Questions and answers - Varnishing for exterior artwork.
(Not really scenery painting but might be of interest)

I hope you don't mind me asking you for advice. I am an artist living in the Shetland Isles and have been commissioned to do an outside mural on Marine Plywood. I was wondering if you could give me some advice. I intend using artist quality acrylic paint on gesso primer - but I'm unsure what varnish to use - given the sometimes extreme weather conditions here. I really would appreciate any advice you could pass on to me!

Thanking you in anticipation,


Some extracts from my reply...

Let me tell you about my “Town Hall Door” Find it on my Causeway Art Studios site under“trompe l’oeil” (Remember to close the separate window once finished with)

The builders had covered it with a very rough ¾ inch thick timber sheeting which here they call “Sheafing”. It was also damp. I knew my painting was only to last a maximum of 2 years so contacted the Dulux paint laboratory people. I have their number if you want to follow this route. They recommended Dulux Weathershield Masonry Paint. I pointed out it wasn’t masonry but wood and they said on wood it would last at least five years and perhaps more.

Why am I telling you this? Because an exterior mural in the Shetlands must surely merit some free paint!! Especially if it is a community venture I can give you the address to write to for free Dulux paint for community ventures.

Of course Weathershield masonry paint does not need a varnish.

Similarly why not ask your acrylic paint people (W&N or Rowney?) if they would be willing to give you some paint in view of the location and publicity the project could generate.

Now let me tell you about my “Dinosaur” Find it under Parade Floats on my site. This had to last for two outings. It was made of a chicken wire mesh over a timber frame armature. The wire was covered (Papier mache method) with squares of canvas and then painted with ordinary household vinyl matt emulsion. (Used inside houses for decorating walls) Whilst building the thing we ran out of canvas and so “his” legs were covered with about five layers of newspaper instead.

Come the day of the parade it poured with rain (as it does in Northern Ireland and probably the Shetlands as well!) I worried about his paper legs but all went well. We won “best in show” and three weeks later it was in another parade with the same beast in other town where we won "best in show" again. Dinosaur was then taken to a council yard where it sat amongst the rubbish lorries and street-sweeping machines for at least another two years out in all weathers and survived completely intact. Painted newspaper legs and all. It was only after those two years or so that he started to disintegrate and was finally broken up. The moral here is that even ordinary household vinyl matt emulsion will stand outside in bad weather without any varnish for a good long time.

Yes I have used varnish - for large areas of acrylic paint murals. (And I am talking 30 feet long by twenty feet high here) I used ROSCO CLEAR ACRYLIC FLAT TRANSPARENT GLAZE. Rosco are a theatrical paint suppliers. I can give you their address if you want to know more. Very dear but the beauty of their products is you HAVE to dilute them. So you get more than you pay for, if you follow me. You cannot use this varnish neat from the tin and have to water it down at least the same amount again. I bought a one US Gallon tin of it (3.785 litres) so you see it comes in huge quantities (which is why I ask how big your mural is to be) It is an American firm but have a base in the UK.

For small acrylic painted things (see Folk Art on my web site) -but not acrylic fine art paintings, I used to use an American varnish called Ceramcoat. Wonderful stuff that dried in ten minutes so. I have been known to put ten coats on an item in one day. However they will not ship less than one US gallon now so I have given up. Perhaps they now have a UK agent. Must look them up on the web.

So now I use varnish called “Right-on” manufactured in California by a company called Pace Industries but I bought it here in Northern Ireland in a folk art shop (actually the only folk art materials shop in the whole of the country - probably gone out of business by now). However it takes half an hour to dry and needs several coats to give a sheen.

Do you get your paints by mail order? I suspect so considering your location. Me too. I use a London firm called Wheatsheaf. They are very good, have a huge (free) catalogue and a fast delivery. Although I see they charge more for delivering to off -shore islands.

They sell several acrylic varnishes by Winsor and Newton; Daler-Rowney; Liquitex; and Golden. Haven’t tried any of them myself. Again I can give you the phone number of Wheatsheaf to get a catalogue from these if you wish.

Hope some of the above is useful. Isn’t the Internet a wonderful thing for these sorts of encounters?

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