Question: What does fire scale look like?
How does fire scale present on a polished piece of silver jewelry?
Please see updated information on fire scale and fire stain on my webpage: Soldering 101 – Oxidation, Flux, and Firescale Prevention. Updated: 1/27/17.
(fire scale/stain on silver) I think this link to my page: Soldering 101, will help. Firescale/fire-stain usually shows up (clearly) when polished. It looks like a purple bruise.
Question on Oxidation, Firescale, and Oxygen Concentrators
“I’m producing a lot of fire scale. My studio is in my house, so I’m reluctant to set up acetylene. Is there a larger oxy/propane torch you might suggest? I’m thinking of getting an oxygen machine to eliminate buying those expensive oxygen bottles from the hardware store.”
Is it fire scale or is it oxidation, that you are experiencing? Here’s my page on the topic. If it is oxidation, moving to the Mapp gas and getting a larger torch tip could help. Maybe, it is taking too long to heat your metal. When you fire metal too long it allows for considerable oxidation to develop – especially with sterling and base metals like brass, bronze, and copper. A larger torch tip, like this #7, the Melting Tip, or the Twin Tip (you can solder from both sides at the same time), should help heat things up faster. Have you checked out Argentium silver? Very awesome metal. It contains Germanium, which is released when the metal is heated. The Germanium coats the outside of the metal, reducing, drastically, the fire scale and oxidation. It also takes a long time for it to tarnish – although, rates vary depending on what chemicals are present in the environment. Please see my webpage on sheet metal and wire.
If you are getting a lot of fire scale, look into reducing your heat, completely coating your metal with flux or an anti-scale product, or don’t finish to a high shine (see my soldering 101 page for an explanation). You can also switch to Argentium. More information on fire scale can be found on my Soldering 101 – Oxidation, Flux, and Firescale Prevention page. You can try a product like this: FirescoffTM.
Here’s a brief discourse on Scott’s experience with an oxygen concentrator, at Ganoksin.
Question: My ring has fire scale, how can I remove it?
“I’m trying to solder a gold-filled ring, and I have bought the Firescoff. I have already followed the instructions step by step, but still can’t solder a perfect gold-filled ring, it still has the fire scale. Could you please tell me how to do with this?”
Firescale and Surface Oxidation both occur in metals containing copper-like your gold-filled metal as well as sterling silver, brass, and bronze – among others.
The same is true of most fire scale. When the fire scale does show up is usually during the final polishing stage and appears like a gray/purple bruise on the metal. (See my webpage: Soldering 101 – Oxidation, Flux and Firescale Prevention for an explanation!)
Question and Answer: How to remove fire scale/stain.
You state you: leave too many “fire marks” – what do you mean by that? Are you using pickle to clean the metal after soldering? Or are you seeing that gray bruising after polishing (fire scale)? If you are seeing fire scale, try doing something like what is in this Rio Grande article. If you have oxidation from soldering, try a nickel pickle: Here’s one article from Hoover and Strong. Here’s a product – Rio Clean Pickle – designed for nickel, brass, and bronze.
Question: I have fire scale/stain on my piece – how to remove it?
I’m a total newbie and also don’t have any equipment yet. I am taking a jewelry class. I just made 2 pieces and didn’t manage to polish the fire scale off before running out of time. What would you recommend to try to polish the fire scale away? It’s mostly around/under bronze stars that are soldered onto the sterling piece. It’s tricky to get at but very noticeable. Desperate to remove it!
I’d really like to try to achieve a mirror finish. Seems like sandpaper/finishing paper might be the way to go. My other thought is to take it to a local jeweler and see if they can do anything with it. I’m attaching pictures of the pieces so you can see what I’m talking about. Recommendations of specific papers to buy would be really helpful.
Please see my webpage: Soldering 101 – Oxidation, Flux, and Firescale Prevention for updated information on the formation of fire scale/fire stain and how to avoid and remove it.
Fire scale/fire stain is difficult to remove and the only predictable way to remove it, that I’ve found, is with sanding or etching. You could try using a 50% sodium bisulfate-based pickle and 50% hydrogen peroxide. One of my viewers swears that that works. I need to experiment with it. Check the metal every couple of minutes to see what’s happening. You should see bubbling around any areas that contain copper. Usually, the metal will have a matt finish, after the immersion in pickle and peroxide so, you might have to burnish it with a brass brush or use a buff with rouge. It may work – it may not.
Question: Should I protect my piece from fire scale/fire stain with an anti-fire scale coating when soldering?
“Since you are the great and powerful guru of silversmithing, maybe you can help me.
Flux is used at the points you intend to solder to aid in its adhesion. When soldering, do I need to protect the piece from fire scale with a boric/alcohol bath first?
I just purchased Battern’s liquid flux and thought I was all set. Now I am receiving advice about the bath first. What are your thoughts? What brand flux do you use?”
Total immersion or coverage would only be important if you were concerned with fire scale/fire stain because you were creating a mirror finish, at the end. According to the research, that I just completed, if you are working with sterling silver, bronze, brass, or gold (besides 24K) you should either: 1. flux the entire piece or 2. use a fire scale preventative. Check to be sure that the preventative can also be used as a flux. See my updated information on oxidation, fire scale, and fire stain.
