Neil…If you have a kiln, put the mold into it until you are ready to pour. Then you will need even more hands. An important step prior to rolling or drawing is to remove all the sharp edges and any flashing. Then you should forge the ingot. This changes the crystal structure and makes the metal more conducive to drawing or rolling. This may be a challenge for a 200 gram ingot. I just did a 40 gram pour today the same way that I always have. Following is a description of my process.
Make sure that you have a fire extinguisher and smoke alarm nearby and open a window or start an exhaust fan.
Check the scrap for magnetic material that doesn’t belong there. Put it into a container that you can seal and shake it with a small magnet.
Do a visual for anything non-magnetic that doesn’t belong there.
Set up you flame proof area and collect all the tools and materials that you might need during the process so that they are nearby. This should include as pair of tweezers or some kind of metal probe in case you need them.
Open your mold and oil the surfaces that might be in contact with the melted metal.
Burn off the oil until it smokes. Be sure that any surface that has condensation on it dries off. You don’t want melted metal and water vapor together in an enclosed space.
Assemble the mold if it needs to be.
Check you crucible to make sure that it doesn’t have anything in it that shouldn’t be there.
Put the crucible and mold next to each other and heat them together.
Once the crucible is heated a bit, add the scrap a little at a time.
Sprinkle in some Borax
Once the metal melts, stir it with a graphite rod to mix it well and collect whatever will stick to the rod. I have thought that everything was melted only to find a piece of fine silver that hadn’t reached the melting point for fine silver. So take you time and stir until everything is melted and mixed.
Go back to the mold and heat it, then back to the crucible.
Now the hard part. Point the flame at the melt, but also the path in the crucible that it will follow to get to the mold. Keep moving the flame back and forth and when you are ready, do your pour.
Real important - have a couple old cooking mitts handy to open the mold if you have to touch anything that was heated during this process. I learned that from experience.
Open the mold if it is closed.
Remove the ingot and put it on your anvil for a while before you quench.
Grind/sand off any flashing or raised bits.
I am not sure about the pits. As long as they aren’t sharp, leave them. My only concenrn is that they may be big enough to roll over and create a bur later in the process. I have never had pits like you describe and I worry that there may have been foreign material in the bottom of the mold or it was slightly damp.
Forge the ingot from one end to the other on all sides moving in the same direction on each side.
Anneal, quench and dry.
Repeat the forge, anneal, quench dry process a couple times. You are changing the crystal structure prior to rolling or drawing.
Start your roll (either flat or square to eventually be drawn into wire)
I usually anneal, quench, dry after each mm of reduction. That’s one turn on my mill.
When you get to where you want to go, anneal, quench, dry and then mark the stock with its thickness or gauge and what type of metal it is. Sterling and fine can look a lot alike.
If I have made sheet and I know that it isn’t going to be reduced anymore, I will often sand it to remove firescale and prepolish the piece of sheet. It’s a lot easier to do this to one big sheet than a bunch of little pieces that you have spent time cutting, sawing, forging or whatever only to change the shape to remove firescale.
I am sure that I have missed a step or two, but this is pretty much how I recycle scrap.
Good luck…Rob
