# Joining multiple pieces of African Mahogany



## Alex Lapointe (Mar 14, 2021)

Hello all,

new member and first time poster. I am new to working with exotic woods, and I am a bit hesitant to potentially screw up expensive slabs.

I am building a bar and want to make it out of 7/4 African mahogany. It needs to be about 32” wide by about 9’ long. The only access I have to this type of wood locally is quarter sawn 7/4 about 9” wide by about 10’ long.
I need to join 4 pieces to make the required width and then rip it down. I have looked into splines, glue only and other joining methods. I know glue is stronger than most woods, and the bar will have the appropriate overhang support, but I just want to see what other recommendations are out there. I have also heard that mahogany can have a lot of tension in the grain depending on how you rip it down.

I’m open to any suggestions. The bar will eventually be finished with a bar top high gloss epoxy hopefully with a hand made live edge.

Thanks in advance!


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## epicfail48 (Mar 27, 2014)

A properly prepped joint thats just glued will end up being nearly as strong as just a solid board, personally i dont feel you need anything else added in. Biscuits, dowels, and the like are useful to keep boards aligned, but i dont feel that they really add any strength. After all, if youre already at max strength, you cant really go upwards

One thing to watch out for, some breeds of mahogany can have a pretty high oil content, which will interfere with glue if present. To be on the safe side, wipe down the surfaces to be glued with some acetone on a white cloth, keep wiping until the cloth stops picking up color from the wood. Cheap insurance for a glueup


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## Tony B (Jul 30, 2008)

All at is needed is a good glue-up. Same old story - the glue-up joint is stronger than the original wood. When I first started out in woodworking, I heard the story but Idecided to put it through a test. 
Find some scrap wood and glue two board together The following day, lay the glued boards across some bricks or 4x4's.
Give the joint your best shot with a sledge hammer when it splits, examine the broken area. The glued up area will show that the break is on either side of the joint or possibly part on one side and part on the other side of th joint.


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## difalkner (Nov 27, 2011)

Welcome to the forum! I agree that biscuits and other pieces like that really don't add strength but they are quite helpful for alignment. One thing to keep in mind is that while you're starting with 7/4 thickness you'll be doing great to end up at 6/4 if you're only leveling the top side, likely closer to 5/4 if you're leveling both sides.

David


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## B Coll (Nov 2, 2019)

Alex Lapointe said:


> Hello all,
> 
> new member and first time poster. I am new to working with exotic woods, and I am a bit hesitant to potentially screw up expensive slabs.
> 
> ...


Just a glue up with a proper prepared edge is more than adequate. Biscuits and dowels are useless. Make yourself a few pairs of cauls with a very, very slight taper to put increased pressure inboard. As long as the boards are consistent thickness you should get a perfect glue up. Here is another tip. If preparing the edge with a jointer, mark the edge with an arrow pointing towards the fence. At each joint, the arrows should be opposite each other. Even the slightest of deviations in a 90 degree fence set up will be compensated for. The fence can be 5 degrees out and you will still get a perfect glue up.


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## woodnthings (Jan 24, 2009)

difalkner said:


> Welcome to the forum! I agree that biscuits and other pieces like that really don't add strength but they are quite helpful for alignment. One thing to keep in mind is that while you're starting with 7/4 thickness you'll be doing great to end up at 6/4 if you're only leveling the top side, likely closer to 5/4 if you're leveling both sides.
> 
> David


Your technique is very important when using a biscuit joiner ..... as I found out after my slots and biscuits didn't align. Your *boards or slabs must be the same thickness *no matter your joining process or alignment will be a crap shoot. And all the slots must be referenced off the same surface, either the back or the top for best results. Any variation in the distance down from the plate or up from the table to the slot will be an issue when trying to join the boards together. You Tube will have videos on how to use a biscuit or plate joiner.


https://www.youtube.com/results?search_query=using+a+biscuit+joiner
















When using my joiner, I removed the standard issue table plate which you can set to different angles and I used the larger and wider base instead. I referenced all my biscuits from the work table surface since the biscuit joiner's table plate was removed. I was chastised for removing that table plate, but turns out it was not only "allowed" but preferred! All my efforts are exposed here:








Biscuit joiner project for a buddy


So Walt the computer whiz and budding woodworker calls up and says "Hey, you got a biscuit joiner?" ....Yup, Never used it though. .... "Bring it over, I've got a project I need it for." ....OK, I'll be there shortly and I'll bring the computer with no sound... "see Ya." Actually I brought over...




www.woodworkingtalk.com


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## Alex Lapointe (Mar 14, 2021)

Great info guys thanks. I do not have a planer or joiner, but the wood I’m looking at is already kiln dried and cut and flattened. It’s not rough sawn. I’m hoping to get away with a table saw or a track saw just to clean up the edges, if required at all.


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## Steve Neul (Sep 2, 2011)

Without a jointer I would recommend putting splines in the joint. Glue alone is pretty good however making the joint with a saw the texture of the saw cut makes the joint a little weaker. Running splines would compensate for the loss you would have. If you have finished ends you could always stop the dado back from the ends so the splines wouldn't show. Another option would be to put dowels in the joint.


