My advice is to not choose Walnut for your first project. It will be an expensive learning curve. Walnut ply is well over $100 per sheet, literally triple the cost of other furniture grade woods. The plywood comes unfinished, so you don't have to worry about that. I see plenty of pre-finished Maple and Birch panels these days, but never seen Walnut pre-finished sheets. Heck, you have to search for Walnut ply. If you are serious about using Walnut, consider making a dummy one as practice out of cheap materials. Paint Grade Poplar and shop grade Birch or MDF would be good to practice with.

Walnut varies greatly in natural color---so getting even a close match between dimensional and ply will be tricky.

The best way, IMHO, would be to buy the ply and then try to find the wood that most closely matches it.

Now, the advice aiden gave about the cost and the making of a test or prototype is absolutely correct.

Even Norm Abrams makes a prototype as a test piece.

Nthing Aidan & Handymac that you should practice on cheaper materials. If this is really your first attempt at woodworking, you're almost certain to generate a fair bit of unintentional scrap. You won't always have a clear understanding of what to do next, and to avoid being completely stuck you'll guess. Sometimes those guesses will be wrong. You'll enjoy that learning a lot more if it isn't expensive. Find a mentor who can help you through the basics if at all possible.

I also think Handymac's strategy of buying the plywood first and then finding solid to more-or-less match it is a good idea. If I were to buy walnut plywood I'd have to special-order it; I'd have little or no control over the color of the plywood, whereas I can pick and choose from a pile of walnut boards.

I agree with the above posts. Think of it as clothing designers do. They always make and fit a muslim sample before cutting into the silk dupioni. Likewise, I suggest you make a mock up out of MDF before cutting into your walnut. Not only does it save the walnut, it allow you to get your act completely together. The second time you make anything, it always goes better and faster.

My other suggestions is to get unfinished ply and then you can stain to match. When you cut ply, it splinters and all other things happen that require touch-ups anyway. I think you're better off just staining the whole thing. Of course, you will have to test several stain and stain combinations on scraps of ply, but at least you'll have total control.

Since you are only making one, I'd suggest building the box from birch plywood, and veneering it with walnut door skins if it turns out well. That way you can cover any mistakes and the skin application comes at the end when dings and damage will be minimized. Even if you successfully created a nice walnut box, in handling it is very easy to ding or chip the veneer.
Casey

Thanks for all your responses. It is good to know that the walnut plywood comes unfinished.
You have pointed me in the right direction - I will get cheaper material and make a mock-up first as a learning exercise - i have a bunch of plywood and mdf pieces lying in my garage which would serve very well as practice pieces and then move on to the real thing. I have to admit that I was not confident if I could pull it off with Walnut wood on the first attempt. I will be back asking a ton of questions if i am stuck on the way.

You are in the SF south bay area? The place to go for Walnut ply and any other species of wood is Aura Hardwood Lumber on Phelan Ave between Monterey Hwy and 7th. They are set up as a wholesaler to cabinet shops but deal with the public also.

Here is a link that might be useful: Aura's homepage

Getting walnut veneer (as used in plywood) to match solid walnut wood is often a battle.

The veneer was handled during cutting and does not absorb coloring the same as solid wood.

Aniline dye is generally more forgiving, and you can alter the color intensity easily to test how the separate pieces match up.

aidan, thanks for the tip! I am in the south bay and so far I had only heard of global wood source. I will check Aura out.

brickeyee, where can I get aniline dye?

Aniline dye is available from Woodcraft, Woodworker's Supply, Mohawk and others.

Moser has a good assortment available at Woodworker's Supply.

My first woodworking project when I was about 18 was a shelf system using walnut plywood and solid walnut for the uprights and angled supports. I was able to easily match the solid pieces and the plywood and walnut band edging. Hope yours goes as well.