Information and prices are generaly from 2005 and are aimed at the UK market.

Metals

Brass

Easist way to get brass is carboot sales, general auctions and charity shops. Buy bits that are priced cheaply for their weight and melt them down. This generaly produces poor results and lots of slag as additives seperate out but can be cheap. Some brass bought this way does contain nasy chemicals and should be treated with great care. Getting brass rod from places like B+Q is a possibility but is VERY expencive, around £20 per Kg. John Winter sell 7Kg ingots for £7.60 per Kg.

Aluminium

Your local car or motorcycle scrap yard might help you here. Pistons are mainly made of aluminium as are some barrels and some engine casings. With casings you can get into trouble as some look like aluminium but are infact a manganese composite.
John Winter sell 7Kg ingots for £8.50 per Kg.

Bronze

You can apparently obtain bronze from scrap pipe fittings and water pumps but you'd have to know what your looking at. It is also possible to use old bronze bearings but these are normaly phospher bronze which may not be what you are looking for.
John Winter sell 7Kg gun metal ingots for £11.00 per Kg.
Tiranti sell stuff they call 'bronze filler'. I understand this to be 89/11 bronze in a powderd form. I've not tried it to date but see no reason that this couldn't be used for casting. The price varies from £6.18 to £11.50 per Kg depending on the quantity.

Bell Metal Bronze

In the UK finding small (less than a ton) quantitys of bell metal can be real problem if you're not in the trade or don't have close contacts in that respect. The only place's I have been able to source bell metal from is bell founders who are willing to let you have some of their stock. The most affiable in this respect being Taylor Eayre and Smith Ltd AKA John Taylor Bell Founders who may give a quote on request. However, please note that selling bell metal is not their normal trade and they may refuse to do so. Be nice, treat them with respect and there should be no problems though.


Foundry Supplies

Most foundry supplies can be got from John Winter including sands, tools, crucibles, books and just about anything you might want.
There is also Engineering & Foundry Supplies Ltd who do a similar line to John Winter. Some bits are cheaper some more expencive.
Different things can be got from differnt places though and some for a worth while saving. My home foundry was built using fire cement from wickes diy center, a metal bucket and a pump for an airbed from the local garden center Badshot lea garden center and copper pipe from the local plumbers, Target Heating (no web site that I can find).
Some of the tools I use are home made others have been appropriated from blacksmiths, car boot sales and ebay.


Books

Some of these books are dificult to get so the listed suppliers may not have them and you may need to find alternative suppliers
Title Author ISBN comments
Foundry Work For The Amateur Terry Aspin 1854861689 from John Winter. Good starter
The Complete Book Of Sand Casting C. W. Ammen 083061043x from John Winter. Very American but good info
On Divers Arts Theophilus 0486237842 from W.H.Smiths. Pre-Tudor stuff. Lots of interesting stuff including some casting
Pirotechnia Vannoccio Biringuccio 0486261344 from The Building Centre Bookshop. 16th Centry metalwork. An interesting book covering everything from extracting the ores to casting almost anything. Not so easy to read but if you're interested in a snapshot of the metalworker in the 16th Centry this is excelent.
Metals in the Service of Man William Alexander, Arthur Street 0140224475 from Amazon. General metal working including casting and types of alloys
The Craft Of the Bell Founder George Elphick 0850336481 from Whitchapel Bell foundry. Lots of interesting info on the history of bells and where you can find differtn ones etc. Includes sizes, shapes, tuning moulding and so on. limited on the casting process but high on the bells and history.