If oxidation is present in the metal, and it has been through several soldering/annealing steps, and you want a mirror finish, the heat from the buffing process will probably bring the copper molecules up to the surface in a random pattern. It is explained more in the link above so, please check that out.
Question: Does Pripps Flux work better than boric acid and denatured alcohol for preventing fire scale/fire stain?
Do you create a high polish on your finished pieces? That is when the fire scale/stain shows up. It doesn’t always happen though.
I don’t think any one type of preventative works any better than another – although, people can get pretty heated up in the defense of their fire scale/stain preventative. I use just plain flux and try to avoid overheating. Anything that reduces the amount of oxide development, works. The temperature range of the flux/dip is crucial – if pieces are heated past the max temp range, the flux/dip stops working. Most have working ranges of up to 1800°F. I think, that if you aren’t seeing fire scale/stain, then you are doing something right and I’d keep doing whatever you are doing. Although you do have most of the ingredients so, you could make some up and see what you think. Wish I could be less vague but, I haven’t found anything that I feel is superior to another – yet!
*There are other fluxes/dips that have higher ranges but, they are usually used for platinum. Also, soldering on charcoal helps because it creates a reducing atmosphere.
What is the best way to avoid fire scale/stain altogether?
Use Argentium silver. Period.
- How to Set Up a Torch – have a torch, need to set it up? Here’s how.
- Soldering 101, part one, and Soldering 101, part two
- All About Solder – You need to understand what you are working with!
- Flat Square Edges on Metal – Important techniques for creating square edges like on ring shanks, tubing, settings, etc. – pretty much any two pieces that you want to solder together!
- Getting Ready to Solder – Important steps before you solder.
- Identify Wire Solder – Mark your solder before confusion reigns!
- Jewelry Studio Safety – Extremely important information that every jeweler should know! Don’t risk your life or your health! Know the dangers of metal dust? If not, don’t sand anything – yet!
- Creating Consistently Sized Spheres – how do you make perfectly round spheres? You might need to know!
- How to Anneal Silver Sheet – an important skill to have otherwise, you can damage your metal and work twice as hard!
- Annealing Wire – Want broken wire? How about melted wire? Need your wire soft and bendable? These tips will help you to avoid these problems and work with ease!
- DIY Fume Extractor for the Studio or Shop – One of the BIG ONES for studio safety. Learn to make your own!
- How to Make a Bezel and Set a Cabochon Part One – Want to solder thin material to thick? Want to set a stone or two? Learn how to create and solder bezels.
- How to Make a Bezel and Set a Cabochon Part Two – Ditto from above.
Soldering Jewelry: How to solder settings, bails and wire. – We solder dissimilar shapes and sizes of metal together, all the time. Want to stop melting your settings or bails? Can you solder wire without melting it?
- Soldering Jewelry – Sweat, Flush, or Applique Soldering – How to solder two pieces of metal on top of each other. Learn tricks for successful joining of dissimilar sizes and how to apply solder.
My YouTube Soldering Playlist – A list of all my soldering videos on YouTube.
Related Web Pages
- About Solder – Learn all about the material you use.
- Acetylene, Torch, Tanks, Safety – A huge page with so much more than info on Acetylene! Learn all about torches, soldering, and how to protect yourself!
- Charts – Soldering related charts. Includes things like annealing temps, compressed gas valve sizes, what temperature does your gas burn at, and what are the melting points of your metal. Also, there are wire gauge charts, millimeter to fractions and inches charts, drill bits to wire gauge charts. Lots of information!
- Cleaning Metal – nice to know if you plan on soldering anything!
- On Pickle, Acid, Crock Pots, and Baking Soda – How to remove the schmutz left from soldering, how to make your own pickle, how to use pickle, and how to neutralize pickle. Tons of info!
- Oxidation, Flux, and Fire scale – Why does oxidation occur? Why do you keep getting fire scale, how do you get rid of it. Learn the whys of what is happening when you solder and the solutions.
- The 4 Steps for Successful Soldering – The 4 steps will help you to achieve soldering success!
- Identifying Wire Solder – How to mark your solder so that you always know what type it is.
- Jewelry Tools – Harbor Freight – Cheap tools for the studio!
- Miter Cutting Vise and Jig: Having a hard time squaring up the ends of your ring shanks? Check out this tool!
- Q&A: Firescale/Firestain – See what others have had problems with and find the solutions!
- Q&A: Annealing – How long to hold your annealing temps. Kiln annealing.
- Q&A: Wire Questions. Balling up wire, tapering wire, work hardening wire, straightening wire, and more!
- Recipes: They aren’t just for cookin’ anymore!
- Pickle Recipe – make your own pickle
- Prip’s Flux Recipe – make your own flux
- Removing Broken Drill Bits From Your Metal -snapped your drill bit and can’t get it out? Here’s how to remove broken drill bits.
- Removing Copper Flashing i.e.: How to remove the copper coating you might get from pickling. Also, how to remove copper from brass or bronze that comes to the metal’s surface after soldering.
- Wire and Sheet Metal
- What Torch to Buy: Trying to figure out what you need to make fire in your studio? Check out this information before you buy!
- Soldering in a Nutshell – my list of basic necessities for soldering.
- Soldering Questions – One of the most asked after subject matter. Many of my web pages have been inspired by soldering issues and questions.
- Torch/Gas Questions – Portable vs. regular torches, problems with the torch, butane torches, water torches, setting up a torch safely, buying torches.