Pete Costa
06-15-2020, 9:42 PM
Apologies in advance for a lengthy post. My neighbor has asked for help on his pandemic project - a large built-in bar for his basement. It's an L shape, approx 7 ft by 14. He has built a solid base structure of framing studs and plywood (glued and screwed). He wants to wrap all of it with African mahogany - veneered plywood and battens on the sides and solid 5 inch wide boards for the top (for total of 20 inch width). This is where I'm supposed to provide support, but this is pretty far beyond anything I've ever done. I know that I need to allow for seasonal movement as well protecting all parts of the boards from the inevitable spills, etc. a bar top experiences. I also realize the glue up will be a bear of a challenge. Here's my current thoughts, welcome any and all suggestions.
- First challenge is that he wants single, continuos length boards on each side of the L. We let the wood it acclimate in his basement for a week or so, and then milled it in my shop. I only have a 6 inch long bed jointer, so we squared an edge first, ripped to width, then flattened a face best we could. Flattened is a very relative term given the length of these boards. All still have some bow and least one board has a significant localized kink in it (more on that below). Finally we planed them all to 3/4 thick and sent them back to his basement. The planed surface will be top side
He originally wanted to have the two parts of the L shape meet in a big miter. I explained how those joints might open up significantly with seasonal movement. We decided instead to do an overlapping pattern where board 1's end grain buts against board 2's side and board 2's end grain buts up to board 3 (which is parallel to board 1). I'll use a full width tenon across the end grain to go into a groove on the mating sides. I "think" this is the best option to minimize visual impact of movement, but am not sure. We are near max seasonal humidity, so at least we should be a max board width.
- Getting the boards to lay flat will be tricky to say the least. I'm going to use biscuits referenced off the top face and Titebond three (color is right and it's waterproof). I'm not sure if I should glue up 4 boards at once and then attach to the plywood base or get one board attached and then glue/attach the rest individually. I'll probably try to convince him he needs to buy a bunch more clamps to pull this off, which I will happily store for him once we're done :)
- In either event, I intend to solidly connect the center of the glued up panel to the plywood base from below with screws and construction adhesive. I'm hoping that the adhesive will have some flex to it so boards can move a bit. The outer edges will be secured down with construction adhesive and screws with slotted holes to allow for some movement.
- I'm hoping that between gluing up the boards to each other and securing the glued up panel to the base, we can resolve the remaining bows or twist in the boards. For the one bad kink, I may cut a series of kerfs across the bottom to allow it to bend flat more easily.
He wants to finish the bar with polyurethane. We'll do the bottoms and end grain before securing it to the base and then do the top once everything is in place. I need to make sure the construction adhesive can attach to the poly.
So what am I getting wrong or just plain missing?
Thanks,
Pete
- First challenge is that he wants single, continuos length boards on each side of the L. We let the wood it acclimate in his basement for a week or so, and then milled it in my shop. I only have a 6 inch long bed jointer, so we squared an edge first, ripped to width, then flattened a face best we could. Flattened is a very relative term given the length of these boards. All still have some bow and least one board has a significant localized kink in it (more on that below). Finally we planed them all to 3/4 thick and sent them back to his basement. The planed surface will be top side
He originally wanted to have the two parts of the L shape meet in a big miter. I explained how those joints might open up significantly with seasonal movement. We decided instead to do an overlapping pattern where board 1's end grain buts against board 2's side and board 2's end grain buts up to board 3 (which is parallel to board 1). I'll use a full width tenon across the end grain to go into a groove on the mating sides. I "think" this is the best option to minimize visual impact of movement, but am not sure. We are near max seasonal humidity, so at least we should be a max board width.
- Getting the boards to lay flat will be tricky to say the least. I'm going to use biscuits referenced off the top face and Titebond three (color is right and it's waterproof). I'm not sure if I should glue up 4 boards at once and then attach to the plywood base or get one board attached and then glue/attach the rest individually. I'll probably try to convince him he needs to buy a bunch more clamps to pull this off, which I will happily store for him once we're done :)
- In either event, I intend to solidly connect the center of the glued up panel to the plywood base from below with screws and construction adhesive. I'm hoping that the adhesive will have some flex to it so boards can move a bit. The outer edges will be secured down with construction adhesive and screws with slotted holes to allow for some movement.
- I'm hoping that between gluing up the boards to each other and securing the glued up panel to the base, we can resolve the remaining bows or twist in the boards. For the one bad kink, I may cut a series of kerfs across the bottom to allow it to bend flat more easily.
He wants to finish the bar with polyurethane. We'll do the bottoms and end grain before securing it to the base and then do the top once everything is in place. I need to make sure the construction adhesive can attach to the poly.
So what am I getting wrong or just plain missing?
Thanks,
Pete