Introduction: Foam Sword Props

I love swords. They just have so much style and character. To appropriate a quote from Jedi Master Obi-Wan Kenobi, They're an "elegant weapon for a more civilized age". Or at least that's how I like to think of them anyway.

The problem with swords is that they can get expensive and they're not exactly "safe" to carry around everywhere, which is a problem if you've decided to dress up for Halloween or a similar event and you're character has a sword. Many conventions don't allow real swords (or even hard wooden swords) and when trick or treating or going to a costume party the more responsible option is a fake sword (especially if there will be drinking at the party).

So, what do you do if the character you're dressing as has a very specific weapon and there are no toy versions available commercially or it's too expensive?

You make it out of foam board of course!

Step 1: Supplies

The main ingredient of this prop is obviously foam board, specifically extruded polystyrene, or insulation foam board. This comes in several flavors. The most popular option that I've seen seems to be "Pink board", which is Owens Corning brand, but you can use DOW blue board or Pactiv green board. For our purposes it makes no difference.

It also comes in different thicknesses, so you can buy whichever thickness is most appropriate for your sword. Depending on the thickness you get you're probably looking at spending about $15-30 per board, but they come in 4'x8' sheets so you can make tons of swords!

Tip for those more frugal prop makers out there: If you only need the one sword, find some friends who need costume weapons as well and split the cost. Or check with local builders or suppliers to see if they have any damaged sheets they might be throwing away or selling for cheap.

Aside from the foam you will need:
-A Saw (very fine-toothed)
-Sandpaper
-Paint

An Aside: For this particular sword I used some scrap foam I had on hand and had to glue two pieces together. If, for any reason, you have to do something similar be careful what kind of glue you use. You need something pretty heavy duty, but certain glues can eat away at the foam. The one I used is some construction adhesive I had on hand called QB-300 but I'm sure there are other things out there as well.

Step 2: Design

The sword I made was from the anime The Qwaser of Stigmata. I started by looking up reference material for the sword (of which there is an unfortunately small amount). Then I drew it a couple different ways to make sure that I understood the shape and how to transfer it to the foam. Once I thought I had it down I just free hand drew it on to the foam (I did use a yard stick to get straight lines). If you don't want to chance it or you want it to be really precise you could print out a picture in sections and trace it onto the foam.

Step 3: Cutting It Out

For this step I actually used a key hole saw because it has fine teeth on it, the teeth are all straight instead of sticking out to each side like some saws, and the smaller blade allowed for more detail. I also used a coping saw to get the curve underneath the handguard.

I've heard of some other ways but unless you want to get really fancy this works fine.

I'll borrow a line from Phil of Modern Family here and say, "Slow is smooth and smooth is fast." This foam crumbles apart pretty easily if you're not careful so if you want a good clean line use slower smoother motions than you would normally use with a saw. In fact, before you cut out your sword you might even try sawing on a corner you won't be using to get an idea of how it cuts.

Like I said before I was using scraps, so my foam was actually a lot thicker than I wanted. To remedy this I started by cutting it in half. then I just carefully cut it out.

Once it was cut out I needed to "sharpen" the blade. To do this I drew lines to show how deep I wanted the angle of the blade to be and another line down the side for the edge. Then I used those lines as guides and sawed the edges off. I got a little over eager here and you can see where my cut was a little wavy near the base of the blade.

Step 4: Smoothing It Out

No matter how careful you are with the saw the cuts will at least look pretty rough. To fix this I just sanded the whole thing down with sandpaper. I started with a medium grit sandpaper and smoothed everything down and rounded all of the edges. This is also where you'll want to give it any detail. This sword didn't require much detail but it just looked so plain that I had to do something. I actually just used my sandpaper to sand down the foam a bit and leave a ridge going along the guard. It's hard to make out in the picture but it starts at the blade and goes to the bottom of the guard.

If you need more detail than that there are plenty of ways to make it happen. Files would work well, or a dremel. The foam is soft enough that you could probably use tons of things that wouldn't work on harder materials. You can also attach plenty of things to it.

