Cracked Mahogany coverboard repair - New construction

[Speedboy]

I am currently building the cold-molded mahogany runabout Rascal by Ken Bassett. I epoxied the final deck layer (1/4" Honduran Mahogany) over the okoume plywood (first layer) back in December. Last night (after our first >80 degree F day) I noticed that the cover board on one side had developed a 3 ft. long crack down it center (<1/16" wide). The coverboard was from a 12" wide plank that was resawn to create two pieces. What is the best method of repairing the crack? Some options that I have heard discussed:

1) Famowood or other wood filler.
2) Mix epoxy with mahogany sawdust to create a filler.
I am concerned about the ability to blend these repairs. Note that I do intend to stain and varnish the mahogany.

I would prefer to fill the crack with mahogany, and am considering used a "V" shaped router bit to create a consistent size groove where the crack is located. Then cut a "V" shaped piece of mahogany to epoxy into the groove and sand flush. Has this been done before? Since the crack is not in a straight line, I was going to tack in place a temporary guide that followed the crack and run the router along this edge to locate the groove directly over where the crack is located. Will this work? Any ideas would be appreciated.

Thanks,

Speedboy

[Andrew Craig-Bennett]

Well, seems likely that it is a drying crack, due to the mahogany moving against the ply.

I would be rather inclined to do nothing with it, but proceed to stain and varnish as you intend to. It is of no structural importance, it won't show much under the varnish, and it may close of its own accord in more humid conditions, in which case filling it with a hard filler would be a serious mistake.

Having said which, a friend carried out a repair on a long drying crack in the side of his 30ft sailboat's coachroof coaming using just the method that you propose to use, and the repair has held for three seasons now, so, if you do feel a need to repair, I think you are on the right track.

[Jay Greer]

I have had success using furniature blemish repair burn in sticks for damage on varnished boat components..
These sticks are made of sealing wax and come in every color imaginable. They can be purchased from Mohawk Finishes. Also Woodcraft and Rockler stock some but not in all colors.