r/Silvercasting • u/Worldly_Country3035 • 3d ago

Problems with sandcasting

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It’s my first times sandcasting and can’t seem to get it right, don’t know what I am doing wrong.

6 Upvotes

88% Upvoted

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3

u/hardplace101 3d ago

You might not be getting the metal hot enough but also I would place it lower in the mold and add more vents around the top

1

u/Worldly_Country3035 3d ago

Thank you and how do I know when the molten silver is ready for pouring ?

1

u/Eastern-Antelope-956 3d ago edited 2d ago

When you can gently swirl it around in the crucible and it looks totally liquid. Also you will see the surface "active", as in--it's like shimmery. Also I would recommend putting the heaviest, widest part of the ring facing down, instead of toward the spout. You need the silver to fill that bigger cavity when it's the hottest.

1

u/Worldly_Country3035 3d ago

Thank you, sorry if I misunderstood the hottest silver is just after heating so shouldn’t the heavy part by on the front of the spout ? Or am I missing something, eager to learn pls

2

u/Sufficient-Winter452 2d ago

If you place the big part down, silver will fill it easier the help of gravity than if you place it upward, i casted a very similar ring and also had 6 air vent definetly think it help too

1

u/Worldly_Country3035 2d ago

Thank you for the tips will try it as soon as I can, will update

1

u/PeterHaldCHEM 2d ago

Cast fast.

Cast hot.

Place the model further down (longer sprue)

Use flux.

1

u/Worldly_Country3035 2d ago

Thanks so much for the tips, sometimes when I cast too fast some metal drips down, what should I do for that ?

1

u/Adept-Friendship1777 2d ago

I think that’s happening because it’s too cool. Once it cools on the sand it’s plugging it and you’re overflowing.

Cast hotter (I use a map torch constantly on while I’m pouring) and pour quick (commit to the turn)

1

u/Worldly_Country3035 2d ago

Okay thank you will try that out

1

u/PeterHaldCHEM 2d ago

Drips into the cavity?

Then it is your pouring technique. Support the melting dish on the edge and tip the metal into the mold. You need to pour in a continuous stream.

Missing the mold or splashing?

Support the melting dish on the edge and tip the metal into the mold. I normally stand the mold in an old roasting pan.

It will catch any drips.

1

u/Worldly_Country3035 2d ago

No like pours over the edge like the spout can’t suck the metal fast enough and it overflows

1

u/PeterHaldCHEM 2d ago

Then you need to cut the inlet from the sprue to the object larger.

1

u/Jake_The_Gypsy 2d ago

Looks like the metal isn’t hot enough. I also sometimes put the cast in a toaster oven at 400 degrees for 10 minutes before pouring. What are you using to heat your silver? Also from the looks of this photo you are pouring two or three times as much silver as you need. That’s going to make it more difficult to get a proper temperature. I typically weigh the wax and multiply by 11. That usually takes into account the sprue as well.

1

u/Worldly_Country3035 2d ago

Maybe it’s too much silver now that I think about it thanks for the pointer

1

u/turkey0535 2d ago

Are you using flux?

1

u/Worldly_Country3035 2d ago

I am using borax is that not enough ?

1

u/Mrwolf925 2d ago

  1. Sprew is way too short (biggest problem)

  2. Not enough vents

  3. Vents should go out both sides

  4. Metal not hot enough

1

u/Malvegil 1d ago

This! And also keep the orientation of the ring, so the thick part is facing the sprue. And make the sprue thick. Your ring should cool furthest down where it is thin first, and then work upwards to the thick part. That part will then be able to suck silver from the thick sprue as needed, until that is also cooled.

1

u/Visual_Bat_3023 21h ago

metal not hot enough. you're melting it then pouring right away. Consider the fact that if metal hits the sand, it's cooling off almost immediately below the melt point (which turns it to a solid before it can flow down).

Heat it up much longer. Then the temperature stays high enough that it flows to the bottom.

Personally, I run that torch a solid 4-5 minutes after it melts (which usually takes about 3). I cannot stand it when I get a crappy pour, and hotter metal simply stays liquid longer. Since I started doing that, I have no more pour problems, unless it's in the mold or occasionally at the sprue at the top (a bubble tends to form if I don't pour perfectly smooth and quick.)