Arrgh! Help on birch plywood

[Jay Knoll]

Hi everyone

I'm building a stand for my CMS and planer (shop notes vol 14 no 81). Bought some "good two sided birch plywood for the case/doors. I put a sealing coat of shellac on the doors today, after lightly sanding them with 220 and 400 grit using my Rotex.

When I applied the shellac, I'm getting a "greyish" pattern in the surface. I'm wondering if it is bleed through form the inner lamination layers? I was pretty fastidus about wiping off the surfaces before finishing.

I let the first coat dry, then hit it with the rotex again using 400 grit -- I"m leery of going though the "good" surface veener.

Here are some pics, don't know if "discoloration" will show clearly but thought I"d give it a try.

Any ideas on how I can improve the finish (other than painting)? I know "it's just a shop cabinet" but given the amount of time I've put into the project I want it to look as good as it possibly can. Thoughts and suggestions will be most appreciated

Thanks

Jay

[Alan Turner]

I can't comment on birch, but if the birch face veneer were really maple, maple does react with iron, including iron in water, and that will give you the gray color.