The actual post is on my blog, so I would suggest reading this over there.
Oh my, this has become far more popular then I had even anticipated. Because of this, I’m going to rewrite parts of this so it makes a bit more sense.
Before I really get into it I would like to say; I am not a very experienced (or good) prop maker. I did/wrote this on a whim and my results aren’t that great. But if you put more time into it then I did I’m sure you can get spectacular results!
This is a very easy way to make a lightweight (woodless) prop. It will work best for larger weapons, but I’m sure it could be altered for just about anything. Although this is easy to do, it does take a lot of time (mostly drying time between steps) so it isn’t a “night-before-the-convention” type of project.
-Cardboard (a smooth sheet as large as you want your prop to be.)
-Expanding foam (I used the brand “Great Stuff” purchased at home depot for $4)
-Craft knife (Or X-acto knife)
- 1" Masking tape
-Wallpaper Paste (Or tacky glue)
-Plastic cups and spoons
-Celluclay or some sort of paper mache (Mine was purchased from a local craft store [Michaels])
Now that you have collected your materials your ready to get started!
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Step 1: Designing and cutting your base
You will want to start by sketching out your sword/blade/prop design onto the cardboard. Or, you can sketch it out onto newsprint (or some other cheap paper) and trace it onto the cardboard later. This way you can erase and alter the design as much as you want before even touching your cardboard.
Then outline your sketch in a sharpie, following the lines you like best. (If you drew your design on paper, cut it out and trace it onto the cardboard.
Go ahead and cut around your outline, this can be done with scissors, craft knives, or an X-ACTO knife. Whatever your most comfortable with, and find works best. I used a craft knife and achieved good results, though an X-ACTO knife would probably be better.
Try to take your time on this and work slowly, you want it to be very smooth and accurate to the desired shape.
It’s time for foam! Oh the joys that come with foam. I used the brand “Great Stuff” because it was the cheapest, it comes in cans that look very similar to spray paint cans for $3. My sword took around 2 regular sized cans (which was far more then I had expected) so I would recommend getting a lot more then
Well now that you have your cardboard base their is nothing stopping you from using foam! foam time! I use the brand "Great stuff" because it's the cheapest, my home depot sells "Large" cans (about 4" taller then the average spray paint can) for $3.50, it took about 2 regular sized cans for my sword so i'd recommend getting a lot more then you expect to need. (And some cans come broken and won't spray, another reason to always get extra!) I'd recommend wearing gloves, the foam doesn't smell at all but it does get all over the place so i'd recommend doing this in a garage or outside and then moving it inside. Or just lay down a lot of newspaper, and wear 'cruddy' clothing you don't mind wrecking. Then simply shake spray the foam all over your cardboard, I like to hold the can about an inch from the cardboard and go quickly making sure EVERY part of cardboard is covered. Then spray water all over it, since the foam dries in humidity the water will make it dry faster and poof up more.
Lah de dah, waiting, waiting. The foam takes about 3 hours to dry TO THE TOUCH it says 15 minutes on the can, but the 3 times i've worked with it it's taken between 2-3 hours. Then you can flip it over and spray the other side.
Waiting, waiting lah de dah! After about 8 hours your foam should be totally dry! Now you can start carving! I use a craft knife for all my carving; be warned this is dangerous a lot of the time your carving toward yourself and you need the knife extended all the way out so the blade is about 4"-5" long.
You can also use an X-ACTO knife or any type of knife your comfortable with, craft knifes seem the easiest and safest to me. Then jump on in and carve! Don't be scared..you can always add more foam if you need to, I spent about an hour staring at mine before I gave in and carved xD
Whoo! your done carving, for this project it took me about 6 hours of carving which I did in two sessions (why yes i am a slow poke!) Now your gonna wrap your entire sword/blade in masking tape. Masking tape is the brownish yellow stuff that comes in 1" or 3" thicknesses at home depot. I'd say start with the 1" thickness, it may take longer but it'll look a lot smoother.
Now find a TV show or turn music on, something to amuse you well you cut hundreds of little 1" x 1" squares. This doesn't take to long but make sure you have lot's of extra's. I like using confetti more then strips, it just seems easier, and less messy.
Now you get to make your concoction >:], it's pretty much 1 cup of water and 1/3 a cup of wallpaper paste (or glue). But wallpaper paste works better, you can add more if you want there's no "exact" amount but keep in mind that it will be sticker and harder to work with the more glue you add. Mix like a lot, and regularly throughout using the mixture.
Paper mache time! woot! This can get very messy, so lay down lot’s of newspaper or work in an area that can be cleaned easily. For those who don’t remember how to paper mache things, or have never done it before, it really is super easy. You’ll just want to dip a piece of confetti’d newspaper, stick it to the sword/blade/whatever your working on, and smooth it over with your finger. And of course, repeat a few hundred times until your prop is covered. I know this step seems a bit pointless, but it is really important.
Now you can either decide to be patient and let it dry naturally (which can take several days) or you can pull out a heat …or hairdryer. With a heat-gun you must be very careful you don't light it on fire - this is not the look your going for- or maybe it is it's not the look I'M going for! I just used a cheap hairdryer on high and it worked pretty well. It took me about 15 minutes to dry one side.
You know it's dry when the newspaper turns white, or at least obviously lighter then it was when it was wet. (You’ll see a big difference) Once it turns white stop drying it, wait an hour or so and home back. The newspaper should be gray again because the moisture underneath is coming to the surface. Go ahead and manually dry it again, then flip it over and do the other side. After that’s done leave your “masterpiece” overnight. It should be fully dry in the morning, but it depends how many newspaper layers you used, I used one and it was fully dry the next day.
Well now it's time for a different, much more disgusting type of paper mache, it's the pulp type you add water to. I'm going to tell you outright to completely ignore the instructions. Put the powder in a cup and add water until it turns into something with a consistency similar to clay, then add a spoon full of glue. Add more pulp if needed until the mixture resembles clay that won't stick to your hands. I used the brand Celluclay because it was the cheapest (About $25 for 5 pounds at Michaels which I got 40% and $3 a pound is a REALLY good deal). But I suppose any type would work.
Once it feels like clay you can start putting it on you prop. I would put a big glob on mine, then smooth it out with my fingers and water.
Once it's as smooth as you can make it squirt water onto it and smooth some more. Repeat again, and again until the entire prop is covered. Once again it’s time to dry, you can use a heat gun/hair dryer to dry it but be careful throughout doing this. Make sure you dry it until it turns a lighter color and then STOP, otherwise it'll crack. Give it an hour and water will seep to the surface and then you can dry it again.
Then you can sand and paint your sword. You can sand paper mache without issue, but it won’t become smooth, it tends to become fuzzy. Which is actually a good thing, just make sure to paint on a layer or two of primer before doing your actual paint job
I hope that was helpful!