how do I glue boards together well?

[Robert Engel]

I bought the boards pre planned so they should all be the same thickness.

This is the source of your difficulty. My approach to gluing up panels is "keep 'em big and thick as long as you can".

Obviously this doesn't apply to your situation, just thought I'd mention it.

That said, there are various alignment aids that will help such as biscuits, dowels, Dominos.

If you don't have the tools for that, a slot cut with a router to accept a spline will work quite well.
Another way is a tongue and groove joint.

[Mel Fulks]

IF you have an old beefy jointer with a wheel adjustment outfeed you can raise outfeed a thou or two .That will make
a "sprung" joint, (slightly open at middle area). Then with one clamp at each end you can press down any piece that's
too high and clamp middle of length. Used to be a standard architectural millwork technique demanded by management.
Much easier with wheel adj outfeed since it's easy to calibrate adj wheel to know where you are going and how to get
back. Yes...I post this every year

[Mark Daily]

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Some helpers like like these might be beneficial, but some sanding is almost always necessary to get a perfectly flat surface.

[Mel Fulks]

MORE: I also had a standing offer of $20.00 to anyone who found an open end ,interior or exterior, on any panel I made.
Never had a claim. Lots of jobs had over 100 panels.

[Jim Becker]

I bought the boards pre planned so they should all be the same thickness.

I missed this in my original read of the thread. There is pretty much zero chance that purchased pre-surfaced boards are all going to be the same thickness. They will be close, but chances are they all came off a machine at different times or are from different trees or are at slightly different moisture content, etc. You will always need to pick a surface for each board that will be "top" and then either index on that surface or the opposite one for your glue up. One surface can be reasonably flat, but the opposite side will most likely have more noticeable variations in thickness. In full disclosure, the same holds true for stock one prepares in their own shop from rough. It's extremely unlikely that eery board will be perfectly the same thickness.

[Kevin Beitz]

I give up trying to get them flat. I built a 12 ft x 8 ft router plane.

[Lee Schierer]

Before gluing, I arrange the boards the way I want them, draw a large V across all the boards with chalk. This gives me the order I want and the orientation when I begin gluing. I used to try gluing up 3 or more boards all at once and found the same problem Adam is asking about. Through experience I learned that I could glue up two pieces at a time and work the boards working from right to left by aligning the end to the right at the joint with a C-clamp, then working to the left tightening the bar clamps one at a time while also leveling the surface that would show right at that bar clamp. I would glue up four board panels two boards at a time and then glue the two board pieces to each other. I have far less sanding to do on the final panel assembly which makes up for the time lost only gluing them two at a time.

[Jerry Olexa]

Biscuits help a lot initially in alignment.....Your concern is common but biscuits eases much of that.

[Allen Arin]

Its better to glue in pairs instead of gluing one by one and there must be some issue with the clamping technique check with that too.

[Mel Fulks]

Only once did I have a problem with panels. Boss had a customer who made it clear to him that she wanted good
panel matches. With picky customers I've always been the panel guy. When the job was done he told me she had
tears in her eyes as she gushed about their great beauty. Then they hired some hacks to do the finishing. They looked
like they had dark varnish stain. Lady was in shock. Panels were then soaked in a bath tub to remove the "finish".
They used ACETONE Several weeks later he told me all the panel glue joints were coming loose and I was never again to
use sprung joints. I boogied out. Never work for a dim bulb

[Will Blick]

you got some great advise here
this thread will live on, as everyone struggles with this... some less than others...
In addition to many of the comments above...
when I thickness plane my wood, I am assured all boards are the same thickness, this helps a lot.
I clamp up lightly, then install in the same direction of the clamps, my massive alum. beams I purchased for this purpose, they are almost 2x4 size, and heavy, no flex. I clamp those to keep the boards from creeping...once in place, I tighten the glue up clamps, then re tighten the alum bars down, a bit of a dance to get there, but FLAT!! Its hard to get cauls to give you enough pressure in the middle as these boards want to dance!
I also used to use dowels, with a Dowelmax, yes, it works very well, but what a time sink, and its easy to mis align one. Dominos are easier and work good, but also time sink. Never had great success with bisquits, too loose, although, they are better than nothing. There is also 90 deg male / female edges you can put on your boards that will assure edges are aligned, but the entire panel can still bow, hence the benefit of the two at a time process...

lots of options, pick and chooze based on your project details...


BTW, did everyone notice, woodpeckers recently offered a one time tool to address this issue, but IMO, the force on the cross members is NOT downward enough. Other makers have provided similar clamps for years. If you follow the glue manufacturers recommendatoins of approx. 100 psi at the glue joint, that is a lot of clamping pressure, the boards will always follow the path of least resistance and creep unless they are constrained. Or, as others suggested, you provide waaaay less clamping pressure than recommended. In most cases, less pressure will work if your boards are jointed well....and they are thicker. the tinner the wood, the less glue area.