I do not have much experience soldering gold to sterling silver…and am looking for advice, please.
I am working on a project…it is a sterling silver cross, with ten 4K yellow gold bezels…
I am designing it in CAD
the 14K yellow gold bezel cups are approximately 1.0mm thick
the sterling silver base (a cross that will hold the 10 bezels) is about 1.5mm thick where the bezels will sit…the bezels will sit within a recessed area, that is effectively about 1.5mm deep (created by 1.5mm high “walls” on the 1.5 mm thick base)
the base and bezels are solid…the holes will be drilled through after soldering bezels in place
should I anticipate any “mixed metal” type of melting scenario…? (14K yellow gold/ sterling)
what grade solder would you recommend in terms of melting compatibility…gold or silver?..hard, medium, easy…?
My advice to you is to make sure you heat up the sterling silver until the solder joins the two metals, if you heat up the gold, it could melt before the silver reaches temperature.
Yes, if you over heat the gold and silver they will melt together. Someone explained to me once that you’re basically making solder when you overheat them.
When I solder silver to gold I use silver solder. I use easy solder when I can, just so I don’t have to heat it up as much.
I’m pretty sure that this has been asked before and that others have different opinions, but that’s what I do and it always works.
The main thing is that you have to watch closely and if you see any hint of the two metals melting together pull your torch away very fast.
Well, Julie. An others have suggested you have to come from the bottom. You have a 1.5 mm base and a 1mm bezel (which gives you a little bit of leeway) … but not much. I would not attempt this with standard sterling on sterling … gold spells disaster. Gold’s thermal transfer coefficient is WAY less than standard sterling. Silver transfers (well standard silver) fast - really fast and gold don’t – much at all. You probably can’t even pull this of with gold on gold. Maybe, just maybe. It’s gonna be iffy with silver on silver. The bezel is always going to get hotter much faster. With all respect to Jeff … if you see it melting … game over :). I’d use hard silver solder … kinda depends on what you are going to do later. It’s going to alloy anyway, so not sure it makes much difference. You stand a HIGH chance of melting the gold bezel first … and with a 1.5mm silver base …umm yeah. Argentium (which I keep harping on standard sterling) has a thermal coefficient much like gold. I love to work with high karat gold. Maybe Argentina not so much. Love hate relationship. That is for another thread. It is good/standard practice to always come from the bottom anyway. I’ve done silver on silver from the top if it’s a ring and I have to and keep the heat off the bezel. And use plenty of white flux. I SO have fire scale. It’s why I use mostly Argentium, which has its own issues. High karat gold is a joy to work with. Gold gives zero or very little warning if it’s going to melt … but you get used to it.
if it was all sterling i would just join the bezels to the base and cast as one…but alas…
would making the bezel bottom thinner help…?”…
if i wasnt opening up the bottom i would consider posting the bezel and drilling through and then just soldering at the post?…or perhaps even just welding at post?…but alas…
hmmmm…maybe 4 posts near the perimeter of the bezel bottom…drill through…weld at posts on bottom side of base……drill out bezel bottom and base center after welding posts…avoiding. post area…?
or drill thru bezel and base, and weld around that opening…run a bead around…messy messy
and as for soldering as my first post…with the bezels sitting in the recess, in a pretty tight fit… i dont think i will be able to observe the solder flow…oh my…
Hi,
also, i will mention that i did search the archives first, but mist posts seemed to involve the use of thin bezel wire…or small gold balls…i am still researching…
i was curious about soldering together mixed metals of more mass…
i just read that higher karat gold are easier to solder onto sterling silver?…if this is the case i am happy to switch to 18k yellow gold…any comments on this?
I wouldn’t worry at all. As long as you keep the flame on the silver and use easy solder like @jeffg-moderator suggested it should be simple. I just soldered a 2g 14k bezel onto a silver shank the other day and it worked great. Just heated it up from below! I think I make have even used medium solder.
i made the bezels and base “solid”…thinking it would help metal flow in casting…
actually, after casting i can bur the bottom opening out of the bezel…that would reduce the mass of the gold portion of this equation…?…would that help me…?…or am i thinking of this backwards…?…i want the silver to heat the gold…?…so less gold heats faster…?…and solders?
