QuestionQUESTION: Hi Thomas how are you?
I wanted to know if you can help me with a problem I am experiencing during melting sterling silver (about 1 or 2 kgs). I am facing a problem when pouring the molten silver into the cast iron mould, to make it a brick. The entire amount can't be poured at one go to fill the mould since it will splash out. So I pour a little, wait for a second or two and then pour the rest of it in. After the silver solidifies, and it is taken out of the mould, one or 2 big air bubbles are found.
I would really appreciate it if you can suggest something by which this air bubble problem can be avoided.
Thanks in advance.
Stu
ANSWER: Stu, my experience is to pour the entire ingot at one time. Any time for the metal to cool between will result in a porous or otherwise defective ingot and if milled the top and bottom parts may come apart.
If heat can be kept on the silver the entire time, a slower pour can be made and pour all the metal into the mold. That is my best advice. This may require an assistant to hold the torch. If the metal is melted in a crucible in a melting machine, still, the pour must be all at once and uniform in pouring.
This is my best advice. Not seeing the ingot mold you work with, I cannot offer further advice. Perhaps the mold is too shallow for the pour of the metal and a larger mold is needed.
I do wish you the best in this work. I hope you are able to pour a uniform and consistent ingot of the silver. The amount of silver you are pouring is quite large. Have you considered using several smaller ingots?
Best wishes with the pouring. God Bless and Peace. Thomas.
June 9, 2008 8:32pm
---------- FOLLOW-UP ----------
QUESTION: Hi Thomas, thanks for the prompt reply.
Applying heat while pouring the silver is a good idea. Will try it today. I have considered using several smaller ingots, but I need a large brick in order to extract large sheets of silver.
Thanks a lot for your help
-Stu
Answerfollow-up to Stouvant.------------------------------------
We had the need for a very large sheet of high karat gold at one time and this was done by placing the flattened gold sections on heat proof table and with torch, fusing the edges together. Of course, with silver this would be very, very difficult.
Honestly, it sounds like you need the heat on the silver while creating a slower and more controlled pour. Otherwise, you certainly need a larger mold.
In the 1700's, some silversmiths would place a layer of fine dry sand on a flat surface and pour the silver across the sand. Then will tedious work, clean the silver and hammer all into a sheet suitable for forming tableware items. I do not suggest this method and I have not used it.
Thanks for the follow-up. I am glad you got back. Also, when you follow up, if I do not answer, the allexperts machine thinks I have not answered your question! This will clear the board of the question. I am glad you did respond and again wish you the best in forming an ingot large enough for the sheet of silver you need.
God Bless and Peace. Thomas. June 9, 2008 9:05pm
