John

A normal sized router should do the trick just fine. I like the little one but would certainly use one of my other routers if I did not have the little one. Also you will find that the top skin of the deck is closer to 1/8" thick than it is to 1/4" thick. The balsa core in the center of the deck is 3/8" thick and then you have the bottom skin of the deck that is close to 1/16" thick.

As far as the suggested repair I will draw a picture as soon as I can get some time later today and post it for you. But here are a couple of things I can tell you now. First, the tickened epoxy only goes between the top and bottom skins around the perimeter of the 5" hole you will cut through the top skin. And that assumes that the balsa core is degraded in a larger area than the 5" dia. cutout. While I'm on the subject, you need to know the only way to give the thickened epoxy body so that it will not sag out and run out of the area you are putting it into is to use cabosil (also known as fumed silica). You will want to use micro fibers or 1/4" glass strands to give the epoxy strength after it is cured but you will also need to mix in cabosil to thicken it to a peanut butter consistacy so it will stay where you put it.

Then in the area where you have the 5" cutout you will wet out possibly as many as 8 layers of 1708 biax cloth one at a time to build the core area up to the 3/8" thickness that that original balsa core took up. Then when you are built up to the the point where the glass is filling the core area and even with the bottom of the top skin you will lay down the 8" circle of glass first to get a complete bond with the entire beveled area and the glass you put in the core area. After that you will follow with the 7" circle of glass and then the 6" circle of glass and if the center is still slightly below the surrounding deck area one more layer of glass 5" in dia.

When all of this sets up use the grinder to knock down any high spots and mix up some more epoxy to use as a fairing compound and this time you will need to use cabosil and microballoons. Probably about twice as much microballons as cabosil. The cabosil once again gives the epoxy body and keeps it where you put it and the microballoons will make sanding it later much easier.

Does this help or would you still like the picture? I'm happy to do it but I have some work I need to get done before I can.