Switchblade [Prop]

A prop knife created for a college performance.

IMPORTANT MENTION: If you're going to replicate this method to use for [whatever], then please keep in mind that from a distance it resembles a real knife. People may think it's a real knife. It is harmless- but... just don't be an idiot.

If you're going to use any prop that resembles a weapon in an open space: make it very clear you're filming, rehearsing, etc - have a sign maybe.

Step 1: Set-up - What You Will Need.

Currently our college is doing a production of Twelve Angry Men, and needed two identical "unique" switchblades. As we didn't already have props we could use, I tasked myself to make them. Having made one: I decided to record the process of making the other.


  • A flick comb. (Novelty comb resembling a switchblade.)
  • Filler. (I used 'Polyfilla', but you could also use a model filler or a car filler.)
  • Detail pieces (Optional.)

Tools & bits:

  • Craft knife and/or scissors.
  • Sandpaper (A fine grit. I used C470.)
  • Masking tape.
  • Paint brush(es)
  • Paints
    • Grey Primer
    • Chrome Enamel
    • Red Acrylic.
    • Matte Sealer (Optional.)
  • Polycement (Optional.)

Step 2: Cutting

First take your comb, and using a sharp tool (such as a craft knife, or large scissors) cut the plastic into the desired shape.

Step 3: Masking and Filler.

Mask off the areas you want to avoid getting paint on, before applying the filler. This will make the process easier as sometimes you could accidentally remove the filler with the masking tape.

I decided to have a smooth part on the grips, as the knife is described as being "unique". You can do this, but is entirely optional.The main thing is to fill in the slits of the comb with Polyfilla. In fact, if you want you can leave the grips alone entirely- I recommend editing them however, to change it from the cheap plastic finish.

Wait for the filler to dry - then sand it smooth. You may need to do this a few times to get a result you're happy with.

IMPORTANT - Make sure that you don't apply too much filler to the "blade", I did this by accident and had to sand it again later on. If you apply too much it won't go back into / come out of the casing without outside help.

Step 4: Painting

Before I painted the prop, I added a small detail piece I had from a model. I just applied this with come Polycement.

Make sure you're happy with the filler, and that it's sanded how you want it, before applying the paint.

I first applied a coat of grey primer, and followed up by painting the blade chrome, and the grips red. (I also chose to apply a coat of matte seal, this is optional, and I did it just to try to protect the paint a little since this prop is going to be passed around a lot.)

And that's all there is to it. Enjoy your prop knife.

"That's not a knife. This is a knife."



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8 Discussions


2 years ago

Very cool! Would you recommend a similar idea for a knife to be used for stage combat? Does the "blade" have any kind of fragility?

2 replies

Reply 2 years ago

I couldn't really give you specifics, without knowing of how such a knife would plan to be used.

From our use(s) of this knife(s): It's really about the quality of the switchblade, and the quality of which you prep the "blade".

I just hit the blade with a force which we use in stage fighting; the "blade" was already sturdy due to it having previously been a comb (and you have the stainless steal back-plate to keep it straight.), and it's safe to say that the prop would be durable for stage combat (within reason (I would say it can be hit, thrown, and dropped- but brute force may cause some damage.)).

If you were to be doing this though, I would recommend a 'Car Filler' over the 'Polyfilla' I used - as it is made to be much stronger a material.


Reply 2 years ago

Terrific! Thanks for getting back to me. In truth, your reply found me as I was in the middle of my build for the prop. I suspected it would do, and your reply further validates that.

In fact, a liberty that I've taken; I trimmed a small amount of comb AFTER having spackled, which is resulting in a fine "serrated edge". Perhaps not appropriate for a switchblade, but works as a detail for a more battle-ready piece.

Thanks again!

Jimmy Toe

2 years ago

this thing is fantastic, so real looking, scared the hell outta my mum with

1 reply