Loose objects

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In my experience, NO. pressure inside a closed vessel acts on objects inside in a uniform manner for the most part, I.E. the surface of the liquid is under as much pressure as any items floating in it. The one exception to this is items that float only because of trapped air bubbles. Pressure shrinks the bubbles, sometimes causing the items to sink. But if you really want stuff to go all the way to the bottom of your castings, overfill them and use something over the top to mechanically hold them down. IE, fill the mold with your items, pour resin to cover add a few more items and tape a popsicle stick or something like that over it. then pressurize to minimize air bubbles trapped by the items.
 
Whether a solid object floats or sinks in a liquid depends on the relative specific gravities or densities once the surface tension on top of the liquid is broken. This is true under pressure or vacuum. Objects with densities greater than PR (which is about 0.9 to 1.0 gm/cc) will sink and object with densities lower than PR will float on top. IF the densities are the same, the object will remain in the liquid where you last put it.
 
BRobbins629 said:
Whether a solid object floats or sinks in a liquid depends on the relative specific gravities or densities once the surface tension on top of the liquid is broken. This is true under pressure or vacuum. Objects with densities greater than PR (which is about 0.9 to 1.0 gm/cc) will sink and object with densities lower than PR will float on top. IF the densities are the same, the object will remain in the liquid where you last put it.
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I THINK he said no.:wink:
 
BRobbins629 said:
Whether a solid object floats or sinks in a liquid depends on the relative specific gravities or densities once the surface tension on top of the liquid is broken. This is true under pressure or vacuum. Objects with densities greater than PR (which is about 0.9 to 1.0 gm/cc) will sink and object with densities lower than PR will float on top. IF the densities are the same, the object will remain in the liquid where you last put it.
Click to expand...
So in other words, some will and some won't.:)
 
Thanks...pine cones don't float because they can be wedged in a mold. It's little seeds that are a problem. I suppose I need to build a mold with higher walls and then have a piece a hair smaller to push down over the top like a lid.
 
workinforwood said:
Thanks...pine cones don't float because they can be wedged in a mold. It's little seeds that are a problem. I suppose I need to build a mold with higher walls and then have a piece a hair smaller to push down over the top like a lid.
Click to expand...
Sounds like a complicated way of doing what wax paper and a weight will do.
 
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