# Joining 8/4 walnut boards for desk top



## jimmyjames (Nov 23, 2012)

Hi, contemplating making a desk top 60"x32" out of 8/4 walnut boards joined together. Lucky me i have access to a 36" thickness drum sander to use after i join and glue the boards together. My plan is to just glue the boards together with titebond 3 and clamp, some say to use biscuits etc, i myself find biscuits useless. How would you guys do it? Would you just glue them togther and clamp the crap out of them without anything like biscuits/dowels/ etc?

Im going for a look similar to this


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## b sco (Nov 8, 2010)

If you have good fit at glue joint, no dowels,no bicuits.
I've never used either and never had anything come apart,going back to high school woodshop 36+ years ago.
I think biscuit joiners are a gimmick no one needs.


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## cabinetman (Jul 5, 2007)

b sco said:


> If you have good fit at glue joint, no dowels,no bicuits.
> I've never used either and never had anything come apart,going back to high school woodshop 36+ years ago.
> I think biscuit joiners are a gimmick no one needs.


+1. :yes: Use glue, clamps, and cauls. No need to *"clamp the crap out of them"*. Proper clamping will help insure a nice flat result. You could get some unwanted "U" shape by an exertion of the clamps on the bottom or top edges pulling in that direction.










 







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## bzguy (Jul 11, 2011)

In picture top "floats" in metal frame, simple glue joints would never come apart, assuming wood is dry.
If it is going to be attached, use slotted screws from bottom, or some other system that allows for some movement.
Since end grain is going to show, if so inclined, you could "show off" your joinery skills with sliding dovetail joints.


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## Dave Paine (May 30, 2012)

+1 with clamps and cauls. I personally would use a single dowel just for side to side alignment, but it is personal preference.

If a board had a high or low spot, I would use dowels to get this into alignment.

As others stated, the boards should be a good fit. So check the edge to edge joints and straighten as needed to get a good fit.

Good luck with the drum sanding. The top is going to weigh a lot.


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## cabinetman (Jul 5, 2007)

Dave Paine said:


> +1 with clamps and cauls. I personally would use a single dowel just for side to side alignment, but it is personal preference.
> 
> If a board had a high or low spot, I would use dowels to get this into alignment.


In lieu of dowels, cauls from both sides can be used. Wedges used in conjunction with cauls can motivate a high spot to move.










 







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## GeorgeC (Jul 30, 2008)

cabinetman said:


> +1. :yes: Use glue, clamps, and cauls. No need to *"clamp the crap out of them"*. Proper clamping will help insure a nice flat result. You could get some unwanted "U" shape by an exertion of the clamps on the bottom or top edges pulling in that direction.
> 
> 
> 
> ...


"clamp the crap out of them" also produces too little glue in the joints and leads to later joint failure.

George


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## Midlandbob (Sep 5, 2011)

It's rare to over clamp wood. Walnut especially 8/4 takes a lot of glue pressure . The quality of the jointing(fit) is very important. Resist the idea athat you can clamp a small crack closed. You need to plane/ joint it. Alternating which face of the board against the fence keeps the surface flat. (I mark each side of a glue line I and O for in and out.)
There have been a few excellent articles in FWW on the science of glue ups.
-http://www.finewoodworking.com/membership/fwnpdf/011194036.pdf
That s a link though you may need a registration to access it. Lots of clamps with the 45 degree rule. 1/2 clamps on bottom and top to keep the pressure even.
I use c clamps applied only snugly on the ends at each joint to avoid slipping.
Ideal glue amount has small squeeze out all along the top and bottom. This line of glue beads scrapes off easily so wiping is risky as it can force the glue into the surface affecting the finishing.
It's very satisfying turning a group of board into a large surface. Careful selection of the order to make a pleasant transition of grain patterns is vital.


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## jimmyjames (Nov 23, 2012)

By clamping the crap out of it i meant using alot of clamps, i joined some 2x4's on one edge to lay on the top and bottom so i can clamp the boards to keep them lines up so i dont have as much finish work along with clamping them horizontally across the grain, i know what glue pressures are needed. For the frame i allready have the plates that will screw to the bottom and they have obround holes to allow for movement, i would really like to make it out of 12/4 boards but unable to find any around here and the slabs i found are far to green to do anything with and also they want a fortune for them, everybody with a walnut tree nowdays think they have a gold mine, i cant wait till the spring when i fell about 20,000 board feet of it and flood the market for the cost of cutting and kilning, theres a shop in town charging $14brdft for common 4/4 walnut....wtf...


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## bzguy (Jul 11, 2011)

jimmyjames said:


> i would really like to make it out of 12/4 boards but unable to find any around here.


