Sandpaper & Sealer for Stone Carving
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The final stages of a carving are just as important as the early ones. Sandpaper and sealer are what turn a finished carving into something that lasts — smooth to the touch, protected from moisture, and looking its best for years to come.
Sandpaper
I use two grades of sandpaper — nothing more, nothing less. Start with 80 grit to find and remove any remaining chisel marks, lines, or areas that still aren't quite right. Once you're happy with the surface, move to 240 grit to bring it up to a smooth, clean finish. On Oamaru stone, 240 is as high as I go — anything finer than that is genuinely a waste of time on this type of stone. The difference between a properly sanded piece and an unsanded one is significant. It's worth doing properly.
Two things to look for when buying sandpaper for stone: first, go with wet and dry sandpaper — it's far more durable than standard dry-only paper and will last much longer on stone. Second, pay attention to colour. Oamaru stone is a creamy white, and because the stone is porous, fine dust from the sandpaper can work its way into the surface. If you use dark sandpaper (like black silicon carbide), that dark dust can show in the finished piece. Choose a sandpaper in a light, neutral tone — aluminium oxide in beige or tan is ideal — so any residual dust blends with the stone rather than staining it.
First Sand
Removing tool marks and levelling the surface
80 Grit Wet & Dry Sandpaper
The first stage of finishing. 80 grit removes chisel marks, evens out the surface and highlights any areas that still need attention. Go for wet and dry — it lasts far longer on stone than standard paper. Choose a light beige or tan aluminium oxide rather than black silicon carbide so the dust doesn't stain the stone. Buy a pack; you'll use a few sheets on a larger piece.
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Final Sand
Bringing the surface to a smooth, clean finish
240 Grit Wet & Dry Sandpaper
The final sandpaper stage. 240 grit brings the surface to a smooth, clean finish on Oamaru stone — and this is as fine as you need to go. Wet and dry paper again, and the same rule applies on colour: light beige aluminium oxide, not black. Take your time here and the sealer will go on beautifully.
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Masonry Sealer
Oamaru stone is porous — if left unsealed it will absorb moisture and stain over time, especially outdoors. Sealing is not optional if you want your work to last. Which sealer you use depends on the scale of the piece.
Smaller Sculptures
Diluted silicone sealer
Silicone Masonry Sealer
For smaller pieces I use a silicone-based masonry sealer diluted with water — roughly one part sealer to fourteen parts water. This gives good penetration into the stone without over-saturating it. It protects against moisture, brings out the natural warmth of the stone, and dries quickly. Ideal for indoor display pieces and smaller sculptures.
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Larger Sculptures
Heavy duty industrial sealer
Industrial Masonry Sealer
For larger or outdoor pieces I use a heavy-duty industrial masonry sealer. It's solvent-based and takes a few days to fully cure, but it gives a much more robust level of protection. Worth the extra wait if your sculpture is going to live outside or needs to handle the elements long term.
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💡 Shaugn's tip
Don't rush the finishing stages. The sanding sequence — 80 grit first, then 240 — takes time but it's what separates a professional-looking piece from an unfinished one. And always seal. Oamaru stone unsealed will absorb moisture and stain, and there's no fixing it after the fact. Seal it properly and your sculpture will look great for years.