will be seams on the sword part bc it wont all fit on the foam board make the single bases seam under the handle so that it is still reinforced by all the layers of the handle then make the 2 inner sword ones cover the whole base seam so that it reinforces that seam but also is having the handle reinforce its own seam****
use your schematics to trace the layers onto your foamboard going from largest to smallest and the cutout the foam board shapes with a box knife
now glue together the 1 base layer and the 2 inner sword layers (1 on each side of the base layer ) remember these 3 layers will be made up of 6 pieces bc they are so long that they need to have seams
once you get them glued together put heavy objects ie books and other things all over the top of the sword to make sure the pieces stay together( i would suggest having wax paper under it so it wont stick as much) ****** THIS IS PROBABLY ONE OF THE MOST IMPORTANT THINGS I CAN TELL YOU MOST GLUES WILL MELT FOAM soo i use gorilla glue it dries in about 1 hour and has a STRONG hold the only downside is it foams when drying so use very very little near the edges or it will foam out the cracks you can also use liquid nails but personally i prefer gorilla glue and walmart has gorilla glue so ya its easy to find
once the sword bases are glued glue the remaining pieces the same way
now sand you sword's edges until your happy with it
**** i know on the handle with so many layers the edges will look really rough even after you sand so you can paper mache over them so that their smooth ( personally i was on a time limit so i didnt and even then its not that noticable)*****
once you sand you can add the engravings to her sword by taking the end of a pencil and pressing into the foam slightly so that it indents the design you can also paint on the design but i think the indented version lookes a lot nicer
now your sword is completely made you just have to paint it BUT a lot of paints will melt foam too (spray paint!!) so first you have to use primer on the entire sword i did 2-3 coats to be safe and it gives the foamboard extra strength
once it is completely primed make sure you didnt miss any spots bc any spot not primed will melt and then you will have a tiny hole if you did miss a spot hit it w/ primer in the spot or you can just put a little elmers glue over it
once you have primed the sword i would use silver spraypaint do a few coats of that its super shiny and you wont get brush strokes
then paint on the details w/ a couple of coats of acrylic paint.( you will have both a dark red and black designs) ****** watch out though bc the acrylic can chip off at this stage***
once your sword is completely painted cover it with polyurathane, laquer, or some type of clear sealer this will make you sword glossy and prevent the acrylic paint from chipping
now ur done but if for some reason you need to touch up something small i know i use sharpies to touch up all of my props
I hope this tutorial is helpful. If anything is unclear or you just have other qusetions feel free to pm me.