Jimmy, you can give the top the appearance of any thickness you want by mitering and gluing edges of desired thickness.
I'd use horizontal grain for long edges, vertical grain where end grain would be for quarter-sawn slab look.
If you click on my pics, you'll see a 7 species coffee table with a 3" thick top.
This is all mitered out of 3/4" stock.


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## johnmark (Jul 21, 2012)

is the table picture the project you're on?

lots of choices for joining it besides glue.

tongue and groove being one. you could also add boards on both ends and make multiple mortises in them and tenon the table with a little expansion room in them.

This would prevent cupping, though you've got very thick boards.


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## JMartel (Nov 30, 2011)

GeorgeC said:


> "clamp the crap out of them" also produces too little glue in the joints and leads to later joint failure.
> 
> George


I actually just went through an old Fine Woodworking article that disproves that. 

http://www.finewoodworking.com/item...ferent-woods-need-different-clamping-pressure

Most woodworking clamps won't overclamp the joint.


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## jimmyjames (Nov 23, 2012)

JMartel said:


> I actually just went through an old Fine Woodworking article that disproves that.
> 
> http://www.finewoodworking.com/item...ferent-woods-need-different-clamping-pressure
> 
> Most woodworking clamps won't overclamp the joint.


I personally think its.almost impossible for a glue joint to fail, even when clamping something during glue up and get a little tiny bit of glue on a piece of wood and accidentally glue a board onto another its impossible to get it off without ripping out the wood, especially with what im doing, a 2" thick board joined is an awful lot of glueing surface. On the cupping i will be alternating the grain direction. 

On the. End grain of the table, is there a way to keep the end grain from darkening when i laquer it? Ive heard of sealing the end grain but will it make a difference when using just lacquer?


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## Dave Paine (May 30, 2012)

jimmyjames said:


> On the. End grain of the table, is there a way to keep the end grain from darkening when i laquer it? Ive heard of sealing the end grain but will it make a difference when using just lacquer?


I have been happy with sanding end grain to a higher grit before finishing. It seems the smoother surface results in less finish being absorbed and so not as dark.

Higher grit is 600+. Works for me, I hope this works for you.

A sealer can also work. Try Zinsser Seal-A-Coat which is essentially a dewaxed shellac product.


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## johnmark (Jul 21, 2012)

it's definitely possible to overclamp.

i've done it with a 3/4" top. It fell over after a overnight clamping and it snapped apart very cleanly. I just planed the sides and went again.

with this style:


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## GeorgeC (Jul 30, 2008)

JMartel said:


> I actually just went through an old Fine Woodworking article that disproves that.
> 
> http://www.finewoodworking.com/item...ferent-woods-need-different-clamping-pressure
> 
> Most woodworking clamps won't overclamp the joint.


I think that you need to read that article again.

"Conversely, extreme pressure can produce weaker joints, however, this is unlikely with common woodworking clamps."

George


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## cabinetman (Jul 5, 2007)

With well fitted edges, it doesn't take excessive clamping pressure to make a good glue joint. If there is even a very thin film on each surface, extreme clamping pressure wouldn't starve the joint. Wood is compressible, and if clamped to the point of crushing fibers, you would still have materialized a glue joint, but it's possible to get a deformation at the clamp location.










 







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## cabinetman (Jul 5, 2007)

johnmark said:


> it's definitely possible to overclamp.
> 
> i've done it with a 3/4" top. It fell over after a overnight clamping and it snapped apart very cleanly. I just planed the sides and went again.
> 
> with this style:


I've tried the inserted magnet and the block can get knocked off or re-positioned too easily. I glued blocks to the clamp as below...much better IMO.
.
















 







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## JMartel (Nov 30, 2011)

GeorgeC said:


> I think that you need to read that article again.
> 
> "Conversely, extreme pressure can produce weaker joints, however, this is unlikely with common woodworking clamps."
> 
> George


Read the linked page at the bottom:

http://www.finewoodworking.com/item/27122/how-to-glue-up-joints-the-right-number-of-clamps

The maple required 9 pipe clamps. 9,900lbs. It depends on the wood. 

"Most woodworkers are underclamping their joints during glue up. To help avoid this, professor Roman Rabiej developed some simple keys to clamping success. (Read the full article on the topic.)"

"For most hardwoods, however, normal woodworking clamps can’t get close to these levels of force. But joints clamped at the recommended levels will be quite strong enough, with the glueline being stronger than the wood itself. You’ll achieve a glueline thickness well under the recommended maximum, which is about 0.004 in. To give a point of reference, the cover of a (like Fine Woodworking) magazine is 0.005 in. thick."



Basically, we're both right.


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## JMartel (Nov 30, 2011)

Double post.


