I have used the Garnet Sandpapers about as long as I have been working with wood. It is very inexpensive, and is relatively long-lasting.
This paper is every easy to spot, with the orange-color hue that it possesses.
Garnet Sandpaper Cons: It is relatively weak, has a softer grit than some of the other papers discussed here. It is not a good choice for power sanding, where it wears out very quickly.
Also, Garnet sandpaper tends to load up rather quickly and you will go through a number of sanding sheets for some of the sanding operations. Garnet is useful for guitar finishes only for the water-borne finishes as it loads way to quickly on the spirit finishes.
Garnet Sandpaper Pros: When it is used new though, with sharp grain, it will make quick work of rough-sanding wood and removes scratches very quickly.
This is a great paper to use on end grain, or with woods such as Mahogany, Spruce, Alder and other similar open-pore wood and it tends to close off the open grain by burnishing the surface and allowing stain to penetrate very evenly.
Aluminum Oxide Sandpaper:
Aluminum Oxide paper is another popular choice for many woodworkers and luthiers alike. You can identify this type by the white, yellow or gold coloration of the grit surface.
Steer clear of the dark brown aluminum oxide papers as these are very cheap and the so-called bargain basement varieties, as these will not be worth the savings in money of the higher grade papers that are available.
If you purchase one good, overall sandpaper for woodworking usage, then the aluminum oxides would be your best choice as it is relatively inexpensive, and longer-lasting than the garnet papers.
Aluminum Oxide Sandpaper Cons: If you are planning to stain wood as referred to in the Garnet section above, you would be best to do the aggressive rough-cutting with Aluminum Oxide paper and finish up with Garnet, to get the burnishing action.
Make sure you purchase the good quality papers out there and not the bargain basement types. Purchase from a reputatable supplier and you will be very pleased with your purchase.
Aluminum Oxide Sandpaper Pros: Your all-around best choice in Aluminum Oxide Sandpapers would be for the P-grade, no-load variety for the biggest bang for your buck. The grit on the Aluminum Oxide papers stays sharp much longer and has less tendency to round over due to its tuffness.
Also this paper is a good choice for taking down a finish very quickly and since it is available in a no-load variety, you will get very long-lasting qualities from this sandpaper choice.
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