"What's in the box?"
"Pain." He felt increased tingling in his hand, pressed his lips tightly together. How could this be a test? he wondered. The tingling became an itch... The itch became the faintest burning... It mounted slowly: heat upon heat upon heat... . The burning! The burning! He thought he could feel skin curling black on that agonized hand, the flesh crisping and dropping away until only charred bones remained.
This excerpt from Dune exactly describes the feeling of getting a tattoo burned into skin using a laser cutter; however, this is just the feeling. When sight, smell, and sound are added, the process turns out to be quite an experience.
The sound by itself (meaning no body parts in the cutter), is probably the easiest thing to deal with. It is just the normal whine of gears, belts and cooling fans. When that sound is mixed in with the sensation of burning flesh, it turns the laser cutter from a simple machine shop tool to a futuristic torture device.
The sight is not too bad, just a light tracing its way back and fourth across the body. As long as you don't think about the fact that the small wisp of smoke trailing the light, is actually vaporized skin, everything will be fine.
The smell is bad. It does not travel far, but when you catch a whiff of the burnt flesh stench, it is quite nauseating. The thought that you have just inhaled some of those vaporized skin flakes, and they have settled on the bottom of your lungs, is the worst.
I am leaving a disclaimer out of this, because any person with access to a laser cutter who is dumb enough to try this, deserves what they get.
Step 2: Circumvent the safety
Step 3: Find your pain tolerance
The jolly roger wingdings tattoo below was done using the highest power setting, and around 70% speed. While the pain was tolerable, it burned so deep that after a gentle rubbing the skin completely peeled off.
The final settings I used were 90% power and 90% speed.
Strong enough to burn, but quick, so that it does not penetrate deep enough for the skin to instantly peel away afterward.
Step 4: Get etching!
Keep in mind that simple outline designs (like the robot and smiley faces) will hurt much less than the solid designs (pacman and space invader). If you can not tolerate the pain, choose a simple line drawing design.
After choosing your design, lay out some painters tape on the bed of the machine, and etch it. This will give you the exact location of the etch, and give you the opportunity to position your body part (hand, arm, foot, etc.) correctly. It will also let you know the duration of the etch, and how long you can expect to endure the pain.
Place your body part in the machine and set the focal point to the skin height. Lasers need a pretty exact focus, so you probably have a window of about +/- one centimeter. Outside of this range and the laser will not be intense enough to burn the skin.
Show off your cool burnt skin tattoos to random people and watch them recoil in horror and disgust.
Step 5: Soothe that burning sensation...
I noticed that creams, lotions, or aloe help soothe the burn, but kill the contrast.
Make your choice.
Step 6: Safety!
I stoopidly forgot that the laser beam was completely exposed on the left side before it hit the final mirror.
Shortly after the space invader etch started, I noticed a lot of smoke. This smoke was not coming from the etch, but from the left side of the cutter, where the upper part of my left arm was resting. When I looked over, I saw that my shirt was smoldering.
I was so focused on keeping my forearm in place (as to not ruin the tattoo), I did not notice that the laser was no longer etching it, but rather cutting a gash into my upper left arm.
Needless to say, I only etched my right arm from that point on.