Solder – The Glue That Holds It All Together
Solder (pronounced sodder – at least in the USA) is used to join metal components together to produce a finished product. How exciting!
Solder is composed of alloys that produce a material that melts at a lower temperature than the metal you are soldering together. If the solder didn’t melt at a lower temperature than the metal, you would end up melting the metal. This is also a practice, but it’s not soldering. It is called fusing.
A lot of jewelry is made using a technique variously called silver soldering, hard soldering or brazing. It is an important skill to learn for the metalsmith, as much of your jewelry will require solder joins. Learning to solder will also increase your design scope and offer you more design solutions.
The two goals you should be looking to attain, when soldering, is achieving the strongest bond possible and color matching – matching the solder to the metal. On that note: I’ve yet to find a good copper colored solder. I use silver solder with copper. If I control the amount of solder used (not too much/not too little) and clean up any excess solder well, the seams are difficult to discern. I often use Patinas, which help to disguise any solder lines that I find distracting.
I have used gold solder or gold-filled solder with brass, bronze and gold filled. But, due to today’s RIDICULOUS gold prices, I try to stay away from gold solders – unless I’m working with gold.
I’ve just ordered brass and copper solder so, I’ll be checking that out soon and reporting back.
- Solder – Solders are alloys of metal. Vague? Well, the composition of the solder depends on the core metal, the manufacturer’s recipe” and the type of solder. Most silver solders are composed of a percentage of silver and zinc. Likewise, gold solders are mostly gold with other elements added depending on the color of the gold. The amount of gold, present in the solder, varies by what karat the gold is. See below for more information on gold solder. There are copper solders and brass solders as well as other types. These solders have various issues and are not always perfect matches for your metal.
- Use the highest temperature solder that you can. Usually, you can do 2-3 joins per type.
- Solder pits when the zinc is burned out by over-heating. Keep temperatures as low as possible to avoid pitting, while still providing enough heat to flow the solder.
I’ll explain solder and it’s interaction with the metal it is being used with in my more detailed section: Soldering 101. (coming soon)
Before we get started here, I want to note something VERY IMPORTANT: When soldering, your solder needs to be as clean as your metal. Also, solder needs to be fluxed – unless it is in a paste form that includes flux.
Hard Soldering VS. Soft Soldering
- Soft soldering employs much lower temperatures (at or below 450°C/842°F) than Hard soldering does. A soldering iron (electric) is employed. In soft soldering, the solder flows over or around the metal. This type of bond is somewhat strong but, not as strong as hard soldering. Soft soldering tends to be messier as the solder needs to be present on the outside to hold the items in place.
This box bezel was made with soft solder (and not well). The solder was laid over the base metal (most likely copper tape used in stained glass windows). This gives, the paper thin copper, strength and a silver color. Note the unsightly globs of solder. As to its strength: you could peel back this bezel with your fingernail.
- Hard soldering involves very high temperatures (see the chart below). It involves the use of a gas torch which is capable of reaching and surpassing the melt and flow points of the solder. This type of bond is molecular and is much stronger. Silver soldering also allows for neat, clean joins as the solder doesn’t act as a support but has, instead, become joined molecularly to the metal.
This box bezel was made using silver/hard solder. The solder doesn’t need to be draped over the metal to support the structure. Instead, the solder flows into the surrounding metal, allowing any excess solder to be removed – leaving a clean, crisp surface.
Although not a perfect example, I think it will help you visualize the difference between the two types of soldering. Think of soft soldering like using tape and hard soldering as using super glue.
Silver Solder Details
“Solidus is the temperature at which a metal starts to melt; liquidus is the temperature at which it is fully melted.)” from Working with Argentium Silver – Tips and Procedures by Cynthia Eid**.
I’ve included the liquidus points of Argentium, Sterling Silver and Fine Silver as a comparison with the temperatures needed for solder flow.
- Sterling liquidus point: 1640˚F (893˚C) – 1650° F (899°C)* (varies because it is alloyed)
- Fine silver liquidus point: 1761˚ F (961˚C) (Pure metals have a single liquidus point)
- Argentium 935 liquidus point: 1610°F (877°C)** – 1657°F (903°C)* 1657°F/903°C***
- Argentium 960 liquidus point: 1700°F (927°C)****
|Solder||Flow Points||Use for|
|Extra-hard or IT||1490°F/810°C||Joins if to be enameled|
|Hard||1450°F/788°C||First soldering and additional joins|
|Easy||1325°F/719°C||soldering areas of less stress, repairs;
I borrowed the chart, above, from Riogrande.com and altered it. Note: solder flow points vary depending on the maker. Check with your supplier to find out what temperature your solder flows at.
