Capt Nemo
Bronze Member
I finally got around to building a grease table.
The table is similar to a miller table, only in the first 6" it's slickplate, then a 1/4" drop onto the grease section. I built the grease section to be removable for addition and removal of the grease. The active side is .030" below the sides, so that a scraper can level the grease during application. 10 stainless screws hold the platter on the table. I'm using the same 180 GPH fountain pump as my miller table, and the leveling bar from it as well. I built the rear support at a higher angle than my miller table as water testing gave better coverage at the high angle.
For testing I used Vaseline for the grease. I was having a problem with the scraper pushing the Vaseline down the table giving poor coverage. I had to smear the Vaseline on, so it didn't give a nice smooth surface to the grease. Vaseline and acrylic don't stick very well to each other. The Vaseline was also somewhat crystalline, so it might have been too cool to spread easily. I was also surprised at how much I needed to get the .030 thickness. I did have to play with the angles a bit to get good coverage of the grease as the ridges would cause water problems. I had one area that water just wouldn't cover unless it was channeled by a sand slick. I ran a mix of miller table tailings from beach sand and stream material that I knew would have at least some gold. The slick plate worked fine and as I was applying material, I did see at least two pieces of gold sliding down. The drop catches material behind it like would happen in a normal sluice, and the irregular surface of the grease also caught and held material. But otherwise, all the black sand left the greased area. This machine does run a lot faster than a miller table. After running, I checked the table at 10X and found about 12 pieces of gold stuck in the grease. I didn't find any gold past the first 2" of the grease, so it looks like a good capture technique. I haven't panned out the tailings yet, just too busy packing up EAA. The amount stuck to the table would be about the amount needed for fanning in a pan. The only bad part is the separation from the grease. Heat the grease till melted, pour off, then clean with alcohol.
I'll wait until I have a few buckets of table tailings before running the grease table. Even though it's faster than a miller table, there's less work after the run to get clean gold.
Here's the table.
Near center is a piece of Superior beach gold (flat), and in the upper right by the bubble there's 2 pieces of Nugget Lake gold (rounded). Both are within an inch of the drop on the table.
The table is similar to a miller table, only in the first 6" it's slickplate, then a 1/4" drop onto the grease section. I built the grease section to be removable for addition and removal of the grease. The active side is .030" below the sides, so that a scraper can level the grease during application. 10 stainless screws hold the platter on the table. I'm using the same 180 GPH fountain pump as my miller table, and the leveling bar from it as well. I built the rear support at a higher angle than my miller table as water testing gave better coverage at the high angle.
For testing I used Vaseline for the grease. I was having a problem with the scraper pushing the Vaseline down the table giving poor coverage. I had to smear the Vaseline on, so it didn't give a nice smooth surface to the grease. Vaseline and acrylic don't stick very well to each other. The Vaseline was also somewhat crystalline, so it might have been too cool to spread easily. I was also surprised at how much I needed to get the .030 thickness. I did have to play with the angles a bit to get good coverage of the grease as the ridges would cause water problems. I had one area that water just wouldn't cover unless it was channeled by a sand slick. I ran a mix of miller table tailings from beach sand and stream material that I knew would have at least some gold. The slick plate worked fine and as I was applying material, I did see at least two pieces of gold sliding down. The drop catches material behind it like would happen in a normal sluice, and the irregular surface of the grease also caught and held material. But otherwise, all the black sand left the greased area. This machine does run a lot faster than a miller table. After running, I checked the table at 10X and found about 12 pieces of gold stuck in the grease. I didn't find any gold past the first 2" of the grease, so it looks like a good capture technique. I haven't panned out the tailings yet, just too busy packing up EAA. The amount stuck to the table would be about the amount needed for fanning in a pan. The only bad part is the separation from the grease. Heat the grease till melted, pour off, then clean with alcohol.
I'll wait until I have a few buckets of table tailings before running the grease table. Even though it's faster than a miller table, there's less work after the run to get clean gold.
Here's the table.
Near center is a piece of Superior beach gold (flat), and in the upper right by the bubble there's 2 pieces of Nugget Lake gold (rounded). Both are within an inch of the drop on the table.
