Bob Oswald replies: Soft maple tends to stain blotchy due to differences in grain density. A couple of products have worked well for me. Seal-A-Cell by General Finishes and Seal Coat by Zisner. Both are very thin, that is, well diluted products, so they tend to absorb deeply and quickly into the soft grains and not so in the hard grains. Follow the directions about how much to apply and how long to let it sit before wiping off. They both do a good job of evening out a stain effort. Because of the sealing effect, it takes more stain or a longer dwell time to get the same density as untreated wood.
BJ Tanner replies: Maple has a tendency to blotch. This may be minimized through use of Minwax conditioner. Conditioner also works well on cherry. I allow the conditioner to dry completely before applying stain or dye.
Conditioner is a slow evaporating solvent (most likely deodorized kerosene) that inhibits the absorption of the stain or dye. Maple also shows sanding scratches due to it’s close grain and smooth surface. Typically I will sand to 150 grit (higher if scratches are still present). Sand only to the level necessary to make the scratches disappear. Sanding to too high a level will burnish the surface and will prevent absorption of the stain or dye which is already an issue with maple. Prep all surfaces equally or you will have color variation due to differences in absorption.
Another approach is to tone your lacquer providing an even surface color.