Turtleback Lamp Info
Tiffany’s turtleback tiles were pressed from iron molds and iridized
while still hot. The Studios produced them in several sizes, shapes and colors,
but the most common style and the one which they usually employed in the leaded
shades is a large ovoid shape, approximately
6” x 4 ¾”. More often
than not, this turtleback was not used whole, but was cut into smaller
rectangular shapes to form a band around the shade.
Each piece was cut at random from a different area of the turtleback, so
that it transmitted the light in a unique way and gave the shade a very
always wrapped his turtleback tiles with lead came rather than copper foil.
He probably did this because the lead came had more ‘give’ in it and
thus was better able to absorb the stresses from heat and other abuses that the
thick and fragile glass mass was subject to.
Because the edges of these pieces were up to a half inch thick, they had
to be heavily chipped to fit into the came, a difficult procedure that required
a lot of skill and patience. Odyssey
has avoided this problem by providing the craftsperson with almost-ready-to-fit
tiles for our T1434 mold. These
tiles, Product #TB1434, are made in the correct shape and have a thin edge all
the way around. We have copied them
directly from originals, so they look authentic- with a highly irregular back
surface and even facsimiles of the big chip marks around the edges.
Our tiles come in four separate pressings, each of which refracts the
light a little differently, to give them that random look of Tiffany.
will notice that our tiles do not fit flush against the mold, meaning that the
‘foil edge’ is raised up and cannot be joined to other regular glass pieces
around it. For this reason the
tiles must be installed in the shade after it is pulled from the mold.
This creates obvious problems and here is how you solve them.
Cut all of the regular flat glass tiles and fit, foil and tack-solder them onto the mold in the regular manner. Be sure that these geometric tiles do not protrude into the space reserved for the turtlebacks. You can bead the outside while the shade is still on the mold if you prefer, but, if you don’t, take care to see that the tack-soldering penetrates enough to hold the shade securely together.
will see that the shade is now in two sections, an upper ‘cap’ and a
‘ring’ around the bottom. These
sections are joined together with 18 pieces of copper wire that bridge the gap
all the way around the shade. The
wires, which should be at least 14 gauge thick (Odyssey’s reinforcement wire
is good for this) and 3” long, are soldered at both ends onto every other
vertical lead line around the mold. There
are 36 vertical lead lines that abut the gap, so you need 18 wires.
Once the wires are securely in place, you can remove the shade from the
soon as the shade is off the mold, install the ring to give you something to
hold on to. Be sure to level it as
outlined in the Instruction Manual. The
rim can also be installed at this point, but we prefer to get the turtlebacks in
The turtleback tiles come in patties of four. These must be cut apart along the edge line that is visible around each tile. We strongly recommend that this be done with a diamond band saw, to avoid losses. Once the tiles are separated, wrap each one tightly with 1/8” U lead came and join the butted together ends with a little solder. (Not that it really matters, but Tiffany seems to have always positioned the butt joint at the center bottom of the tile.) Use a lathkin to be sure the lead is flush up against the glass and there are no light leaks.
remove one of the spanning wires and position the tile in the center of the
created gap. The camed edge is not
exactly level, but position it as best you can to meet flush on both top and
bottom. Also, check to see that it
is centered between the vertical lead lines on both sides.
Now tack it in place at the points in the center, top and bottom, where
the vertical lead line intersects it. Remove
an adjacent wire and repeat the procedure.
There may be a small gap between the turtlebacks, but don’t worry about
this. The lead lines are supposed
to be heavy and in Tiffany’s they often approached 3/8” wide.
On the other hand, the turtlebacks shouldn’t be so wide that they push
each other beyond the lead lines on the side.
If they do, they’ve been cut too big and you’re going to run out of
room as you move around the shade. For
all turtlebacks beyond the first one, tack them to the adjacent turtleback as
well as to the top and bottom. Repeat
this process all the way around the shade.
all of the turtlebacks are installed, you can fill the gaps in with solder.
Remember that the lead came melts at a fairly low temperature.
If you’re a copper-foil person and haven’t worked with came in a
while, it’s probably a good idea to practice a bit before putting a hot iron
on your shade. Tiffany did not ‘bead’ the lead came around his turtlebacks
in the usual sense. He just filled in the gaps to a smooth concave
surface that left the edge of the came clearly visible.
The rest of the shade is finish soldered in the regular manner.
A final note regarding patinas: Tiffany did not finish the lead came around turtlebacks in his normal patina. Usually it was painted a kind of dark army green color. This was done because he could not copper-plate the turtlebacks (and consequently the lead around them) because their iridescent surface was conductive and plated very nicely. This plating, besides being opaque, is quite adherent and does not come off easily. When it does peel of, it often takes the iridescent coating with it! To get around this, it appears that Tiffany plated the shade before the turtlebacks were installed, i.e., while the bridging wires were still in place. This allowed him to get a nice patina on the regular part of the shade and paint the area around the turtlebacks. This little anecdote should serve as a warning to anyone who is considering plating a shade with iridized glass.
From the Odyssey Web Site
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