I've done swirl three times on guitars already. And hundreds of test dips
Testor paints dries too quick for me (that's unadvantage) but dissolves slow and steady (advantage). For swirling more than two colors you need the opposite - dissolving fast and drying slow. That's why Humbrol paints are better.
My experience:
- adding more borax speeds up dissolving
- higher temperature speeds ud dissolving and drying
- thinnig the paint speeds up dissolving
- using more paint gives better colors (I think Sarradan should use more paint, see red on picture below - while doing swirl on the guitar I used less red paint, on scrap I used more)
- wait too long with puring next color and it'll 'eat' the first
- dip, use something to clean the surface of water and pull out the guitar
- blow the water off with an air gun
My latest (test...) swirl.
I've used less paint on the body, that's why the colors are different and it actually like red and black ants Red and black are humbrol paints, yellow is testor (it didn't dissolved well...).
Previous swirl:
And a movie
Last two paints were thinned too much and when I pured white (ok, too much...) black was already dry.