ElTanko

Hello all, newbie here. After some advice on weathering. I bought some Humbrol satin varnish last week and now need to get washes for panel lines etc. So my questions are:, is one initiall layer of varnish enough? and if I get the Humbrol enamel line wash, does the enamel thinner help to wipe away any overspill on the model using a cotton bud etc? Thanks in advance.