5th August 2015 - Allen Atkins
Allen began his demonstration by explaining that some woodturning purists don't like colouring wood - and then telling us that if we didn't like colouring it was just tough because he was going to be doing it anyway :-)
It's a contrary subject because many people don't want to use wood with good figuring for colouring - but to get the best out of colouring that's exactly the wood you need.
Having got his piece of sycamore mounted up on a screw chuck, trued up and a 50mm mounting recess cut Allen showed us how to create a decent ogee shape by dividing the flat space into three, cutting the concave surface into the outer 2/3 then marking the middle of that 2/3 to replace the second line and cutting the convex surface from that line to the centre. It worked and I'm sure there are a few of us who will be giving it a try soon.
Having turned and sanded the outside of the bowl Allen finished it with two coats of sanding sealer (sealer plus 50% thinners) to make sure any stray spirit dye didn't get absorbed into the wood on the base. Then the bowl was turned around and mounted on the recess to start work on the top.
Allen cut a nice smooth surface across the area to be dyed making sure that there was a slight gradient down towards the centre to make the bowl more friendly to the hand. As the dyes and finished make any defects stand out Allen took some time to make sure he was happy with the sanded finish before carrying on.
The lathe bed was covered with a cloth and a tray of spirit dyes. Allen suggested using the smallest possible piece of paper to apply each colour. Bigger bits of paper just absorb more dye which ends up being wasted.
First he applied a thick coat of black over much of the width. Then he sanded if from the outside in to create a gradient from dark to light. More colours were added from the centre out and each knocked well back to create a series of overlapping gradients some just a band of colour, others radiating from the centre.
A little pump bottle (a FryLite bottle) was used to apply a little meths to help to blend the colours. Throughout Allen was trying to avoid hard edges and aiming at a gentle blending of colours. To tidy the edge he uses a black permanent marker, holding it on the surface as he rotates the bowl by hand. He admitted that the whole process is something of a lottery with plenty of rejects. He suggested that beginners might leave the bowl a little thick so that they could cut the surface back to have a second go if the first was unsatisfactory.
Once he's happy with the colour Allen leaves the bowl to dry thoroughly before applying laquer over it. He then applys four coats of acrylic lacquer at 15 minute intervals so the coats merge together and waits a further 24 hours before burnishing the surface.
Once the rim surface is finished he starts hollowing the middle. First he cuts a groove with a parting tool to give bevel support to his bowl gouge and make sure it doesn't skid back and ruin all of that careful colouring and finishing.
Allen admitted to having recently gone through the bottom of a bowl and so made a point of checking his depth over and over to make absolutely sure it didn't happen again - always a good idea!
All went well until Allen bought out a bowl with the rim lacquered and finished to demonstrate cutting the bowl in the centre. An afternoon in a plastic bag in a hot car seemed to have softened the lacquer causing it to get damaged against the paper wrapping as well as liting it off the surface slightly, possibly due to moisture in the wood pushing it off. Whatever the cause it ruined the finish and also made the laquer chip horribly when he came to sand the inside of the bowl.
As is so often the case seeing something go wrong and trying to understand the causes was very instructive and we all felt sympathy for Allen as he realised what a mess the warmth and humidity had made of a nicely finished surface.
By the end of the demo some of us who had previously not considered using dyes were thinking that it might be interesting to experiment with some colouring at some point to see what we could do with it. Many thanks to Allen for giving us a very proficient and thought provoking demonstration of a technique which many of us have never tried.