How to Remove Scratches from Glass
We often get asked how to remove scratches from glass and gemstones and here we tell you how and with what tools you can do this. This does not apply to tempered glass or windshields, they will require replacement or specialist advice as the glass may crack or distort the view (as in the case of a windshield)
For scratches on fused, engraved, blown glass, household glass objects, watch glass or jewellery pieces, cabochons and gemstones, here's a couple of options for removing those unwanted marks.
CAUTION. We recommend always trying out these two options on a rough piece of glass or stone before using to remove your scratch. They are abrasives and can cause distortion to your material.
Aluminium Oxide and Diamond paste are both excellent abrasives for removing scratches, and if used well will bring the surface of your material back to it's original state.
The depth of the scratch will determine what grade of paste to use. A very deep scratch for instance will require a coarser paste to begin with and then finish off with a finer one.
It can be difficult to determine what grade of paste to choose. Ideally it is best to have a couple of grades in your workshop so you can begin to remove the scratch with the coarser one and then fine polish the scratch back to it's original state with a very fine one such as a 1micron. If you use just one grade of paste, lets say a 1 micron, but your scratch is quite deep it will take much much longer to work it's magic, but have patience and you it will be removed eventually.
Aluminium Oxide Abrasive Paste
White Aluminium oxide abrasive paste is used for its hardness and resilience. It is widely used as a polishing abrasive, in particular for the removal of scratches from glass. (And if you need to polish and smooth hardened steel, this paste works wonders)
It comes in 4 different grades: 1 micron, 3 micron, 6.5 micron and 10 micron. The 10 micron is the coarsest grade and 1 micron the finest. The paste is pre-mixed with water and 20g of it is squeezed into an easy to use syringe. This makes it easy to apply and causes less mess around the studio or workshop than the powder versions you can find.
Diamond Polishing Paste
Use your diamond grinding paste on a felt bob, wooden peg or a piece of leather. This option might be best to use for the removal of scratches on delicate work such as watch glass, gemstones, cabochons, antique glass or glass engraved pieces. Our diamond polishing paste is ready to use, no need to mix with any lubricant and it comes in a handy 5g syringe so nice and easy to apply.
Attach a mounted felt bob into your drill (unless you choose to use a piece of leather or wood - this can be a better option when using the very fine diamond polishing paste (0.25, 1 micron) otherwise it may just absorb into the felt bob.
Apply a little paste to your felt bob, wooden peg or piece of leather Use a coarser paste for a deeper scratch and a finer paste for hairline scratches.
Working through a couple of different grades is often the best way to remove your scratch. Start off with a coarser one and then polish up with a finer grade until the scratch in your material is no longer visible. 1,500 RPM to begin with, then speeding up as you feel necessary. If you choose to use a piece of leather, dab a little of the diamond paste onto the leather and work into the material, again working through the grades as you go until the scratch is no more!
The other alternative is to use a rubber silicone polisher on a mandrel fixed into your Dremel or other rotary hand drill. Be aware, these polishers grind material away.
Mini Rubber Silicone Polishers
Here's what you'll need:
- A hand/hobby drill (an adjustable chuck might be needed to hold shank of mounted felt bob)
- Rubber silicone polishers in varying grades - possibly wheel or knife edge shape if you want to polish a large area of scratches. Cylinder and bullet will localise your polishing. A mixed bag of each shape might be a good idea.
- Screw mandrel(for use with the wheel and knife edge shaped polishers)
- Taper mandrel(for use with the cylinder and bullet shaped polishers)
Attach your silicone polisher to the relevant mandrel and place in your drill.
Applying little pressure make sure not to exceed 7,000 - 10,000 RPM.
Step 3Work your way through the grades i.e begin by using a black polisher (medium grade) for instance then follow that with a blue (fine) and then a pink (extra fine) until you've achieved the finish you desire and the scratch in the glass is no longer visible.
You may have heard that toothpaste is another alternative for removing scratches in glass. However, toothpaste is an incredibly light abrasive and will do no more than fill in the scratch mark, best kept for ones teeth!
Lastly, if you're looking to remove a scratch from a plastic watch glass, then Polywatch is the answer.