OT: Large machinable spheres...

[Don Y]

On 8/7/2023 12:50 AM, Martin Brown wrote:

On 06/08/2023 08:53, Don Y wrote:
On 8/5/2023 9:00 PM, Lasse Langwadt Christensen wrote:
Steel would be too heavy. Aluminum might be too soft
(too easily marred)

Any other materials I can explore?

https://www.ebay.com/itm/144428340712 ?

That gives me an idea of what the sphere bitrex mentioned might weigh.

And, if \"stone\" proves to be the right option, then I can just
wait for the Gem & Mineral Show, this winter, to see what I can pick up
locally (let the seller come to me instead of the other way around)


Stones of that size would be expensive. Though sphere grinding machines for
making spheres of rock crystal and the like are big with crystal healers (and
glass spheres I think are available on eBay for a price).

If you are prepared to mess around a bit defect free concrete or U-crete might
be a good fit. The latter was a product that I thought never really took off
the way it should have done. Polyurethane bound concrete tough enough to do
instant repairs on runways (but AFAIK it sank without trace). Turns out it is
still around as an expensive flooring material.

https://www.master-builders-solutions.com/en-au/products/ucrete

How light/viscous is it? E.g., could I put some (*flimsy*) forms
*in* a mold to exclude the material from filling those portions
and then, after \"hardened\", extricate the forms -- exploiting the
fact that they were *just* robust enough to keep the material
from occupying those spaces but not sturdy enough to resist
being manually \"torn out\"?

[Keeping in mind that there could be several inches of material
sitting atop such a flimsy form]

Defect free concrete was strong enough to make car suspension springs out of
but processing again was fiddly and I think sank without trace.

http://concrete.ie/wp-content/uploads/2018/10/ultra-high-strength-concrete.pdf