I’m again working on (sizing up) a platinum ring that some other
jeweler worked on.
This jeweler used acetylene to heat and white gold solder to solder.
If you have never worked on platinum before PLEASE for God’s sake
either ask questions on Orchid or turn the job down.
Paf Dvorak
Hi
If you have never worked on platinum before PLEASE for God's sake either ask questions on Orchid or turn the job down.
This is why I have a network of those whose skills are different
from mine.
This is such GOOD advice.
Richard
If you have never worked on platinum before PLEASE for God's sake either ask questions on Orchid or turn the job down.
Would you elaborate on the reasons for this?
Helen
UK
Paf,
believe it or not, some retail store offer an option to sizing with
plat.
or white gold. Especially when plat was vastly more expensive than
gold was, years ago. I know because my retail clients have done it
for years.
Some of their customers at the time could or wouldn’t pay for the
plat. and I would do the sizing at the customer’s risk only. So not
ALL jewelers are ignorant to how to size in plat. it’s just maybe the
customer’s preferance, still, I know the frustration you speak of!
Steve Cowan ARISTA DESIGNS LLC
Would you elaborate on the reasons for this?
Because it’s completely different: you weld it, not solder it. You
should have a completely separate set of tools for working platinum.
Elaine
As long time platinum smiths during a time when jewelers with
platinum skills were rare, Tim and I have seen just about every
horrible thing done to platinum rings brought to us by clients who
were unhappy with the previous work.
We’ve spent endless hours boiling plat in Aqua Regia to get rid of
the contamination of gold solder and then rebuilding the pieces
properly. Good money, but we’d rather not have to do it. Especially
the boiling Aqua Regia part. We’ve literally dissolved a couple of
exhaust fans from the fumes.
Have fun and make lots of jewelry
Jo Haemer
timothywgreen.com
Would you elaborate on the reasons for this?
Because it's completely different: you weld it, not solder it. You should have a completely separate set of tools for working platinum.
No, you can solder it. I have platinum solders. It seems like
welding since it’s so blindingly hot, but with proper eyewear you see
see that it’s soldering.
Paf Dvorak
So not ALL jewelers are ignorant to how to size in plat. it's just maybe the customer's preferance, still, I know the frustration you speak of!
It’s not so much the white gold, that I can fix/replace. It’s the
using acetylene that sends me over the edge.
Paf Dvorak
I’ve never used an oxyacetylene rig outside of welding shop back in
highschool. Honestly can’t imagine wanting to deal with that nasty
black soot getting all over my bench.
What happens when you use it on platinum? Cracks from carbon
contamination?
Even with an oxidizing flame?
Willis
No, you can solder it. I have platinum solders. It seems like welding since it's so blindingly hot, but with proper eyewear you see see that it's soldering.
It’s welding if you use an Orion or a PUK 
CIA
It's not so much the white gold, that I can fix/replace. It's the using acetylene that sends me over the edge.
Paf, maybe I misunderstood, but wasn’t the situation a platinum ring
where the sizing had been done with gold solder, adding a gold piece?
Given the much lower temperatures for this; at those soldering temps,
the platinum would not be harmed by acetylene, nor would the platinum
develop pits or the like from it, since the platinum never gets
anywhere near it’s melting point, or near any temp where it might be
absorbing carbon or other stuff from the flame. So any problems
you’d see would be in the gold solder, and that, I’m assuming pits in
the solder seam or the like, can result with any of the fuel gases,
with acetylene being no more likely to cause them, when working with
gold solders. I’m thinking the problems, if any, in such seams would
be simple poor fitting of joints, not proper cleaning of the metals
and solder, dirty flux, overheated solder, or any of the other
various reasons solder joints can be pitted. Did I miss something?
Or are you referring to other jobs, done with the otherwise proper
platinum materials, but still pitted or faulty, which you’re chalking
up the acetylene use?
It does occur to me to mention that oxy/acetylene, while a poor
choice for working platinum, can actually be used if you have no
choice. If the flame is set sufficiently oxidizing, then there will
not be free carbon left in the flame when it hits the metal, so
problems can be avoided. And even if this isn’t done, if the metal is
very clean, so there are no traces of silica (in fluxes, soldering
pads, even just house dust where silica may be a part) on the metal,
then the free carbon in the flame won’t actually cause problems.
