# Best way to edge-glue boards for table top? To biscuit or not to biscuit??



## jonmakesthings (Feb 28, 2016)

Hey guys, seeking some advice on the best way to edge glue boards for a dining room table top. The boards will be 1 1/2 thick, 5 to 8" wide. Assembled top will be somewhere around 40"x72". Most likely going to attach it to the frame with figure 8's.

My biggest question is whether to use biscuits or not. I don't have a biscuit cutter, I would just rout out slots with a plunge router if I went that way, and using strips of wood as the biscuits. They would probably provide more stability during the glue up, keeping everything lined up.
What is your experience with biscuit joints?

UPDATE: Another question, would biscuits add much strength to the joint as opposed to just glue?


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## Kirk650 (May 8, 2016)

I often use my biscuit joiner to line up boards. It works real well. Using the router and wood strips should work just as well.


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## OSU55 (Dec 14, 2012)

Best way to do panel glue ups is well jointed edges and clamping cauls to line the boards up. Here's how to make and use them.


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## jonmakesthings (Feb 28, 2016)

OSU55
Thanks, I've been thinking about trying cauls, they seem easier to make and use than I previously thought.


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## ArlinEastman (May 22, 2011)

Most people that I know just edge glue it and put it in clamps. They do take off just about .003 out of the center and can not remember why. I have also seen many people say biscuits and things like that swell in the joint from the glue and lift up the wood.


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## MadMark (Jun 3, 2014)

Flip the grain cup on each piece. Its called a splined joint when it runs long. Glue alone is as strong as you can get. The spline looks nice on the end and helps in alignment.
Make sure the edges of your stock are crisp & sharp. Cauls are nothing than cross joint boards. There is nothing to 'make'.

Glue up in pairs and plane while you can. At least half the sanding is eliminated this way.
M


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## knotscott (Feb 27, 2009)

If the joints mate properly you really shouldn't need biscuits. They can help get the boards aligned, but so do splines. There's no substitute for flat, straight, square, and uniform thickness.


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## bbasiaga (Dec 8, 2012)

> Flip the grain cup on each piece. Its called a splined joint when it runs long. Glue alone is as strong as you can get. The spline looks nice on the end and helps in alignment.
> Make sure the edges of your stock are crisp & sharp. Cauls are nothing than cross joint boards. There is nothing to make .
> 
> Glue up in pairs and plane while you can. At least half the sanding is eliminated this way.
> ...


Most of the time, especially for wider pieces, people make calls with a slight radius to them. This transmits the clamping force along the whole length of the call, even when applied by clamps to the end. It works well. Math class in action. It is pretty easy to make them. Takes about 10min to make a set.

Note..my phone refuses to allow the proper spelling of 'call'

Brian


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## Unknowncraftsman (Jun 23, 2013)

I just don't see the need for biscuits,Cauls,splines.Wood that's faced flat on a jointer then planed.Edges square to the faces don't need any help to lay flat.
A flat assembly table with decent clamps is all I ever need.I do use spring clamps on the ends.
Things do get slippy with the glue just a little adjustment with my finger pressure is all that's needed.


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## Tabletop (May 9, 2016)

I've Built literally hundreds of tables and have come to this conclusion, "do what you feel like doing". It's that simple. The fact that your using those thick boards will give you plenty of gluing surface and make a strong joint. However, it's only true if your boards are making contact through the entire depth of the board. Must have square, clean edges. When do I use biscuits, when using reclaimed lumber and for big glue ups(anything more than just half a dozen boards).

Reclaimed lumber may have spots where I can't get two clean solid edges together. Multiple boards plus all that glue makes for a headache trying to keep them flat/straight when you start clamping and the boards start sliding with all the glue. .


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## becikeja (Sep 12, 2010)

I use biscuits, not sure why, just do.
Hmmm. Maybe I should re-think this.


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## endgrainy (Mar 25, 2013)

I used dominos to align the boards on my recent dining table top glue up. Typically, I just edge joint the boards (as the joint is plenty strong) but trying to align several 8' long boards is a pain, even with cauls. The dominos made it pretty exact, and is super easy. Trying to remove even 1/16" of post glue-up discrepancy over 8 feet is a pain.


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## Mikesawdust (Jan 29, 2010)

I usually skip biscuits, and just join the edges clamping and aligning as necessary. I've run into several issues in the past with biscuits, mostly from not planning better or changing plans. 1. If they are too near the ends and you change the length, you end with a biscuit showing. 2. if you need to re-flatten the surface when the wood moves on you, you can have a biscuit surface on you. 3. Make sure you let the glue dry completely and the wood dry from the moisture added, because the glue is in a pocket the surrounding wood swells for a couple of days and if you flatten it before it settles you end up with low areas at each biscuit after it dries out. 4. Check the biscuit joiner closely and often, I had a pin work it's way out of the machine part way through the operation and wasn't aware till I tried to line up the boards. 5. Test the joiner on scrap pieces to confirm its set at the correct thickness and depth, painful when you start to glue up and realize the boards are still 1/32" apart because the depth was set wrong.


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## MrFid (Mar 9, 2013)

http://www.rpwoodwork.com/blog/2016/03/11/edge-to-edge-joints-part-1/

This is part 1 of an 8 part blog on edge joints. Rob is a great writer along with being a skilled woodworker. I am not connected with him other than being a fan.


