If you wanted to use the solder with flux in you could melt it, and the flux will form a layer on the top of the moulten metal. This should be quite easy to skim off before using the solder -but it seems a long way round to me.
PS be careful with this stuff, it will kill you if exposed to it over time -definately not a good idea in confined spaces.
When I needeed whitemetal for bearings, Geof Treseder the proprietor of Carn Metals, and a former Geevor tin miner, made me a batch of material to approximate a tin rich BS alloy and very successful it was too. He won't handle toxics like arsenic and cadmium, but tin, antimony and copper are fine.
Although not cheap in absolute terms, it was significantly cheaper than proprietaty whitemetals, though these have traces of toxic which impart specialist characteristics.
Talk to Geoff - I found him very informative. and helpful.
John Ambler Sussex, UK Return E-mails to email@example.com
If it si just for practising I have had pretty good results using old wheel balancing weights. If you go down to your local tyre shop they will usually let you have them for the price they get as scrap.
I'm not sure of the comosition but it is harder than lead and many years ago I had some pretty good success casting toy soldiers with it.
Antimony is almost as poisonous as arsenic (MAC 0.5 mg/m^3 versus arsenic's 0.2 mg/m^3 for continuous workplace exposure over a 40-hour week).
It is however used in small concentrations in such alloys, and is not particularly volatile, so provided you wash your hands after using it there should be no problem. In fact I would not worry about using alloys containing small amounts of arsenic provided I knew about it so I could take care. It is very useful in casting metals as it expands on solidification (like water, but unlike almost all other substances) and a small percentage makes the castings crisper. It was used in printing type metal for this reason.
Just one point to make, the OP was asking about models which, like it or not, may well end up being played with by kids so all this talk of lead and even more toxic elements is surely inapropriate. All that is needed is the most common type of lead free solder which is tin and copper, readily available from any electronics supplier such as Farnell and RS without flux cores, it does have a slightly higher melting point but nothing unmaneagable.
I take your point on safety but I did specifically ask about lead \ tin in the subject.
My reasoning really is for ease and simplicity. The lead models won't be played with by children.
I asked about tin \ lead as I want something easy to practice with. If the bug bites me and I get to grip with the basic problems I can see myself moving to whatever metals I can work at home and are good at taking a cast and strong for fine detail.
For the moment though I suspect half a kilo of tin \ lead will give me all the metal I need to cast and recast various size practice pieces.
The only models I'll be keeping at the moment will be rough half figures of passengers to be painted and go inside model coaches away from touching hands.
There is a slight safety gain also for me as a novice as the melting point is a little lower and less special preparation will be needed.
I also already have a pair of goggles and some heavy gloves :)
My lead \ tin solder is on it's way to me now and i'm going to try a few open casts first in some baked off plaster of paris. I'm quite excited.
Pete, you may need to research the painting of lead figures. Oxidation of the lead has a nasty habit of bleeding through the paint after a year or two, or even lifting it off in lumps. I used to paint soldiers in a mis-spent youth, mostly plastic (which gave no problem) but occasionally in white metal, and I speak from sad experience. ISTR that there are recommended steps to at least reduce the damage, which may for example involve using a base coat of polyurethane varnish. I can't be sure I remembered this correctly though, so I suggest you research in books for military modelling or wargaming.
Alternatively, do you really need to use metal? There are other casting materials, such as resin. I think a company called Alex Tiranti used to sell the equipment and materials for all manner of casting, including polyurethane mixes to make moulds for whitemetal casting, to professional users, don't know if they are still trading.
Fair enough, but frankly the difference between the two is minimal in practice.
The worst danger to watch out for is moisture, pour liquid metal into damp moulds and you can get an explosion which showers you with molten metal, not nice as I can personally testify 8-(.
As David has pointed out there is also the issue of painting, I'm into Warhammer myself so have painted a lot of white metal figures with no problem but of course they've been lead free for a long time because lead was banned in toys.
I hadn't considered that. I'll need to read up on this I think.
Maybe I'll leave the little guys for a while.
Wargaming resources sound a good place to start.
I've just won a whitemetal model making book on ebay so I can't wait to read that to.
Yes but what fun it was :)
I have other ideas for resins but like to keep things tidy and easy. I'm in my get to grips with melting metal phase at the mo :)
Yes they are trading. I took the hint from a post above and looked them up. They look quite established now and do a white metal begginers kit. (I'm going the cheap and cheerful direction for the moment :o))
Actually I am keeping notes on URLs and sources as I thought I'd add a footnote to this thread once I had all the basics ready with a list of resources I had come across.