Made a container for melting aluminium

[Ed.]

I am hoping to some foundry work to cast some scrap Ally into some rollers for a belt sander I want to make. So needed to make a container to hold the molten ally, found a small length of 125mm x 4mm SHS and welded it to a 8mm base plate, put a 1/2 link of some 13mm chain on the bottom so that I can fit a hook in it to provide a bit of lift from the bottom. At the top I welded a 19mm nut to a bit of flat bar and welded that on towards the corner, I will thread a long 19mm bar in to it to lift the container out of the flame and add the hook for a bit more pouring control.

Added a bit of angle for a spout and put a bit of 8x15 mm flat bar on the top to help stop the dross/slag falling into the mold.

I was going to pretty up the welds a bit but realized that on the first pour it is going to be covered in ally dross so not much point! It's pretty ugly but so long as it works and is functional I will be happy. The plan is to put it onto a fan forced wooden fire and I have a 50mm Propane torch to help melt the ally pieces into it.

Spent a few hours using a blender to pulverise 10Kg of clay kitter litter into a fine powder, now just need to get the sand from the local garden supply. It it has been raining fairly hard here for the last couple of days so I might have to wait a bit till their stockpiles are drier.

One thing that I still need to find out is, once I mix the sand and clay and wet it down a bit so that the clay can bind the sand granules, do I have to wait until the water evaporates off before I can pour the Ally? If I do it straight away wont the steam effect the casting?

 

[The_Yellow_Ardvark]

I use the lower 2/3 of a steel body CO2 fire extinguisher for mine.

 

[Ed.]

I have a whole heap of old ally window frames which are just laying around which I need to get rid off, so they will be the first to go into the pot. Thinking about going to the motor wreckers to try and get an old cracked head which I will try to break up and use that as stock as well.

 

[The_Yellow_Ardvark]

@Ed.

Cylinder heads, alloy blocks can be nice to cast, but do contain a lot off ferrous and no ferrous arts what have to be removed. This takes time effort and energy.

2 ways to deal with that.

1: Trade them against smaller parts of scrap alloy at the scrap yard.

2: My preferred method, is to melt them down into an alloy bloom in a open pit fire. That way you use the energy from you crucible fire twice, One to melt your pour and the other to melt the scrap.

 

[Ed.]

What about damaged alloy wheel rims, would the magnesium component in them cause any problems if I got the pot too hot?

 

[slim_boy_fat]

I use the lower 2/3 of a steel body CO2 fire extinguisher for mine.

Ah, but you have ready access to them.

 

[The_Yellow_Ardvark]

@slim_boy_fat

Oddly, steel CO2 cans are a rarity. Most are alloy, hence the Pie Key people interest in them

 

[The_Yellow_Ardvark]

What about damaged alloy wheel rims, would the magnesium component in them cause any problems if I got the pot too hot?

Get the temp right you get bathed in a nice white bright light and the neighbours complain

 

[slim_boy_fat]

Get the temp right you get bathed in a nice white bright light and the neighbours complain

And you know this......how?

 

[The_Yellow_Ardvark]

@slim_boy_fat
Well, it is like this.

I had 4 hydraulic control blocks, ex lorry loader crane parts. But all were rusted up. So it was a pain to strip them down.
So I heaved them into the pot belly stove to melt them out and..........

 

[Ed.]

So back to plan A then? Might have to go to a scrap metal yard and see what they have got.

 

[wookie]

I had 4 hydraulic control blocks, ex lorry loader crane parts. But all were rusted up. So it was a pain to strip them down.
So I heaved them into the pot belly stove to melt them out and..........

Any chance you could do this again but this time take pictures, it'd be great to see

 

[Parm]

Don't pour hot molten metal into a wet or damp sand mould. There's a very good chance that the sand mould will explode.

In foundries they use phenolic resins activated by amines to cure the sand moulds

 

[frank horton]

green sand is what I thought they use for moulds........is that weted or does it stick together on it's own......cost a lot more than norm sand.......

just askin.........

 

[MattF]

Slightly wetted, but only enough to bind the sand mix. Not enough for a steam related incident.

 

[The_Yellow_Ardvark]

@MattF

Beat me to it.
I use soft building sand.
Best test is to grab a lump and squeeze.
If it feels wet or damp it is to wet.

If it feel dry and gritty to your palm and it crumbles with sharp crisp fracture lines it is good enough.


The other good thing you can do is pierce lots of vent holes all over the top of the flask. I use a 2mm brazing rods. Then make the open riser as wide as possible.

 

[Pete.]

You know that a steel flask will slowly get dissolved by molten aluminium, right?

 

[The_Yellow_Ardvark]

You know that a steel flask will slowly get dissolved by molten aluminium, right?

I do yes.

That's why my next one will be an old 5kg steel CO2 and lined with furnace clay.

 

[slim_boy_fat]

I do yes.

That's why my next one will be an old 5kg steel CO2 and lined with furnace clay.

And it sounds like you have an adequate supply for the foreseeable future anyway.

 

[The_Yellow_Ardvark]

Didn't say I had one. @slim_boy_fat. Just "my next one"