# Edge jointing two pine boards advice needed



## controlfreak (Jun 29, 2019)

I have done this on smaller boards but in this case I will have two boards 7' lone 7" wide 7/8 thick. I will edge joint the boards and then glue. I have lots of F clamps, 4 to 6 pipe clamps and a couple of parallel clamps. Also have a variety of trigger handle clamps. I realize that thing get squishy and move when pressure is applied. So I need to put together a plan of attack. I can use pipe clamps to help stabilize but not enough to firm the whole length. I could augment with cauls clamped as needed. And I can breakout a bosch biscuit jointer I picked up at a yard sale for $15. Not so much for strength but to assist with alignment issues. I will need to resist torqueing down the clamps with all my might as I have done in the past and give this a light touch this time. I can only imagine the anxiety of gluing up a table top.

Any input would be appreciated.


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## splintergroup (Jan 20, 2015)

I'm a big fan of cauls for jobs like this and have fallen to the seduction of biscuits on occasion. For something that long, even three biscuits would help you get the initial alignment close enough to slap on some cauls and git-er-done.

Lay out half of the clamps on the table to clamp from underneath and the other half reserved for the top. You'll want to raise up your assembly from the table so you have room to move clamps in/out as needed.

After applying and spreading the glue (I'd do both surfaces), you should get the cauls placed and lightly clamped.

Apply the bottom side clamps evenly spaced and clamp enough to keep them in place. Given your widths, you can probably have the clamps at the ends about 4"-5" in. 
Remember the clamp pressure spread rule, imagine (or draw out) a set of 45 degree lines from each clap head towards the joint, the lines between clamps should slightly overlap.
Place the top clamps so you have an equal number of clamps top/bottom and snug up.

Increase the pressure on the cauls and check that the parts are flush, adjust if necessary.

Another round of torquing up the clamps (from the inside out), then a final tightening.


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## dbw (Dec 2, 2013)

Definitely use biscuits. At least 1/ft. Definitely use cauls. Put Painter's/masking tape on the entire length of the glue line (directly over the glue). The tape will keep the cauls from sticking to the workpiece. You might consider ripping the boards into narrower pieces and then alternating the direction of the growth rings. Using boards which are 7" wide invites cupping.


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## LesB (Dec 21, 2008)

I would definitely use the biscuits to keep it all lined up as you clamp it together. Once you pull the two boards together with the buscuits it won't take much to keep them clamped while the glue cures. I would think 4 pipe clamps should do it.

One technique for spreading out the clamping pressure it to use cambered cauls. You can make your own from some scraps. Here is a fine wood working video on how….


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## Mosquito (Feb 15, 2012)

Sounds like you have the solutions at hand. Biscuits would certainly work to help with the vertical alignment, and if I was concerned about that, I would use it. Could also put a groove down the edge of both boards and use a spline for the same purpose.

I'd probably go for it with just the boards, doing my best, and then just hand plane it flat afterwards myself


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## HokieKen (Apr 14, 2015)

Biscuits are my go-to for getting something that long aligned. Cauls are a good idea to keep it from bowing. Especially if you aren't using parallel clamps.


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## Davevand (Feb 10, 2016)

Biscuits will only get you close when aligning the boards, you will need cauls to get the boards perfectly aligned. You will also need scraps blocks for your clamps to keep them from digging into the soft pine


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## CWWoodworking (Nov 28, 2017)

Start in middle then work you way towards ends. This kind of splits it into 2 more manageable glue ups.

6 pipe clamps should be plenty. I personally don't use cauls or biscuits.

I think this type of glue up is easier than some others. Longer 4/4 boards are easier to put in place if they have a little crook in them.


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## brtech (May 26, 2010)

> Biscuits will only get you close when aligning the boards, you will need cauls to get the boards perfectly aligned. You will also need scraps blocks for your clamps to keep them from digging into the soft pine
> 
> - Davevand


The cauls the prior comments talk about are placed on the edges of the boards, and are used to tighten the joint along the length:

```
caul - board - board - caul
  | ------ clamp -----------|
```
You can also use a caul on top and bottom of the joint to align the boards

```
----------|<br>
|_______ caul<br>
|_ ___board board<br>
|________caul<br>
---------|
```


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## SMP (Aug 29, 2018)

Rub joint and 6 clamps is fine for that size IMO.


