Foam blades

[AnAgileKoala]

I’m working on a cosplay with a sword but I made it out of Eva foam because it’s quite large(about 6ft). Does anyone have any tips on how to get it as close as possible to a fine point on the blade edges?

 

[3DVagabond]

You have two options. Either:

A: You take a sharp edge and shave it to the thickness you want it to be.
B: You can sand it down to the thickness you wanted to be.

 

[AnAgileKoala]

You have two options. Either:

A: You take a sharp edge and shave it to the thickness you want it to be.
B: You can sand it down to the thickness you wanted to be.

To sand it would I use something like a dremel/rotary tool with a sanding drum or is there something better?

 

[3DVagabond]

It would be better for you to use a dremel to get the job done faster. However, be warned that when you sand the foam, there will be dust floating around where you are sanding. You will have to sand it outside to minimize the exposure. Sand it outside with a mask and use a fan to keep the dust away. That's something I learned when I was trying out for my first cosplay in foam.

 

[AnAgileKoala]

It would be better for you to use a dremel to get the job done faster. However, be warned that when you sand the foam, there will be dust floating around where you are sanding. You will have to sand it outside to minimize the exposure. Sand it outside with a mask and use a fan to keep the dust away. That's something I learned when I was trying out for my first cosplay in foam.

Ok, thanks. Ik it’s unrelated but, do you happen to have experience with foam clay because I just noticed the clay I used on my cross guard broke after drying? Do you also possibly know how to avoid that?

 

[3DVagabond]

Unfortunately, I have no answers for foam clay. I never used it nor went back to foam work since my first costume. It was a total failure for me. You will have to use your favorite search engine to prevent that from happening. I'm more of a 3d printing/sewing kind of guy.

 

[AnAgileKoala]

Unfortunately, I have no answers for foam clay. I never used it nor went back to foam work since my first costume. It was a total failure for me. You will have to use your favorite search engine to prevent that from happening. I'm more of a 3d printing/sewing kind of guy.

Ok well thanks again for the dremel tip.

 

[PlanetAlexander]

I second the Dremel/rotary tool; you can also use a belt sander, though for something of THAT size, it might be too tricky! Cutting the edge down beforehand to get that taper will save you a lot of time and dust when sanding.
In regards to the foam clay, the issue is probably that it isn't as durable as normal foam. It's a lot softer than EVA foam and the thicker it is, the longer it takes to dry too. What are you trying to do with the clay?

 

[AnAgileKoala]

I second the Dremel/rotary tool; you can also use a belt sander, though for something of THAT size, it might be too tricky! Cutting the edge down beforehand to get that taper will save you a lot of time and dust when sanding.
In regards to the foam clay, the issue is probably that it isn't as durable as normal foam. It's a lot softer than EVA foam and the thicker it is, the longer it takes to dry too. What are you trying to do with the clay?

I’m trying to make the details on the cross guard and the hilt which are made of PVC. The details arnt super small, it‘a more like adding a pair of ridges down the whole guard.

 

[PaiganBoi]

Using foam clay on naked pvc pipe is not recommended. It doesn't grap onto it very well. There is slight shrinking when foam clay dries and it can potentially Peel away from the pvc. You would have to skin the pvc with 1 or 2mm foam then apply the clay. An alternative to clay would be to make the ridges from Eva foam. You can make them yourself or use triangle shaped dowels.

 

[TurboCharizard]

One more for belt sander or if you can snag it, a hand held detailing belt sander, something like this.

I've used belts for sanding large surfaces of EVA and XPS foam on blades and other props so it's doable, you just need to be attentive to how much you're removing and not to snag the prop in any of the moving parts. Spearhead as example of this process.

One thing to consider when working with belt sanders is the grit of the belt. Usually it's fairly abrasive to remove as much material as possible which will leave a fairly fuzzy texture behind on EVA. Sand, heat seal with a heat gun and then come back with finer grit sandpaper to smooth everything out before heat sealing again for a glossy texture.