How To Polish Rocks With A Dremel (Step-By-Step Guide)

I get asked quite often if a Dremel is a good tool for polishing a rock. So today I'm going to polish a rock with a Dremel and we'll find out. I'll keep track of how long it takes and we'll look at the costs involved and then hopefully we'll make a more informed decision if you want to go that way or do something like buy a rock tumbler. So the materials we're going to need are obviously a Dremel. This is the 100 model. I think this is the cheapest one they make. I'll be trying that as well as this one. This is the 4000. I think that's one of the more expensive models they make. I have a flex shaft on this one which is another added expense but this will keep the motor away from the water that I'm going to be using. Although I'm not going to have the Dremel down in the water and I don't really think it's a danger to have this close to the water but you'll have to make your own decision about that. Other things you're going to want is definitely a respirator. That's what I'll be using or if you don't have one of those at least wear a dust mask. There is going to be some dust. I'm going to try to keep it down by using the water. I'll dip the rock or whatever I'm using to grind with in the water. That keeps the tools cool and the dust down. You need ear protection or at least you should have ear protection. I have AirPods Pro. These are the second generation and these are rated as hearing protection plus you have entertainment while you're working. And then you're going to need some different grinding things. We'll look at those closer when I start actually grinding the rock. The rock I've chosen to do is this pudding stone. It's a pretty little pudding stone. It's pretty small because I don't want to be here all day doing this. But I think that's a pretty good representative rock. It's fairly hard. It's not as hard as an agate. I don't know exactly what it is in the Mohs scale but I would guess somewhere between six and seven. So I didn't want to do a super soft rock like a Petoskey stone because that's not really fair because that'll get done a whole lot quicker than this rock would. All right. Well, let's get started. Here's what I bought for grinding and polishing. These came in a set with 50 grit and 116 grit. 116 seems kind of specific but that's what it said. These scare me a little bit. Most diamond tools you don't have to worry about cutting your fingers on them. On my calving machine I can touch any of those wheels while they're running and it doesn't hurt my fingers at all. Even my trim saw I can put my finger on it while it's cutting a rock and even though it's cutting a rock it won't cut my finger. That thing though I think might draw a little blood. So I've got a pretty small putting stone here and I'm going to have to just be really careful not to hit my fingers. We'll see what happens. Then for polishing I got these. They look like this on the other side. They go from 50 grit up to 10,000 grit. They also stick on a little Velcro thing that goes in the Dremel. I've done this before with these things. These are just little thin polishing pads that also go on a Velcro thing. This one's 2,000 grit. I didn't have a big complaint about the ones that were the higher grits but the more coarse ones like the 50 or 80 grit, they really didn't do the job very well and so I'm hoping these do better. The reason I bought these is because they look just like these bigger polishing pads that I've used on my bigger grinder and these work really well. So I'm hoping these work the same way. We'll find out here in a minute. All right so let me get my safety equipment on and we'll start things up. Oh one piece of safety equipment I didn't mention is safety glasses so you want those also. All right I have my scary bit installed, got my rock ready to go. The goal here is just to make sure this rock doesn't have any low spots when you're done. So you can see right there on the top there's a low spot. I'm going to take this down or this down over here or a little bit of both. I'll probably just take that down and when you get done there shouldn't be a low spot in the middle. If you look all over this rock it's just bumpy, it's rough. So some spots are lower and some are higher so you're going to go over the whole thing and just smooth it out. What you're going to have to be careful of with this bit is not dig in this corner or this corner. You want to work in the middle here. So when I'm doing this I want to go like this. I want to avoid digging in like that because that's going to leave a gouge in a hurry. So try to keep the rock so that it's like that. After about six minutes of grinding this is what it looks like. I did notice it was starting to chip in a couple places, the jasper especially. And so I think it's time to go to a finer grit. I'm running my Dremel at 15,000 RPMs which is on the slow side, it goes up to 35,000. So I'm just doing that based on, that's what I picked. There's no documentation that came with these bits at all telling you how