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## jimintx (Jan 23, 2014)

I use biscuits because they are easy and cheap and I have no reason to not use them. At the very least, they give me a personal sense of a more secure joint, and such peace of mind is valuable to me.

I've never experienced a biscuit causing the wood above it to rise due to the biscuit swelling. My guess, if that is happening, is I suspect the biscuit is too close to the surface, and perhaps it is too large.


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## Dwain (Nov 1, 2007)

Knotscott is preaching the word in a short and sweet manner. Biscuits aren't needed, but the may help with alignment. If the boards are good (straight and flat) then they aren't necessary. I used biscuits on some of my first tables, but the tops were two inches thick, so swelling really wasn't much of an issue. I'd say to try it both ways, see what happens. It certainly won't hurt, it just may not help as much as you think it will.

Good luck. Have fun. Get to the shop!


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## ssnvet (Jan 10, 2012)

I use biscuits….

Primarily because it makes me feel like I didn't totally waste the money I spent on a nice PC biscuit jointer :^p


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## 000 (Dec 9, 2015)

Depends on the size of the table and how many boards are being glued up.
On bigger tops biscuits are an advantage, I don't care how straight and flat your boards are, biscuits save time lining up the boards before glue starts to set up. 
On the other hand some good Cauls work well also. 
Preparation before the glue up is important. 
Nothing worse than things not lining up and glue starting to set up and before you know it you have a mess on your hands.

I have a table top in my shop right now, that someone else made, and you can see the telegraphing from the biscuits on every seam. Looks like the wood swelled then got sanded and the wood shrunk where the biscuits were.
Probably a good idea to keep them as low.

I don't buy into the theory that biscuits don't add strength, (just not a significant amount).
Do a test. Put 2 boards together with glued biscuits, (no glue on the edges of the boards) 
now compare to 2 more boards with no biscuits and no glue on the edges of the boards, 
which is stronger? :>/


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## jimintx (Jan 23, 2014)

I love that test you suggest, jbay. 
I bet we can predict the outcome without doing the experiment.


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## jonmakesthings (Feb 28, 2016)

Thanks guys. I spent a good part of today planing the edges flat on the boards. Getting to know my plane very well haha. I'm just going to glue, no biscuits. However I'm also putting breadboards on the ends so I'm definitely going to spline those joints to help keep the top from warping


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## rwe2156 (May 7, 2014)

If you're hand planing the top make sure the grain in each board is going the same way. Of course depends somewhat on wood, but I STILL make this mistake sometimes.

I don't use biscuits anymore I find if the stock is decent and flat not necessary. But if there is a boards with a little bow I'm looking to cancel out, I might use them.


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## distrbd (Sep 14, 2011)

On long boards I use two dowels ,one on each end (approximately) to stop slipping/sliding of the pieces but using cauls is a must for wide glue ups .


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## RogerM (Oct 31, 2011)

True flat butt joints are very strong. Biscuits help align the stock and adds a little more strength. Make your own call as to how strong you want the joint.


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## AlAmantea (Apr 22, 2014)

> Most people that I know just edge glue it and put it in clamps. They do take off just about .003 out of the center and can not remember why.
> - Arlin Eastman


Arlin,

This removal of .003 to .005 of material from the center of the boards along their length is known as a "sprung joint". This type of joint helps to eliminate gaps in the center of an edge glue up, and reduces the number of clamps needed for a long edge joint glue up. When the boards are clamped up, the outer ends of the joint touch before the center, creating more clamping force at the outside ends of the glue up.

Gentlemen, if your big concern here is in alignment and shifting of the board during the clamping process, try sprinkling a little bit of salt onto the joint during glue up. The salt crystals embed themselves into the edge of the board, preventing the boards from moving during the clamping process.

I also am in the camp that believes biscuits DO provide strength to a joint the same way that a spline does, in addition to assisting in alignment during assembly. The only real difference here is the length of the spline.

Pocket holes drilled on the bottom side of the joint could also be used with great success.

Anyone with experience in using biscuits can tell you that they need to be placed at least one third the thickness of the material away from the face. Biscuits are made from compressed beechwood, and are designed to swell in the slot once glued. This is not a defect of their use, it is by design. The defect comes from the lack of knowledge in using them properly. In edge glue up thicker than 1 inch, I always use a double row of biscuits just the same as I would use a double row of splines. This can assist in preventing the glue up from bowing during clamping as the clamps are tightened.

Always alternate your clamps from top to bottom, placing even numbered clamps on the top face, and odd numbered clamps on the bottom face (or vice-versa).

Cauls are an excellent way to help with face alignment as well.

Then again, spring clamps placed on the ends of the joint can be almost as effective.

There are many ways to achieve the goal of a straight, flat, panel during a glue up. The right way depends on the preference and experience of the craftsman, the tools and materials at hand, and the condition of the workpieces.

Use what you you feel comfortable with or have used before with success. Don't be afraid to try another method.

With today's glues, even a simple butt joint will end up stronger than the wood itself if given time to fully cure before stressing the joint. This doesn't mean leaving it in clamps overnight, but resist the temptation to start smoothing or working joint until the next day.


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