Friday, 29 November 2013

Shrink Pot Tutorial Pt 1

I've posted before about shrink pots but thought it may be of use to some beginners to publish a step by step tutorial of how I make them at the moment. This is just my method, I'm sure there are equally good alternative methods, It's just my personal observations, thoughts and methodology.
            Firstly, I tend to leave the outside of my pots predominantly debarked but natural, so I tend to make them in volume in the spring when the sap is rising. This is because the bark is extremely easy to remove, even over burred sections, as you will see further into the tutorial. When choosing stock I would advise against using material that has grown under stress such as a twisted branch or branch growing in exposed windy aspect: these tend to give less stable pots that are more likely to split on drying. Here's a lump of Silver Birch; it doesn't matter if it's been down a few weeks, it will still shrink enough to seal the base.
                                                                                           
Here I've cross-cut the log into pot sized pieces. I try to avoid knots or other awkward figuring near the rim or base as this can make things awkward for fitting the base and lid later.
   I deliberately leave the bark on at this stage to minimise bruising whilst the blank is clamped for boring. As you can see I clamp it in position with cross wedges:-
Using hand augers produces quite a lot of torque so I try not to use and auger too wide in diameter relative to the size of the pot . I have split pots at this stage in the past by using too large an auger.

I tend to bore slightly off centre because the pith of some species is quite soft and difficult for the lead screw to bite into.

Depending on the size of the pot I may bore straight through or bore from each end to the centre.

Next job is to open up the hole with an in channel gouge. Only thing to be aware of is using a gouge of tighter radius than the auger; otherwise you risk getting the gouge pinched (trapped) in the material.

Carry on working outwards.

Work with the gouge to a wall thickness of about half an inch (excluding bark)

Remove the bark by scoring then peeling with a blunt knife.



As you can see, spring harvested timber is easy to peel.

Next smooth the inner walls with the spoon knife down to a thickness of roughly 3/8" at the base and maybe a little thinner at the rim.


Now I square off the base at the disc sander for a good reference surface for the marking gauge.


I like to leave a good 1/4" between the bottom of the pot and the base groove.

Plough out the groove. I like to use a flexcut 5mm scorp for this job.

Mark out the base disc on some seasoned stock. This is oak about 1/4"-3/8".

Roughly cut out the discs on the bandsaw fitted with a 1/4" blade.


Back to the disc sander for final fitting and thicknessing of the disc to fit into the groove.

Push the disc into the groove and set aside to dry and shrink to a seal.
That's the mechanics of the vessel sorted. More refinements and examples to follow in part 2. 
Cheers John

2 comments:

  1. Good clear instructions John, well done. I've not read the second instalment yet but if not covered there - I sometimes drill a couple or even three adjacent holes in bigger pots to aid getting started with the gouge.

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  2. Thanks for sharing your experience Richard.

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