Advice required on varnish or altfernative

[Deeps123]

Some advice please, my great grand-daughter has presented me with a little bird house she has decorated with acrylic paints and I need to know how I can protect it for use outside. Not sure if I need to seal it before varnishing or what , just don't want to mess up her artwork. Grateful for any advice

 

[AES]

I've finished toys with acrylic paint (artists colours) and when FULLY dry have over sprayed the lot with clear acrylic varnish. But that was for indoor use (mainly!).

I would have though that any clear varnish, ideally satin unless you want high gloss, which also says "suitable for use outdoors" on the tin would be fine, BUT as above, make sure the colour underneath is really fully dried (if the little girl has "slapped it on a bit" then that COULD take up to a week - look for a corner or somewhere where the colour's a bit thick and if you can get your finger nail into it, it's still not fully cured).

 

[Deeps123]

Thanks AES , I will give that a try, I have a tin of exterior wood varnish I will check the label and see if it is suitable.

 

[ED65]

Most varnishes will work fine directly on top of acrylic paints as the solvent in varnish isn't a solvent for the acrylic binder. They also bond well, even a smooth acrylic surface is full of microscopic texture that gives varnish something to hold on to. If the paint is matt, even better.

But there is a problem posed by light. Unfortunately nothing you put over the top can protect from light in the long term.

Don't know how you feel about the potential for this fading but you should prepare yourself for some colour changes, with cheaper paints (esp. children's paints and some craft lines) being made largely from pigments that aren't lightfast. Bright colours will be the worst offenders. The weakest colours – all yellows, most reds – will eventually become ghosts of their former selves, and greens may turn blue over time as the yellow component fades. Blues will tend to hold up well because good blue pigments are inexpensive. Any black should be fine too as carbon is cheap