Turn A Seedpod Complete With Pearl Seeds
Monday 11 January 2010
The Trinitas seedpod is the most recent addition to my seedpod series, which I have been adding to gradually over the years.
I have been intrigued and pre-occupied with seedpods for many years; the first one saw the light of day back in 2001.
My Trinitas seedpod is a flow-on from a previous pod, the Andromeda - the shape of the flower of that name inspired the Andromeda pod.
Having previously made a living off the land, I developed a strong affinity with nature. Inspiration is all around us: whilst at first you look for it, eventually you are so receptive to it that it will jump out and hit you squarely between the eyes.
Then, it is a matter of having a system to retain the received information; though most of us rely on our mental filing system, a note/sketch book is a safer way.
A few of my pods are semi-copies of real pods; however, most of them are a far cry from the original inspiration, and have taken on a life of their own.
Most of my design work is a progression of ideas from nature; previous ideas from that source; and last but not least, my mind-set at that particular time.
The wood I chose for the pod is our local sheoak (Allocasuarina fraseriana). This is quite a dense wood with a tight grain; it takes detail very well and is ideal for a small piece, such as a seedpod.
Wanting to insert cultured pearls, as seeds required some thinking about in order to get all the steps in proper sequence. Many sketches helped to visualise the end result.
Pair of compasses, compound drop saw (or bandsaw), pair of callipers, duct tape, hollowing tool, chisel, pyramid shape burr, cylinder burr, diamond disc, acrylic paint, spirit stain, spray-on furniture lacquer
Select your wood to suit the finished size you have in mind. In my case, I used a piece 130mm (5 1/8in) x 70mm (2 3/4in) diameter. Because this piece consists of three sections, this needs to be marked out and cut. Use a pair of compasses to draw out the required diameter and draw a line to the centre point, squaring off the baseline. Keeping the compass on the same radius, bisect the circumference starting at the previously drawn line. You will find having gone round that you will arrive back exactly on the point where you started. Meanwhile, you have divided the piece into six equal portions from where it is easy to mark out the piece into three equal sections
To cut the blank into three use a compound drop saw. However, "There are many roads that lead to Rome," so if you are careful, a table or bandsaw will also do the job. A sanding disc on your lathe will clean up the cuts to give a perfect fit. Some wood glue on all the surfaces, a sheet of newspaper in between, three clamps to keep it all together, and hey presto! We're nearly ready for some turning. Before you put chisel to wood I suggest you make a full-scale drawing of the item. You are then able to set your callipers to whatever section you are turning and transfer the exact measurements, and consequently the exact drawn shape. Incidentally, this is a good procedure for any piece you may wish to make. A full-scale drawing (even on a bit of cardboard) will allow you to get the most out of your costly blank
A paper glue joint needs to be treated with some respect, so ensure to take care during this step. The idea is to split the blank in three when we want to, but not before. Therefore, it is important to use a ring-drive as well as a live ring centre when turning between centres - these hold the pieces together instead of wedging them apart and having them bounce off the wall. With the help of your full-scale plan, you are now ready to turn your shape. Turn a spigot on the base so you can hold the piece in your scroll chuck, and now you are ready for hollowing
Not having any support at the opening end now means you will need to do something to stop the piece splitting apart, like a ripe banana. A great tool here is 'duct tape', which helps ensure that the piece will not split during this process. Duct tape is strong yet has a certain amount of stretch - perfect for this task. Wrap the tape tightly around the neck. Next, drill a 10mm (3/8in) hole to the required hollowing depth. After this it is just a matter of peeling the wood off to the correct thickness - as per the plan you have previously drawn out. The hollowing tool used here was one of of my own design and manufacture (see overleaf), with a HSS hookcutter on the business end, but a scraping tip will work as well
Here is the homemade hollowing tool shown more clearly. The tool is made out of 'bright steel rod' which is generally used for shafts - it is a higher tensile than the black steel. The outrigger is not welded, but a bigger diameter section is drilled to the exact same diameter as the shaft-steel and pinned and clinched together. The adjustable spring can be set to the required thickness, with the spring trailing on the outside until the desired thickness is attained, when it will just run clear of the piece (see previous step). The cutter is made out of HSS (High Speed Steel) using the drill press and the grinding wheel
Having satisfactorily hollowed the piece you are now ready to mark out the bits, which need to be cut away to create the points. You can mark this out later if you wish, but I find now is the more convenient time. A line on the piece while the lathe is spinning gives you the depth of your incision. The point is exactly halfway between the glue joints; all you need is a pencil
Take a wood chisel and place exactly on the paper joint. A few gentle taps with a mallet and you will be relieved to find you have your three equal sections
Here are three pieces at various stages. Using a coarse sanding disc is an easy, controlled way to do your rough shaping