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## MrRon (Jul 9, 2009)

Biscuits will not get your boards to align perfectly. You will end up with one board higher than the other. A long spline would be better, but you have to get the dimensions perfect within a thousands or 2. My way of doing it is to put small nails (brads) in the edge of one board, then clip the nails short. Apply glue and clamp. The nails are to keep the boards from slipping out of alignment from the slippery glue. Also a doweling jig will be more precise over biscuits


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## SMP (Aug 29, 2018)

> Biscuits will not get your boards to align perfectly. You will end up with one board higher than the other. A long spline would be better, but you have to get the dimensions perfect within a thousands or 2. My way of doing it is to put small nails (brads) in the edge of one board, then clip the nails short. Apply glue and clamp. The nails are to keep the boards from slipping out of alignment from the slippery glue. Also a doweling jig will be more precise over biscuits
> 
> - MrRon


Sounds like you are either using the wrong size biscuits, or you need to fine tune your biscuit joiner to the size you are using. A tuned biscuit joiner will absolutely align the boards up and down, but you will be able to slide the boards length wise


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## 4wood (Jul 12, 2018)

Clamp everything without glue first.


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## Unknowncraftsman (Jun 23, 2013)

I've never used biscuits for gluing up table tops. As long as the edges are square to the faces the small amount of unevenness is trivial. I do use spring clamps on the ends. 
I've heard biscuits can leave a witness mark due to the glue shrinking down. So keep them centered as possible 
4 wood has it right clamp everything dry make sure the ends are not open the slightest when clamped in the middle.
Wet both side generously 
Good Luck


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## controlfreak (Jun 29, 2019)

Lots of great advice. I think I will make some cauls and not do the biscuits. If I am not perfect on the biscuits I won't be able to adjust or bring it back. I like the idea of a dry run on the clamp up too.


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## Sylvain (Jul 23, 2011)

If you need 7' final length, use slightly longer boards (1"?) in case it would not align perfectly at the ends.

Edge joint the two boards together. This will compensate any slight out of squareness.





from about 2'40" up to what he says at about 3'50".

If it is not grossly out of square it should not slip.


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## Andybb (Sep 30, 2016)

I did a huge glue-up recently and used cauls.









2 vids to watch Stumpy Nubs & Puget Sound Woodworking.% I used techniques drawn from both of these. I'd advise you to watch them both. If you're only using 2 boards there really is no reason to cut a curve in them. Just use Stumpy's tape method. He shows different caul methods depending on the size of the project. One thing I did learn is that even the slightest curvature can cause the caul to actually bow "up" in the center if you crank down on the clamps too hard.


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## splintergroup (Jan 20, 2015)

Biscuits can leave a divot, but usually the reason is the wood above and below the biscuit will swell from the moisture in the glue. If the board is scraped/sanded flat (often done within an hour to remove the squeeze out), when the glue finally dries the wood will pull back as much as it expanded. Since it was leveled, it will now fall below the surface leaving an apparent divot.

As to the squeeze out, I like to do a dry clamp up, then apply a good coat of paste wax along the seam, both sides, about an inch on either side. Any dried squeeze out will fall right off. A wipe with mineral spirits will remove the wax.


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## MrRon (Jul 9, 2009)

> Sounds like you are either using the wrong size biscuits, or you need to fine tune your biscuit joiner to the size you are using. A tuned biscuit joiner will absolutely align the boards up and down, but you will be able to slide the boards length wise
> 
> - SMP


I find the biscuits I use are never all the same. Some are loose; others are tight. The joiner I use is a Porter Cable, the first one made. I have never been able to get the boards to butt perfectly. One board would always stand proud of the other by a few thousands. I could always feel the unevenness when running my finger across the joint.


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## shipwright (Sep 27, 2010)

If they are flat and well jointed you could rub join them with hot hide glue and leave the clamps on the rack.
I s**t you not!


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## Andybb (Sep 30, 2016)

> One board would always stand proud of the other by a few thousands. I could always feel the unevenness when running my finger across the joint.
> 
> - MrRon


Thousandths?! Biscuit or not I think you're still going to have to sand it no matter the technique. Cauls will do as good a job as a biscuit. I take big stuff like tables to the local mill and pay $100 to sand flat.

Biscuits are supposed to be loose. They expand after they get "wetted" by the glue. However, even a biscuit will still be off by a few thousandths. Never met a joint that didn't need a little touchup.


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## Sylvain (Jul 23, 2011)

When buying boards from a Big Store, they are not necessarily of the exact same thickness. 
I glue them up and anyway I have to plane after.

I guess it is for the well board of your Moravian Workbench.
see the no nonsense glue up process here:




planing after glue up




 (first two minutes)


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## controlfreak (Jun 29, 2019)

You are correct @Sylvain it is for the tool tray on my Moravian workbench The wood is from the BORG so I am just trying to get them as flat as I can. I will check those videos out, Thanks.


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