Reddit mentions of Novacan Black Patina for Solder

I would suspect the detail loss near the pouring cup might be due to you forcing it with the wood. The zinc is likely solidified on the surface touching the mold, and as you push down with the wood you are causing it to flex that solidified area, and actually decreasing the detail. You could try one or all of these relatively cheap, quick and easy solutions to see if it would help.

Wear the proper safety gear (faceshield, leather and cotton clothes etc) when doing this as these bit of advice could increase your risks for getting molten metal on yourself.


1: Preheat the mold: Try heating it up the mold in an oven. Not sure what your silicone mold formula is but even heating it to 100-150 C would probably help. This might actually increase the lifespan of the mold as the low thermal conductivity it molds can cause uneven expansion and cracking because of it. If you put it in a small metal container and buried it in dry sand so just the pour cup was showing, then heat it all up, it might even work better as the larger thermal mass of the entire container would help keep the metal molten longer.

2: Building up a larger pouring cup with clay. A larger mass in the pouring cup might solve the detail issue because it will provide more hydraulic pressure on the metal. Mix 2 parts fire clay (though most any water based clay would work) with one part sand, and use that to form a funnel that would hold maybe an additional 2-3 tablespoons of molten metal. Again burying this is a metal container with sand to support the clay pouring cup might help. Note safety gear is extra important here: This could lead to a popping and spraying of the metal due to steam from the moisture in the clay, you could use straight clay for this also, but the sand decreases the likelihood of trapped steam. It probably wont happen, but putting hot metal in the neighborhood of water, there is alway the chance.

3: The old bucket method of centrifugal casting. Put mold in steel bucket with a sturdy handle, fill the bucket with sand. Fill the mold with metal then quickly pick it up and spin it around over your head several times. This video shows the technique and explains how it works. A good 10 15 second spin would likely be plenty. I am sure I don't need to point out the dangers here, I suggest practicing a few times with a bucket of sand to get the feel. This is a technique used for centuries to get good detail in small castings.

You could combine all these to help get a good casting, but I would try the larger pouring cup, and the bucket spin casting first. The Bismuth will help with casting details. If you want to try the Zamak again, I would preheat the mold, and the higher heat will decrease the mold life, but you still should be able to get a fair number out of a good silicone mold.

As for plating, there are some options. Home electroplating with copper is fairly easy, and there are a few methods, this covers the basics of one. For the copper sulfate, I use root killer, which is granulated copper sulfate, and mix a fairly weak solution. This means it will take longer but the coat will be more even. Move the object while you are plating, you will get more even results. I have gotten fairly nice results on cast aluminum with this method, but never tried it with tin.

There are other methods out there for plating with other materials, including commercial kits and such, a google search will help find them. As for artificial aging, you could try Novacan Black Patina then polish it back with some steel wool for an aged tin look. Or go simple, Black shoe polish is a good approximation.

I put this in a spray bottle, and dowsed it pretty good, and it turns the metal black almost on contact, but i guess there might have been some oils on the mod, even though i was wearing gloves, and it just didn't lay as thick on the edges and other spots so when I sanded the clear it just went right through.