How much for a 100g lump of Tungsten?

ISTR there are several tungsten alloys of different densities available for weights. 100 grams of "tungsten" darts would be cheaper than this.

I suspect that depleted uranium might be cheaper; if you can get hold of it!

MMm. What are fishing weights made3 on now? You might be able to cast them in resin and grind the thing down to the exact weight.

Does it really need to be W? Would lead do - just over half the density, so cube root of 2 times the size in each direction.

And lead is easy to cast.

As a guide:

Thomas Prufer

here is interesting

Depends.

Eg, for just the machining, in lots of about 10, excluding the cost of the bar, you could probably get some not-fool here to cut a 20mm pure tungsten bar into 20mm lengths, drill and tap, finish nicely, for about £15-20 per. Machining pure tungsten is a sore-headed bitch.

That would probably drop to about £8 per if a machinable tungsten heavy alloy, density ~ 17.5g/cc, was used instead of pure tungsten.

Of course that does not include the cost of the bar - which is highly variable in small lots, probably about £8-40 per.

Another possibility is casting tungsten powder in epoxy or similar. Tungsten powder is readily available at about £7-8 per 100g, epoxy is cheap, casting is easy - though the density will be only about 13g/cc max, and probably less.

A third possibility is sintered tungsten powder alloy, cast/sintered in shape. Mix W powder with a fine nickel braze powder like nicrobraz 30, ram into moulds, induction heat. Very strong, density up to about 16 g/cc.

-- Peter Fairbrother

Thanks Peter and all,

Casting tungsten it is then :-)

Hmmm...

(Poor Dogs!)