Perhaps, steve, because I occasionally misspell it, you couldn’t
find it in your catalogs? It’s spelled wesgo, with a G.
Sometimes listed under crucibles, other times, melting dishes…
Often, they’re only called “high heat for platinum”, without
actually mentioning the wesgo name. visually distinguishable
from their much cheaper and otherwise similar cousins, the
standard clay melting dish, because the fused silica has a coarse
crystaline or granular appearance, almost like the texture of
cheap jadeite. The surfaces are smooth, just the material itself
looks like that…
In use, you CAN melt these things a bit, when actually melting
platinum. The surface will glaze over. But it won’t penatrate
deeply, and the block will still support the metal just fine. By
the way, to reuse platinum scraps, I take a diamond burr and
carve a 3/8 inch wide groove, roughly V shaped, but rounded on
the bottom so it’s not all that deep, near one edge of the
dish’s bottom. You can then easily melt a variety of scraps
together into that groove, forming a rough “wire” ingot. Melt it
down so the top surface is smooth. It will fuse/stick to the
crucible when hot, so just let it cool. On cooling, it pops free
of it’s own accord. Turn it over. The surface that faced the
melting block will be pocked and rough. Fuse the surface with
the torch without melting the whole mass, and you’ll now have a
longish, roughly oval cross section bar, smooth on both sides,
that you can run through your wire rolling mill to make wire. To
make sheet metal, melt just in a shallow rounded depression
(like the bottom of the actual melting dish) to make "button"
shaped "ingots, again fusing over the back side again after the
initial melt, so it’s smooth both sides.
One note: When grinding these blocks with that diamond burr to
carve that groove, wear a GOOD respirator, or work it wet, so the
grindings form a sludge, not a powder in the air. This is silica
flour you’re producing. Don’t breath it.
And, occasionally the bock will end up, after some melting or
soldering operations, with dark stains of one sort or another.
Usually the result of the fumes from some impurity, like
overheated solder which got accidentally in the melt, or worse, a
bit of gold etc. The block is not ruined. Just use a very
sharp, oxidizing flame, with no metal around. Go slowly over
the block and heat enough to lightly fuse the surface. You’ll
burn off the impurity. You’re vaporizing metal, here, so do this
with good ventilation. done right, the block won’t go quite back
to clear white, but it will clean up nicely enough. These things
last a long time, so take care of them. I’ve got one nice
little block, the actual wesgo soldering block rather than the
melting dish, which is now almost 15 years old. I’ve resurfaced
it once or twice with a lapidary type diamond flat lap, but other
than that, it’s still going strong.
Gesswein: 96-97 catalog, the latest I happen to have, page 102,
260-8810, $18.92 (1996-7 price). For more money, (like 40 some
dollars and up), Gesswein also sells the wesgo brand soldering
boards, which have the advantage of being larger. That $41.65
(96-97 price) board is 4x4. A better buy is the 4 x 12 one for
$72.30, which you then, with a lapidary saw, can cut into three
of the 4 x 4 boards if you wanted, or use as is… Stock numbers
aRe: 830-2400 (4x4) and 830-2410 (4x12)
Rio Grande: 98 catalog, page 80, lists only the high back
version. But I’d be very surprised if they didn’t have the
regular type too. The high back type is # 704-034. It won’t
work well, due to both a tapered base, and the tilted top edge.
Rio also sells various types of solder blocks for platinum.
Don’t know if they sell the actual wesgo type of fused silica
block. I got one block from them that is more like a fine
grained fire brick materials. it works, but deteriorates much
faster than the wesgo type.
Swest: current catalog. Swest doesn’t list the wesgo name, or
carry the wesgo soldering blocks in the catalog, but the do have
the melting dish, listed at $17.50, on page 39. Number 170-030,
listed as “high heat crucible”
Frei and Borel, 1998 catalog, page 86, #122.815, $20.35
Contenti: 1999 catalog. page 75, item 170-714, straight side
platinum melting dish. $18.95
I’ve not mentioned the company phone numbers… Figured I’d
leave you at least some of the homework… (grin)