Varnishing questions

[woodbury22uk]

When I did my first weathering a long time ago I practiced on a small piece of plastic sheet that I had scored some lines on and then sprayed with grey primer. I also used gouache paints which are entirely water soluble even long after they have dried. It meant I learned how paint and washes settled in crevices and how to dry brush colour. I could wash off the colour and start afresh with a clean test piece until I knew what I was doing. I did eventually use some weathering powders on the same test piece.

[Bealman]

That sounds like a great idea! 

[Grassyfield]

Im confused so just want to carry on about this. On most videos on utube people are using enamel thinners with oil paint, not white spirits. So just to confirm am i correct enamel thinner is perfectly fine to use with oil paint for making washes and thinning it. I was thinking of getting this Humbrol Enamel Thinner. I plan on using oil paints and powders only not enamel paints.

[woodbury22uk]

As a beginner I would recommend you use a thinner made for oil paints.   I really cannot see the point of choosing enamel thinners. It just introduces another uncertainty. Where you buy your oil paints you will find a dozen oil paint thinners, mediums and solvents alongside to suit gloss, matt, silk, and all sorts of surface finishes. When you have mastered the basic thinned oil paint weathering, then you could experiment with solvents like the Humbrol thinners. When I began I eliminated the major uncertainty, my skill level, by using water soluble gouache. I could correct as I went along. I still use it sometimes when testing out a livery application on a 3D print.