Izzy Swan shared the woodworking tips featured in this video.
The video brings an experienced sanding expert into Izzy’s shop to walk through five common sanding mistakes and how to fix them.
The guidance covers proper use of random orbit sanders, sensible grit progressions, surface preparation before finishing, and practical tips for tricky materials like MDF.
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Random Orbit Sanders: Let Them Run
One common mistake is tilting or pressing too hard with a random orbit sander, which prevents the pad from doing the work it’s designed for. A simple test is to mark the pad while it spins — if the mark becomes visible the tool is being overloaded or tilted and isn’t operating properly.
Keeping the pad flat and letting the machine do the cutting reduces swirl marks, extends abrasive life, and avoids unnecessary wear on the sander. Light, even pressure produces a more consistent surface and makes subsequent sanding steps faster.
Grit Progression: Don’t Skip Steps
Skipping grits is a very common time-saver that ends up costing time and materials, because coarse scratches take much longer to remove with a much finer paper. A sensible progression moves from a coarse grit to a medium grit and then to progressively finer grits so scratches are reduced incrementally.
Following a proper sequence (for example, coarse → medium → fine → very fine) prevents overworking abrasive, reduces loaded paper, and preserves tool life. The result is faster, more pleasant sanding and a cleaner final surface.
How Fine to Sand Before Finishing
Sanding finer than about 220 grit on raw wood is often counterproductive because very smooth, burnished surfaces can reduce mechanical adhesion for penetrating finishes. If the wood surface is polished too much the finish may fail to bond and can peel or check away from the substrate.
For most bare-wood finishing scenarios, stop at a grit that leaves enough tooth for the finish to grab — typically up to 220 — and reserve ultra-fine sanding for surfaces that will be finished differently, like over sealed or painted surfaces. This approach balances smoothness and reliable adhesion.
Raising the Grain: When and How
Raising the grain means deliberately swelling the wood fibers with water so they can be knocked down with a final light sanding for a smoother, more uniform finish. The best time to raise grain is near the end of the sanding sequence: wet the surface after the second-to-last grit, let it dry, then finish sand with the final grit before applying finish.
Avoid using solvents like alcohol to raise the grain because they evaporate too quickly to be effective. Using water is simple and predictable and gives the last sanding a more consistent surface to accept finish.
Card Scrapers vs. Sanding Before Finish
Card scrapers and hand planes cut cleanly, but using them right before finishing can lay the grain down unevenly and cause blotchy absorption with sprayed or wiped finishes. Short, aggressive scraper strokes can locally burnish the surface and create areas that accept finish differently.
If a scraper is used for shaping or smoothing, follow it with a final pass of fine sandpaper (such as 220) before applying finish to ensure an even surface and avoid blotchiness. This extra step helps finishes apply uniformly across the whole piece.
Working with MDF Edges
MDF is economical and stable, but the exposed cut edges are porous and can look rough if not treated properly. Rather than heavy fillers or exotic treatments, a targeted abrasive approach and a light sealing coat can close the surface and make the edge blend with painted or primed faces.
A sharp, closed-coat aluminum oxide abrasive works especially well on MDF edges, letting a light seal coat and one more sanding pass produce a smooth, finish-ready edge. This technique keeps the workflow simple while producing long-lasting, neat results.
Why These Tips Matter
These sanding fundamentals reduce wasted time, extend abrasive life, and improve final finish adhesion and appearance. Applying sensible grit progressions, proper tool technique, and targeted surface prep makes finishing less frustrating and results more predictable.
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Matt’s Take
These are my personal thoughts and tips based on my own experience in the shop. This section is not written, reviewed, or endorsed by the original creator of this project.
The pad-marking test for random orbit sanders is brilliant — it’s such a simple way to know if you’re using proper technique. I’ve seen so many people bear down on these tools thinking more pressure equals faster work, but all it does is create heat and wear out pads prematurely. When the sander is working correctly, you can almost feel it wanting to glide across the surface.
That point about not going beyond 220 grit on bare wood really hits home. It seems counterintuitive at first — shouldn’t smoother always be better? But I’ve learned that finishes need some mechanical grip to perform well. Going to 320 or 400 grit might feel like you’re being thorough, but you could be setting yourself up for adhesion problems down the road.
The MDF edge technique is particularly useful since that material shows up in so many shop projects. Those fuzzy edges can really telegraph through paint if you don’t address them properly. A good closed-coat abrasive makes all the difference — it cuts clean without loading up with the fine dust that MDF loves to produce. Taking the time to seal and sand again might seem like extra work, but it’s way less effort than trying to fix a finish that highlights every imperfection.