[ExI] horseshoes, was: RE: i predict chaos

spike at rainier66.com spike at rainier66.com
Wed Jan 5 20:53:19 UTC 2022



From: extropy-chat <extropy-chat-bounces at lists.extropy.org> On Behalf Of Adrian Tymes via extropy-chat
Sent: Wednesday, January 5, 2022 10:07 AM
To: ExI chat list <extropy-chat at lists.extropy.org>
Cc: Adrian Tymes <atymes at gmail.com>
Subject: Re: [ExI] horseshoes, was: RE: i predict chaos


On Wed, Jan 5, 2022 at 9:23 AM spike jones via extropy-chat <extropy-chat at lists.extropy.org <mailto:extropy-chat at lists.extropy.org> > wrote:

As I was typing a reply, an idea occurred to me.  Perhaps you have seen someone make a sandcast something at home, using molten aluminum.  You make the model out of a kind of specialty wax, then you pack around it with a fine-grained sand mixed with a specialty silicate infused ceramic epoxy stuff, let that harden, then pour molten aluminum onto the model, the wax melts and flows away, chip away the mold and there’s your aluminum thing the same shape as the wax model. 


OK, well I suppose one could make a horseshoe that way, but another idea would be to make your model out of tin/lead 37/63 eutectic, as used in the electronics industry for solder.  That way the model would be soft enough to work with a hammer without making all that racket that hot steel makes when you work it and it would still be rigid enough to do the kinds of fit checks and such that the modeling wax isn’t strong enough to withstand.  Example: tap a threaded hole in the tin/lead model, that might create a workable threaded hole in a sand casting.


When your cast sets up, Turn the casting upside down, put it in an ordinary propane webber grill full blast, let the metal melt and flow out since it only needs to get to 180C.  rig up a homebrew blast furnace with a leaf-blower and charcoal, with the structure made of those interlocking garden-wall stones, where you substitute metal pins in place of the plastic ones to hold them in place.  


Now you have your horseshoe shaped cavity (or cavity shaped like a car part (such as an adapter plate)) in your sand cast, your crucible of molten iron, ready to pour.  Hmmm… pretty expensive horseshoe perhaps.  But we would have fun rigging up the stuff we would need.


So here's another idea.


Start with my old programmable shape array - https://patents.google.com/patent/US6487454B1/en - pressing a disposable surface coated with something that hardens with electricity.  (I hear that a paste of corn starch + silicone oil hardens up to a consistency similar to concrete with 12V @ 500 mA.)  Press it into the shape of the mold you want (as designed in some CAD tool), apply electricity, remove the array (since it might not stand up to high heat), pour the molten iron, wait for it to cool, cease applying electricity so the mold becomes soft, and remove the mold…




Now yer thinking Adrian!


Before we do that however, we aughta get a 3D printer, make something, get one of those kits people used back in the olden days when kids had hot rods and were sand casting custom pistons (note to our younger audience: a “hot rod” is a car or bike with a modified… (oh never mind (we had fun.)))  I suppose we can still find that stuff somewhere.  


We make a model on a 3D printer, pack the ceramic mud around it, heat cure the mold in a webber grill, pour in the molten iron (or we might even be able to use steel) on top of the plastic model which boils away, you get an iron whatever it was we printed.  Adrian in your case since you are in the space biz, we use aluminum which is easier to work with than molten iron.


Full disclosure: I haven’t done this procedure myself.  I have seen it done only, but since I haven’t actually done it, I assume that I suck.




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