laminating gold and silver?

[medusa]

I have a bit of a special commission (OK, it's the girl's 21st so not really a commission!). I've been making mobiles strip bangles and got quite good at them now and I want to make one which is silver but with gold laminated over the top. I intend putting the gold halfway along the the length on one side and then continuing over the other side with the gold strip cut diagonally so when it's all put together the gold is all on the outside with the silver on the inside.

But I'm not sure how thin I can get away with the gold. I was going to use 18ct as I have some medium 18ct solder already. Would 0.3mm be too thin? I'm planning on using rectangular sterling wire in 5x1.7mm size.


(and sorry I've been quiet lately, shift work is a biatch!)

[CJ57]

There will be others more informed than me on this Liz but nice to see you back :)

[medusa]

Cheers Caroline. I have a rare day off to think about this before I get it made. I've missed being here!

[CJ57]

It's been interesting recently!

[Dennis]

I had difficulty following this question Liz, until a later light bulb moment, when it dawned on me you might have meant Möbius not mobile. The real problem with adding a gold strip onto the surface of silver is that it would have to be sweat soldered and in close contact with the backing.

So personally, I would shirk having the gold too flimsy, and go on to 0.4mm thickness and finally give it a light rolling on my mill and re-flux and re-heat, to make sure it is well soldered.

I would also use silver solder, probably easy, to avoid the gold sinking into the silver. Welcome back from me too, Dennis.

[medusa]

heh, flippin' autocorrect!

If I go .4mm would it be rubbish if I used 14ct? I suppose if I went 9ct I could go for .5mm but I was hoping using a higher carat plus gold solder would keep the integrity of the laminate. Also do you mean roll the two strips together before soldering or after? Or both?

I was going to sweat the solder on the gold first and then lay the silver on top and heat.

[Dennis]

heh, flippin' autocorrect!

If I go .4mm would it be rubbish if I used 14ct? I suppose if I went 9ct I could go for .5mm but I was hoping using a higher carat plus gold solder would keep the integrity of the laminate. Also do you mean roll the two strips together before soldering or after? Or both?

I was going to sweat the solder on the gold first and then lay the silver on top and heat.

1. I've never even seen 14 ct, but you are right in thinking 18 carat is the best contrast, unless of course you oxidise, in which case dark grey to gold is the best contrast of all. As you probably know, high ct gold will stay bright.

2. My idea of putting it through the mill , very very lightly, is to remedy if it ends up a bit bumpy after soldering. Any pressure will cause the gold to have a wavy edge, so the result will be unpredictable. However it is a way of using gold wire, which is a cheaper option. You can practice with copper wire on brass or similar.

3. I would always sweat solder so that I can see the top, in this case in two parts. That way what you see is what you get.

4. Two reasons to use silver solder: Over spill of gold solder onto silver is ugly and impossible to rectify completely. Gold solder has a high meltimg point causing various difficulties when having to heat such a large piece of metal. Dennis.

[medusa]

Cheers Dennis

Cookies do 14ct. I was going to order it cut from sheet rather than roll round wire down but I was also planning on passing the final piece through the mill as well.

Good point about the problems with gold solder (I think I should just try and sell the bit I have!). Would you sweat solder onto the silver and then lay the fluxed gold on top then? I usually use hard solder because it flows better and for this job I'll be using a lot of heat to join the ends (for which I will have to use the gold solder for). Does that make sense?

[CJ57]

I would solder the back of the gold and then wire or clip it firmly to the silver. If you solder the silver the solder will spread on the silver probably well out with the area you want to solder the gold to if you get what I mean

[medusa]

Caroline, do you mean sweat silver solder onto the back of the gold? Because I'm laminating both sides I'm anxious about it all coming apart. Plus there is having to solder the two ends together. I hope I haven't bitten off more than I can chew!

[medusa]

Well I just did a mock up using copper. I laminated 1mm of copper onto some silver wire and rolled it down to well over 4x its length and the copper is clear and bright. I used various abrasives going through the grades from very coarse to fine and still no rub through.

I have made the purchase, opting for the 18ct rather than 14ct for a better colour. I will post pics if it works out ok!

[Dennis]

Well done Liz, it looks as if you are on your way now. Regards, Dennis.

[CJ57]

Caroline, do you mean sweat silver solder onto the back of the gold? Because I'm laminating both sides I'm anxious about it all coming apart. Plus there is having to solder the two ends together. I hope I haven't bitten off more than I can chew!
Don't know if you still need me to answer this as you seems to have tackled it but yes that's what I meant!

Looking forward to the pics Liz.

[medusa]

Thanks both.

I have my gold now. I've glued it to the silver before cutting the diagonal (in my mock up rolling the copper raised as it was on the silver made the rolling process slightly wonky so I'm soldering 1mm silver as well so the surface is completely flat for rolling) probably on wednesday

Does anyone have any thoughts on if I ought to use enamelling solder instead of hard solder for the laminating? My thoughts are that as I'll need to get the bangle really hot for the gold solder to flow when I join the ends (I can't tell if the small panel I have is medium easy or hard, though I have a small amount of what I know for sure is 18k easy wire, I'm just not sure if it's enough for the job). I'm hoping the repeated rolling and annealing will have created a really perfect bond by the time I come to join the ends, but don't want it going Pete Tong on the final stage.