Big ole big-hole beads

Or, the joys heat-sucking mandrels

There are several conditions that can cause hollow mandrel wound beads to collapse: the artist may lay the coils down unevenly, with gaps; the coils themselves may separate, & gap); or, the beginning coils may not stick firmly enough to the release and/or air may leak through the release. The latter two conditions are exacerbated by uneven heating. Thus, if one lays down coils too slowly, with too-infrequent warming passes, they cool and shrink, voila, gaposis. If the mandrel is insufficiently hot, the glass may stick, but not really bond. With mandrels of 1/8'' (3mm) or less, this isn't really an issue; but larger diameter mandrels, even those made of tubing, act as heat sinks.

4 ``bighole'' beads. Largest, 32x45mm, hole 11mm (7/8'') in diameter. And my goodness, pink Italian soda-lime has a brownish cast.

I get around this in various ways, such as air-drying the release and preheating the mandrels in a kiln. In fact, these beads were made with 3 different types of mandrels. The biggest one, on the left, and (I think) the one to right, were the two made on cross-drilled stainless tubing. This is a technique/tool I learned from Stevi Belle. You drill a hole near the end of your tube, plug the tip of it, and build your mandrel wound hollow like usual---except, you can blow air through the little hole. This is nice when you've let your bead cool too much, and it cracks: you simply heat it, heal it, and puff it back out, with no loss of volume. Thus, this technique is a variation on glass-blowing, but gives the support of a mandrel---the best of both worlds.

The disadvantage is that you must rotate a mandrel 3/8'' in diameter.

The other roundish bead, 2nd from the right, was made on a quarter-inch solid mandrel---very heavy! Again, once your wrist gets used to the weight, it's not so bad, but I haven't been making large beads regularly for a long time. Guess I should get serious about learning arm balances.

And finally, we have Arrow Springs' "Emiko" big-hole mandrels, in which a cylinder is brazed to a nice thick (but not too thick) solid mandrel---this keeps the weight down, the newest incarnation features a highly textured surface to grip the bead release, as well as a rounded tip for folks wanting to make solid vessels.

So far, I'm kinda liking the first option the best, but I'm only 4 beads into this project. It will be interesting to see how it evolves. If nothing else, I might finally start making glass pis, one of my favorite accents back in my stringing days.

pix taken 20aug07; intro written 19aug; post 22aug.