This sounds like the material I've been using for exterior, vertical declining dials. I have had good success. The material is easy to work with a saw and router. It is uniform, dimensionally stable and weather proof. Some of my dials have been up for over ten years. In this time the paint has faded but the "wood" is unaffected. The dials need to be touched up when ever the house is repainted.
What we need are inorganic UV resistant pigments. Perhaps I should be using ochre and bear grease to mark my dials. Indian pictographs using such materials have survived in this area for many centuries. Roger Bailey Walking Shadow Designs N 51 W 115 At 05:54 PM 3/3/00 +0000, Tony Moss wrote: >Fellow Shadow Watchers, > Professor Noel Dilly and Sarah Edmondson-Jones >recently exchanged ideas about materials for sundial making which called >to mind being asked to make a 'budget' sundial for which the first >suggesion was marine plywood. The architect involved claimed problems >with delamination and suggested 'Exterior Grade MDF' instead (Medium >Density Fibreboard for non-UK readers) and, although I'd never used it, I >expressed grave doubts as to its durability. To put the matter to a >crude test I immersed narrow strips in water for two weeks while checking >for water penetration and signs of delaminating, swelling, softening etc. > While not totally impervious the results were most impressive. > >In many respects it's the perfect material being flat, smooth, fairly >cheap and unlikely to warp or twist in addition to being iso...??? >(forgotten the word) meaning 'working equally easily in all directions' >In some ways it is like non-brittle slate. Given edge-sealing and a coat >of paint I think Exterior Grade MDF is a good candidate for large, >low-cost dials. A woodworking router with a 'veining' cutter for >hourlines and some templets for numerals should yield a good-looking >'carved' dial which would be cheaply replaced as the years take their >toll. > >To meet budget and deadline I stuck CNC-cut PVC numerals on with >cyanoacrylate gel to combat the expansion/contraction of the two >materials at different temperatures. > >That is one sundial which will never appear in the BSS Register I think >Patrick. ;-) > >Tony Moss > >P.S. to my JPEG sub-listers - patterns are still at the foundry awaiting >casting. > >
