Thread: Souce of moulding sand?

if you had the tools you could make a steel mould ??

do a websearch for refractory supliers and for local foundries in your area. There is a good mob online who do mail order but I cant think of their name off the top of my head. If I think of it I will post it. Another possibel is if there are any manufacturing jewelers nearby. short of that get some magnets and drag them through your local creeks to extract magnetite sand.

For a leak-proof flexible mold, you can use high-temperature silicone sealant, usually used at flue penetrations in walls. Expect to pay well North of $10 per tube from fireplace or wood stove dealers. If you don't mind the smell while casting the lead, and if only a few castings, ordinary silicone works too, but it deteriorates rapidly.

Apply a bond-breaker to the pattern (hand lotion works). If you use a wax pattern, the bond-breaker is un-necessary. Smear the sealant to a thickness of about 5mm and let it cure; this may need to be built up to correct sagging. While it's curing, encase it in plaster of Paris, with a separator wall if needed (which is most likely), to hold the shape. Devise a clamping mechanism for lead casting.

Take everything apart, and re-assemble without the pattern, for lead casting. The plaster need not cure: the silicone provides insulation, and cracking is of little consequence anyway, provided adequate clamping.

This technique can be used on patterns with undercuts, but with several additional steps, and/or a two-part mold. I'll add it to my list of pending new threads.

Cheers,
Joe

This fellow is in Sydney I belive. He has a great website all about casting, And a great section on moulding sand, Everything you need to know is here...
Matt.
Shed stuff, Foundry stuff, Lathe stuff

Call Cast Metal Services. They have an outlet in Sydney. I picked up 25kgs of oil bonded moulding sand for $85, and this has been excellent for casting aluminium. I used to stuff around trying to mix my own green sand etc but never got it right. This stuff works straight out of the box and as it can even be used for casting iron (1400 degres celcius) it will give excellent results with lead, which I believe melts around 1000 degrees cooler than iron.

Thanks for all the input. After trying some suggestions ( salt & flour, plaster of paris) with some spectacular failures, I contacted Paul from Cast Metal Services and have ordered 25kg of Petrobond. They have also provided data sheets and an overview of their services. My biggest problem has been to eliminate moisture from the mould which boils when pouring the lead, and fills the casting with voids, while splashing molten lead all over the workshop. The Petrobond will apparently eliminate this feature and reduce the terror factor, which is not completely minimised by leather gloves, faceshield and apron while pouring.
Cheers
Graeme

Hi Graeme,

Been using petrobond (from CMS) for years now. You are correct in that having no moisture content, you won't get steam, but will aluminium you get a shed load of smoke!

Lead has a much lower melting point, so hopefully it's not too big an issues for you, but I'd thought I'd warn you first. I made the mistake once and ended up with a house full of black smoke.......

The Petrobond arrived today, so I decided to try it out straight away. I already had the cope and drag made and the wooden pattern was from the previous attempts.
I used babypowder as a release and the sand packed in beautifully, really quick to use.
The pour was very easy, no fizzing, bubbling or splashing (or black smoke) I guess that lead isn't hot enough to burn the oil binder in the stuff. The finished cast only needs a little bit of cleaning up with a file or wet and dry.
The result is encouraging enough to want to try some aluminium or gunmetal. (I'll need a better crucible than the old stainless saucepan.) Thanks for all the input.
Cheers
Graeme

Excellent to hear. I was ready to give up on casting til I found this petrobond. It really works wonders hey!

Brendan