Cold Casting Metals (from a 3D printed master)?

[ednadolski]

Has anyone ever tried cold-casting metal parts?

/>https://www.smooth-on.com/product-line/metal-powder/
https://www.smooth-on.com/products/nickel-silver-metal-powder/

I'm thinking perhaps of doing detail parts this way, or possibly even something like turnout frogs that could be used with hand-built turnouts.  Could be based upon a 3D printed master, but doesn't necessarily have to be.

For a frog, I guess one could use a nickel-silver powder, tho it is not clear to me how other properties such as conductivity, solderability, or paintability would come out.


Ed

[JeffB]

For something like turnout frogs, why not just use castable printer resin and have someone cast it in Nickel silver?  There are places that do that.  A modeling friend of mine uses Precision Scale for his brass casting, and they do nickel silver parts too.

I've had a few parts done in brass that way (I didn't print them though).  I've also done parts in 3D printed stainless steel, which has a really rough finish, so if you can't or don't want to sand and buff the surfaces of the print, is probably not the best way to go.

Jeff

[Chris333]

Fast Tracks 3D prints crossing frogs and casts them in nickel.

[Lemosteam]

This process works really well for small flatcars too using tungsten powder, just like the video.  Just adds a ton of weight to the casting (respectively).  I just hate mixing chemicals, I always find a way to screw it up.

Bubbles are the nemesis in this process, so a vacuum chamber would really be best.

[Rasputen]

Could you ever solder something that is made from 50 percent resin?  It seems like the heat would damage it.

[thomasjmdavis]

This process works really well for small flatcars too using tungsten powder, just like the video.  Just adds a ton of weight to the casting (respectively).  I just hate mixing chemicals, I always find a way to screw it up.

Bubbles are the nemesis in this process, so a vacuum chamber would really be best.

I am tempted to try casting underframes using this method.  Would save a lot of bother trying to find locations for weights in a variety of cars.  Where does one find tungsten powder?

[Lemosteam]

I am tempted to try casting underframes using this method.  Would save a lot of bother trying to find locations for weights in a variety of cars.  Where does one find tungsten powder?

Google is your friend.  It is very expensive at around $29 per half pound.

[peteski]

Fast Tracks 3D prints crossing frogs and casts them in nickel.

Could they be using the lost wax investment casting technique?
A 3D "tree" with parts is printed using wax, then it is encased in investment (type of a clay).  When the molten metal is poured in it burns off the wax and fills the leftover cavity.  This is usually done using  centrifugal casting method. This is the same technique that has been used for many decades for making jewelry, and also for small brass detail parts (like horns) used on brass models.

I doubt any of the metal filled resins will be conductive enough to be used as electrically live frogs, and as others said, likely difficult to solder.  Plus those parts would likely be softer than the adjacent nickle-silver rails, so repeated abrasive track cleanings will wear out those parts quicker than the railhead. 

[Chris333]

It is a 3D dental printer that prints wax. The wax is burned out to make a casting:

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Just like Shapeways "brass" is first printed in wax and then cast.

[peteski]

It is a 3D dental printer that prints wax. The wax is burned out to make a casting

Just like Shapeways "brass" is first printed in wax and then cast.

Well then, it is what I said: lost-wax investment casting.
https://en.wikipedia.org/wiki/Lost-wax_casting

[Chris333]

Just don't know if it will work "cold". 

[Lemosteam]

Electro-plating may be an option for the (cold) casting.

[peteski]

Electro-plating may be an option for the (cold) casting.

That method (pot-metal casting, copper and finally nickel-silver plating) is used on Atlas C55 frogs and after multiple track cleaning the plating gets removed.