I am engraving and enamelling castings in Britannia. Have started getting cloudy patches which might be due to safety pickle residue. Thought I would start barrelling in steel shot and maybe a nitric wash. What order should I engrave, barrel and wash? Any help would be much appreciated.

ASK THE EXPERT - Kristin Anderson

Britannia metal or britannium is a pewter-type alloy proximately and typically 92% tin, 6% antimony, and 2% copper.[1]

Favoured for its silvery appearance and smooth surface. Because of this composition it would melt before vitreous enamel fuses.  So you cannot enamel on Britannia. You could use Resin.

 

 I would not tumble (barreling) in steel shot - especially not after engraving because much of the crispness of the engraving will be lost.

In Sterling Silver, I would engrave first, then Nitric Acid dip as little as possible consistent with getting rid of the fire scale.

I am using Britannia silver it is 95.84 silver the rest copper. It gets slightly less fire stain than sterling silver. Sorry I did not make that clear.

OK, 

Here is a fantastic PDF on Enameling on Britannia Silver from the Guild of Enamelers - It is a fountain of information - Hope it helps -

Hi Amanda, although I don't engrave I do enamel on Britannia silver castings. I usually heat up in the kiln to 800C and pickle only if absolutely necessary. I suppose because I'm working on the cast surface I am not exposing any 'new' surface area and often find that the only bit of oxidation is where I have removed the sprue. I can deal with that bit by hand polishing. I barrel (actually usually in my magnetic rather than tumble polisher - mainly because it's quieter) then just heat up again in the kiln to get rid of any residue from the tumbler. Then I enamel and hand polish the edges at the end. I'm no expert but hope this helps :-)

Thanks I will read it thoroughly!

Thanks Lynne I wIll give the heating a go.

ASK THE EXPERT - Tom Ellis - Bill HelwigBilll Helwig would suggest that the castings have  
minimal porosity but should be tumbled in needle shot to burnish or  
compress the surface.  The metal then may need to be depletion gilded  
- heated hot enough to turn the metal black with scale, then put in  
new pickle to remove the copper oxide, then glass brushed and rinsed.  
This process should be repeated until the metal remains a grayish  
white after heating.  You are removing the copper and enriching the  
silver content at the surface.  Glass brush before applying enamel.  
Certain enamels react to silver (those containing cadmium - yellows,  
oranges. and some reds) and those containing gold (reds, purples,  
pinks).  A clear for silver may need to be put down first.