Making a paper maché kitchen knife
Published by Manning on October 15th, 2018
I made this paper maché kitchen knife prop to go with one of my evil gingerbread people that I made for Halloween 2018!
I actually did another fake knife project several Halloweens ago, but the goal of that project was to create lots of knives very quickly, and I knew they’d be hanging up high enough that no one would get a good look at them, so they didn’t need to be perfect. For this project, I wanted to create a fairly realistic knife that would stand up to a bit of scrutiny. It was actually pretty easy!
I made the basic shape for the knife out of three layers of foam board. I took our biggest kitchen knife and traced it onto foam board, and then drew a slightly more exaggerated shape around that and cut it out. You’ll see for the blade portion I only included the back edge of the blade; that way the back edge will be thick, but of course I want the blade edge to be thin.
I traced the handle two more times and cut ’em all out.
I cut out two pieces of poster board to create the edge of the blade. I taped them around the middle piece of foam board, and taped the other two foam board handle pieces in place.
I covered the entire knife handle in very thin strips of masking tape (not shown) to smooth out the edges a bit. I covered the blade with a piece of shipping tape on each side; this is to help prevent the poster board from warping when I add…
Paper maché
I then covered the knife with tiny pieces of paper maché — one layer all over and a couple more at the connection of the blade and the handle. You can read about my paper maché process and materials here. The short version is: I use Roman PRO-543 universal wallpaper adhesive (paid link) and alternating layers of newspaper and brown wrapping paper.
Painting
Before painting, I covered the knife blade in three light coatings of spray gesso (not shown), to smooth out the texture of the paper maché a little bit. I don’t use gesso for all my projects, but I do use it when I want a surface to be very smooth. I normally don’t mind seeing the subtle texture of the little scraps of paper in most of my projects, but I wanted the knife blade to be as smooth and uniform as I could get it. Anyway, the gesso helped!
When that was dry, I spray painted the whole knife silver and let that set for a day.
I then used a piece of very thin (1/4″) masking tape to create a line along the edge of the handle. I protected the blade with newspaper and masking tape, and I spray painted the handle black. I removed the masking tape to reveal the line of silver down the handle.
The masking tape didn’t work perfectly (it rarely does) so the line was a little blurry, but I fixed it with some silver and black acrylic paint and a small paintbrush. Even though the masking tape doesn’t always work perfectly, it’s still great for giving you a very clear guide to work with when finishing your painting by hand. Trying to paint a straight line like this with no guide would be a nightmare!
Oh yeah, I also painted silver dots on the handle.
I then did a very light dusting of black spray paint on the blade, let that set, and then I hand-painted a silver edge along the blade. The dusting of black is there to let this silver edge stand out as even brighter/shinier.
I brushed a coating of clear gloss onto the blade to make it nice and shiny. All done! I’m really happy with how this came out!
I glued the knife into my gingerbread lady’s hand with a hot glue gun. Check out my article about my evil gingerbread people for more pics!
About Manning Krull
How to make a 4-foot paper maché alligator
My violin skull mask, Mardi Gras 2015
Three-headed paper maché dragon sculpture
October 15th, 2018 at 7:39 pm
I feel like I’ve been waiting for this blog my whole life and I only just found you!
I am making a giant Cheshire cat grin for a Halloween trunk or treat project. I’m using three large pieces of foam core board horizontally to make a giant grin that will fit across the hood of a Honda pilot. How would you suggest I join the three pieces together? I was thinking of hot gluing scraps of foam core across this seems to secure them together from the back. Thoughts? I appreciate any advice you may have.
Your work is impressive.
Thank you!
October 15th, 2018 at 8:17 pm
Thank you so much, Patricia! I think your idea about gluing scraps across the back is perfect; I might do exactly that — but, depending on how strong you need to make this thing, you could also consider making the whole thing two layers thick, with six pieces of foam core. Cut one down the middle, and stagger how they’re glued together. This will make the whole thing a lot more rigid. I did a quick sketch of what I’m talking about: