How to Personalize a Utility Knife With Acid Etching

I've been wanting to try this for quite awhile. I thought it would be a cool way to personalize a utility knife by etching it with nose cone art from a World War II era P40 airplane.

Utility Knife

Belt Sander

Sand Paper Various Grits

Spray Paint

Ferric Chloride

Water

Plastic Container

Styrofoam

Electrical tape

Ice Pick or equivalent

Drill Press or Drill

Countersink Bit

3/16" drill bit

I bought a two pack of the classic Stanley 99 utility knife and disassembled one of the knives. One screw and it comes apart.

Next I sanded off the Stanley logo because it would have gotten in the way of the etching. I used a belt sander for this be careful don't sand too much because the aluminum is not very thick so you can burn right through it.

Next paint both the inside and outside of the shells with black spray paint. Make sure you get good coverage because this will act as the resist to the acid bath so any exposed material will get etched by the acid.

Next I used an ice pick to scribe the image on to the front of the two shells. I drew guide lines on to the rest of the piece using a white map pencil because I want to add dots to simulate the rivets on a plan. But in reality I could have waited to draw on the guide lines as I ended up having to redraw them anyways. If you make a mistake with the drawing you can use an acrylic paint pen to touch up any areas. Just go over the area with the pen let the paint dry and correct your mistake.

Once I was happy with the design I used some electrical tape to attach the shells to some Styrofoam make sure to leave the design clear of any tape. The Styrofoam allows you to suspend the piece upside down in the acid bath which results in a better etch. I use Ferric Chloride mixed with water in a 1:1 ratio to make my etching solution. I keep the etching solution stored in a plastic Tupperware tub.

*The acid will not eat through the plastic or the Styrofoam.

I left them in the acid etch for 30 minutes which was probably too long, 15 minutes would have been plenty of time. Later you can see one of the shells where the acid ate right through the aluminum. I think this was also partly due to sanding off too much material. If I do this again I will definitely try to be more careful and leave it in the etch for a shorter time.

When you remove the pieces from the etching solution make sure to rinse them off thoroughly in a bucket of water. I used a 5 gallon bucket of water mixed with baking soda to neutralize the acid. Then I dried off the pieces with paper towels.

As I mentioned earlier I wanted to simulate the look of rivets so I used a countersink bit and my drill press to make a bunch of tiny indentations. I used the guide lines as reference lines for the "rivets". Once I was happy with the look I used some Acetone to remove all the spray paint from the outside.

After removing the paint I cleaned up the finish using some 400 grit sandpaper. I was going for more of a brushed aluminum look. I also spray painted one of the razor blades red just to mimic the look of the red nose cones on P40s. There were a couple of spots near the top where the metal had thinned out so I decided to drill three 3/16" holes to help hide the damage which I feel added to the finished knife.

Overall I am really happy with how this turned out. The etch is pretty deep and turned out pretty good despite my poor artistic skills.

This was a fun and easy project and I could see how this could be personalized in tons of different ways especially for the artistically inclined.

Thanks for reading and I hope you enjoyed this Instructable.