Making a Viking Axe - Part 2

Design the Viking/Celtic pattern

Part two of creating the Viking axe is to design a Celtic inspired pattern which will be etched onto the axe head.

Using Silhouette Studio I created a template which roughly matched the new shape of the axe head. The design weaves together a mythical dragon with a more traditional Celtic knot. 

11 - Viking axe celtic design
Proposed axe design in Silhouette Studio Business
Mock up of design

I based the design on a YouTube video by ArmStreet who specialise in Viking replicas. 

I did a quick mock up using the file produced by Silhouette Studio against the image I took when polishing the axe head. The design sort of works but I need to modify the lower outline to better fit the curve of the axe.

After recreating the outline and using the ‘warp’ tool in Silhouette Studio Business to better fill the outline, I then mirrored the pattern and nested the two stencils. The vinyl I have is 12″ wide so both can be cut from a single sheet.

Stencil images reshaped to fit

Printing the stencil

Cut screen in Silhouette Studio
Silhouette Cameo 4 vinyl cutter

I’m now ready to send the stencil to the Silhouette Cameo 4 vinyl cutter. Little did I know at this point that I had made a basic mistake with the cut configuration, but more about that later.

The cutter I have is capable of using sheets or rolls of vinyl or paper/card stock. For this stencil I’m using a 12″ by 18″ gloss vinyl sheet with came with the unit.

Once the Cameo 4 had finished cutting out the stencil, it was time to start removing the vinyl which is not part of the design. This is referred to as “weeding’. It’s here where I realised I had made a mistake. When designing the stencil I’d thickened the outline of the pattern to make it easier to see on the screen. Unfortunately that had the effect of turning the outline from a single cut into a double cut . I thought the machine took longer than it should have to finish the cut and it turns out every line was effectively cut twice. It also meant that when weeding I had to remove a very thin outline of vinyl from around each section. Not an issue but a learning point going forward.

Weeding the stencil
Finished stencil

Eventually, all of the superfluous vinyl is removed and the stencil is starting to take shape. 

This then highlights the next challenge as each piece of the stencil is stuck independently on the backing sheet and relocating each piece one by one would not allow accurate placement.

The answer is to use transfer tape which effectively creates a negative of the stencil.

The transfer tape is a low tack vinyl which is placed over the top of the stencil and smoothed down. Once it is in place the stencil is reversed and the original backing sheet is carefully peeled away. This leaves the stencil parts, adhesive side up in the correct position ready to be placed on the axe head.

Transferring the stencil to the axe head
Fully masked prior to etching

Before placing the stencil it is important to make sure there is no dirt or grease on the metal. I first use acetone to wipe the axe head down and remove any debris and oils. I finally use isopropyl alcohol as a final cleaning step. 

To ensure the adhesive sets well, I warm the axe head over a gas flame prior to placing the stencil. After smoothing down the stencil it’s time to carefully remove the transfer tape making sure none of the sections lift. Finally I used pieces of the scrap vinyl to mask off the rest of the axe head. 

Preparing to etch the axe head

The process of electrochemical etching uses low voltage DC (Direct Current) electricity to etch the surface of the metal. I prepared the electrolyte solution by dissolving common table salt in a bucket of water. The salt is used to increase the electrical conductivity of the fluid. For the electrical supply I’m using a bench DC power supply for the initial etching process then will switch to a custom built unit to supply low voltage AC for the marking process.  

Etching equipment and vessel
Axe head suspended in electrolyte
Etching at low voltage

The item to be etched needs to be suspended in the electrolyte so that all areas to be etched are submerged. During the etching process, ions move from the anode (+ve terminal) to the cathode (-ve terminal). This means I need to connect the positive supply to the axe head and the negative connection to a piece of metal suspended in the electrolyte. 

Once connected, I set the power supply to constant current mode and set a max voltage of 16V and a current of 6.1A.

Time for a health warning. 

Using saltwater as your etching electrolyte can be rather problematic due to competing side reactions. The main one being electrolysis of salt, which produces chlorine at the anode and hydrogen at the cathode. The other product of electrolysis of NaCl solution is sodium hydroxide, which remains in solution. This is a real problem, since transition metal hydroxides are notoriously insoluble. So the hydroxide would combine with any metal ions you managed to generate and precipitate the metal hydroxide creating what I like to call “a bucket of crap”.

10 minutes in
Electrolyte after 40 minutes
Axe head after 1 hour etching

Earlier I mentioned both etching and marking, so what’s the difference?

When etching using DC electricity, metal ions are moving from, in this case the axe head to the piece of metal connected to the negative terminal. As this is a one way trip the surface of the etched metal is removed but left in the same condition as the base material. Effectively just a bit lower than the masked-off material.

What if we could change the colour of the etched surface and create a permanent contrast?

Well you can and that’s where marking comes in. It’s essentially the same process as etching but this time uses AC (alternating current) electricity. The result of AC marking is a dark oxidised mark on the surface of most metal. In most cases, the process only affects the colour of the topmost layer of the surface exposed to the electrolyte.

Once etching and marking was completed, I rinsed off the electrolyte which had turned into a thick sludge. After drying off the axe head it was time to remove the stencil and mask to see the results.

All of the vinyl had stayed in place and there was no leakage or significant under-etching of the fine lines. The etch itself is around 0.5mm deep as can be seen in the close up image.

Close up of the etched surface
Removing the stencil
Axe head ready for finishing

The use of a salt water electrolyte meant the axe head would corrode very quickly if left untreated. After cleaning and drying the axe head I gave it a quick wipe down with an oiled rag to prevent any further oxidisation.

For final finishing prior to fitting to the haft, I intend to use a brass wire wheel to burnish the etched areas. The bevel on the cutting edge will be shaped and brought up to a mirror finish as will the rest of the un-etched metal.

Now, on to carving the haft/handle and fitting the axe head. Head over to Making a Viking Axe – Part 3 where I will be engraving the haft and weathering the assembled axe.

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