Soldering sheet metal

[susieq]

I'd like to make a bangle which is silver on one side and copper on the other. As I'd be piercing the design out of sheet metal, can someone advise how to solder the two together to get a really neat join?

Would I use solder paste (which I've not used before) over the whole sheet. Total thickness of the two sheets will be 3mm (maybe 1mm silver and 2mm copper to cut down on the cost). Sheet size 10cm x 10cm before piercing.

If soldering two sheets 10cm x 10cm together would be a problem, then I could cut both pieces out first (it's a reasonably simple shape) and then solder them together. Would this be a better option? I guess I could then cut small pallions and lay them between the two sheets along the edges. If I went down this route, then presumably I would have to aim to solder the whole piece in one go? Would I lay the piece silver side down and heat the copper or the other way round? And does it make a difference if I use 2mm copper to 1mm silver.

And what if I decided I wanted three layers?

Sorry there's so many questions. Am i being too ambitious for a newbie?

I haven't got a torch yet, but after reading through several threads have decided on the Nimrod T75 micro torch which sounds a better option for bangle soldering than cookie's basic one.

Thanks

Susie

[ps_bond]

Personally, my approach would be to sweat solder the two sheets together - clean and flux one sheet, scatter with paillons, heat until the solder just flows; pickle, reflux and stack on top of each other then heat both sheets (ideally from both sides - I stick them on a tripod for this, but there's all sorts of ways of doing it). Once the solder flows, run around the outside edge with the torch to make sure the solder is drawn out to the edges fully.

You will need a big torch to get enough heat into the metal, and I'm not convinced the T75 would be up to it - I'd probably go for one of the propane (not butane) brazing torches from the DIY sheds.

[Dennis]

Dear Susie,
If you have not already read it, have a look at the thread 'Help With Soldering'.
To solder one sheet on top of another it is best to use the sweat soldering technique. Place pallions at about 5mm intervals all over one fluxed sheet , heat until they just melt and let cool. Place the other fluxed sheet on top and reheat until you see the liquid solder appear at the edges. you get less distortion if you let it then cool slowly on the block before pickling. Paste solder is less reliable in situations like this and could give you a very imperfect join.
You will also need a lot of heat, which means a big torch, but less so if you can reduce the sheet size. You can also reduce the amount of heat needed by using easy solder, but this is best done with Easy-flo flux which allows easy solder to flow at the lowest possible temperature. Note it is no good for hard solder. Further things to note:
1. If you get this wrong it will be virtually impossible to re-do, so don’t let this be your first soldering experience.
2. The solder is much harder than sterling alone, so the resulting double sheet will be much harder than you might expect.
3. If your joint turns out to be imperfect the layers will partially separate when you bend your bangle.
Forgive me for saying so, but if you are inexperienced you might be much better to join a class where help is at hand.
We need your feedback, so please let us know how you get on. kind regards, Dennis

Sorry Peter, I was still struggling with this when we cross posted. I have also failed to paste the URL for the post on soldering. Dennis.

[ps_bond]

Not to worry, Dennis - was this the link you were after?

http://portalgc.knowledgebase.net/di...1&docid=111370

(Argh - that's not the one, is it?)

How about -
http://www.cooksongold.com/forum/hot...soldering.html

[Dennis]

Thank you for doing that Peter. I was having trouble with my post because the damn URL would not turn blue when I clicked on Post Quick Reply. However it did when I tried it now, so I deleted it again. kind regards, Dennis.

[susieq]

Thanks for the advice Peter and Dennis.

I've done a term of evening class but working full time and with few tools at home my projects are going frustratingly slowly. I need to spend more time thinking through my ideas so I can take full advantage of the tutor's expertise so at the moment, being in between terms I have lots of potential projects in my mind but without the experience to know what's feasible. I once spent the whole of one of my classes filing down five cabochon settings to fit around the first of my bangles - not the best use of the fee for the evening! It's still not finished as I ran out of time to polish out the firestain I caused by trying to heat the bangle up too quickly when I soldered it and until I finish polishing it I can't set the stones in. Just hope i can remember which stone goes into which setting .... although I did number the stones and have them in separate packets.

Then there are the two pendants i was making for xmas pressies which are unfinished because I needed to drill a 2mm hole for the jumpring but the chuck on the drill is untightened/tightened by what looks like a bent nail and I don't have the strength to change the drill bit. By the time the tutor got round to helping me it was nearly time to pack up and then one of the other students nearly emptied the contents of the barrel polisher on the bench taking the top off too hastily so she got side-tracked and my holes never did get drilled as we ran out of time.

So I really need to get my act together progressing projects at home where I can and then taking the difficult stuff into class for the tutor's help.

Anyway, back to my original reason for posting - I won't be bending the metal once the pieces are soldered together but will be cutting out the centre hole for the wrist and then the design for the outer edge - a sort of oversized washer with a hole in the middle but with a rounded triangular outer shape. It sounds like i need to cut out the shapes first and then solder them together to cut down on the surface area and make it easier to solder. And I'll leave it for a project to solder in class where we use the big torches (which I'm still slightly afraid of!).

When I finish something I'll be sure to post a photo of it.

Now I'm off to research some accessories for the pendant drill my oh doesn't know he's getting me for xmas - ho ho ho.

Susie

[Joe]

No need to stop working on things over the hols... try Micromesh for polishing on a budget! It's a sort of posh sandpaper going from rougher grades to sand out firestain to very fine grades which will give a high polish; available in cheapish sets from Ebay.

You don't say where you live, but a trip to Maplin can secure you some budget tools, like small drill bits. I would caution you about spending too much there though - there is a good reason why some of the tools on the Cookson website are more expensive than their cruder hobbyist counterparts and there are a number of things you'd do better treating as an investment (needle files especially).

If you're investing in the Foredom from Cousins then wait for Santa to show you the free accessories they add... and be careful when buying pendant bits - there are two standard collet sizes and you must buy the correct ones for your drill!

[Dennis]

Dear Susie,
I am sorry that your class is so busy, but you don’t sound like the despairing kind, so all you have to do to begin with is to scale down your work so that you can do it at home.

One of the first things I bought when I started was a cheap barbeque base in the January sales, with a metal guard at the back, as a soldering station. Then I added a few soldering blocks, a tripod and some gauze so that I could heat from underneath. I Started with a mini-torch, but soon realised that I would need something bigger. So then I bought a Taymar/Camping- gaz torch from Homebase which is self igniting and uses a butane/propane mix. The Go-System is good too, but which you choose depends on availability of refills. I use it to this day, but now I have two for heating large items. They look scary, but can be turned pretty low once warmed up.

As Joe said, Micromesh is good, but also try various domestic scourers for a rougher texture. For needle files you could start with one flat coarse cut and one half round medium cut and some screw on plastic handles. You also need a five inch saw frame for sheet up to 10cm square and a simple cheap hand drill to make access holes. For the rest only buy what you need for the moment. Sorry if this is too much unwanted advice. Dennis