Regardless of whether your boxes are made of plywood or "furniture board," AKA mdf, the outsides of that material will have a wood veneer of your choice. Typically the inside of the cabinet will be a light birch, but that varies. For cabinets with glass doors the insides generally match the outside. Similarly, the outside sides of the boxes will generally also have the birch unless it's a side that will show like the end of a run or next to the refrigerator. Those will have "finished ends," meaning they will also have a veneer to match the fronts.

Just looking at cabinets, you won't be able to tell whether the boxes are furniture board or plywood without further investigation. They look the same because what you see is veneer regardless of what's under the veneer.

The preferred finish for interiors regardless of boxes material is laminate. It's more water resistant and durable. And, there is no need to spend the money to upgrade the boxes from furniture board to plywood at all. Your money is better put towards usable upgrades like drawer stacks or the more expensive wood for the door, etc.

The cabinet maker normally makes the boxes with the melamine interior and I guess particle board...is that the same as furniture board?
Is this sufficient then for the boxes?

Also what would be better for drawers between melamine or metal?

> "furniture board" AKA mdf

MDF and furniture board are not the same thing. In cabinetry, you will find furniture board used for the carcase and MDF used for door panels.

MDF (Medium Density Fiberboard) is a homogeneous board made from wood fibers.

Furniture board is the same thing as "particle board" (known as "chipboard" outside North America), and is made from larger wood chips. Particle board comes in many grades, from outrageously shoddy through very good; quality cabinets use the very good stuff.

People get way too hung up on the supposed virtues of plywood over furniture board. In reality, with appropriate construction methods and proper installation, either can be used to create cabinets that will last decades.

The biggest real-world difference I can think of is weight - plywood is significantly lighter than furniture board; upper cabinets made of plywood are easier to install.

I'd take metal drawers over furniture board. But if they are plywood with melamine, that would be fine. Melamine is humble perhaps but really practical.

But do avoid particle board or MDF or whatever it's called for drawers. They work too hard.

(My painted cabinets had painted interiors.)

"furniture board" AKA mdf

True, but I was using terms people recognize without caring exactly what the stuff is. It doesn't help that "furniture board" isn't a specific compositional material - it's a name given to the good stuff that's used in good cabinets. You're absolutely right about plywood, furniture board, and mdf being available in everything from incredibly cheap to really lovely. Think about the cheapest plywood available used to cover a broken window vs the much finer variety that can be veneered with a lovely outside and used to make good furniture. The same is true for mdf. My daughter has an ottoman that goes with a rocking chair that broke when her toddler climbed on it. When we took it apart to repair it, the stuff under the fabric was almost sawdust. That is not what they use in quality cabinetry.

Just make sure to go with plywood for your sink base. Other than that , go with the mdf and put your money to other upgrades.

My plywood boxes (from Conestoga) have a clear "conversion varnish" on the inside that so far is impervious to dirt and oil drips.
The wood interior is my preference, and especially with glass door uppers.
Casey