Question 1

Silicon Carbide

Accepted Answer

Silicon Carbide Magnified 50x

Klingspor Abrasives Silicon Carbide is a sharp, very hard, brittle and closed coat abrasive. Best suited for sanding glass, plastics, rubber, ceramics, solid surface and between coats of finish. Also used with some non-ferrous metals, sharpening of alloys, stainless steel and tooling steel.

Silicon Carbide is also sometimes referred to as Wet/Dry sandpaper. First made popular in the automobile industry in the early 20th century, SC has been widely used across many industries. Due to its very hard properties (Almost as hard as diamond) it can cut rather than plow through many materials like glass and plastic. However because it's so hard, it's also very brittle. This brittleness allows for a property called "Friable" which means when it breaks or fractures, it exposes a new part of the grain. What this means is a consistent scratch, when you start sanding with 120 grit, it remains 120 grit for the duration of the service life of the abrasive.

Due to the brittle nature of SC, it can break under light pressure. Make sure to not force workpieces into the abrasive or press down too hard when using a hand applicator like a rubber block. Light pressure will allow the abrasive to do the work and last longer. This is also the reason it's not recommended for bare wood applications. SC will break off in wood grain and the scratch is deep. It will show u

Question 2

Tru-Blu Aluminum Oxide

Accepted Answer

TRU-BLU Discs TRU-BLU is or special heat treated, Closed Coat, Aluminum Oxide on an X-Weight Cloth backing. Originally designed for the aeronautical industry, it has woodworking advantages. Mainly with use on plywood and MDF (Medium Density Fiberboard) these discs will close off the porousness of these materials, making finishing easier. X-Weight cloth means that its flexible in one direction to be used for hand sanding. We sell Tru-Blu in 10 packs of discs

Question 3

Stearated Aluminum Oxide

Accepted Answer

PS33 Disc

Klingspor Abrasives PS33 (Known As Stearated Discs) is a non-loading, semi-open coat, aluminum oxide (AO), resin over resin coated, paper-backed abrasive. This means you get exceptional service life, a clean sanded surface in bare wood sanding applications. Can also be used on primers, solid surface, aluminum and paints.

Stearate coating

||| The image above shows what a Stearate coating on top of an abrasive would look like. Notice the cascade look of the stearate.

Our PS33 Stearate discs, grits 40-320, are NOT top coated with a stearate. Instead, the Stearate is mixed into the resin that holds the AO grain onto the disc. This means the disc will not shed stearate onto the work surface, which has been known to create finishing issues with water-based finishes. Semi-Open Coat refers to the amount of grain covering the surface of the disc. See Abrasive Coatings for more details.

Resin Over Resin (ROR) coating is how the abrasive grain is applied and locked onto the backer substrate.
With the PS33 Stearated discs, you have a phenolic resin maker coat applied to the paper backer, which then the AO is electrostatically aligned perpendicularly, for maximum grain exposure and a size coat of phenolic resin is applied over top to lock in the AO grain.

![Coated Abr

Question 4

Sharpening with Oil Stones

Accepted Answer

SHARPENING WITH OIL STONES by Paul Rolfe

Oils stones have been in use for a very long time. With good technique, you can be assured of getting excellent results. There are options available that will take you from rough metal removal to a polished, scalpel-sharp edge. However, if you like numbers, and like to progress through very specific grits, then oil stones may take some getting used to. You’ll have to get to know your stones and choose them based on the job they do and not the grit numbers that are stamped on them. Oil stones, particularly the Arkansas stones, are all very hard and will last you a very long time. In fact, they will probably never need flattening unless they are used in a school or commercial setting.

The natural versions (Novaculite or Arkansas stones) do not come in defined grits. They are graded on the basis of their density and color. Going from medium to fine to very fine, they are classified as soft, hard and black. The soft Arkansas stone, BRAC11, is a good starting point if the blade is in fair condition and does not need much reshaping. If there is a nick in the blade or if it needs a new bevel established, use one of the man-made oil stones first. After the soft Arkansas stone, move up to the hard Arkansas stone, TA00001. It will refine the

Question 5

Dual Mode Sanding

Accepted Answer

Bosch Dual Mode Sander

| What is dual mode and when should I use it? Dual mode sanders mean they have two orbit patterns. Most have around 3/16"(5mm) and 3/32"(3mm) orbits. The larger orbit is meant for heavier stock removal grits (36-100) on wooden surfaces, while the smaller orbit is for cleaning up the large orbit scratches and finish sanding grits (120-220)

| What's VSC? Depending on the abrasive and grit, some discs can be more aggressive than others and they can grab at the workpiece. Naturally, you'll want to press down harder to keep a jumping sander or loose board under control which now you're working your sander harder than needs be. If you have Variable Speed Control sander (VSC) then we recommend to set it at 3 or your middle setting to start. This way you have some room to adjust for both your style of sanding and the application you're sanding. Turn the setting up to max and use 36 grit, you will do some heavy stock removal but creates heat and a lot of dust. For the finer grits, too much suction from the vac causes the workpiece to get sucked up to the sander. Naturally, we do the same thing and add more pressure down to the sander. Drop the amount of suction and slow the sander down to midway. Adjust as needed. When sanding between coats of finish, turn the sander down low and switch to the 3/32" orbit. Two reasons, one is the sander isn't needing to be aggressiv

Question 6

AZ-Plus Alumina Zirconia

Accepted Answer

Alumina Zirconia Magnified 50x

Klingspor Abrasives PS36 ( AZ-Plus ) is a stearate coated, semi-open coat Alumina Zirconia on a paper backer. Alumina Zirconia is a tough grain like Aluminum Oxide, but has a property of being hard and brittle like Silicon Carbide called "Friable." This means that when you start with 60 grit, the grain gets under pressure it breaks like an icicle, revealing a fresh new part of the grain that is still 60 grit. From here it slowly wears down like AO making it longer lasting than other abrasives. Being a Semi-Open coat allows for loading to occur and having a stearate coating (Blue in this case) allows for that loading not to stick and glaze the abrasive.

||| If this abrasive is better than most why not just sell it and nothing else?

AZ-Plus being aggressive causes issues with bare wood, especially if finishing with stains or dyes. It's the sharp grain that breaks causes deeper scratches than AO in the same grit range. Now, this doesn't mean you can use it on bare wood, you can but you would have to follow up after with AO to smooth out the scratches. When we make AZ in belts we call them Planer Belts which refers to the heavy stock removal of wood. From 24 to 60 grit these belts will dimension surface grain quickly. 80-120 will smooth out those scratches. You can ever get this

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