Reference · How-tos · Decks

Pre-sanding deck strips with 320 grit

Sand the tanganyika strips smooth before they go on the deck, so that they don't splinter and the caulking seam stays crisp.

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1. 1Sorting the strips

   Lay all the strips side by side and sort them by width and quality. Use the best strips for the deck; set aside damaged, rougher or narrower ones. You can still use those later for short pieces.

   

   Tip from Pingu57: It looks as if not all your planks are undamaged. Use the best planks and throw the rest away, or keep it for small pieces later.

2. 2Sanding between folded sandpaper

   Fold a piece of 320 grit sandpaper double and lay the strip in between. Move the paper away from you, never towards you, otherwise the strip snaps. This sands the flat faces and the edges smooth in one movement, without burrs. After the first few strips you see the difference at once.

   320 grit

   Tip from pietsan: Fold a piece of sandpaper double and lay the strip in between; that sands the flat faces and the edges at the same time. But move the sandpaper away from you, otherwise the strip snaps.

   Watch out: Every strip has a good and a bad side: on one side the sandpaper snags now and then. Fold over the corners of the sandpaper and it stops snagging.

3. 3Breaking the edges and blackening the sides

   Chamfer the edges of the plank very lightly ('breaking' them); that helps against splintering, although it never prevents it entirely. Then blacken the side over its full thickness with the oil-based pencil. Because the side is black over its full thickness, the caulking seam stays visible however far you sand the deck later.

   

   Tip from *Hans*: When you blacken the side edges with a pencil, the side is black over its full thickness. You can then sand right down and the caulking seam still remains visible as a black line.

4. 4Sanding the laid deck, not rasping

   After gluing, smooth the deck with sandpaper. A rasp or scraper seems to spare the caulking seam, but leaves scratches in the wood; and the caulking seam won't disappear anyway, because the sides are black over their full thickness. If you do scrape, go with the grain.

   

   Tip from Pingu57: I would expect the splintering to happen when you scrape against the grain.

   Watch out: The trial deck also ended up askew. So when laying, watch the alignment too, not just the strips.

Result

After pre-sanding the strips looked crisp and the difference with the first trial was large. We have pre-sanded every batch of deck strips since, even though it costs an evening per batch.