Please see my webpage on Wire and Sheet Metal. In it, I discuss the properties of various metals, including Argentium, Sterling Silver and Fine silver. Metals are listed first by type (alphabetically) and then alphabetically in their groups. So, Argentium is at the top of the Silver Section.
For a great explanation of liquidus and solidus and the reason why alloys have a range of points for liquidus and solidus, please see this page from the Argentium Guild Blog: Definitions – Solidus and Liquidus by Charles Allenden.
*From AGS Metals
** Cynthia Eid – Working with Argentium Silver – Tips and Procedures
***Rio Grande – Technical Sheet on Argentium 935 Casting Grain
****GS Gold – Argentium and Silver casting grains. Casting Grains and Casting Alloys. Cast temperatures, liquidus temperatures for many metals.
Argentium solder flow points
I don’t know why extra hard has a lower flow point than medium hard – doesn’t make sense to me. Information from Riogrande.com. So, flow points are for their solder.
Argentium wire solder:
- Medium Hard: 1420°F/771°C
- Extra Hard: 1411°F (766°C)
- Easy: 1331°F (722°C)
Argentium paste solder (includes a flux/binder):
- Hard: 1420°F (771°C)
- Medium: 1340°F (727°C)
- Easy: 1295°F (702°C)
- Super Easy: 1185°F (640°C)
Sheet solder has the same gradation and flow points as wire solder.
Forms of solder
Silver solder comes in:
- Paste: generally comes mixed with flux
- Sheet: cut pallions from this sheet. I use French Shop Shears to cut little strips along one edge – like fringe. Then, cut across the fringe, at whatever length you need, for your pallions. You can cut only a few or the whole row at once. Keep storage containers, like these little plastic thingies, to keep different types of solder separate. Label the containers, IT, H, M, E, EE or whatever you’d like.
- Wire: Use as is or flatten it using a rolling mill or a hammer. Then clip the rolled edge to size. For even finer pieces, clip lengthwise and then across. You can make some minuscule pieces this way. Don’t forget to clean solder before AND after running through the rolling mill or hammering it. Never put damp or wet solder into your rolling mill. You will have rust for days…
- Pallions or Chip Solder: I don’t like these as the sizes are pre-determined. If you need a teeny, tiny bit, you have to try and cut a little weeny square of metal in half. If you need big pieces, you need to load a bunch of tiny chunks. Crazy making. Buy sheet and cut your own. Save money too! Yipeedoodles!
Paste and sheet solder can be marked, on their surfaces, as to the type of solder it is but, wire solder is difficult to write on so, a bending system has been devised to mark the wire. Generally, there are only three commonly used bends for hard, medium and easy. I’ve added my own markings for extra easy and IT. See below.
Below are the markings for wire solder:
IT HARD MED EASY
- Differentiate the types of solder by either A) Bends, B) Hammered ends C) Color Coding D) Stamping E) Engraving. This way, you don’t get it confused with silver wire. I put the identifying bends into both my roll of solder and the pieces that I cut off. If you have pallions, keep them in separate, labeled containers. Sheet can be stamped on engraved.
Tips for Solder Storage
Solder, both wire and sheet, can be stored in gallon zip-lock bags, labeled with the type, re-order number, price, and supplier. Better yet, use Pro-Tectant Anti-Tarnish Bags, so your solder doesn’t get tarnished.
Pre-cut solder pallions will tarnish. To protect them from tarnish, use an anti-tarnish bag to store them in. Better yet, buy sheet solder (cheaper) and cut your own. Cut only what you need, at the time.
In Vol.9 No.4, August – September 2013, Wire Jewelry Magazine: Trade Secrets: Teachers share some of their best tips, by Ronna Sarvas Weltman, Artist Kate Richbourg has a great idea for wire and, I think, solder storage. She uses three ring binders with page protectors to hold each different gauge and type of wire. She stiffens the protectors with cardboard. On the spine, she writes the metal type. Great idea Kate!
