Gluing Up a Cherry and Maple Tabletop cherry & maple
A woodworker gets advice on allowing for movement when gluing different wood species together. December 20, 2005
Question
I have a customer who wants a table top built from cherry and maple boards, glued side by side. Is there anyone out there who can advise how to do this? Are there any special adhesives that I should use to bond two different woods?
Forum Responses
(Adhesives Forum)
From contributor A:
How large is this top and does the end grain present itself on the short or long side?
From the original questioner:
The table will be 6' long, and about 3-1/2' wide, including 6" hinged drop leaves on either side. As for exposed end grain, we haven't come to a decision yet. We're looking at some different designs. Are you concerned about splitting, or differing expansion and contraction rates of the two woods showing at the ends?
From contributor A:
My concern is not with the different woods or adhesion, but with the width of each piece. It would help to keep the width to no more than 3-4" if possible, and attach the top in a way that allows it to expand width-wise. If a breadboard edge is used, it too needs to allow for expansion.
From contributor B:
I've made several countertop pieces with mixed species. Cherry with maple is familiar to me, as I have put together three of them with 2" wide pieces. One of these has a breadboard end. I suggest you make absolutely sure that both species are at the same moisture content by checking it at a fresh cut several inches into the wood. I would be confident that the movement across a 30" piece would be no more than 3/4" (assuming it isn't QS stock). One half inch expansion slots at the outer attachment points will assure you enough room, and the same goes for breadboard end, if used.
From the original questioner:
I'm unfamiliar with the use of expansion slots. Would you explain?
From Gene Wengert, Sawing and Drying technical advisor:
Cherry and hard maple will swell and shrink about the same amount when the MC changes. Joining them will not be a special problem. However, whether you use mixed species or not, with such a large top you need to be careful to assure that all the pieces are the same MC, that the MC is 6.0 to 6.5% MC, that the surfaces are freshly prepared, that the customer knows that annual cycles of humidity will cause some movement and joints with the leaves may not be perfect at times, and that a skirt on the bottom to hold the legs must float - to name a few items.