Ask yourself what solder would be more difficult to remove if it was inclined to wander. Gold solder is a lot more expensive than silver. I would be inclined to presolder the backs of the bezel cups with easy solder and get it done unless you will be doing a lot more soldering after you solder the bezel cups…Rob
I think Jeff’s advise is sound. ( easy solder). I’d cut out the flat area before soldering, leaving a small step for the bezels to sit on. I’d start with the center and work out.
Do you use a soldering block in your approach to soldering? This can hamper your ability to heat evenly. I was taught to solder without using a soldering block to support the piece being soldered. I’d hold the cross in tweezers at the bale. Most times, the soldering blocks acts like a heat sink, where the piece being soldered won’t get hot enough. I was told, and found that it was best to be able to apply heat from all angles, particularly underneath the object being soldered. When the joint is hot enough, the solder will be drawn into the joint. But both the silver and gold need to be heated. I’d use a largish brushy flame to begin with, and as the metal gets hot, I’d intensify my flame, but I’d would keep it moving over the joint. By clipping small fresh bits of solder and placing them between the gold and silver, they can be drawn into the joint. First, from the top and as the solder starts to flow, then, very quickly moving the torch to the underneath the area of the joint. The first melting of the solder, the flow point is the lowest so it’s important to remember that solder will flow to where it’s the hottest!
As to the metal you use, that’s of course your choice, but the contrast between the silver and 18K gold is very rich, and is more noticeable.
I meant to write ~ By clipping small fresh bits of solder and placing them between the gold and silver at the beginning of the operation, they will indicate the temp, and show your progress, as they’re drawn into the joint. Both the joint and the solder will need to be clean and fluxed.
ok…so…i am trying to wrap my head around soldering gold to sterling…so i am gonna talk out loud here…let me know if my understanding is correct…
it seems to me that the key factor with soldering 14KY gold to sterling silver is in the flow points of the solders used…
that the melting point of 14KY metal at 1476F is very close to both 14KY 18K and SS
hard solders (1425F, 1475F , 1500F)
medium solders (1360F, 1405F, 1420F)
14 and 18KY easy solders are still a bit close at 1335F, 1360F range
so, it seems like the safest bet is SS easy with the lowest flow point at 1285F
so the 14KY gold piece may melt if i inadvertently exceed the flow temps when soldering…
whereas 18KY has a higher melting point of 1660F
which is closer to sterling silver melting point of 1640F
which would seem like they are both high enough to handle the hard and medium solders
but the safer bet would be the medium or easy solders in either 14 or 18KY, or sterling…
using whichever color/ one would result in the least cleanup…ie: assuming that the solder may run up the sides of the lower mass piece which would get to flow temp faster…
so…to summarize, i should go with 18K bezels with medium or easy 18KY solder…correct?
and i havent quite wrapped my head around the thermal transfer coefficent concept yet…as it applies to my components…
so…then…
i will be heating the much larger mass SS base…and heat will be constantly running away…
as i am heating the SS, the heat will be transferring to the gold…but not running away from the gold
sooo…does this mean…that the gold piece will be gathering heat and holding onto it…thereby getting hotter and hotter…especially being that it is much smaller
while the SS gets heated but is constantly losing it…thereby not getting as hot as the gold, at the same time…
so…also…perhaps…making the SS base thinner, where the bezel will sit, would help to get that area up to temp closer more at the same time…?…
even though the cross base as a whole is much more mass…and a giant heat sink…if i make the two touching areas of a similar mass thickness, would this help make the soldering process easier…from a thermal transfer coefficient standpoint? or no, because the base mass is soo much bigger…?
i sound confused, right? I am trying to grasp the “whys”…
i think i need to open up the bottom of the bezel, so that i can observe the solder flow…
hmm…sweating the solder on first…doesnt that raise the flow temp on the next heating…?
hmm…gold repair solder!…lower flow temps than plumb solders…i must investigate this!
NO!
You are over thinking the problem. I feel it’s more about controlling your torch. As a general rule if I’m soldering yellow metal to a white metal piece, I’ll use a white solder that is of the same material. In this case, SS soft solder, just makes it easier. With a karat gold solder, it’s been my experience that it can burn into silver before flowing and is much harder to get the results one would want.
My mention of flow point of the solder is only for you to realize that when you heat it to the flow point, you change the temperature at which the solder will melt and flow again, raising it. This can cause you to over heat your work trying to get the solder to flow repeatedly.