fast to run them. So it's on to the next grit. This is 116 grit. I'm switching to these little polishing pads. This is 50 grit. It's actually the same grit as the first one but you can see that that's not going to be digging in like the first one did. So let's see how this works. I just turned this on at 15,000 RPMs and the pad just flies right off, the Velcro doesn't hold it on. So I was going to try the other Dremel and that's exactly what I was going to try the other Dremel for is to see if those would stay on at high speeds and I can tell you right now they don't. So I'm down at about 10,000 RPMs with this one. I didn't go over the entire surface of the rock with that one since it was more coarse than the second one I used, but I just looked for any spots that were noticeably low and ground them out with that. It was pretty aggressive. I'm impressed with that one. So I'm on to 100 grit next. Thought I'd dry it off this time so you could see how it's looking dry. Much smoother. I did go over the whole thing that time, took about four minutes. So next up it's 150 grit. I'm going to dry this off between every stage now. Took three minutes that time. And by drying it I think you can see any imperfections a little better. Like that little thing and that little thing. I might take those out. Maybe right there. So I'm going to spend another minute on this. Let's call it four minutes. And then I'm going to go on to the next step. Now I decided those are not spalls. Spall is like a little shallow fracture. I think they're actually clasts in the rock. Whatever they are, they're not coming out easily so I'm just going to leave them. So the next grit is 300. And another little tip I have for you is line up all your grits in order and take a picture of them because each color is a different grit and eventually these, at least on my bigger pads, as you use the Velcro and you tear it on and off, these numbers get harder and harder to read. And if you can't read them, they're kind of useless because you've got to do them in the right order. So just take a picture and then you'll know. Or either that or jot down all the colors and the grits if you want to do that, but a picture is really easy. Not looking a whole lot different between stages. But the next one here is 500. Still not seeing a whole lot of change. I think it's getting a little smoother. Here's 800 next. Next up is 1000. That last little polishing pad was kind of a milestone. It was the halfway point of the pads like this, not including the first two. So I've got seven more of these to go. This one is, what is this one, 1500. Next one is 2000. It's starting to look a little shiny. 3000 next. 100 to 5000. 6000. Two more to go. 8000's up next. One more to go. Finally made it to 10,000. Well it's done. And I think that looks pretty good. I could get this a little bit shinier in a rock tumbler I think, but this is pretty close. So I'm happy with the shine. Also happy that I'm not bleeding, so that's good. I think these are a little more dangerous than I originally thought though. I was thinking about the diamonds in them. This machine here has diamond wheels on it too. And I can touch any of these wheels when it's running and it's no problem. Doesn't hurt at all. These, it's not the diamonds that are going to get you, it's these little bumps when they're spinning at 10,000 RPMs. They do hurt when they hit your fingers, because I hit my fingers a few times and I didn't like it too much. So they're a little bit dangerous, but probably not that bad. So let's talk about how long it takes to do this. I didn't time all of them because it was turning out to be about three minutes apiece. So I added up the ones I did time and then just counted three minutes for the rest of them and it came out to be 54 minutes. So that's just the time that you're grinding. That doesn't include changing from this bit to this bit to this thing and Velcroing the different ones on and drying the rock off in between. You're going to be at least an hour if you count all that stuff in. So figure around an hour for a little tiny rock like this. You know, if you make the rock bigger, it's going to take longer than that. In a rock tumbler, you can fit, I don't know, rocks this size, maybe 30 or 40 of them in a little barrel. And if you've got a big barrel, you can fit a lot more in there. And it might take weeks. It's going to take weeks and it could easily take months to do that barrel of rocks. But the rock tumbler is doing all the work. You're going to look at them once a week. You're going to go through the barrel and clean it out. For a little barrel, it's going to take you, I don't know, 10 or 15 minutes. And if you divide all that time over all those rocks, it's not really that bad. It doesn't take very much time per rock because you're going to get a lot of rocks out instead of just one. So if you want something done that same day, this is a way to do it with the Dremel. If you don't mind waiting and you don't want to do all the work yourself, I'd suggest going with the rock