Poor man's casting - how do I do it?

[kwackers]

I've looked at various articles on casting and they all seem to go the same way, lots of expensive space hungry bits along with tons of advice that seems 'overkill'.

So what I'd like to know is, how does someone like me who wants to make a few small castings (say out of ali or brass) go about it without investing real money...

I'm sortof thinking that I've got a big blowtorch and lots of scrap aluminium, surely I can make a dent in some sand, blast the aluminium in a melt-proof pot of some description and just pour it in...

Apologies if this sounds over simplistic, but that's basically what I'm after. Can I get reasonable results from not a lot of outlay (and in particular without more equipment filling my already pretty tight workshop)?
I appreciate something better than an old tin can might be needed to melt the aluminium and I'll need a bag of casting sand to make a mold with.
(I even appreciate casting stuff could become addictive and grow with the result of squeezing something out of the shop!)

All advice and recommendations gratefully received.
 

[Bogstandard]

I was only talking to Stew about this the other day.

When I used to show my engines at the Malpas steam rally, the chap on the next stand along used to make all his own ali castings, and make wonderful full sized copies of small turn of the last century engines.

He was telling me he did everything the old way. Everything, he said, came from his little garden plot, except for his melting pot, which was an old stainless kettle and the metal he was melting, plus a few bits of wooden planking he had scrounged.

He was telling me that he used an open flame pit, burning wood and charcoal for melting his metal, and his moulding material was dried out soil that had been finely sieved. There must be a bit more to it than that, but he said he never bought any of the specialist materials and other gubbins, and his castings were very acceptable.


Bogs

[andyf]

Kwackers, you might find this to be worth a look:
http://mikesworkshop.weebly.com/foundry.html

Andy

[Rob.Wilson]

I've looked at various articles on casting and they all seem to go the same way, lots of expensive space hungry bits along with tons of advice that seems 'overkill'.

So what I'd like to know is, how does someone like me who wants to make a few small castings (say out of ali or brass) go about it without investing real money...

I'm sortof thinking that I've got a big blowtorch and lots of scrap aluminium, surely I can make a dent in some sand, blast the aluminium in a melt-proof pot of some description and just pour it in...

Apologies if this sounds over simplistic, but that's basically what I'm after. Can I get reasonable results from not a lot of outlay (and in particular without more equipment filling my already pretty tight workshop)?
I appreciate something better than an old tin can might be needed to melt the aluminium and I'll need a bag of casting sand to make a mold with.
(I even appreciate casting stuff could become addictive and grow with the result of squeezing something out of the shop!)

All advice and recommendations gratefully received.
 

It is as easy as you say .

Large blow touch  ,, the type that roofers use and a few fire bricks and off you go . the bricks can be stacked away when not in use .
Something like this
 

Rob

[joshagrady]

Even easier, use a microwave oven!  Here's an article (translated from the Spanish original) that should help you get started.  Obviously, this technique will be limited to smallish amounts of metal.

[Rob.Wilson]

Hi  joshagrady

Interesting     


Rob

[cidrontmg]

Hi  joshagrady,
Another weird use for a microwave oven! Interesting indeed, as is the whole site
( http://www.cientificosaficionados.com )
where it came from. Thanks for that.
 

[kwackers]

Thanks for the links and advice guys!

Some good stuff and more importantly confirmation along the lines I'd hoped - just melt 'n pour!

The microwave is interesting - not least because my missus has a little firebrick kiln that's specifically designed to melt small amounts of glass in the microwave, the idea that it might also melt metal had passed me by... (Although I doubt it could melt enough to cast anything bigger than a drawing pin).

As an aside, my first attempt at melting metal with my blowtorch was some lead I'd hoped to cast into new sash window weights.
I fitted the largest head I had (which was the size of a bean can) and then figured an old aluminium saucepan would probably do as a makeshift crucible.
I loaded it up with lead and sat it on an old wireframe garden chair, pointed the blowtorch at it and pulled the trigger. An enormous roar filled my ears followed almost instantly (and to my delight) by the lead rapidly melting into the pan and then a second or so later by the pan folding over into the lead....

If anyone has any use for some leaduminium alloy - I've a block of it here.

[cidrontmg]

 

 

[fluxcored]

After spending close to a year reading up and trying to source materials locally, I was on the verge of giving up because I could'nt find any of the recommended sand, insulation, refractory, etc. at a good price.

One evening I just made a wood fire in an old drum which I bored a hole at the bottom to allow me to feed the fire with an old electric spray gun compressor. My crucible was a pipe with the bottom welded shut. My molding sand was the building sand I'm currently using to build with.

It worked well - I've melted down a lot of old hard disks and must say they're a great source of ali.

I've since then made an ingot tray out of angle iron and obtained some clay from a potter to make some green sand.

I am busy building a gas fired foundry with an old lawnmower deck as a base. I've already cut down the deck but still have to weld it and add some wheels before I can start with the foundry. But my heart is'nt really in this project because the wood fire works OK for my needs and wood is so cheap around here.

I have'nt melted for some months because it's raining again - thank heavens our drought broke - but I collected some good scrap and am itching to cast a fixed steady.

Important though is just to understand the risks and safety issues.

[johnbaz]

Hi
When i worked on our light railway plant we used what's known as green sand, it's mixed with Bentonite clay and water in the correct amounts so that you can squeeze it in the hands into a solid ball- too wet and it could explode (you can put water on molten metal but not the other way round as it instantly turns to steam and shares the molten metal out between all within range!!)

Once the sand had been mixed, it has to be 'rammed' around the pattern, a joint made with inset locating dowells so that the pattern can be removed, once it's been rammed hard enough a feed system can be made by drilling a hole through from the top of the mould and then separating, on the bottom then a feeder can be carved from the hole to the void where the metal will run (mould cavity).
If it's going to have a top part (a cope) then vents may need to be cut in to stop the rising metal causing a vacuum resulting in an incomplete casting.

The feeder should be opened up to a cone shape so that it's easier to hit with the ladle, the vents only need to be thin say, 3mm dia..
When the mould is ready it should be gotten warm so that the molten ally doesn't chill and solidify or cause cold lapping, once it's nice and warm and put together you'll need to weight the top down or tie it together with steel banding wire as the molten metal can push the top part up causing a breakout...

In the heavy foundry they use an epoxy mix, the sand is chromite for the face of the moulds and silica for the backing, it's mixed with acid and resin and dries rock hard!!

Hope all goes well, we used to make cannons, ashtrays, parts for guns etc when we didn't have a foreman on with us


John