By using a largish flame to begin with, you are heating the whole piece, both the silver and gold, bringing them up close to the correct temperature. This is achieved by applying heat form all angles and particularly form underneath. And when you get it closer to the correct temperature, you make your flame hotter and more intense in the area of the joint, heating both the silver and the gold. Having put the small clips of solder on first,(less than a mm) as they start to melt, you very quickly redirect the flame to the back side of the cross opposite the solder, this will draw the solder through.
As I mention in the above post, I’d cut out the flat area before soldering, leaving a small step for the bezels to sit on. This will allow better heat transfer and a keep the bezels square in the mounting.
How you use your torch is the key. Knowing how to read your metal as it gets hot. Where and when to apply the correct amount of heat.
Many of my designs incorporate mixed metals, mainly white, rose, and yellow gold, and gold & platinum, but I feel it’s how I control my torch, not the “thermal transfer coefficent concept” that I had to master.
This is a great thread as it’s filled with helpful information.
First, to really get into the “why’s” is way above what my feeble artist brain can explain (let alone understand) but we are very lucky that the forum has engineers, physicists and material scientists who have explained this concept in the past.
If you search Eutectic Bonding within the forum you’ll find your answers. There are a number of threads explaining Eutectic Bonding in Orchid. In a nutshell, some metal combinations like silver and gold when they are touching and heated, lower the metal temperature of both metals at the area of contact.
Jim Binnion does a great job of explaining it here. It’s what makes Keum-Boo and Mokume work.
On to the actual question how to solder a gold setting onto a silver base. As many are saying it’s not that hard, but you’ll need to practice first Julie. That sucks when using gold because it’s expensive to practice with. Maybe you can design some test pieces that will also be finished jewelry so you’re not wasting materials.
Back when I first saw that gold and silver fuse easily I was completely caught off guard as I had no idea that would happen. Then for a while I decided to push it and not use any solder. Just fuse together silver and gold. That worked but it required way too much concentration to be practical, so I went back to silver solder to connect silver and gold components. I did try using gold solder, but my success rate was less, so I stuck with silver solder.
Lots of people solder silver and gold together. It’s not that hard, but there are some issues that will be resolved by hands-on experience.
While this is great information, it is too much for me. I just figure out what color solder would be easier to clean up and then use the lowest temperature solder that I can, subject to whatever else needs to be soldered…Rob
I’ve done applique work with mixed metals… it’s not a problem soldering things together unless you overheat everything. using low melting point solders will do the trick easily. solder the gold bezel ends together with a higher temperature gold solder first. then tack them on to the cross using low temperature silver solder. gold solder is more expensive and will not “flash” into joints.
so far as eutectics are concerned, there is a gold/ copper eutectic and silver/copper eutectic. This isn’t much of a problem unless, the work is overheated… soldering gold onto silver avoids the problem, as there is no well defined gold/silver eutectic… heat the silver base carefully until the silver solder flashes…
Contrary to what has been said, there is an eutectic point for gold and copper at 40 atom% copper to 60 atom% gold… the eutectic point for silver and copper is approximately the same. gross weight% has to be coverted to atom% by taking into account the atomic weight of gold compared to the atomic weight of copper. , copper is lighter than either gold or silver. gold has an atomic weight of about 197, copper is 63.5, silver 108… copper is lighter than either gold or silver, so it will take proportionately more copper than the gross weight percent to get to a eutectic alloy… the atomic weights are fractional due to the presence of isotopes but rounding off to a whole number is okay…you can find all of the phase diagrams just by googling eutectic points… getting the phase diagrams let me make my own solder…cheaper than buying solder, without the added zinc which really lowers the melting points and makes mixed metal work difficult… eutectics are only for copper with either gold or silver. it’s the lowest melting point composition of a copper/silver or copper/gold alloy.,… using eutectic silver is not recommended for making solder as it too gray looking against a higher silver content allow. I experimented with embedding brass and silver wires in a design into eutectic silver/copper within a sterling silver base… the result was a gray looking metal that contrasted with the shinier and whiter sterling… it’s off color and is not suited to soldering…the more copper makes the alloy grayer, the more silver makes teh alloy brighter… moving away from the eutectic composition raises the melting point either going towards more silver or towards more copper…
tri-metallic alloys don’t have a single eutectic but are complicated curved 3D surfaces along which the melting point varies with the content of three metals…I don’t know if I’m making much sense in being understandable… the phase diagrams show it all…just google them.
