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Experience with Rio's anticlastic bracelet forming kit

I am interested in making anticlastic bracelets and would like to
know if anyone has used the new anticlastic bracelet forming kit for
the Mark III (Rio #100598), what they thought about it (is it easy to
use, produce good results, etc.) and if anyone had instructions how
to use it. I will be using the kit to form silver, 14k and 18k
bracelets and had the following questions:

  • What is the thinnest and thickest gauge of material that can be
  • How narrow or wide can the material be (from 3/4" to 2 1/2")?
  • Will metal that has been textured prior to forming be affected?
  • Can overlay or small bezels be soldered onto material prior to

I’m also curious to know which method yields the best product (old
school or Bonny Doon).

Any help in this matter is greatly appreciated.

Hi Michael,

Bonny Doon makes two different anticlastic forming tool sets. Since
each tool set has advantages and disadvantages, both anticlastic tool
sets are being made by Bonny Doon.


o New tool: The metal is formed/pushed by a steel anticlastic
tool/form into urethane

o Original tool: the metal is formed/pushed by urethane against
delrin anticlastic forms/tools - MATERIALS the tools are made of
affect the thickness of metal that can be formed with the tool

o The newer tool set has an anticlastic form made of steel, which
pushes the metal into urethane to form it. The advantage of this tool
is that it is very strong, capable of forming wide, thick metal.

o The original anticlastic forming set has 4 anticlastic forms made
of delrin which push your metal into urethane. The delrin cannot form
metal that is as thick as metals that the steel former can form.

o BOTH tool sets have the advantage of being able to form metal with
overlays, or texture, without damage.

o David Anderson has successfully set small cabochons in bezels prior
to forming with the new steel tool. However, that is not advisable
with the original delrin tool set.


o The new steel tool set is one 2-inch wide curve of steel. Any
width, up to 2", can be formed with the same tool. However, they all
have the same curvature.

o The original delrin and aluminum set has 4 widths: 1-2", 3-4" 1"
and 1.25". The narrowest has the tightest curvature. The curvatures
get progressively shallower, as the delrin formers get wider. It is
difficult to form an anticlast wider than 1.25"


o The new steel tool is very straightforward in how it is used. The
press is used like a giant hammer, pushing the metal into the
urethane, and you can make sure that the metal is centered as it is

o The forming with the original anticlastic tool occurs out of
sight, making it tricky to be sure of symmetrically forming metal
that is not a straight strip of the same width as the delrin former.

  • It is difficult to definitively state thickness and thinness
    limits, since every case is different. Both can form thin metal. The
    new steel tool is definitely capable of forming stiffer/thicker
    metal. I don’t think I’d recommend trying to form anything heavier
    than 14 gauge sterling with the original tool, but I’m not sure that
    it can do that, really; since anticlastic forms are so strong, I’ve
    never felt the need to use anything thicker than 18 gauge sterling
    silver, myself.

In terms of instructions, your question reminds me that I need to
write them! I’ll try to get right on that. In the meantime, since
the set works very similarly to the new Bonny Doon synclastic former,
you could read those, and learn the main concepts. The instructions I
wrote for the similar synclastic former are posted on the discussion
group at . Or, if you email me, I could
send you a pdf.

Cynthia Eid