For this evening’s demonstration, BCTW was pleased to host Robert Till, who has demonstrated for the club many times previously.
For this first part of tonight’s demo, Robert introduced everything to do with using ‘Green Wood’. Green wood or wet wood is kept in clingfilm to keep the moisture in, in this way it stops the drying-out procedure from being so quick and allows the wood to dry with less stress and hopefully less cracking.
It must also be kept in mind that whilst shaping the wet blanks and letting them stand after this can cause them to warp and move out of shape, which some might want. If any of the items do crack it gives the turner another avenue to produce something with added features. Robert gave a good explanation of why and how to treat the ‘Green Wood’ prior to it drying out completely.
The wood used in the demonstration is Cedar, with the first project to be a rough-turned bowl from a half-split branch. This is mounted by means of a screw chuck, but do not overtighten it as it may cause damage to the wood and become loose. The tail stock is also engaged for safety to stop the blank from flying off.
Robert used a bowl gouge which had a long grind feature with a 48-degree grind, he went on and produced a tenon as a mount for the chuck, prior to this though the outer shape was produced to a level that needed additional work when the blank had dried out some more.
With the blank being reversed and mounted to the chuck the waste from the middle of the bowl was removed, this being done to a set size again prior to it being finished off after drying out. Robert then used PVA glue to coat the outside of the bowl and also the rim but not the inner of the bowl, this was where he wanted the moisture to come out without undue pressure on the fibers of the wood.
At this stage a set of kitchen scales can be used to measure the weight of the blank with the remaining water or sap content, this was written onto the blank with the date, and this could then be checked out in the future to see how much moisture has dried out from it. Keep checking weight until it becomes stable or no more moisture is coming out. It can also be checked via a moisture meter to check the percentage of moisture held within the wood, this needs to get down to about 10%.
Robert then referenced the sanding of the projects whilst wet, this needs to be carried out when the blank has dried out more and the abrasive does not clog up so much, the project is then finished with finishing oil.
The second project was again Cedar which would be made into a vase time permitting with a thin wall. The blank was made round by using the side wing of the bowl gouge, a roughing gouge can also be used but care needs to be taken if there are a lot of twigs and branchlets protruding.
When round a tenon was put on one end, if you require a lid to be fitted it would be best to put a tenon on each end prior to separating the parts. The outer part of the vase shape was achieved by Robert using three different tools a bowl gouge, a spindle gouge, and a spindle roughing gouge. This was taken down to an acceptable shape that was pleasing to the eye.
When this was achieved a 20mm hole was drilled down the blank to a sufficient depth ready for the hollowing out process, with the hole drilled some of the tension had been taken out of the wood, to help the drilling process candle wax can be applied to the drill to aid with the drilling process.
For the hollowing process, Robert showed a number of tools that he uses but settled for a Simon Hope hollower with an 8mm cutting tip. He hollowed out the piece until it was about 6mm thick. He then used an LED light internally on the hollowed-out vase.
Robert then started to remove waste from the outer again and took the thickness down to about 4mm, This showed up well on the screen with the light being visible through the wood thickness.
If you do not have time to complete the hollowing-out procedure then pack it with the wet shavings and cover it again with clingfilm but leave the hole open so that the moisture can run out.
Robert answered all questions directed at him throughout the evening, as a club we must thank him for an interesting demonstration with some good advice being given
For this evening’s demonstration, we had 27 club members present.
Thanks go out to all people who helped the evening go without any problems and to the members who helped with the setting up and taking down procedures.
Report by Barrie Fisher, edited by Steve Hackett