I say that because my understanding of the problem is that carbon
itself is not what contaminates the platinum, but rather, at those
temps, carbon is able to reduce the silica (silicon dioxide) down to
the metal, silicon, which then can be absorbed/diffused into the
platinum, and it is these traces of silicon added to the platinum
alloy which is actually the cause of the pitting and brittleness seen
in such situations… It is the combination of that free carbon at
high temps, and the virtually ubiquitous presence of traces of silica
everywhere, that gives rise to the problems. I first heard this
explanation in a paper presented at the Santa Fe conference something
like 25 years ago, I think, and it makes sense. It nicely explains
why contamination problems with platinum can be caprecious, sometimes
appearing, and sometimes not, even when apparently the same mistake
is made. If I’m wrong in this and someone knows better, please
advise
Peter
It’s not so much the white gold, that I can fix/replace. It’s the
using acetylene that sends me over the edge.
Paf, maybe I misunderstood, but wasn't the situation a platinum ring where the sizing had been done with gold solder, adding a gold piece?
As I’m sure you all (who repair antique jewelry) know, and those who
don’t can surmise, you never know who did what before you got the
job.
Yes, there was white gold repair solder on the ring, plus the
platinum next to the gold solder was extremely brittle.
And what you said about using oxy/ace could be true, but an LP tank
and regulator ain’t so expensive that one must use oxy/ace on
platinum.
(I’m unreasonably or not afraid of an LP tank in the shop so I
drilled a hole in the wall and ran a hose outside to my tank that’s
sitting on a slab of concrete that I made for it. The regulator and
blow-back valve is on the tank outside as well. It wasn’t expensive,
in fact I paid for it all with one platinum size-up job.) There’s
simply no reason to use oxy/ace to solder/weld platinum! (Or to use
white gold on it except for retipping if you can’t take out
diamonds.) I like Stuller’s X white gold for retipping platinum
because it’s so white.
Paf Dvorak
What happens when you use [acetylene] on platinum?
It gets real brittle.
The soot can be avoided by turning on a little O2 when you light it,
of course I’m working under a make-shift fume hood so even if I
light it straight, the soot goes up the chimney.
Paf Dvorak
Oxy acetylene torch, slightly crack the oxy, then add gas and
ignite, no soot.
I sure hope that you have back flash units on both hoses directly
behind the torch doing this. Even then it is inviting an explosion of
interesting proportions if the O2 pressure is ever even slightly
higher than acetylene and the tip is blocked for even a second!
M Chapman
I sure hope that you have back flash units on both hoses directly behind the torch doing this. Even then it is inviting an explosion of interesting proportions if the O2 pressure is ever even slightly higher than acetylene and the tip is blocked for even a second!
I know you were addressing Richard, but I certainly have check
valves on all my hoses at both ends.
Paf Dvorak
I sure hope that you have back flash units on both hoses directly behind the torch doing this. Even then it is inviting an explosion of interesting proportions if the O2 pressure is ever even slightly higher than acetylene and the tip is blocked for even a second!
I know you were addressing Richard, but I certainly have check valves on all my hoses at both ends.
Check valves and flashback arrestors are not the same thing. A check
valve prevents a higher pressure gas from flowing in the wrong
direction, such as oxygen going into the fuel gas hose, but it won’t
stop a flashback.
Depending on the fuel gas you are using a flashback creates a 5,000F
Whether you use acetylene, propane or natural gas you should always
have a flashback arrestor on both the fuel gas and oxygen lines.
Check valves alone are insufficient.
Ed Howard
G-TEC Natural Gas Systems
I like Stuller's X white gold for retipping platinum because it's so white.
A good method for retipping platinum prongs, that is if you don’t
have access to a laser welder, is to ball up small pieces of
platinum nipped from plat wire, flatten them slightly on you bench
block, then solder them on the filed flat prong tips with 19K or 20K
white solder. Your tips stay platinum and the thin seam, though
slightly visible, is a pretty good color match.
Mark
I never use gold to solder platinum. there are easy melt platinum
solders ifyou need to use them but most times hard to med will work
on anything if you are not good at simply fusing the metals with a
thin sheet of platinum…
Panama Bay Jewelers
Check valves and flashback arrestors are not the same thing.
Right. Check valves on my torches, flashback arrestors on the hoses
at the regulators.
(Actually, looking at them closer I realized I don’t have any
checkvalves anywhere and instead have flash arrester’s all around.)
Well, I haven’t blown up yet so they must be working.
Paf Dvorak