Thread: Sand Casting. Who's done / doing it ?

Just wondered who among us is up to speed on sand casting or actually doing it ?

Something I doubt I will get a chance to learn to do in this lifetime, but keen to find out who does it to make small gun parts or have the skills to make small gun parts.
Simple shapes and around 60x30x20mm and want to be cast in mild or low carbon steel

I will be visiting a Casting Shop in CHCH Wednesday to follow this up with them and get a ball park price on a couple of parts I need replicated reasonably urgently.
I need to find out shrinkage rates from original parts and how complex the parts can be.
I'm guessing you can blank out any negative details that wouldn't un mould from the sand.

I've been dealing with a company in the UK who do make some of the parts I want but they aren't intending making a run for some time and then there is the whole Gun Parts are dangerous thing and permits etc.
Cost is not the issue but timeliness is.
I've been dealing with the UK guys for 6 months and got nowhere

Now want to get these projects back on track

We used to do it at college, only in Aluminium and no double happys, had a coal gas/oxygen furnace, made out of a small fire bricked lined drum.
Black sand, wet enough to bind, in two boxes, like a sandwich seperate with a sprinkling of dry white sand.

There was a very comprehensive article in the Shed mag a while back. I've done a little of it, but nothing complicated - and nothing critical on shrinkage as it was all needing to be machined after.

It was pretty much all as Maca suggested, two sand boxes with 'green' sand just damp enough to stick and two split forms.

The Shed mag article was good in that it discussed lost wax casting, which if done right can get better and more accurately cast results. I'd look into that and go from there maybe? And I won't mention that the last thing I cast in sand was a castle a few weeks ago haha.

A former workmate of mine has a wax 3D printer that prints directly in wax ready for use in investment casting. I know he gets lots cast in silicone bronze but I think he gets some ferous castings done too. If that's something that could be of use I'll try to dig out his details for you.

Originally Posted by No good names left

A former workmate of mine has a wax 3D printer that prints directly in wax ready for use in investment casting. I know he gets lots cast in silicone bronze but I think he gets some ferous castings done too. If that's something that could be of use I'll try to dig out his details for you.

I'm up to speed on printed lost wax

Want to understand sand because I can copy existing parts that i don't want to wreck

I wonder if plaster of paris may be usefully for this.... Same sandwich idea but a more permanent mold.

I did my trade as a molder greensand moulder
Then things changed to hardsand but I've been out of that game for many years now.
Shrinkage rates is more a pattern maker and I'm sure there is someone on here that was a pattern maker.
There is still a few foundry's around I know of 1 in Wanganui and Palmerston North as well.
When you are trying to cast iron or steel it's not really a back yard job.

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Originally Posted by Micky Duck

I wonder if plaster of paris may be usefully for this.... Same sandwich idea but a more permanent mold.

Sand is easy to work and just vent to let the air out and prevent pressure, worse was breaking up the WW2 aero engine parts to fit the crucible. We’d heat it with oxy/acetylene and smash it with a sledge hammer. Had a guy lose an eye with a flying bit. Teacher did it after that, in full kit

Originally Posted by 25/08 IMP

I did my trade as a molder greensand moulder
Then things changed to hardsand but I've been out of that game for many years now.
Shrinkage rates is more a pattern maker and I'm sure there is someone on here that was a pattern maker.
There is still a few foundry's around I know of 1 in Wanganui and Palmerston North as well.
When you are trying to cast iron or steel it's not really a back yard job.

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I did School holiday work and then the first part of my NZCE sitting on a big lathe at AF Martins, when it was on Main street. Turning all the recently cast iron bits hot out of the foundry into machined parts. Whenever I could, I would go and watch the pattern makers filling the boxes, vibrating them then standing on the wooden forms to impress them into the sand. Was quite a cool process to watch. But bloody dirty. And even dirtier to machine cast iron all day long. The old timers with 10 plus years on a lathe just turning mind numbing quantities of cast iron were just one big black stained humans. Coming to work on a Monday morning they were still covered in black creases

I've made a few patterns and helped a bit during the casting stage but only with ally and bronze... Ally shrinks around 2% and bronze nearer to 4 or 5 % .not sure about steel though. some of the bronze alloys are stronger than mild steel and can be heat treated to be much stronger again - is bronze out of the question? are you able to put a photo of the part up

Yip I work in foundry's for the best part 20 years covered in iron dust and black from the sand dust knocking out the castings once poured.
A real dirty job but some of the things I made were pretty cool.
From parts for Rolls-Royce cars to bollards for Super Yachts.

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I worked for a pattern maker years ago and we had shrinkage rules specific to the material the pattern was being made for.

The shrinkage rate for cast steel is roughly 2% but I would go to 2.5-3% to allow a finishing margin as sand casting leaves a rough finish. If you are using an original part as a pattern, it would be best to tape it all over to allow for shrinkage. Large flat surfaces also need some extra as they tend to shrink in the middle a bit leaving a hollow surface.

A bloke on another forum cast a reloading g press in alluminium. Come up very good.

Originally Posted by Oldbloke

A bloke on another forum cast a reloading g press in alluminium. Come up very good.

Yeah I cast a few for a guy out of cast iron a few years back.
I was meat to get a finished one for payment but I'm still waiting

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