Looking for a few tips on a one off cast blade

Hi guys, looking for a little help.

I'm making a prop sword cane, and shooting to make one convention friendly. Having a real metal blade is the easy route, but wouldn't pass muster if it ever came to that, and honestly I'd prefer not to have a potential real weapon on me in those places.

So, I need a one off blade that is about 29" long, 1/2" wide, and 1/4" thick. This includes what goes into the handle to secure the blade.

I am mostly concerned with methods for casting something so long and skinny that won't be flimsy or break easily. It needs to stand up to abuse. I have a bunch of epoxy resin and fiberglass supplies handy, but am willing to acquire other materials needed (and am not worried too much about cost, I hate working with the cheap stuff).

I made one attempt at it by creating two half molds out of fiberglass (cut 1/8" thick piece), and then pressed them together. I'm thinking at this point my best bet might be to just patiently layer epoxy resin and thin strips of glass until I fill each mold, then with enough resin to make sure it's full press it together. I don't care if I need to do filler work at the end, I just need a shape and strength.

How about putting a wood or metal core in the cast ? It would give it more strength but should still leave it safe for convenetions.

I agree, putting a core into it should help. Also molding a grove into the blade should go a long way in creating stability and strength.

I saw some balsa strips at the local craft store...Michael's. They also had some metal tubing and wooden dowels that might work...

Home Depot and Lowes carry various widths and thicknesses of aluminum strips. If you don't file the edges sharp, and leave the end blunt, that should work. I've made Con swords and knives with it before.

vixr said:

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I saw some balsa strips at the local craft store...Michael's. They also had some metal tubing and wooden dowels that might work...

I was just poking around online and for just a few bucks I could get a small hardwood dowel to use as a core that would fit inside. I'm going to go that route and am very optimistic.

I'm trying to avoid having any metal in the blade, just so there can be no confusion as to this being a prop. It's also a bit of a challenge for me to learn something new about fabrication.

I'm thinking get a dowel that is enough smaller that I can still lay down a couple of thin layers of fiberglass on either side, with the dowel in between them. Say 1/8" thick for my 1/4" thick blade?

should be fine...remember that the wood will absorb a little of the resin.

vixr said:

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should be fine...remember that the wood will absorb a little of the resin.

I knew the wood would soak up resin, is there any extra trick to letting it soak up first some before doing the final cast of the blade? I just don't want the wood absorbing resin to draw in extra air bubbles.

Also one thing I forgot. For epoxy resin what would be an ideal release agent?

vixr said:

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the fiberglass guy here at work says to use car wax for the mold release, 3 or 4 coats in the mold...the paste kind that comes in a round tin. I would just paint the dowel with epoxy first to seal it. I remember from wood shop that the end grain would soak up more than the long grain...please dont quote me on that.

The fiberglass guy here at work just mentioned that the epoxy will get hot, if enough is laid up at one time...I dont know if that is a factor for you.

I've used epoxy resin for fiberglassing before, just didn't do any of it out of molds. I did have it get too hold and do the resin equivalent of curdle in the pot before when I mixed up a bunch in really hot weather.

I wouldn't mind the resin soaking into the dowel to make it stronger and bond well to the rest of the blade. I think I might just paint it with resin first once or twice. Get the same effect as sealing it, just let the resin cure first.