Wet & Dry sanding mandrels
Following on from last month’s blog on diamond wire saw blades to cut through otherwise very hard to reach areas, the story continues here with cleaning up the cut faces of one of my recent pieces of work.
The matau had a narrow slot through the curved mid-channel of the piece. I now had the choice to use a grinding wheel to open it out, or else a diamond file. In the event I decided to widen the slot with an abrasive wheel which neatly followed the saw cut, then use my 100 grit medium sized half-round file to follow the groove around the arc to clean up on one side and then the other. The circular culmination of the channel, the centre of the koru, needed a round file of the right size to clean it up.
I used a mandrel with a piece of Wet & Dry paper (W&D) wrapped around it to sand the smaller radius curves down and remove the coarse tool marks from the files. I began with 240 grit paper and followed with 600 and finally 1000 grit paper.
For the larger radius curves I used a sanding block wrapped in W&D by hand. I hesitate to show you the next picture as this is not what you are supposed to use a stainless steel rule for, but I didn’t press too hard and it worked very well in the situation with no damage to the rule! As a carver you will often need to improvise and there is everything to be said for it!
It came out quite neatly.
But let’s talk a bit about the different tools you can make up or buy to perform this task:
Most importantly, bearing in mind your electric drill or point carver normally turns to the right viewed from the body and looking towards the tip of the tool, you need to wrap the paper around in the right direction. A band of rubber is good to secure the outer edge of the paper
You can see the selection I use in the picture below.
When sanding using power tools you need to keep your work cool to avoid overheating and the appearance of white flecks in the stone, so moisten the paper and work occasionally, and when it becomes dry again from the friction, dribble a few more drops of water onto the workface. The W&D is sufficiently robust to take it, and to form itself into the shape of the tool. If you have several turns of paper they will gradually wear away, but not before you complete most jobs.
A final thought is to keep each mandrel tagged with the grain size of the W&D paper that is on it so you may be able to use it again for the next job.
Leave a Reply.
On this page I intend to add monthly updates on aspects of jade carving. I also plan to invite more experienced carvers to offer a "master-class" on a particular subject of their choice. With this I hope to enthuse both the novice and the expert in this ancient and beautiful art-form/craft. And comments are welcome!