Once you're done any detailing just give it a quick sanding with a fine grit to get it nice and smooth.

To anyone like me who hates sanding: Don't worry, this isn't super tedious. The foam sands very quickly.

Step 5: Painting

Before I talk about painting I want to add that if you want a really fantastic looking prop there are various finishing techniques you can use first that will help give you a more professional look. I left this one as plain foam but you could probably use paper mache, or you could use an auto-body filler like Bondo and give it a really smooth realistic finish.

Foam is pretty sensitive to chemicals so you have to be careful with how you paint it. First off, do not use oil based paints against the bare foam. It will eat into it. Secondly, even if you use acrylic spray paint it can eat into the foam if you spray it on too thick. If you choose to use spray paint just apply it in very thin layers. You could also paint a primer on first which would give you a nice base layer to work from. Then you wouldn't have to be as careful when painting it.

For this sword I didn't bother with anything fancy because it's just red. I tried to spray paint it in thin layers and for the most part that worked out... until I got impatient. But that's mostly just on one part. After I spray painted it I dry brushed some black acrylic paint into the detail so it would stand out a bit more.

Step 6: Finished

Before I go I should add that while this is sturdy enough to carry around as a prop, if you tried to use this sword to fight it would snap in half pretty quickly.

So there you have it! That's how you make a foam sword. Now you can have a pretty inexpensive and incredibly safe prop next time you want to dress up as your favorite sword carrying character. I wish I had a better picture of the finished product, but this was for my brother-in-law's cosplay and I was in such a hurry to get it finished for him I somehow forgot to take a "completed" picture. Doh. I was able to get this quick cell phone picture texted to me at least but I still feel pretty stupid.

I hope you enjoy this and have fun making all kinds of swords!

Comments

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StarKiller89 made it!(author)2016-04-04

What kind of glue did you use? The glue I have melts the foam.

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The+Rambler made it!(author)2016-04-05

I used a construction adhesive called QB-300. There are other construction adhesives available as well that are designed for gluing foam together. Mostly you want to use something that isn't oil or solvent based.

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StarKiller89 made it!(author)2016-04-06

Awesome! Thanks! :D

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Hino-chan19 made it!(author)2016-02-23

What type of thickness did you use for polystyrene foam? I am thinking of 1 1/2 to 2 inches for my alibaba saluja sword from magi

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The+Rambler made it!(author)2016-02-24

What I started out with was about 4" I think and then I sawed it in half to make it thinner. I think you would be fine 1 1/2" to 2". Really it should just be about what feels right for the sword you're making.

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Hino-chan19 made it!(author)2016-03-03

Thank you!

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abblesindatardis made it!(author)2015-07-26

I'm seriously considering using this method to make Stocking's sword from Panty+Stocking. I'm excited to find a tutorial that's actually pretty simple. Any tips on the stripped paint job?

(P.S. have you ever actually watched Qwaser of Stigmata?? Because that anime is suuuper weird... Though this is coming from someone who's cosplaying a character named Stocking sooo.....)

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The+Rambler made it!(author)2015-07-27

Just looking at a Google image search I would say I feel like if I was doing it I would paint it white, seal it, mask off the white parts with painters tape, paint it blue, pull of the tape, then probably add the smaller lines with a small brush and seal the whole thing again.

(Honestly, I've never seen Qwaser of Stigmata. I had what the weapon does described to me but I don't really even know what it's about. There sure is a lot of bizarre anime out there though.)

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KarissaA made it!(author)2015-06-15

I'm probably sending this way too late to get a reply but I'm making dantes rebellion sword from devil may cry. I'm wondering where you get this kind of foam. Home depo? Lowes? And I don't have the first clue on how to shape it. I know I need more than a saw. It looks very difficult

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The+Rambler made it!(author)2015-06-15

You can get it at Home Depot or Lowes. Usually on the contractors side but if you can't find it just ask for insulation foam board and they should know what you need. You may have to laminate some sheets together depending on the thickness you want and the thicknesses they have available, but for that sword you probably won't have to. As far as shaping it I used nothing but a saw and some sandpaper. Details might be tricky but as far as general shaping it is far from difficult.