tumbler. And then there's the costs. So I was going to try this Dremel, but I know from the past, using these little sanding sandpaper discs, these fly right off the Velcro and this is going full speed. And this only has one speed. These things flew off at just 15,000 RPMs on this. I had to dial it down to 10,000 RPMs. So you're going to need a variable speed Dremel like this one. Oh, by the way, you don't need this. This is a drill press. I'm just using this because it has this little hanger to hang this on here while you're using the flex shaft. But this is the 4,000. The cheapest one I could find was the 3,100 that has variable speed on it. And that costs about $50. So got $50 for that. If you want the flex shaft, that's another $35. You don't need the flex shaft. I think you could use this. You're not dipping it into the water or anything. You're dipping the rock in the water once in a while. I don't think there's a lot of danger there, but you'd have to make that decision on your own. So anyhow, if you need to buy these, $50 plus $35 is $85. But I'm going to assume that most people that are asking about whether they can use a Dremel or not probably already have the Dremel. That's why they're asking the question. So I would not go out and buy a Dremel just for this purpose. I definitely wouldn't do that. Even if you have the Dremel, you need to buy this stuff. These bits were $17 for the whole set of them. And I think this is going to be a more effective bit than this little tiny one. That's going to wear out quicker. I think it might be a little bit harder to use. It's going to probably dig in a little bit more. So I think you want the bigger discs, or drums, whatever you call them, cylinders. I was looking at the wear on these because I was worried that these were going to wear out really quickly, because some of them do. And I think I can see a little bit of a dip in the middle, so I think I can see a little bit of wear on that. But there's quite a few of them in here. It'd be better if you could get a whole set with just this size, and maybe you can, but this is what I was able to find. This one, I don't see any wear at all on it. It did wear, obviously, but I can't see it. It's not noticeable. So I think these are going to hold up pretty well. I was pretty happy with those. And then there's these little guys. These worked so much better than these did. These things wore out pretty quickly, and they just weren't very effective. They were good at polishing, but they weren't like the 50 grit one, or the 80 grit one of the earlier ones. I forget what the lowest grit is. Wasn't taking the scratches out like I wanted it to. So I just wasn't happy with those at all. These were pretty good. $18 for the set of them, and I don't see any wear at all on them. Once again, I know they did wear, and they're going to wear out eventually, but they seemed to hold up really well, and they worked really well. So these were a good purchase, I think. In a rock tumbler, you're going to have to purchase grit. As long as these are lasting, I think these are going to last a long time, although you're not going to be doing, you know, the 30 or 40 rocks that are in a rock tumbler with this. You're going to do a few rocks with this, but it'll go through quite a few rocks. So I don't know, I'd call it a wash, because the tumbler grit's probably going to cost you more, but you're going to get a lot more rocks done. So cost-wise, I guess you have to make up your mind on that. You can buy a rock tumbler, a good quality rock tumbler for just over $100 for like a single barrel one, and then, you know, of course there's Harbor Freight or cheaper things like that. You can get off-brand rotary tools, you can get lower quality rock tumblers, so if you want to go cheaper on any of this stuff, you could. So I'm trying to compare higher quality stuff to each other. So I guess overall, I would go with the rock tumbler, I mean, there's no doubt about it. But if you just want to do a couple of rocks, and you're not into this to do this as a hobby full-time, and you've got a Dremel, this isn't a bad way to go. So I guess you're going to have to decide how interested in this hobby you are. Maybe start with a Dremel, spend your $35 on your little polishing things here, see how that goes, and if you like it, then you can buy a tumbler. By the way, I'll put this on my Amazon storefront. I have a linktree, or you can look in the description of the video, and somewhere you'll find my Amazon storefront. And this stuff's in there. I do get a little commission if you buy something from there. It's just a convenient way for me to show you where it is, though, so you can look it up on your own, but if you want to know exactly what I got, that's where you can find it. So I'll leave you with that, and I want to leave you with a playlist of rock tumbling videos that will show you all you need to know about rock tumbling. So if you're interested in this hobby and want to get started in it, go click on one of those videos, and I'll see you over there.