I found these heavy duty protectors by Avery. You could also, 3-hole punch the Pro-Tectant bags and store them in a binder. Maybe, separate and store them in these pockets by Avery: Avery Big Tab Two-Pocket Insertable Plastic Dividers, 8-Tab Set, 1 Set (11907)
Types of Solder
The reason that different grades of solder are used is because they flow at different temperatures. This is important because there is a danger, when soldering your second, third or fourth element on, of unsoldering your prior joins. What I have found, and I’d be interested to see if others have experienced this, is that after two or three joins, the original join becomes less affected by the heat.
My guess on this is that, in the process of adding my subsequent joins, I’m melting out the zinc (from join one or two) and as a result, my solder is now mostly silver – which melts at a higher temperature. Have you ever tried to unsolder something – especially a piece soldered originally with hard solder? I have spent hours trying to remove pieces and I usually end up having the silver crumble before it will separate from its component parts. Makes me nuts! But, it does add to that big, ever-growing, refining pile! Yippee!
- IT (Intense Temperature) or Extra-Hard Solder is 80% silver and 20% Zinc (at Rio Grande). Sterling silver is 92.5% silver so, you can see how close they are in composition This type of solder is generally used – in jewelry making – for soldering pieces that are to be enameled. Its high flow temperature range is very close to that of silver – which is the main reason that it is not generally used for regular soldering operations. The solder flows at 1490˚ F (810˚ C) while sterling silver flows at 1655˚F (902˚C) – a very close call when soldering. You need to be on your toes so that you don’t melt your sterling. The gap is wider with fine silver as, it’s flow point is 1761˚F (893˚C), allowing a little more wiggle room. Most people use fine silver for enameling and this is one of the reasons why.
- Hard Solder (not to be confused with the term “Hard Soldering” – as opposed to “Soft Soldering” – that done with a soldering iron) is almost always used for the first join and for any areas that are liable to be under a lot of stress. You can solder an entire piece with hard solder – if you are careful with flame/heat placement. Hard solder typically is 75% silver.
- Medium Solder – usually the second or third solder to be used. Don’t get confused, like some students have, that you can only solder 3-4 joins – one for each type of solder. That would severely limit the amount of solder joins that you can do. As mentioned earlier, I use hard for several joins and medium for most of the rest. I can accomplish 10 joins or more with 2 types of solder.
- Medium solder has less silver and more zinc in it that IT or Hard but more than easy. Generally, medium solder is 70% silver. I usually use medium as my third or fourth join. It all depends on how many joins you are making and the stress that those joins will have. Say, I’m making a ring with three solder joins: one being the band, then a doodad on top and plunked on top of that, a small 3mm prong setting. What I’d do is: first, solder the ring join with hard. Second, use the medium for the doodad. Third, I’d use easy for the prong. The prong isn’t going to get tons of stress on it – except during the setting process – and it’s very thin and small compared to the rest of the elements. I don’t want to melt the prongs so, I’d use easy because it melts at a much lower temperature. If I put it on with hard solder, I’d have to be very, very careful with my heat.
- Easy solder – Easy solder is composed of about 65% silver and the rest is generally zinc. I don’t use Easy solder very often as I find that I can usually solder an entire, multi-joined piece with hard and medium. Occasionally, I’ll add a small setting on with Easy.
- Extra-easy solder – this solder is 56% silver (Rio’s formula). It contains considerably less silver than IT, Hard or Medium. Therefore, it contains more zinc. Because there is less silver and more zinc, the solder has a yellowish color to it. Also, extra-easy is not as strong as IT, Hard or Medium. I hardly ever use Extra-Easy solder. Generally, I’d say it’s good for repairs – especially when there is a stone in place and you are worried about the heat ruining it. Other than that, I’d stay away from it.
If you are soldering gold, the gold solder you use contains actual gold.
- Gold solder comes in carat form – ie: 8 K, 10K, 14 K, 18K and 22K.
- Gold solder comes in yellow wire, yellow sheet and yellow paste. There is also white gold solder in wire, sheet and paste (all links to Rio Grande). You can also find rose gold solder but, check the ingredients. You don’t want cadmium in it! Dangerous! Read this article from Rio Grande’s Blog: The Studio.
Well, that’s it for now. If I think of anything else, I will add on to this page. Hope you learned something new. For more information on soldering and setting up a soldering area in your studio, please see my videos on Soldering 101 and the, above mentioned, webpages. Thanks. Nancy