A Different Maple Finishing Problem

[Ed Bailen]

When #1 nephew built his new house, he bought 1/2 of the floor from a gym that was being torn down. In exchange for spending a month of weekends cutting staples off the old maple flooring, the rest of the family has unlimited access to the maple left over after he finished the house. There is a LOT of left over maple flooring.

Over the past few years, I've made a number of tables and benches out of the stuff, but the last two projects have me stumped. I'm making two desk tops for our computers. The wife's desk top is assembled from .75 x 1.75 planks joined on the .75" edge. My desk top has the planks joined on the 1.75" edge. On both tops, there are areas where the boards did not meet entirelely flat, and there are some gaps that are less than 1/64" wide. Most of the gaps filled with varnish, but some appear to have some sort of surface tension problem. The varnish beads up at the edges of the crack and refuses to penetrate or bridge. I've tried a wiping varnish and a brush-on varnish.

In preparing the boards for assembly, the top side of the plank was run through the planer to remove the finish, and the remainder of the planing was done on the bottom side to remove the grooves. The sides of the planks were planed only to the point where the tongue and the groove were removed. I could surmise that there was some remnant of the original gym floor finish or wax that was causing the problems with the face-jointed desktop, but that doesn't seem to cover the problems with the edge-jointed one.

Since everything is all glued up, I guess I'm more in need of a solution than an explanation. Does anyone have any suggestions?

Thanks, Ed Bailen

[Bob S.]

Ed,

Sounds like the wood has been burnished and now won't accept stain in certain areas. Maximum sanding grit recommendations from the 'perts is 220 grit. Past that and you'll just be polishing the wood. Suggest you try sanding to say 150 grit and then apply the stain.

Bob S.,

[Bill Wallace]

Things to try are:

1. Thin the finish more. It seems counter intuitive that thinner would fill better but the thinner might have a different surface tension character.

1. Thin with something different, ie if you can thin with thinner or spirits, then try the other one. Same surface tension thing. I've heard of adding soap or some other things in water based finishes to reduce tension. Note sure if there is a varnish equivelant.

2. If you just have a few gaps here and there you can try filling the gaps with slivers of wood. Just tamp in some toothpicks, etc.

Finally, from the repair problems I've had I believe that if you cant quickly find an acceptable mid-finish repair, then sand it off and start completly over, filling the gaps with some appropriate medium first.