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## difalkner (Nov 27, 2011)

Alex Lapointe said:


> Great info guys thanks. I do not have a planer or joiner, but the wood I’m looking at is already kiln dried and cut and flattened. It’s not rough sawn. I’m hoping to get away with a table saw or a track saw just to clean up the edges, if required at all.


Those are good goals but not likely to happen. I've glued hundreds of boards for large panels, plaques, tables, etc. and even when using double biscuits the boards will slip and slide and your clamps will pull them in directions you didn't intend or foresee. 

I would suggest you dry fit everything first to ensure your technique is good and that you have everything at your disposal for this gluing process. It it doesn't go smoothly when you test dry fit and clamp the boards then it's going to be really rough with glue added to the mix. In dry fitting I often find ways I can improve the process once glue is applied.

David


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## woodnthings (Jan 24, 2009)

Slippin' and slidin' with the glue up, for certain. An old woodworker's trick is to drive small brads into the edge of one piece and snip off the heads to a sharp point then slide them together on a flat surface and then the clamps will drive the "pins" into both edges and keep them aligned.


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## Alex Lapointe (Mar 14, 2021)

Thanks guys. I think I may reach out to a local wood worker and see if he can joint, plane and glue all the pieces for me and give it a final planing. Then I can cut it to spec, sand and finish it. This is not a project I want to re-do in a year because it is warped or the joints have popped. I want to do it right the first time so it may just be worth it to have somebody else do the rough work.


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## epicfail48 (Mar 27, 2014)

Alex, thats probably the smart way of doing it. Mahogany isnt exactly cheap after all, and youre completely correct, you dont want to have to go back and fix something later. One thing to keep in the mind for the future, most lumber yards will completely surface whatever wood you buy for a small fee. The place i go to has got the works, giant jointers and planers and drum sanders, and theyll finish to whatever specs i want. Generally the stuff they sell is s2s, but if i need to i can have them do all 4 sides, milled to whatever width and thickness i want. Your local yard might not be exactly the same, but id be willing to bet theyve got a jointer and planer that theyll use if youre paying them

For future projects, i very strongly recommend saving up for a thickness planer, opens up all sorts of possibilities in woodworking when you can mill your own lumber


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## woodnthings (Jan 24, 2009)

epicfail48 said:


> Alex, thats probably the smart way of doing it. Mahogany isnt exactly cheap after all, and you're completely correct, you dont want to have to go back and fix something later. One thing to keep in the mind for the future, most lumber yards will completely surface whatever wood you buy for a small fee. The place i go to has got the works, giant jointers and planers and drum sanders, and theyll finish to whatever specs i want. Generally the stuff they sell is s2s, but if i need to i can have them do all 4 sides, milled to whatever width and thickness i want. Your local yard might not be exactly the same, but id be willing to bet they've got a jointer and planer that theyll use if youre paying them
> 
> For future projects, i very strongly recommend saving up for a thickness planer, opens up all sorts of possibilities in woodworking when you can mill your own lumber


Typical local lumber yards won't have a wide belt sander or a thickness planer wide enough. In my case, for the projects that are too wide for me to handle, I rely on a friend's custom door making shop where he has a 42" wide belt sander. It's the only way to attain a wide flat even surface from a glue up. Thickness planers aren't that wide even for cabinet shops, only lumber mills. Wide belt sanders are used in most cabinet shops these days. Custom door makers are far and few between these days, so finding one may be difficult.


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## difalkner (Nov 27, 2011)

A good friend has a cabinet shop and does some occasional sanding and planing for me; they have a 24" planer with spiral cutterhead and a 36" wide belt sander. You might check with a local cabinet shop and see if they can do this for you.

David


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## epicfail48 (Mar 27, 2014)

I was meaning more to dimension the boards before glueup, though i did fail to specify that, so my bad! My typical glueup procedure for wide panels is to joint both edges and plane to final thickness, then do the glueup. Personal view is that if theres any variance between the boards large enough to require planing, then there was a failure somewhere in the gluing process. Proper use of clamping cauls and well-prepared stock doesnt leave much to clean off


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## Alex Lapointe (Mar 14, 2021)

Thanks everyone for the help. I found a place in NH that has a good selection of what I’ll looking for, although maybe a bit too thin. 6/4 vs 8/4 which will plane/sand down to my desired 1 3/4” final thickness. I also found a local woodworker with a 24” planer and a 36” drum sander that should be able to help me out. 

Lastly, one of the counter tops I need to build needs to be about 11’ 4 1/2”. The longest African mahogany I can find is 10’. Can multiple boards be joined on the long edge with shorter pieces also joined at the end grain to get me my desired length?

Thanks again.


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## difalkner (Nov 27, 2011)

Alex Lapointe said:


> Can multiple boards be joined on the long edge with shorter pieces also joined at the end grain to get me my desired length?


Yes, if you don't mind the joint showing. You could always do a scarf joint and that would be very strong.

David


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## Alex Lapointe (Mar 14, 2021)

I don’t think I would mind the seams. Obviously I wouldn’t just join a 16” piece to the end, I’d make it longer and more random across the multiple pieces I’d like to join. I also considered breadboard ends.


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