I've been to London for a couple of days, but now I'm back...
The way I did it, was just add borax to water(the tutorial way). Then I used urethanlaquer, common Humbrol mini-cans, costs like $1,5 a can. So swirling guitars this way is pretty cheap! And with the cheap laquer, you can fool around alot to learn how the different colors react, without spending more than $10.