Prep for glue

[Romeo Suave]

When glueing on a half inch maple cap or sides to a thru neck what grit sandpaper do you use and what glue?

[Darrel Friesen]

It's preferable for most people to have a freshly planed or scraped surface prior to glueing. Sanding a surface tends to tear the wood fibers and leaves sanding dust behind which doesn't make for optimal glueing conditions or joint strength and is also more prone to leaving a visible glue line.

Some people do use a hard flat block or surface and somewhere around 220 grit followed by brushing or using compressed air to get rid of the dust to prep, but they would be in the minority for reasons stated above.