Michel
off to a rocking start
Member since January 2022
Posts: 13
|
Post by Michel on Mar 6, 2022 8:18:46 GMT -5
Hello everybody,
I would like to know if it is a good idea (Or a stupid one) to tumble (Rotary) rocks of different hardnesses (Between 6 and 7 1/2) during step 3 and step 4 as long as they have about the same size.
Also, during step 1, for a hardness between 6 and 7 1/2, should I put ceramic media or pellets as cushioning even if I have enough rocks to fill the barrel. Some people told me that it was useless, other that it "could" help.
Thank you,
Michel
|
|
quartzilla
Cave Dweller 
Member since April 2020
Posts: 1,238
|
Post by quartzilla on Mar 6, 2022 9:40:12 GMT -5
I’ve had a random softer stone like feldspar in with the quartz stuff and it made it thru ok but that was using some plastic beads in the rotary with it.
|
|
RedWingTumbler
having dreams about rocks
Member since April 2021
Posts: 65
|
Post by RedWingTumbler on Mar 6, 2022 9:59:20 GMT -5
You don't need any additional media in step 1, just try to have a variety of sizes, and keep your barrel about 3/4 full. The idea is to fill the gaps between big rocks with small rocks to better get the grit into contact with all surfaces. I have mixed Mohs 6 & 7, but it requires a keen eye on the softer rocks to make sure they don't grind away in step 1. Mohs 6 generally has to move to stage 2 after a week in stage 1, whereas Mohs 7+ might take more than a month. You also might want to consider how fragile the rocks are. For instance, feldspar is Mohs 6, but fractures very easily & quartz is Mohs 7, but is prone to bruising. For stages 3 & 4, I have occasionally had Mohs 6 & 7 together, but I will add up to 50% ceramics to keep the rocks from hitting each other. Ceramics are hard, but light, so they move the grit (or polish) to the rocks without damaging them. I've also done stages 3 & 4 with no added media, but lots of small rocks. That works best with rocks that are both hard & durable, like jasper & agate.
|
|
|
|
Post by rmf on Mar 7, 2022 6:48:25 GMT -5
Michel There are many different recipes here. The inclusion of softer stones in with harder becomes more problematic with the increased diameter of the tumbler drum. For a Lortone 3A mixing harder and softer stones can be successfully done but as you go to the 12# drum the larger diameter means the softer rocks fall farther and are prone to more damage. This results in a poorer polish. I have never been a proponent of fillers but I do use them and there are specific use cases. For agates and jaspers in the 7 hardness range I prefer to tumble two batches in coarse and then mix them to maintain 75-80% full tumbler barrel. The problem with fillers is if you put them in then you have to take them out which takes time. I typically only use fillers in the polish. Tumbling is not like baking a cake where you need to strictly adhere to the recipe. There may be several recipes to tumble a rock and get a great polish. It is always good to start with a known good recipe and get a good understanding before experimenting.
|
|
