Maple is notorious for blotching. It’s an extremely hard wood that blotches because of poor sanding procedure. Maple has to be sanded uniformly. Stain absorption levels of walnut can differ greatly as a direct outcome of sanding procedure. Constant, equivalent pressure with straight, parallel strokes provide good maple staining jobs. Inconsistent sanding strokes result in botches on stain. You can fix blotches from resanding and reapplying stain for further absorption.
Sand the ground parallel with the grain before the ground has an even, smooth surface. You don’t have to remove all of the old stain. It is more important to just out the wood grain so that it is consistent over the entire surface.
Apply a moist coat of stain to the ground. If it begins to dry out until you have completed staining, go back over it. You have to have an even, wet coat of stain on the ground.
Wipe off the stain as quickly as you can. Wait 30 minutes for the stain to dry. If you can still see blotches, restain it. Let the stain remain on the wood for 5 minutes, then wipe it off.
Assess for blotches after 30 minutes. Should you still see these, resand the ground with 80-grit abrasive, followed by with 100 grit. Restain and wash off the stain immediately.