Friday, September 6, 2013

End Caps

Last time I worked with bike parts, I ended up making a few "end caps." I could use these pieces to cover the open end of a bike part and add a little more visual interest, color and texture to that area of the sculpture. I made extras of these pieces, not knowing for sure if I would use them until after the piece was mostly completed.

detail of "Big SRAM'" sculpture from last year.
This time around I seem to have many pieces that might lend themselves to being embellished with similar end caps. I started making a few last time I threw. I measured the end caps to fit in sets of gears. I have quite a few sets of gears and the end caps could fit in them right side up, upside down or on the end of an extension sticking out of the gear stack.

bike gear
In preparation for throwing I measured the opening of the gear stack, though I have quite a bit of flexibility in how the end caps sits in or on the gears. I have to account for shrinkage during firing, so, though I measured, I need to add about 10% onto that measured size when I throw the form.

measuring the attachment size with calipers
I threw several end cap shapes and several bulb forms "off the hump." The end caps can be simple bowls forms or more complex bowls with lips. The advantage of the lip is a tighter fit and, more importantly, more surface area on which to apply the epoxy when attaching the forms to the metal or plastic of the gear stack.
throwing "off the hump"
An additional advantage of a lip is that it allows more room on either side of the measurement if shrinkage isn't exactly 10% at this temperature--or if my measurements aren't accurate.

measuring the attachment size
I cut the bowls off the hump so that I could throw more pieces with the clay remaining on the wheel. The same day I also threw a bunch of extra forms to work with during the coming weeks. After the end cap bowls dried for one day, I trimmed them and then embellished their surfaces with stamps and sprigs.

undercutting the piece off the hump

trimming a round shape
The end cap doesn't (and shouldn't) fit while it is wet. It will shrink during drying and in the kiln. It should fit after it is fired. I made several different surface textures, but I will probably make additional matching pieces in case I end up using the end caps as sets for one sculpture, as I did last year.

a wet end cap, too big to fit inside the gear stack
After the end caps dry and are bisqued, I will layer underglazes and fire the pieces again. The end caps will be added to the sculptures relatively late in the process. Several end caps will be interchangeable so that I can eliminate pieces that shrink too much, aren't glazed well or just don't seem like the best option.
various end caps

1 comment:

  1. I'd like to watch you do some of this. I find it fascinating.


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