Fake Lichtenberg Coasters

Lichtenberg figures filled with colorful epoxy look great, the problem is that not everyone has a couple thousand volt power supply at home ready to use and I expect that everyone else living with you is going to be livid when they see you rip one out of the microwave oven.
Another downside is their behavior themselves, they are unpredictable going where the path of least resistance takes them, while this is exactly the flair of them I am going to present to you a way to incorporate lichtenberg figures in your design without dangerous electronics and having full control over them.

And all of that with lasers, so have fun making.

You'll need:

Software:

• Inkscape
• Laser control software (Lightburn for me)

Hardware:

• your target piece of wood
• a lasercutter or engraver
  • I am using a K40 chinese 40W laser cutter
• epoxy (pour able)
• pigment (to color your epoxy)
• propane torch
• sanding paper (different grids)
• personal protection (gloves)
• mixing cup
• mixing sticks
• syringe
• clear coat

Since we don't want to or cant produce a lichtenberg figure by ourselves we need a picture of one. So go to google images and start searching for a figure you like.
The problem with using pictures from Google Images on stuff you might sell of course is that you don't have the right to do so. But Google has an option for that.

Images matching your search are by default not filtered at all, so the results in image 1 of this step, lists you all images whether you can reuse them or not. When you click on tool in the top bar of your Google search you will see options to filter your results and one of them is "Usage Rights".

If you want to sell your item with a third party image on it you will have to choose the option "Labeled for reuse" or "labeled for reuse and modification". If you don't want to sell it "labeled for noncommercial reuse" or "labeled for noncommercial reuse and modification" is fine.

Now applying one of those filters will immediately shrink your number of results but you are safe from legal prosecution.

So apply the filter that fits you and download the image you like.

We want to create a coaster that has a logo in the middle of it. Now this would make real Lichtenberg burns a hazzle already, nothing really prevents them from burning into your logo and controlling them with water for such a small object is also difficult.
Start with a blank Inkscape project for your design.

I want to create a coaster, so I set the size of my page to 90x90mm in the document settings, draw a 90mm circle for my coaster outline and add my logo to the middle of if.

Import the image you downloaded.

If you managed to find a vector image of your figure you can already start placing it on your design. But the chances are high that you found a picture from a figure burned in wood like I have.

Since this picture by itself is not usable, the figure has to be extracted from the background.

Select the image and goto "Path->Trace Bitmap" in the top menu of your Inkscape window.
The trace window will open up and present you with different options to extract figures or lines from an image.

Since the dark figure shows really well in front of the light wood, brightness cutoff will work very well. Clicking on update in the bottom right hand corner will display a preview of the result.
Play with the values until you are happy.

Press OK and close the window to return to your drawing. You will notice that there is now another object overlayed on your original image so go ahead and delete the image, not the outline.

Create some copies of the outline and start placing it to create your desired look.

Fill the original 90mm circle black. Raise it to the top by selecting it and clicking "Object->Raise To Top".

Select every object in your drawing and execute "Object->Clip->Set".

You are now left with only the parts of your figure that where positioned inside the circle.

Export the drawing in a format your laser controll software can read.

Import your design into your laser control software and setup the laser process.

What you want are deep lines so go slow and with more power, burning or rounded edges are ok for this process
and even enhance the look of the finished piece.

Since I am using a K40 laser cutter with a miniGerbil, I am using Lightburn with 5000mm/min raster speed and
25% power.

Place your target so that the design is centered on it and hit start.

Depending on what finish you want your target to be you can now either sand it down to create a smooth surface or leave it as is to create some texture.

I am aiming at a flamed coaster with white highlights, so I am not going to sand anything down. Instead, I use a propane torch to scold all surfaces of the coaster. Sharp edges will again be rounded by this process enhancing the look of the fake lichtenberg figure.

If your lichtenberg figures reach right to the edge of the coaster or at least 1cm
to them you will have to mask the outline to prevent epoxy from spilling over the edge. Use painters tape and stick it to the edge under a little pulling. See that there is an overshoot at the bottom of approximately 1cm to fold it over. This way even if your sides are not tight you won't glue the piece to your work surface.

Mix your resin according to the vendor specification and add pigment or color to it. Since the bottom of the created figures is quite dark especially after the torch treatment you want a color that is not very opaque.
I always start with white pigment to create a milky color and then add the color of choice that way you can still see through the cured resin but it will catch enough light to really stand out from the dark bottom and background.

Use a syringe to pour epoxy in the figures and the logo. The less over spill you have, the less sanding you have to do later on.
Pop the bubbles that raise to the surface with a short blast of the propane torch. This will decrease the surface tension of the epoxy, so it will spill over the edges of the figures. If you use a disposable cup for your mixing, I recommend keeping some leftovers to check later if the epoxy is cured or not. This way you can poke it with a stick and prevent marks on your main piece.

When the stick poking in the mixing cup reveals a hard surface, you can start by removing the mask from the piece. The upside of the masking tape is that it will simply pull of the sides. The downside although is that the epoxy will "climb" the sides during curing. To get ahead faster you can file of the sides first or simply use sanding paper. When you wet the sandpaper with water the resulting surface is smoother and the paste of sanded epoxy can be washed away easily. To achieve a plane I will flip the piece around and sand it with circular motions.

Sand until you are happy with the evenness of the piece and only the figure and your logo is still covered in epoxy. At the end increase the grain of your sandpaper to achieve a smooth surface without scratches.

Don't worry if the colors to not pop at this point, the surface is quite coarse on a microscopic level and will catch a lot of light. Spray the surfaces top and bottom of your coaster with clear coat. Make sure the piece is dry after sanding, otherwise the clear coat can bubble up when the water below evaporates. For the flamed bottom make sure that the coat is thick enough to prevent the dark parts from rubbing of.

After everything is dry, your coaster is finished.