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raeann.kiwivaughn made it!(author)2015-01-27

How thick is the foam board you are using?

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The+Rambler made it!(author)2015-01-28

I think this started out at about three inches thick? You can use different thicknesses depending on the project you have in mind. For a larger prop you can start with a thick foam but for a smaller prop you'll have to sand or carve off more material so you can use a thinner foam like 1 1/2" or 2".

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raeann.kiwivaughn made it!(author)2015-01-28

Okay I just don't want to buy some and it be too thin and I was hoping to use yours as a size comparison. I'm making kurome and wave's swords from akame ga kill.

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The+Rambler made it!(author)2015-01-29

If you have specific swords in mind I would suggest figuring out the thickness the sword should be and then picking a foam board slightly thicker than that. Then you would be able to sand down to the thickness you were going for. Also, the Kurome sword in particular looks pretty thin. You probably won't be able to get down to that thin using foam so you might just have to pick a size that will still give the right impression while still being stable enough that it won't break from simply carrying it around. Also I would suggest using ModPodge to strengthen it even if you don't go as thin as that sword is supposed to be.

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The+Rambler made it!(author)2015-01-28

Oh I almost forgot that I cut this foam in half, so if I had foam that was only 1 1/2" thick I would have used that. This just happened to be what I had on hand.

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wandererlostsoul made it!(author)2014-11-28

Do you have any ideas on making the sword from balance of the bladekeeper DOTA II? Thank you :-)

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The+Rambler made it!(author)2014-12-01

Hmm, I had to do a search on that one and if it's the one I think it is it definitely doesn't look easy. I would say there are a lot of different options depending on the tools at your disposal and what you want to put into it but you could definitely do it in foam. I would cut the shape out of foam board, sand it down to get the right bevels and perfect the shape, and then hit it with a couple coats of mod podge. If you go by ModPodge's suggested cure times it will take a long time but give you a really solid result. The only thing about your sword that I would do differently is add some sort of reinforcement to the handle and probably make that thin hand guard piece out of somthing else. You could make the hand guard piece out of PVC, foamed PVC (sintra), foam core, etc. As far as the handle goes, technically you could make it out of something else and attach a foam blade to it, or if you make the whole thing out of foam just glue something to it as reinforcement like strips of PVC, foamed PVC, or even thin Non-corugated cardboard; anything to prevent it from cracking in half. Good luck!

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wandererlostsoul made it!(author)2014-11-28

Do you have any ideas on making the sword from balance of the bladekeeper DOTA II? Thank you :-)

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Schaefur made it!(author)2014-10-08

I'm planning on making the Monado from Xenoblade. How easy is it to cut something like this? You recommend a saw and sandpaper, which makes me think a sharp knife won't "cut it"... *cough*

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The+Rambler made it!(author)2014-10-13

Sorry for the delay. It's pretty easy to cut. The problem is that it can pull or crumble and mess up the line you're cutting but you can avoid that if you're careful. I've cut it with a serrated kitchen knife before. You can also score it repeatedly with a utility knife and kind of break it at the line. What ever way you want to try test it on a corner or some piece that you won't need. Also, you can always cut outside your lines and then sand down to them. That way any rough cut won't show on your final sword.

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KWDragon made it!(author)2014-07-12

Actually, user Ozyglass made wooden swords, but I wanted you to know that your Instructable was the inspiration. We couldn't have done this without you. Many thanks!

Rudkin_Zoro_swords.jpgRudkin_Zoro_swords.jpg
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The+Rambler made it!(author)2014-07-12

Ooohh haha, Zoro from One Piece. That makes more sense. I assumed Zorro from... Zorro. Those look awesome! I'm glad this was helpful. How did you end up making them?

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KWDragon made it!(author)2014-06-27

Thank you for the tips! We are gonna give it a try this weekend for Zoro cosplay.

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The+Rambler made it!(author)2014-06-27

You're welcome! If you're going with the standard rapier that might be a tough sword build using this method but best of luck to you.

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