Metal Casting Zone

Hi Guys,

I'm planning to cast my first piece and have hit a hurdle.

I want to sculpt then cast an essential oil burner, it's "essentially" like an up-turned tea cup with a saucer sitting on top, the saucer takes the oil and the cup at the bottom holds a tea candle, there would be a bottom on this up-turned tea cup but I need to get a cavity/hole at the rear of the tea cup so you can get the tea light candles in and sit it on a base so it doesn't burn the tablet the burner is sitting on.

My knowledge leads me to believe that slip/slush casting would be the way to go so there's room inside to put the tea light candles in but I don't know how I could get this cavity at the back so you can put tea light candles inside it.

Would I have to make this cavity the point where I pour the metal into the mould i.e. the top of the mould?

Are there any tricks I could use to get cavities/holes in hollow castings (obviously I could cut it out but if I can get away without doing that it would be better).

Cheers for any help you can give me.

Peace.

You can use ceramic slip, in a seperate mold, to make a core for your casting.

I used this to make a hollow light mount for an antique tractor light bracket.

Can you put a cross section picture of your item on here?

its very advanced!!! the old time foundry standard was to make a saucer ...cup and spoon mold!!! to prove you knew your stuff in the molding trade.

Thanks for the replies fellas,

Here's some pictures I took of the piece I got the idea from, I want to copy how it functions but give it a different shape/design i.e. where the bee is on this one there would be other motifs.

I've put this on the back burner so all the thought I put into it isn't real fresh in my mind but I recall thinking that making a separate bottom would be a way of getting it to work.

Anyone got any wisdom they'd like to impart?

they are easy to make!!!this is what you will need..... the hollow bit...well you will need to make a solid shape equal to the cavity....this is made from sand with some extra stuff added!!!! (research core mixes) you will also need a pattern equal to the outside.....so in the sand box /flask you make a impression of the outside( if you filled this you would have a solid block looking like the outside image)the solid "core" of sand is now fitted into the mold and the metal poured.... this covers the core with metal....when cool the casting is removed and the "core" is removed by washing out with water!!!! the core can only be used once!!! so a press is made to press the sand into shape for the cores.... this is when you want more than one

Thanks mate, you'd have to suspend the core so it doesn't touch the walls of the impression you've made of the outside though wouldn't you?

Have I misunderstood something?

Cheers.

Your core would be similar to the one I made for the light housing, that I made.
I made a wooden pattern of the inside cavity and then made a plaster mold of that.
Then I made a core by pouring ceramic slip into ther plaster mold and let it set for a while.
Open the plaster mold and put the core into an oven to dry it out.
Luckily mine had a hole at both ends of the core so it was suspeneded well.

Picture didn't seem to come up.
Here is the core that I made.

MayaRefugee wrote:
Thanks mate, you'd have to suspend the core so it doesn't touch the walls of the impression you've made of the outside though wouldn't you?

Have I misunderstood something?

Cheers.you are totally right!!! the guys that make internal combustion engines take days to place their cores. ....2minutes to pour... and if not right!! !!!!!

Thanks for the replies fellas, greatly appreciated.

Coley, the pics aren't working on my computer but your writing got me imagining what you're describing - sounds like it would have been a fun project!

Chainsaw, I'm pretty ignorant when it comes to engines so I apologise if this question is silly - are all engines cast or is it more the hobbiest that casts them?

Giving it a quick thought I can imagine them having a really well calibrated frame that could suspend the cores above the block perhaps with adjustable height dials to get really good tolerances - this is just inexperienced speculation mind you .

Anyway, thank you once again.

Cheers.