To further refine the outside shape you now need to focus on rounding the corners. First, mark out how far the rounding is to go, then proceed with whatever tool you have best suited to the task
Having roughed out your shape the three sections now need to be joined together for the final outside shaping of the pod. Use small nails as 'dowels' to keep each section in its correct position. First, drill two holes on one side and insert nails and cut so only the point protrudes (these are your 'marker nails'). Now, line up the two sections in their correct position and press them together forcefully; the imprints will now give you the exact position for the matching holes on the opposite section. Drill these, insert dowels and now you have one joint done. Use the same procedure for the other two joints. No glue yet, at this stage. Holding the three sections together, use a file, rasp, or coarse sandpaper to tidy up and align the joined sections
The next step is to mark and carve out the interior, leaving a central ridge to attach the pearls onto
It is now time to put the fine rim into place; this is easier than may first be thought. What you require is a 'pyramid' shape burr. When fitting the burr, set the distance between it and the chuck to the thickness of the thin rim, which is about 1-1.5mm. You are now able to use this as a marking gauge. To prevent the chuck from damaging the work, round off the chuck corner by holding the spinning chuck against a spinning grinding wheel. Now, move your marking gauge gently around the perimeter and you will notice that you get a nice even score mark - that is if you keep the Dremel square off the work. Once you feel comfortable with the technique switch on the unit and gently, with even strokes, carve away 1-1.5mm. The cutter shaft can be used as a depth gauge; the deeper you want to go, the bigger the cutter needs to be. All this effort leaves the rim section standing nicely proud of the rest of the pod
Do the same on the other side where the sections do not touch each other - the 'open' part of the pod. If you find your 'fine rim' doesn't look so fine but is rather angular, don't worry, this can soon be rectified with some simple files, rifflers or abrasive paper
Now, mark the veins on the outside of your pod. These veins are relief carved so they protrude about 1mm (5/64n)
The relief carving is made easier by doctoring a cylinder type burr. With a diamond disc cut a 1 x 1mm groove in the cutter. This cutter now leaves a nice neat vein - of course, the neatness depends on how controlled the cut is
Here, you can see the result of using the cutter. Ensure to be as controlled as possible when using this to create a neat vein
It is now time to dimple the interior of the pod. Care must be taken so you do not damage the fine rim, but do dimple right up to it. You will notice here that I am holding two sections together whilst dimpling randomly over the joint - this will help to disguise it
Half drilled sweet water cultured pearls can be purchased from a jewellery supply shop. I suggest you do a web search and compare prices as they vary greatly. You need short pieces of thin wire or small nails that match the diameter of the drilled hole; these are then positioned in place with cyanoacrylate glue. Prepare the position of each pearl by grinding a small dish for them to sit in, in the centre of which you drill a hole for each pin
There is still some work to be done on the outside, and that is the texturing. Use the smallest possible burr to texture between the veins. Practise on a piece of scrap until you have a pattern you are happy with
Now, apply several coats of your chosen colour for the inside of your pod; I generally use acrylic. When dry, the pearls can be attached; a drop of cyanoacrylate glue works very well to hold them in place
The project is finally starting to look like a pod; it is now glue-up time. Use normal wood glue sparingly as you don't want it oozing and dribbling inside the painted pod. Use a small brush to clean up any glue that may show on the inside (watch out for those pearls!) Mix up some paint with a little acrylic modelling paste so as to get a slightly thicker paint, and very carefully paint over the interior joints (as before, be mindful of the pearls). While things are drying, carve the stalk. This is doweled to the pod using a short piece of bamboo kebab skewer as dowel
It is now time for the final touches to be made. First of all staining; I generally use spirit stains. Select your stain colour taking into consideration the initial wood colour and the final colour you want to arrive at (teak brown suited my situation). Because we have a mixture of side as well as end-grain any staining is going to be uneven, for that reason I like to give a sealer coat first. This does make the stain dry slower, but also more evenly. After the seal coat, stain all unpainted parts of your pod, leave it to dry then very lightly sand with about 320-400 grit. This will really highlight your texturing as only the high points are sanded back. To further emphasise the texturing, scrape or sand the top of the veins completely clean
You are now almost finished; I generally use a thin coat of spray-on furniture lacquer for the finish coat; a wipe on finish tends to fill up the texture crevasses. You will notice that if adequate care is taken, the stalk's joint is barely noticeable. A very simple base is easy to make, this one is made of 10mm (3/8in) MDF and was sprayed a matt black. Well, there we have it! Most of us will know that it's possible to handle any seemingly 'impossible' and daunting task, providing that it is broken up into manageable, digestible bites. I hope this stimulates you to create bigger and better things