how to decorate slab plywood doors using a router

[tom coleman]

A friend showed me his bathroom vanity that has slab plywood doors that looked pretty decent. Apparently the carpenter who made them routed a decorative rectangle in each door front and then rounded over all the edges.How did he do this?

I'm guessing that you first determine the offset between your router bit and outside edge of your router base. Then cut a rectangular template sized to take that offset into consideration.

what bit should I use

will 3/4 inch birch ply from HD suffice or do I need a better grade plywood

[John TenEyck]

Are you sure the doors are plywood? Assuming they are painted, I would think they might be MDF instead if they have a routed pattern in them, and that would be my choice for making such a door. The pattern is easy enough to route. Just make a template to clamp onto the door, then run the router with guide bushing around the template. A plunge router is easier for this task, but it can be done with a fixed base router with proper template setup. The choice of bit is up to you, there are many to chose from specifically made for this task.

[glenn bradley]

+1 on a template (or now-a-days, CnC'd by a shop somewhere). This method works well to get that raised-panel-look in MDF. I would think ply will be a challenge due to possible voids, tearout, fuzz, etc. Also, the plys will show regardless of the quality of the cut unless painted and, if painted, go ahead use MDF. I do find exposed BB ply edges on my shop jigs and cabinets to be a "look" I am OK with. I'm not sure I would want it in my home. JMHO.

[johnny means]

Sounds like an MDF door to me too. This can be done two ways, by hand with a template or with a CNC. Doing them by hand requires a special plunge bit and leaves radiused corners on the inside of the "frame", instantly recognizable as cheap. CNCs use finer tooling to leave a square corner and produce a much more convincing look.

[Tony Bilello]

A friend showed me his bathroom vanity that has slab plywood doors that looked pretty decent.
what bit should I use

will 3/4 inch birch ply from HD suffice or do I need a better grade plywood

You can use just about any bit that you would use if it were solid wood.
The Birch Ply you buy at HD is not the kind you want. You will have to go to a real lumber yard and get Baltic Birch Plywood. This is vastly different than regular cabinet plywood in that it is a much higher grade. It has a lot more plys and absolutely NO voids. It cuts nice and clean with a router bit or on a table saw. Most plywood drawer sides are made from Baltic Birch (BB). The top edges are rounded over with a router and barely need to be sanded.
I was in Lowes the other day and got into a conversation with another customer. He asked for Baltic Birch and was arguing with an employee because the employee was trying to sell him regular birch. The employee was totally clueless and the department manager heard of it, knew he didn't carry it, told the customer where to buy it but didn't know for sure what it was.
Many woodworkers on here and other sites don't really know the difference.