null UA-71408823-1

Categories

 Loading... Please wait...
  • since 1976

  • Sales and Support Call: 604-987-5311

Categories

Tool Tart Tips

Posted by Estelle on

So, you’ve laboured lovingly on a piece for hours on end. Your fingers are the claws of death. You feel like you are about to go blind. You’re just about ready to go to final polish and…

Ugh! That purpley grey stain. That dreaded awful bloom that no amount of elbow grease and polishing cloth makes disappear.

Dandandaaa! Your piece has been afflicted with the FIRE SCALE OF DOOM…

Yep. We’ve all been there.

So what happened? These blotches happen on most alloys that contain copper when it is heated in the presence of oxygen. You see it especially well when you put the piece on a white background…

OK so alloys: You have your ninety two and a half parts of fine silver and your seven and a half parts of copper. They merge with the help of some heat and they form various layers in the crystalline structure.

When you expose your sterling silver to the oxygen in the air at higher temperatures when you are annealing or soldering, the copper at the surface is converted to Cuprous oxide. This is reddish pink in colour, the longer you heat, the cuprous oxide converts to cupric oxide which is black. This affects the metal both on the surface and deeper in the metal. According to the Ganoksin.com website, renowned authority on all things metal, Charles Lewton- Brain explains that “Silver has the ability to absorb oxygen at high temperatures and conduct the oxygen to the interior of the metal itself where it can bond with copper atoms present thus causing deep fire scale to occur.”

OK. So now you have a barebones basic idea of what happened to your piece. Now, what are you going to do about it?

Cry. Yeah, I’ve tried that. I felt better, but it didn’t do much for the piece…

Swear. These things tend to expand one’s vocabulary. But then again, I’m single, and my cat doesn’t care…

Seriously though, what do you do?

Due Diligence. Go Read Stuff. There is a lot of information out there. Sure, a fair bit of it is conflicting, but read, try some stuff, find out for yourself what works.

Heat: Be careful when heating our pieces. Though not the sole cause of your fire scale woes, it really doesn’t help to heat things to orange hot, just because you are in a hurry. When it comes to working metal, patience really is a virtue.

Anti- Oxidizer: Since you are in a small studio, it’s unlikely that you will have a fancy- schmancy oxygen-free hydrogen torch. So, let’s be practical. Try using this stuff. I found it helpful.

Depletion Silvering: If the bloom is on the surface, this can work – but leaving your piece in the pickling solution too long can cause other problems….. No, don’t look at me like that. Go read. Find out…

Sanding: Hmmm. Depends on the gauge of metal and the specific project. If you are starting to think there is no one-stop blanket solution for this problem, well then you get the door-prize. Official trouble-shooter status! Yay you!

Polish: Yeah, again, sometimes it can work, but over polishing can actually make matters worse…

Embrace it? Some metal smiths create scale on purpose to highlight certain elements of their work. I admit, I don’t find myself raving about it, but that does not mean that it could be a valid solution. It’s just not my aesthetic.

If you weren’t dead-set on a Tiffany mirror-bright finish for your piece, you have options.If you did want that “I can apply my mascara in the reflection of my ring”, well, then you just might want to ignore the next paragraph.

See, I am not the glittery, sparkly kind of metal smith. I am a bit of a texture junkie.I tend to like a brush finish on my work. I high polish edges and tops of pieces only as an accent.  Silver is soft, scratches easily and I work with my hands. So, for me, this works, Not only do I find this a beautiful solution, it’s also practical. All I can say, is, if you are open to it, try it. It may just open up a whole new world for you…

There you have it. Some thoughts and experiences with a subject that makes most metal bashers wince…

As always, I welcome your thoughts and suggestions. Let me know how you have been dealing with the dreaded issue “that will not be named”. The more we know and learn, the livelier our craft will be…

comments powered by Disqus

Subscribe to our mailing list

* indicates required