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Tipping with a laser


#1

Hi all, I have laser experience (5+ yr.s) and consider myself
competent. One of the things I heard before using a laser is that I
would be able to tip stones with a laser that I couldn’t tip with a
torch.

So… let’s pick a typical repair job; a 10 year old ring, which
maybe has several 2 pt. emeralds, all set in six prong 14ky cup
crowns. Many are worn to different degrees, customer only wants to
spend $XX. So don’t reply that I should replace the crowns, etc. For
the sake of argument I need to TIP THE EMERALDS WITHOUT REMOVING
THEM.

Okay, here I am with my laser, looking at tipping several of these
worn prongs, let’s say they are worn right down to the stone. If
these were diamonds I’d torch-tip with solder and be done. But,
they’re emeralds (or if you’re reading this and are thinking, “Heck,
I can torch-tip emeralds” great, make them opals).

Per all the hype a Perfect Candidate for laser re-tipping, right?
When asking other operators if they can do it, they invariably say
"Sure! I can do that!" When I press for details what they actually
mean is they cut off the prong down low and replace the prong and
probably remove the stone while they’re at it. That is re-pronging,
not re-tipping. When I look at websites selling lasers, they say you
can re-tip anything with a laser - then they show a video of putting
a new prong on.

So, here’s my question - can anyone do the re-tipping job I’ve
outlined? Adjust your beam in such a fashion you can introduce the
new wire onto the incredibly thin remaining tip, that’s flush
against a little, cracked emerald, and end up with a useable new
tip?

Pete

PS - Here’s a site for Laser Star with demo videos, check out the
’Re-tipping an emerald setting’ video. It’s not stone-in-place, and
it’s not re-tipping.

http://www.laserstar.net/jewelrywelding_videos.html


#2

Aside from the fact that I don’t allow the customer to dictate
procedure, I would not elect to retip the example in the way you
mean. 6 tips on a two pointer? Good grief I’m grey enough already!

What I have done, on somewhat larger sensitive stones, is build up
with filler wire, slightly away from the stone, that is, not ON the
stone. The stone’s in place but the fill is made in successive shots
in the direction the prong would have been before seat cutting. Once
I’m satisfied with the size its simple to cut a flat and bend it over
like a regular prong. You can also weld a gold wire to the broken tip
after careful shaping, and grind away what’s not still needed. Kinda
between retip and reprong.

And what’s a 2point em cost anyway? Five bucks? Ten? Yeah you can
shield with toothpaste but at that size its a very iffy thing. Buy a
stone, do the work right and charge accordingly. I don’t mind
jumping thru hoops for clients, but it really annoys me when they
light them on fire. I’m not Mr Kite afterall.


#3

I frequently see broken new tips that were hanging on the paper-thin
remmnants of a worn prong…and a tip is gone. Re-tipping only the
tips is not the best way to go about it. If the tips are worn then
the prong/leg will also be worn. If the prong is ignored then the
new tip is liable to break off easily at the tip/prong junction
because there is more metal above the girdle to catch on things in
everyday use, combined with a thinner tip/prong junction. There must
be a suitable support base for the new and bigger tip.

When soldering on new tips I am more concerned with the back of the
tip rather than what overhangs the stone. I let the new tip protrude
at the back so as to draw a miniscus of solder down the prong and
thus thicken the prong in proportion to the new tip.

Now I use a pulse-arc welder (similar to a lazer in more ways than
one) for retipping I am carefull to achieve the same results. The
new tip has a generous overhang at the back. The first shot fuses
the metal at the back and draws it down the prong. Here the stone is
safe from the blast zone. Second shot fuses one side of the new tip
right up to the stone and the stone is protected by a coating of
silicon carbide sandpaper if the stone warrants it*. Third shot does
the other side with the protection if needed. Further shots are used
for pushing metal down the back of the prong in order to thicken it
in proportion to the new tip. The sides are filed, sanded and
polished to the original width. The back is then trimmed flush way
down the prong. The new tip is then ‘set’ onto the stone using
pliers in a rolling motion, profiled, and finally trimmed intimately
with the stone using a flat graver.

*I find a snippet of 600grit silicon carbide paper pushed up to the
stone/metal junction will shield emeralds and opals from a pulse-arc
blast. The melt-zone can go right up to the paper.

Alastair


#4

I don’t often do retipping with the stones in situ (being a lowly
apprentice), but when I have, the method I’ve used is to make very
thin wire (0.2mm or less), hold the end of it over the tip, and fire
the laser so that the end of the wire is deposited on the tip. This
shortens the wire, which I then move back over the tip, and repeat
until the desired height is achieved.

I only do this for small tips or grains - I doubt it would have the
structural integrity for a large claw. I’d probably try to mask off
the stone somehow - a imagine that a reflected pulse could do damage
to most stones.

Jamie
http://primitive.ganoksin.com


#5

Alastair

I find a snippet of 600grit silicon carbide paper pushed up to the
stone/metal junction will shield emeralds and opals from a
pulse-arc blast. The melt-zone can go right up to the paper. 

Interesting. I have never used the pulse arc, but using the laser
there are similar shields you can use in tight spots like this.

We made one from a piece of scrap sterling wire. Flatten the end,
and high polish it, to make a highly reflective “spatula” that you
can place next to the prong you are repairing, to shield a stone. At
the lower voltages required for gold or platinum welding, the laser
pulse simply reflects off the highly polished sterling. This is the
one time that silver’s much higher welding voltage needs can work to
your advantage.

When working in other areas near a fragile, laser sensitive stone, I
have placed a tiny bit of damp paper towel covering the exposed
portion of the stone. The water in the towel protects the stone from
any possible pulse that might reflect toward it. Laser hits water,
and you have instant cooling and absorption of the energy by the
water, instead of the stone.