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Yet another breadboard question - joining countertop sections

mylescdavis's picture

This is my first post here, finally figured I'd ante up to learn from the ridiculous amount of knowledge on the FWW forums.


I'm working in France (although I'm American) and there's very little here in the way of activity or support for individual woodworkers - I'm very envious of folks doing woodworking in the US for the options you have in material, tools and know-how.

I'm in the middle of a large project building cabinets for a couple of bathrooms and a kitchen.  Boxes are birch ply; face frames, doors and drawer fronts are maple.  Everything exterior is painted (I know, why use maple if you're painting... long story.)

I've committed myself to doing cherry countertops with breadboard ends on these, which have gone fine for the first few small individual cabinets.  However, the bathroom countertop is supposed to be... 9 feet long!  And I was the designer... sigh.  Nothing like the clueless ambition of the first-timer.

As the supply of 9-foot-long cherry is limited here , my idea was to do three sections, and join the sections of the the long countertop with a double-faced breadboard, with a mortise in both sides, and routed tenons in the ends of the tops.  Does this make sense?  I don't know of any other way to join the sections together.

Any tips or thoughts pro or con would be really helpful - thanks!

Westchester's picture

Design (post #170811, reply #1 of 7)

Is it safer to run all the boards all one way given the limited lumber supply - no breadboard  -the width way say about 24 inches deep ? - show the end grain -

SA

 

RalphBarker's picture

Sinks? (post #170811, reply #2 of 7)

With a 9' length, am I correct in assuming two sinks? If so, how are you handling the affects of wood movement on the under-sink connections? Flexible supply lines to the faucets shouldn't be a problem, but the drains probably would be.

Two interior breadboards would seem to divide the counter into logical sections, with the two (presumed) sinks in the outer ones. I'd be concerned about water getting into the joints of the breadboards, however, with all of the issues associated with that. Plus, there's the issue of sealing the sink to the countertop.

Thus, I'm wondering if (well sealed) cherry veneer on an MDF base might not be a better idea.

mylescdavis's picture

Thanks for the replies.  In (post #170811, reply #3 of 7)

Thanks for the replies.  In answer to the first question, I'd rather not show the end grain, and I have plenty of wood, so running longwise isn't an issue.

To Ralph's question, there will be two sinks, but they're the kind that sit on top of the counter - sort of bowl-shaped.  We'll leave plenty of clearance around the drain for movement.  The sinks will be closer together than would be symmetrical, in part because of an L on the right side - there's a Sketchup export of the plan attached.  So, not worrying about symmetry.

Water is obviously a concern, so I'm going to go for the practical approach and use a polyurethane varnish - not the prettiest way to do it, but neither are water stains and a high-maintenance countertop.

The MDF/veneer approach might be good, but, as I mentioned, what's readily available in the US isn't necessarily easy to get here.  Plus, the lumber's cut, thickness, jointed and half of it's glued up, so we've burned that bridge!

Thanks again for the help.

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HowardAcheson's picture

If your plan is to run the (post #170811, reply #4 of 7)

If your plan is to run the "breadboard" connector pieces across the grain of the main panels, you will have a problem.  Your panels will want to expand and contract with changes in their moisture content caused by changes in relative humidity.  The cross grain boards will restrict this movement causing probable warping, cracking or other damage.

If you plan to not glue the breadboard junctions, you will be left with an unsealed seam where water will surely penetrate.  This will cause discoloration and damage to the finish allowing water to get under the finish.

Breadboard treatments are only used on the ends of surfaces and are constructed so that the panels can freely expand and contract.  They are never glued on or otherwise rigidly attached.

Howie.........
mylescdavis's picture

Hmmm... (post #170811, reply #5 of 7)

HowardAcheson wrote:

If your plan is to run the "breadboard" connector pieces across the grain of the main panels, you will have a problem.  Your panels will want to expand and contract with changes in their moisture content caused by changes in relative humidity.  The cross grain boards will restrict this movement causing probable warping, cracking or other damage.

If you plan to not glue the breadboard junctions, you will be left with an unsealed seam where water will surely penetrate.  This will cause discoloration and damage to the finish allowing water to get under the finish.

Breadboard treatments are only used on the ends of surfaces and are constructed so that the panels can freely expand and contract.  They are never glued on or otherwise rigidly attached.


Well, that's something I hadn't thought of, obvious though it seems.  I appreciate it.

Trying to figure out how to salvage this...

1.  Ignore the problem, hope the water getting in isn't too bad.  Obviously, limited appeal.

2.  Butt-joint the ends of the long-wise pieces using a hidden birch ply spline, finish over seam.  Might be OK, if it would work.

3. Use the original idea, but polyurethane the inside of the mortise and the outside of the tenon before joining together in an effort to seal the wood sufficiently.   Useless?

This isn't a piece of furniture to hand down to my grandchildren, it's a bathroom countertop.  If it lasts ten years, I'll be happy, and probably living in a different house, and the new owners of this place will have ripped this out to put in granite.

Any thoughts?

sid works's picture

why not use (post #170811, reply #6 of 7)

those materials elsewhere. and procure the right dimension to do the job properly. it must me wonderful to not have a conscience and pass on a piece of poop to someone else to deal with. we all must deal with our own mistakes, but is a real pains to deal with others.

ron

HowardAcheson's picture

>>>>  1.  Ignore the problem, (post #170811, reply #7 of 7)

>>>>  1.  Ignore the problem, hope the water getting in isn't too bad.  Obviously, limited appeal.

While the water penetration is a long term problem, the most immediate and most severe problem is the restriction of movement.

>>>>  2.  Butt-joint the ends of the long-wise pieces using a hidden birch ply spline, finish over seam.  Might be OK, if it would work.

Not a good solution.  The plywood spline will act just like a breadboard cross piece.  It would restrict the movement of the solid wood panel pieces with all the negative consequenses of the glued on breadboard.  An option is to use a solid wood spline with the grain of the spline running the same direction as the grain in the panel.  This way your spline will expand and contract in sequence with the panels.

>>>>  3. Use the original idea, but polyurethane the inside of the mortise and the outside of the tenon before joining together in an effort to seal the wood sufficiently.   Useless?

Yes, pretty useless.  No finish is 100% impervious to water vapor.  In other words, moisture will penetrate the finish.

Let me say that the biggest issue you have is with the wood movement.  Finish is mostly cosmetic while wood movement is structural.  If you don't deal with the wood movement issue, the problems with finishing are not soluable.  The best solution is to get longer boards or construct the top using plywood.

Howie.........