Sanding Before Cutting

[woodchucker]

I'm not worrying about it, but it is real. as you sand the particles shed from the paper.

Like I said earlier, I do it. But if you do a lot of it, you will notice it.

[Leon]

How much is a lot?

[woodchucker]

That would depend on the grit, the wood (how much the wood holds), how hard you press.

You have to think of it this way. the sandpaper feels sharp in the beginning. Then it doesn't.. most of it does go the dust route. But quite a bit is caught in the wood. Especially soft gummy woods, or open pored woods.

How much you heat up and destroy the bond is part of it, how much cutting you do is another part of the equation. If your just ripping one or 2 pieces, maybe the dulling is light. But if you cutting a lot of wood from the sanded pieces, it will affect your blade faster.

I would imagine your festool would be better than most... since it has one of the better vac systems. But still guilty a little. But something like my PC ROS, would be way worse. My Bosch 1/4 sheet not so good either..

Either way grit has a way of dulling tooling, when you have grit that is not sharpening your tool.

[Leon]

I saw a butt load. I used to sand with 3M and Porter Cable before switching to Festool paper.

I never have had my blades resharpened much more than every 2-3 years.

I have never used a paper with grit that breaks down, although garnet paper will fracture and bread down. I only use aluminum oxide paper and have only witnessed that paper's minerals/grit dull not fracture or flake off.

It makes sense that loose grit would full a blade but in my experience it does not do so enough to give it a second thought.

[Brewster]

I always give boards a blast of compressed air between grits and when done sanding. Not 100% for grit removal, but can't be worse. This is not done for concern for the saw blades, mostly for eliminating any problems of a finer grit picking up a rock from the previous sanding pass and causing scratches.

-BR

[-MIKE-]

You're too nice about it. I'm calling bullshit on the whole theory. :-) If there are tiny amounts of sandpaper grit embedding itself in the grain of the wood, how come it's never shown up in the finish? Why hasn't it interfered with each successive, finer grit of sanding? Why can't I feel it against my skin when I'm checking each sanding? Why does my sandpaper last so darn long if all the grit is breaking off and getting stuck in the wood. Why? Because it's not happening.

The one caveat I will add is perhaps the OP got stuck using some of the same terrible Harbor Freight bulk sandpaper that I bought, once.... once. Half the git would fall off that stuff just taking it out of the cardboard box it came in. I called it single use sandpaper. That stuff

*did* leave grit all over whatever surface you were sanding, so perhaps that's what the OP was using that caused this issue. Perhaps he wanted to use up his whole inventory of the stuff instead of tossing it out and buying decent sandpaper.

That's the only way I could even possibly ever even start to buy into this theory.

[Leon]

In all fairness, garnet paper is designed to fracture and form a smaller grit on the paper as it is used. BUT that is old style paper and is not used much any more, at least main stream.

Something dulls modern blades, wood, and with modern paper the effect is insignificant to notice, in my experience.

I recall a couple of decades ago comments about mixing sanding dust with glue to make a wood filler. There were comments about loose sanding particles contaminating the mixture. I have not seen any recent comments with this concern.

[krw]

...and in particular, silicates in the wood (and don't forget rusted oak).

Why would that matter? It's held in the glue.

[Leon]

Apparently the sparkle of the mineral was an issue.