ship lab joint or butt joint for serving tray base

  • 19 Sep 2017 4:28 PM
    Message # 5270046

    I'm making a serving tray for my wife, and it is quite large (approx 25"x17").  because of the width, I'm going to have to glue up the panel I'm using for the base of the tray.  My first attempt at the base was foiled, as I stacked the 1/4" maple panels on top of one another and they all bowed quite drastically after resting for a week in the shop.  For my new attempt (still maple) I've planed 3 panels down to 1/2" thickness (each is 25"x6"x 1/2") and they are propped up on edge on my bench waiting to be glued up (air space between them). I am hoping they don't bow as the wood has been in the shop for a few months now and it has been quite hot and dry this summer  

    I'm wondering if there is value in planing a rabbet into the panels and gluing them up with a ship lap joint, or should I just use a butt joint?  I plan to use cauls either way, but hoping to minimize the amount of hand planing it will take to even up the joint after the glue dries (my power planer can only accommodate 13") and I prefer the finish from the hand planer of course.  

    The last question... is there a method to arranging the panels to ensure ease of planing after they are joined?  Any tips are welcome!  Thanks!


    Stephen

  • 19 Sep 2017 5:29 PM
    Reply # 5270138 on 5270046
    ROB COSMAN (Administrator)

    HI Stephen, butt joint is stronger than the wood so no need to "reinforce" the joint.  There is a good argument for alignment purposes but if you glue one at a time it is easy to keep the joint flush.  Once that is dry, add another till you are done.  I prefer to pre-plane the boards, this tells you the best planing direction.  Mark it and use this to determine your glue up.

    cheers

    Rob


  • 19 Sep 2017 11:41 PM
    Reply # 5270590 on 5270046

    sounds good!  I'll post some updates as I proceed

  • 12 Oct 2017 8:20 AM
    Reply # 5310252 on 5270046

    Take some stock, could be anything, construction grade or whatever you have in the shop. Square it up, then create some clamping bows (gonna need 4 of these)Leave them full thickness in the middle, and taper them down about an 1/8" to 3/13" to either end. Let's call that the bottom. Now on the top, cut a groove, end to end at least a 1/2" deep. Then wax the hell out of em.(wax will keep the glue from sticking to the bows)When you glue up your panels, apply the glue to the edges. Apply clamps like normal. While the glue is still wet, lay two bows groove down. Lay panel on top of those. Put remaining two bows on top with the grooves up. Apply clamps to the ends of the bows at both ends. Top of clamp on top bow, bottom of clamp on bottom bow. Like a sandwich, pinching the panel between both pairs of bows. Apply pressure with the clamps until the bows are flat to the panel. Looking down the bows, they will look "bowed" across the top.(hence the term clamping bows). This bowed effect will put even pressure across the entire panel, helping it to stay flat and aligned. Also, your clamps that you use to clamp the panel together, put just enough pressure on those to hold the panel together. After you have pressure on the bows, then you can apply as much pressure as you want on the others, and they will still stay aligned. Use slow setting glue as well. Maybe a polyurethane glue. The more working time you have the better. You need to be able to take your time and make adjustments. Get a construction crayon. When you preplane, put a big arrow in the direction of the grain on the top and the bottom of each board. When you glue up the panel, make all the arrow point in the same direction.

    Last modified: 12 Oct 2017 8:27 AM | Richard Blair
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