Archive for March, 2007

Tops, Chatter and Marbling

Saturday, March 3rd, 2007

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In todays MWA meeting Alan Lacer shared with us his passion for wooden tops. He started out by showing us a rather large collection of tops in many different variations. Some of these came all the way from Japan, where tops are a favorite past time and also quite a source of competition!

We saw many different tops: Throw tops, chasing tops, howling tops, stacking tops, small (very small!) tops, large tops… The photos in this article show a small part of the collection Alan brought along.

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Alan also brought along two squared platters turned from slate. This have a very nice surface and are well suited running some of the smaller tops in. Slate can be turned, but depending on the composition and hardness that may sometimes be a very tedious process that requires constant sharpening of the tools (as Alan said: don’t turn that grinder off!).

Next Alan showed us how to turn very small tops. For that he used a small piece of Osage Orange, slightly sharpened and hammered right into the head stock of the lathe. Alan being Alan he used a large Skew chisel to turn those small tops, one being less than 1/2” in diameter, the other less than 1/4”. But even smaller tops can be turned (and painted!) as the photos prove (note the ball point pen shown for scale in one of the photos!).

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The rules for a traditional top are simple: good balance and a low center of gravity. But that those rules are not written in stone Alan showed with the next top he turned: a pear-shaped top, designed to stand on the small end of the shape. For this he used a commercially available hard-plastic insert that made the point of the top. Drilling the hole for this point is often a bit frustrating, as the head and tail stock rarely line up perfectly enough for the point to end up exactly in the center. In the worst case the turning tools cane be used to slightly reshape the tip.

For decoration he added some small V-cuts, which he then bruned with a plain piece of wire. He also added some decorative lines with an acid-free pen, which are available in many colors in art supply stores.

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Chatter

Next Alan turned a more traditional top, and demonstrated chattering techniques as a method of texturing. Many turners are familiar with chattering as an unwanted effect whenever vibrations occur during turning.

Best suited for chattering are end grains of dense woods such as hard maple. Nearly any turning tool, held lightly, can be made to chatter, but easiest is the use of purpose-made chattering tools. These usually consist of a piece of thin steel mounted in a tool handle (look out for Duane’s next Tool-Making session! Lightly applied to the surface of the wood, either with the tip or the full flat side of the tool, soon you will here the typical chattering sound. Only this time it is what we are looking for!

The chattered surface can stand as is, or it can be colored. It only takes a moment to use one of the above mentioned pens with a blunt tip to transform the surface. One can even lightly sand afterwards to take the paint of the high spots for yet another effect.

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Marbling

To demonstrate marbling Alan starts by turning some tops specially suited for marbling. These tops consist of two parts: The disk-like body of the top, which is going to be marbled, and an axle. Alan likes to just pressure fit these to parts together, so that in case the axle is damaged it can be replaced without having to discard a nicely decorated body. In this session Alan concentrated on the bodies.

Works starts by drilling the hole into which later the axle will be pushed into. Then he prepares the upper service, and the lower surface as good as possible before parting it off. He then fabricates a jam chuck to reverse fit the disk and finish-turn the future bottom.

The disks, as well as any test paper used for marbling, need to be coated with an alum solution. Otherwise they will accept little or no color in the marbling process.

For marbling, essentially colors are dripped on a bed of a thicker fluid, in this case carrageenan dissolved in water. The colors are then manipulated by means of combs (toothpicks in a piece of styrofoam), brushes or even cat whiskers. Once a pleasing pattern has been achieved, the object to be marblized is carefully deposited on the bed.

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In the case of paper it works easiest by rolling it into the bed to avoid air bubbles. A shake introduced while doing so achieves additional decorative effects.

To dip the disks for our future tops, a dentist hook tool can be pushed inside the hole drilled into the disk. The disk is the carefully pushed into the bed, upper side first. When the disk is submerged, the backwash will color the bottom. A turn of the wrist while submerging the disk creates a nice swirling effect.

The mabelized material is then carefully rinsed in plain tap water, and allowed to dry thoroughly which may take several days. If the results are not pleasing, the process can be repeated one the disks had time to dry.

The bed can be reduced several times, the leftover paint can be skimmed off with newspaper strips before applying new paint.

Marbeling is a fun process. Many kinds of colors, dyes or inks can be used. Various materials are suited to prepare the beds. And the colors can be manipulated using any kind or combination of tools.

This was a fun demonstration, well worth the price of admission.


Handout: Marbeling

Supplies

  • carrageenan (size material)
  • distilled water
  • blender
  • alum
  • foam brush
  • liquid acrylic paints (Golden is a good brand)
  • container for marbling (11/2” to 2”’ deep)
  • eye droppers and/or wisks made from broom straw
  • rubber gloves
  • plastic drop cloth
  • newspaper strips (1” x 10”)
  • optional combs for pattern making

Source for supplies locally

  • Wet Paint at 1684 Grand in St.Paul.

Practice paper

Ingres Pastel paper in white (available at Wet paint).

References

Books
  • The Ultimate Marbling Handbook by Diane Maurer-Mathison

  • How to Marbelize Paper by Gabriele Grunebaum

Articles
  • Mary Thouin did a two-part article in the Fall 2002 issue and Winter 2002 issue of American Woodturner

  • Jacques Blumer, page 40 of American Woodturner Fall 2003

Links