just like in the other thread you posted and I replied this became very popular do to the steve vai signature models of the 80-90s
They miss the most crucial step on project guitar and thats the clear coat. You have to build several succesive layers and with flat sanding in between to go over the multi stepped finish,
think about it paint is being put on said instrument in a very uneven fashion. Also after pulling it out of the water is a huge step as well.
By the way you dont need to use Borax either
Oh and some paints work better than others
Oh dont forget to wax holes so water doesnt seep into the bare wood causing warpiing
Oh its not oil based paints that work
Oh make sure your clear doesnt react with the paints
Oh make sure you dry it properly to not get drips
Oh make sure you use the proper tempature of water, hence no borax
the list of things not mentioned go on and on and on
Hence why ATD designs(original swirler for Ibanez) and Herc Fede charge upwards of 500-900 for a swirl.
There is a ton of steps that is not mentioned at project guitar, Ive attempted it over 20x with not so good results. Its not just dunking some wood into a water and pulling out a masterpiece. There is a science to it that takes years to become even "Okay" at swirling let alone good.