How to Make a Knife Out of Aluminum Foil

April 13, 2018

Need a knife, but all you have is a roll of aluminum foil? Don’t worry, here’s how to forge one!

The basic procedure is to apply mechanical pressure to shape the blade, and heat it to alter its properties. The heat makes the metal flow so that you can compress it into a new shape, which it then holds better after cooling. Aluminum is a highly malleable metal, as you may have noticed from how easily you can bend aluminum foil. However, this also means that the edge will dull quickly, one reason why you don’t see a lot of aluminum knives at the store.

These steps are based on a Japenese YouTuber. A link to the video is included at the bottom of this post. Enjoy!

1. Gather Supplies.

2. Gradually pull out the foil, rolling it into a new wad outside of its box. The wad should be quite hefty, about half a roll. Rip off the wad for future use. (0:21)

3. Remove the remaining roll of aluminum foil from the box. This will become your knife. (0:22)

4. Hammer the fresh roll of aluminum foil flat, striking it repeatedly against an anvil. It should now resemble a rectangle the length of the original roll. (0:28)

5. Drive out the inner cardboard tube, using the handle of a mallet to loosen it, then a pair of pliers to pull it out from the aluminum foil. (0:45)

6. Flatten the foil more, again hammering it against an anvil. (1:08)

7. Heat the flat bar of foil on a gas stove. Set the burner on low, and heat one end of the bar. (1:32)

8. Hammer the heated end. Use a pair of pliers to hold the foil. Aluminum conducts heat. (1:43)

9. Flip the foil over and hammer it flat on the other side (1:59)

10. Cool the pliers in a wet cloth. (2:03)

11. Return the foil to the burner. (2:05)

12. Continue hammering the bar of foil flat. (2:09)

13. Hammer further on the foil until it is a flat, hard, compact bar. At this point it should have enough rigidity that you can hit the aluminum foil and it rebounds solidly, instead of squashing. You now have a solid bar of aluminum – the body of the blade! (2:36)

14. Take a knife with a shape that you want to copy. Place it on top of your flat bar of aluminum foil. Use a permanent marker to trace the outline of the original knife on your aluminum foil. (2:52)

15. Secure your aluminum foil bar in a vise. Use a jigsaw to cut out the shape that you traced on the flat aluminum foil bar. (3:02)

16. Lubricate the jigsaw as necessary. Cutting an aluminum knife is hard work! (3:22)

17. Place your new knife form in the vise. (3:58)

18. File down the edges of your knife form. (4:00)

19. Use a whetstone #150 to create the surface of your knife tang. (4:12)

20. Heat your knife over a gas burner, set on high. (4:30)

21. Chisel midway to separate the block of aluminum into two, lengthwise. (4:44)

22. Hammer one half further until it is extremely flat. At this point it should roughly resemble a knife. (4:56)

23. Sand down your knife blade. (5:27)

24. Use whetstone #150 to carve a bevel in your knife. (5:40)

25. Use whetstone #400 to refine the knife bevel. (5:53)

26. Use whetstone #1000 to give your knife a sharp edge. Cool the whetstone repeatedly with precise amounts of water. Higher number whetstones have finer surfaces, producing more contact with the knife and more heat, and requiring more cooling. (6:00)

27. Use whetstone #2000 to polish your knife edge. (6:33)

28. Use whetstone #6000, then #8000, then #12000, then #30000, for progressive rounds of final sharpening. (7:02)

29. On a block of wood, trace the outline of your tang with a marker. This will become your knife handle. (7:53)

30. Place the wood block in a vise, and saw out the shape. Then saw the handle in two lengthwise, so that you can place the handle on both sides of your tang. Sand down the handle wood, and brush away the debris. (7:58)

31. Draw two points on your knife tang. These will become the attachment points for your handle. Drill out holes in these points, using a wood board to receive the excess drilling. File the knife smooth where you drilled out the holes. (8:25)

32. Drill holes at the same locations on the wood handles. You can see the distance from drilling the knife into the wood board. (8:46)

33. Screw together the knife between the two handle sides. (8:48)

34. Use a diamond jigsaw to cut away the excess screws from the handle. (8:57)

35. File down the remaining screws in the handle. (9:19)

36. Use sand paper to smooth out the joined handle. File down the wood until it sits flush with the aluminum tang. (9:26)

37. Use a razor strop to straighten the knife and give it a reflective sheen. (9:52)

38. You should now have a knife that looks like the original. (10:17)

39. Cut up your favorite food! (10:42)

40. Place your aluminum foil roll knife proudly on display. (10:52)

Kiwami Japan is a Japanese YouTube Channel that creates unique knife making and sharpening tutorials in Japanese.

The Japanese title hilariously translates as “I want to make kitchen knife of roasted aluminum foil!”

The video demonstrates the creation of a sashimi knife, however you can choose your own shape.