'CA' stands for cyanoacrylate, otherwise known as superglue. As you might guess from the name, cured CA is a hard polymerized acrylic plastic and can be polished to a high gloss, thus making it ideal for finishes on stabilized wood and urethane resin pens, knife handles or other small objects.
A Google search quickly turns up around 790,000,000 results and you can browse through them for more background info, but here is how I do it...
First, it is worth noting that CA cures by exposure to moisture, and even normal humidity is enough to start the reaction, which begins at the surface and almost immediately forms a cured 'skin'. For that reason, it is better, necessary even, to use many thin coats rather that a few thicker coats. Also, the CA starts to cure as soon as it is applied but can take from 2-20 seconds to fully harden depending upon the brand of CA and the atmospheric conditions. I have found that there is a 'sweet spot' where the previous layer is still slightly soft and blends in smoothly with a new layer applied over it.
This process is super fast and easy on a lathe...knife scales take a little more elbow grease but can be ultimately brought to a glassy finish.
I usually begin by wet sanding to about 800, although if the underlying surface is flawed or pitted and is going to require a lot of 'filling' I might only go to 400. The reason for wet sanding is that dry sanding can leave dust in minute pits or cracks that will then be sealed in by the CA and be quite noticeable,and impossible to remove without sanding down to bare wood.
Dry the piece thoroughly after wet sanding as moisture will accelerate the curing process.
Use a lint free paper towel* to wipe on a thin layer of CA. Let cure until not-quite-fully-hard-yet and then apply another thin layer. Repeat 7X (at least 8 THIN layers). I usually follow up with a quick spray of CA accelerator and wait a few moments for it to fully harden before I handle it.
From this point I wet sand up to 2000, being careful, especially around the edges, not to sand through the CA. If you DO sand through the CA you will have to add more thin layers of CA and sand from the beginning. After the wet sanding is complete I buff with ZAM and then finish up HUT Ultra Gloss Plastic Polish
*CA combined with cotton, and some other natural materials can produce enough heat to burn the skin. It also releases dangerous fumes so be careful about wearing cotton (jeans) or using cotton swabs to apply the CA.