# Drop caster?  What's it good for?



## AR1911 (Apr 4, 2014)

Bought some tools at an estate sale today, including something called a drop caster.
It's about 16" long, with a ceramic cup on the end. The cup has a sliding valve in the bottom which uncovers an orifice in the bottom to let out the molten metal. The valve is controlled by a trigger near the wooden handle.  The only printing on it is "DROP CASTER  PAT. PENDING"
I am wondering who uses such a thing, and for what.
The usual web searches don't help me much here.
Obviously it's for adding molten metal (low temp) to a mold, but it's not really a ladle.
Anyone have knowledge of this?


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## Terrywerm (Apr 4, 2014)

Keep in mind that this post is purely conjecture, and I may be way off base.

The drop casting design of this tool may have come about as a result of the fact that impurities in molten metal tend to rise to the top. At the same time, even when the dross has been removed, oxidation is constantly occurring at the top of the molten metal as well, more so with some metals than with others, resulting the constant creation of more dross or slag. Pouring from the bottom ensures the least contact of the metal with air, as well as keeping any dross out of the mold since it floats at the top.

Due to its size, it is obviously used only for very small molds. Small lost wax or lost foam castings would be a good example. Casting of small detail parts for model locomotives and such come to mind here. In use, preheating of the ceramic crucible would probably be recommended as well.


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## Cobra (Apr 4, 2014)

AR1911 said:


> Bought some tools at an estate sale today, including something called a drop caster.
> It's about 16" long, with a ceramic cup on the end. The cup has a sliding valve in the bottom which uncovers an orifice in the bottom to let out the molten metal. The valve is controlled by a trigger near the wooden handle.  The only printing on it is "DROP CASTER  PAT. PENDING"
> I am wondering who uses such a thing, and for what.
> The usual web searches don't help me much here.
> ...




I assume it it is the same. See attached video

http://vimeo.com/50108513/download?t=1396632458&v=119215989&


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## awander (Apr 4, 2014)

Another advantage of the tool pictured is that if the cup is full of molten metal, the weight of all that metal will help to force the metal into the mold. This can help fill the mold completely.

When pouring from a ladle, it is only the weight of the actual metal that is falling that pushes it into the mold.


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## Cobra (Apr 4, 2014)

awander said:


> Another advantage of the tool pictured is that if the cup is full of molten metal, the weight of all that metal will help to force the metal into the mold. This can help fill the mold completely.
> 
> When pouring from a ladle, it is only the weight of the actual metal that is falling that pushes it into the mold.



Because it is a liquid, the same applies to casting from this ladle, the only weight pushing the metal into the interior of the mold is that in the spru.


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## awander (Apr 4, 2014)

The weight of all of the liquid metal above the hole will be pushing on the liquid that is flowing through the sprue.

Take a 9" diameter x 2" high baking pan, and cut a 2" high x 1/4" wide slot in the side of it. Put your finger over the slot, fill the pan with water. Remove your finger and watch how far the water shoots to the side as it drains. It won't be very far.

Now take a bucket off the same 9" diameter but 12" or more high. Cut the same 2" high x 1/4" diameter slot at the bottom of the side of the bucket. Again put your finger over the slot, fill the pan with water, remove your finger and watch how far the water shoots to the side as it drains. It will spurt out a lot further at first, diminishing as the water level in the pail gets lower.

The same thing would apply if the hole were in the bottom off the pan/bucket. Higher pressure pushing the liquid out, as the amount and height of liquid above gets bigger.


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## Cobra (Apr 4, 2014)

awander said:


> The weight of all of the liquid metal above the hole will be pushing on the liquid that is flowing through the sprue.
> 
> Take a 9" diameter x 2" high baking pan, and cut a 2" high x 1/4" wide slot in the side of it. Put your finger over the slot, fill the pan with water. Remove your finger and watch how far the water shoots to the side as it drains. It won't be very far.
> 
> ...




Only way you are going to transfer that pressure to the mold is if the ladle is sealed to the mold opening.  You will get impact spikes as the liquid drops from a greater height.


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## Terrywerm (Apr 4, 2014)

Cobra said:


> I assume it it is the same. See attached video
> 
> http://vimeo.com/50108513/download?t=1396632458&v=119215989&



That link comes up with a page saying "We couldn't find that page." Are you sure that you got the link correct?

- - - Updated - - -

Found the right link:  http://vimeo.com/50108513


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## awander (Apr 4, 2014)

Cobra said:


> Only way you are going to transfer that pressure to the mold is if the ladle is sealed to the mold opening.  You will get impact spikes as the liquid drops from a greater height.



I think the molten liquid will be moving at a greater speed, due to the greater pressure above it. This, in turn will impart a greater pressure to the interior of the mold as it comes to rest.


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