How to easily apply a pattern of any complexity to metal using a welding inverter

Today we’ll talk about metal etching. Namely, we will apply a pattern to the knife.

We will need:

Welding inverter.
Water and salt.
Nail polish.
Cotton wool.

And of course, a blank on which we will etch the drawing. Using the method that I will discuss below, you can apply a pattern of any complexity to metal. But for the first time, as a training, I chose a fairly simple one - Scandinavian runes. We will poison one of these knives.

Preparing for etching

So, you’ve chosen the design, it’s time to apply varnish to the knife. Before this, the surface should be degreased and can be painted. I took the cheapest nail polish, black, so that the design could be seen better. The varnish should be applied in two or three thick layers.

The varnish will protect the surface from etching, therefore the unprotected metal will be etched. Therefore, we remove the varnish, obtaining the pattern we need.

If the design is complex, then you can cut out a stencil on paper, fix it on metal, apply varnish on top, and after drying, remove the stencil. I advise you to apply more varnish so as not to accidentally touch the metal surface that does not need to be etched.

Etching the drawing

For the etching process itself, you will need a welding inverter and a saturated saline solution. The saline solution is easy to prepare; to do this, stir the salt in a glass of warm water until it stirs; when it stops stirring, the solution is saturated. We set the welder to one hundred amperes. Next, we throw the plus from the inverter onto the blade, and clamp the cotton pads into the minus.

We dip the minus into the saline solution and press the cotton wool onto the future drawing.

Since the blade is positively charged and the cotton wool is negatively charged, upon contact, positively charged particles from the metal are transferred to the cotton wool. In other words, we are stimulating an electrical form of erosion. The saline solution also foams and evaporates.

After each press, soak the cotton wool in the solution. Afterwards, remove the varnish using a torch and acetone and admire the result. I would also like to note that this is a forged knife made from a file, that is, hardened high-carbon steel grade U10, hardness about 55 on the Rockwell scale. And at the same time, the drawing turned out to be deep, the relief made me very happy.