[Ronnie1a]

I built a large desktop with 1/4" inlay in the middle of zebrawood. I had to use two pieces of zebra but they were butted together perfectly. I applied 8 coats of General oil and urethane topcoat and sanded between coats. After I brought it in the house from my workshop a very small gap developed where I butted the two pieces of zebrawood together. I am thinking, now, the wood maybe shrunk a little. My wordshop was in the mid 80s in the summer but the house is cooler.

This may sound crazy: can I fill in the tiny gap (1/2 the thickness of a fingernail) with more topcoat maybe using a syringe and needle? The gap is just enough to catch the tip of a ball point pen when writing on paper over it.

 

[Dave Paine]

I think your large desktop has lost moisture causing the inlay to open up.

The finish slows down the exchange of moisture between the wood and surrounding atmosphere, but it does not stop all moisture changes.

How long has this been in the house? I would not attempt to fix until you are sure the table has reached moisture equilibrium with the room. Perhaps give this until next spring.

As we go through winter, the table could shrink some more.

 

[Ronnie1a]

It has been sitting in the house about two weeks.

Do you think it is just moisture and not temp?

 

[Dave Paine]

Do you think it is just moisture and not temp?

Yes, I would be surprised if temperature alone caused a dimension change. Wood density changes with temperature very little, compared to e.g., metal.

 

[Steve Neul]

Moisture changes can have a profound affect on wood. I once moved a 100 year old oak dining room table from Illinois to Texas that was in perfect condition. Within a month a crack appeared on the top and within 3 months there was 7 cracks in the table. Since you built your table there are a couple of things that might have contributed in the joint failing. You might not have had as good of glue joint as you thought. Also if the top wasn't engineered for wood movement the difference in the humidity could have caused it. The 100 year old table I had the skirt was firmly glued to the underside of the top. Because it didn't allow for wood movement when I moved it to a dryer climate the top cracked.

 

[cabinetman]

Percentages in moisture changes are the primary reason, but temperatures can also have an effect. Physically, slight changes to expansion and contraction when warmer or colder, could contribute to the separation you experienced. Part of it may be the glue bond reacting.

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