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## USMCSergeant (Aug 21, 2012)

I don't have as much experience as the above posters I'm sure. When I pieced together a table earlier this year I doweled all pieces with 3/8" dowels. It wasn't difficult at all with a dowel jig. I just wanted a little more comfort that those joints would never seperate.


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## bob sacamano (Jan 24, 2012)

b sco said:


> If you have good fit at glue joint, no dowels,no bicuits.
> I've never used either and never had anything come apart,going back to high school woodshop 36+ years ago.
> I think biscuit joiners are a gimmick no one needs.


 
biscuits have their place. biscuits are levelers. theyre not supposed to be used for strength. theyre NOT slip tenons . just a leveler. if you do glue them in they will swell and then your board will swell from the glue. do NOT SAND IT. WAIT TILL IT DRIES AND THE SWELLING GOES DOWN. then sand it. if you sand to get rid of the swell then youll be left with a dimple when it dries


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## woodnthings (Jan 24, 2009)

*before gluing ....*

There are 3 things to consider when gluing thicker boards of that length. The edges must be straight, flat and at 90 degrees to the surfaces.... not an easy task unless your jointer is set up correctly and your procedure is proper. A 6 ft board is about the limit on a 6" jointer with long tables and even more critical on a shorter bed jointer. 
The next issue is the edges must be at 90 degrees, also not the easiest on a thicker board since any deviation will create a gap on one side or the other. The best way to prevent this is to alternate the surfaces registered against the fence. Label the boards on your top when on laid out the bench, "in" and "out" or "I" and "O" then put the 'ins" against the fence and joint the edge, then the "outs".
This procedure makes the joining boards whether at 90 degrees or 89 degrees mate perfectly, because they are complementary angles. A discussion here: http://www.woodweb.com/knowledge_base/Making_Raised_Panels_Flat.html

Finally, to prevent shifting during the clamping process the use of cauls, bisquits or dowels will be necessary. If it were me I'd use a single dowel in the center of the length to align the middle, then boards/cauls with clamps on the ends. It will be easier to center a single dowel than several along the length and that's really all you need. Lining up several dowels accurately when drilling and then later when gluing up can be frustrating and requires precise marking and no errors when drilling.

This article may prove useful: http://bobgillespie.articlealley.com/the-right-way-to-glue-up-boards-1507064.html


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## cabinetman (Jul 5, 2007)

With all aspects being near perfect, I wouldn't use biscuits or any dowels, as the slightest offset with a dowel or several dowels will prevent alignment at their location. Biscuits don't insure alignment, and are intended to help the mating boards from pulling apart...not worth the hassle. 

So, the process is ready for clamps. It seems at this point it's a simple matter of just setting the clamps and cauls and tightening them up. Well, what can go wrong? Clamps, like pipe clamps for instance have a closing pressure from the clamp ends that can exert more pressure on an upper or lower edge of the board other than the center, if not positioned properly. Many of those clamps the ends do not close under pressure absolutely parallel to eachother. 

When tightening one of those its a good idea to see how the mating edges are reacting as the clamp gets tight. Alternating the clamps position on top of the boards and the bottom of the boards help in creating a straight line of pressure to bring the boards together.

As an example of an improper clamp attachment, lets assume that there is slightly more pressure along the top portion of the edges versus the bottom. As the clamps tighten, the pull can make the combination of boards bow, or curve into a "U" shape. This would be indicative of all the board edges (that may be flat to eachother) and the faces take a shape other than horizontal. The other side...meanwhile...will show that the glued edges are not tight but slightly separated allowing the board to tip away from its mating board. Overclamping (too much pressure) can do this.

The whole point to this drawn out description is when setting clamps to the outer edges of a group of boards to insure that they are set to exert centered pressure to the boards.










 







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## USMCSergeant (Aug 21, 2012)

I will agree with cabinetman here. One of the dowels on my table was a fraction off, and it took me beating one end with a sledgehammer to get the pieces together. I'm lucky I didn't ruin the entire piece.

Here's how I strapped all the pieces together. It worked out great with very little bowing that I cleaned up with a hand plane.


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## jimmyjames (Nov 23, 2012)

Well i went to pick up my 8/4 walnut today at the local sawmill, as luck would have it somebody picked the pile that was also making a table and left pieces that were checked and with too many bark inclusions knots and sapwood.... plus all the pieces that were left were 8' and not 10' so instead of cutting them in half to make a 5' long table i would have had to buy way too much wood and be left with 12 brdft of drop, @ $7 a brdft i just couldnt do it, it would have made the cost go.from $175 to $260... they said they have more coming in next week. On the other hand i did pickup 100brd ft of really clear 4/4 walnut, 20brd ft purple heart and 20brd ft of hard maple with about 5brdft of it being really figured


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