NaCl Window and and Mirror – DIY OC
Well, I decided to give this a try for the OC of the CO2 laser. A simple gold mirror with a hole in the middle and a salt window. The hole was easy, I simply put a glass drill bit into a battery powered drill, and with the bit running under a very small trickle of water in the sink, SLOWELY drilled the hole from the backside of the mirror. When I got through I carefully enlarged the hole to the desired size, about 2mm and then made sure to smooth out any rough edges with the bit. The key here is take your time and use water as a lubricant. ALSO, be sure to turn off any “hammer” action feature on the drill!
The whole process for this took about an hour, I know the hole is slightly off center, but that is ok. The mirror has LOTS of room for positioning inside my mirror mounts.
The next step was to make the NaCl window. To do this I purchased a box of icecream salt and went through it pulling out any big peices that looked promising. Then, I selected the best of those and with a hobby knife, sliced along the crystal structure making a semi flat peice.
The next step was sanding it on each side with a very fine grit sandpaper, then polishing it by simply rubbing it on the smooth wooden surface of my workbench. I finished it off with a polish from a paper towel. To get the round shape so that it fit in my mount I used a standard metal file. Salt is soft, and VERY responsive to moisture. Use this to your advantage 🙂
The results… the mount for this window is nothing more than a gromet that I had laying around. I may transfer it to a metal washer and epoxy it in place later. For now, the gromet makes handling MUCH easier as the oils from my skin also affect the surface of the salt.
On a side note, the window is damn hard to take a picture of without it reflecting light around me 😛