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Getting from raw rock to a polished stone is a daunting task, but if you follow this process you’re bound to get a specimen you’re proud of. The Dremel is a great tool for the job – providing more control over the final stone’s shape and texture than other polishing methods. To make a rock shop quality shimmering stone, all you’ll need is the last rock you found, some sanding and grinding Dremel bits, a rock polishing compound, and some personal protective equipment.
First, shape your stone correctly and scrub any dirt and loose rocks off. Now use the Dremel with a sanding bit and cycle through 3 to 5 different grits – a typical sequence is 600, 800, and finally 1200. Now dip a polishing wheel bit in a rock polishing compound and buff the stone. Finally, wipe it off and find a spot for display.
As you go through this process, you’ll want to keep in mind that the unique properties of the mineral you’re polishing will change how you perform these steps. For best results, estimate or find out the mineral’s hardness before starting out
If you are interested in checking out the best Dremel drills you can find them by clicking here (Amazon link).
Step 1. Cut the Rock Down to Size
I know you want to get straight to getting a shine on the rock you’re holding, but this step is the most important of all of them.
In this hobby, you’ll want to invest in a good hammer and set of chisels eventually, but if you don’t want to get one right now then try to choose an appropriate size stone the first time around – afterward, you’ll have a better feel for it.
Keep these things in mind when sizing the rock:
- You’ll have to hold or clamp this stone while you polish it – a smaller stone will be harder to grip.
- A larger stone takes substantially longer to smooth out. This is especially the case if you have a harder stone.
- Look for natural faults in your rock. You’ll want to take these out if possible because the pressure from sanding may cause them to break.
- There are much less work and time involved in chiseling rock than sanding it off – get as close as possible before you start.
- If the rock is for a singular display, you should choose a larger size than if it will go in a set.
TIP: Cutting rocks to the right size can be tricky sometimes. That’s why I wrote an article with a step-by-step guide on how to cut rocks with a hammer and chisel. Feel free to read it here:
Step 2. Scrub Thoroughly
Get a bucket of warm soapy water and a fingernail brush. Toothbrushes are typically recommended for this task but only use a toothbrush if your stone is a relatively soft stone.
If you do not know what hardness your stone is, look for layering which seems like it would be too fragile or delicate for intense scrubbing. You can also find another stiff, coarse, and strong cleaning material if you do not have a fingernail brush.
Cleaning your stone before you start sanding is essential for two reasons.
- It gets dirt and loose stone off and, while wet and naturally shinier, gives you a small taste of what the final product will look like.
- It will show you if your stone is able and ready to be polished.
A fingernail brush is the only way you can achieve the second task because scrubbing will put similar pressures on the rock to sanding. It will uncover hidden fissures in the stone which may break later in the process.
In this way, you can feel out how much pressure your specimen can take, which is good information in the sanding phase, and you can sort out unfit stones and save yourself some time and heartache.
Step 3. Cycle through Sanding Grits
Now let’s move to the polish part. I try to describe this part in more detail so I divided it into several parts. So let’s start!
If you have one, set your clean, nicely cut stone in a clamp on a stable surface. Otherwise, find a place which you can easily sweep later and get some gloves which you don’t mind sanding a bit.
A Dremel tool with higher RPM is a good idea for the sanding process and is definitely recommended if you’re polishing quartz or a mineral with similar hardness.
Especially if your tool is similar to a Dremel but not the exact brand, check to make sure it has an RPM of above 10,000.
Many times, the battery-powered tools will have less RPM than the chorded tools, so keep an eye out for that if you’re in the market for one.
I recommend buying one of these two dremel drills:
- The first one is a great option if you just started with rocks polishing. This dremel drill offers great value for the money and the kit contains all needed accessories. The dremel comes with 5 step speeds from 8,000 to 30,000 RPM. You can buy it here. (Amazon link)
- The second one is a great option for the more advanced polishers who will use dremel drill for polishing rocks more often. It comes with all needed accessories and offers variable speed from 5, 000 to 35, 000 RPM with electronic feedback for consistent performance. You can buy it here. (Amazon link)
Choosing a first attachment
Now you need to choose a starting sanding grit. The purpose of the first stage of sanding grit is mainly to shape the stone.
Rounding out all the corners and sharp edges and perfecting the final shape should all be done in this stage, but it’s also important to give the whole stone a once-over with the coarse grit or silicon carbide even if it doesn’t need reshaping.
Dremel attachments come with a variety of materials and shapes – here I’ll give you a brief overview of some that may be useful, though you’ll find out anyway if you’re the experimenting type like me.
|Aluminum Oxide||– Brown |
– Typically 3-5 shapes
– Common in most sets
– Typically confused with a sander but made for metal
|Silicon Carbide||– Grey |
– Typically 3-5 shapes
– Common in most sets
– Made for stone and porcelain
– Choose this as a first step if you have some more shaping work to do or if you have an especially hard stone. If the sanding doesn’t seem to work at first, go back and start here.
|Grinding Wheels||– More stability |
– Great for the first round of smoothing or for shaping
|Sanding||– Typically labeled with their grit |
– Feels a bit like plastic
– Mostly come in cylinders
– Most sets come with 600, 800, 1000, and 1200 grits (choose 600 to start for an average stone)
Typically, using a silicon carbide attachment first will have the most effect – you will be able to physically see the stone changing shape as you use it. A round with this tool should only take 3-4 minutes; the sanding rounds will take more time.
You’re done with the first round when the stone is in its final desired shape – no bumps which are big enough to actually change the visible shape of the stone.
Now that you’ve got a feel for the tool’s ergonomics, feel free to choose your first sanding tool’s shape wisely. It’s a balance between pressure and preciseness – be patient and don’t be afraid to switch out the shape if it isn’t working well for you.
Move to the 600 grit and spend 5 minutes sanding each area from different angles. Though the stone might look round, there are different structures on the surface that you can’t see so it’s a good idea to sand from different directions.
Start with the 800 grit when the texture feels smoother to the touch. Spend another 5-6 minutes with this grit, depending on the size and properties of the stone.
In general, try to only switch grits when you see a noticeable difference. You’ll get better at noticing changes through the sanding process, but another trick is to look at the reflection of light in the stone.
Every rock will be different, but if you can see the reflection quality change as you sand, then only stop once the reflection quality stops changing.
A rock’s texture is the best indicator of how it’s responding to the sanding. Try to feel changes by feeling it with the thumb or even rubbing it on a forearm.
Cycle through the rest of the grits in the same way, always choosing a new grit when it has no effect anymore, until the 1200 grit.
If at any time during the process, you feel like it isn’t working well, don’t be afraid to increase the pressure you apply – sanding works with friction and the Dremel is a hardy tool, it can handle it.
Harder stones will require longer and typically more pressure applied but try the former before the latter. Texture and reflectance will respond differently depending on your stone, so remember to study each stone differently.
You can stop when you’re happy with the natural shimmer of your stone. Every stone has a different “maximum” shine, so if you aren’t sure whether or not more sanding will have an effect, search around the internet for polished pictures of your mineral. Remember it will become slightly shinier in the polishing phase.
Step 4: Buff with Polish
Replace the Dremel bit with a felt or leather wheel or cylinder. The best material for polishing depends on the type of stone and the type of polish. The best material and polishing compounds can be found here.
Dip the cylinder in the compound and buff all areas of the stone. This too should take a few seconds over each spot, but minimal pressure should be applied.
Now wipe your stone (it won’t remove the polish) and find a spot to display!
TIP: Do you know you can also tumble rocks without a rock tumbler? Yes, it is possible and it is quite easy. Find out more in the article below: