Oct 23, 2011 · Since we cupel 84 samples at a time, it is impractical to load the lead buttons in to the cupels while they are in the furnace. We place the buttons into the pre heated cupels then load that to the furnace.

Sep 9, 2009 · Typical bone ash mixture for making cupels this mix will make about 250 1 1/4 inch diameter by 1 inch high cupels 9000 grams bone ash 1000 grams portland cement 2500 ml of water When the mixture of ingredients is compressed into a cupel it will show no traces of liquid water. Dry in areas of low humidity for 2 weeks, 4 weeks in more humid areas. source; Fire Assaying for Gold & Silver by ...

Nov 5, 2023 · Hi Moving away from all the harsh acids until I get a fume hood, I've decided to cupel for the moment. There seems to be a bunch of sizes. i.e. 7AL Mabor, 7X Mabor, 8A Mabor, etc Can someone explain what these mean? Thanks Kenzo

Apr 29, 2020 · The lead oxidizes base metals into a slag and when the volume of the lead after it is driven by oxidation is about half, the remaining lead and slag is poured into a assay cone mold, deslagged, and that lead alloy chunk is cupelled in a bone ash cupel. This is an assay scale procedure not for large lots.

Jun 2, 2010 · Since I do small lots and I keep breaking melting dishes. I want to melt in a magnesite cupel hopefully this works since I just ordered some, if it is ok how much silver or gold will I be able to melt. I usually only do about 5gr batches. …

Nov 4, 2021 · ideally you want to cupel at 1750°F and your melt furnace exceeds that temperature with little ability to control it closely. You need more lead to effectively cupel the brazing rod for a 1 gram sample try 15 grams of lead.

Nov 5, 2023 · To cupel properly, you need 2 components for the reaction to happen properly. The first is temperature, 1850 F., the second is a bit of atmospheric Oxygen. The conversion of Pb (Lead), to Pb oxide. Metallic Pb will not absorb into the cupel, only PbO will absorb into the cupel, bringing other base metal oxides as well.

Jan 27, 2023 · Since this thread came back up, I got my little cupel mold out and leached then dried some wood ashes. I mixed the wood ash 50/50 with Portland cement. I moistened it using the liquid mix from a previous post and quickly make up half a dozen tiny cupels. They were supposed to be baked...

Jul 28, 2011 · For directly cupelling bullion, most all of the better books recommend .5 gram samples and 10-15 grams of lead, for the final assay. When running crucible fusions, I try to end up with about a 25-30 gram lead button, but that's a different deal than direct cupellation of the sample. The cupel composition can make a big difference.

Aug 21, 2013 · How long should need to Pre heat the cupel before the cupellation processes; temperature at 1065 degree Celsius While pre heating, is it necessary to open the door of the furnace by a little bit