Panel Clamps - Do they make sense?

[Allan Speers]

I'm about to start a long, involved project, which will include a number of cabinets & solid doors.

I've never been too vexed by large glue-ups, but then I haven't done many, either. I'm trying to decide if I should get some kind of panel clamp. Either 2 of these:

http://www.rockler.com/damstom-38-in-panel-clamp

Or maybe those "bowed wood" things a lot of guys make themselves. (I forget the name.) Both dinguses are obviously time & frustration savers, except one thing bother me about this method:

When you cut your individual strips of stock, no matter how careful you are, they tend to move a little after you've finished milling them. (unless you live on a magical planet, far far away.) So, If you make your strips a little over-thick, and do your glue up "only from the sides," those little stresses stay relieved, and you then re-flatten the whole panel. I'm fond of hand planes, and am a hobbyist in no hurry, so this has never bothered me.

Now, If you use something like that Damston panel clamp, (above) It seems to me that you would me stressing the individual strips, forcing them back from whence they came. After your glue dries, isn' that just asking for trouble?

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Thoughts?

Alternate methodologies?

[Kent A Bathurst]

I'm about to start a long, involved project, which will include a number of cabinets & solid doors.

I've never been too vexed by large glue-ups, but then I haven't done many, either. I'm trying to decide if I should get some kind of panel clamp. Either 2 of these:

http://www.rockler.com/damstom-38-in-panel-clamp

Or maybe those "bowed wood" things a lot of guys make themselves. (I forget the name.) Both dinguses are obviously time & frustration savers, except one thing bother me about this method:

When you cut your individual strips of stock, no matter how careful you are, they tend to move a little after you've finished milling them. (unless you live on a magical planet, far far away.) So, If you make your strips a little over-thick, and do your glue up "only from the sides," those little stresses stay relieved, and you then re-flatten the whole panel. I'm fond of hand planes, and am a hobbyist in no hurry, so this has never bothered me.

Now, If you use something like that Damston panel clamp, (above) It seems to me that you would me stressing the individual strips, forcing them back from whence they came. After your glue dries, isn' that just asking for trouble?

-------------

Thoughts?

Alternate methodologies?

The bowed wood things are called cauls. They are excellent. I have never had any of the issues you are talking about - I don't think there is enough movement to worry about - plus, same species, is going to move the same - unless you have your micrometers in play.

By trial-and-error, I developed a system of cauls and clamps that works wonderfully - small panels all the way to a 44" x 84" dining table. My technique has gotten to the point where, after I pull the clamps and cauls, I run a task-assigned hand scraper to remove the rubbery glue squeeze out. Then, I go back with a good scraper to level the glue joint. That is all it takes. Those boards are dead-nuts aligned. AIn't never grabbed no handplane [and I got a bunch to choose from, if I wanted to]. THis is not magic, it was repetition, concentration on the details, and focus.

I honestly think you are imagining monsters under the bed, Allan. While some may be there, they aren't of this flavor.

Also - on my cauls, I set them up as close together as I can, determined by the interspersed pipe clamps which pull the joints together - caul set - pipe clamp - caul set - pipe clamp. I can get the cauls to about 7"-8" aparts, and still have room to turn the pipe clamp handles. [Your photo show 2 on the ends. That is not enough by a loooooong shot.]

And - the pipe clamps alternate - one on the top, then one from underneath.

The cauls are made from 8/4 HM, with packing tape on the business surface, and 1/2" x 3/8" crossing grooves to sit over the glue joint - the squeeze out doesn't get smeared into the wood that way.

And - I have some bracket/stand thingies that the bottom cauls sit in - gets them the correct height off the table for he C-clamps that pinch them together.

[Mike Henderson]

Wood will do what wood will do, no matter how you clamp it. But you can make a few cauls for about $5 instead of buying those clamps. See here (http://www.mikes-woodwork.com/Cauls.htm).

Cauls are good for getting the boards to line up as you put pressure on your clamps. After you take the panel out of clamps it will go the way it wants to go. That's why stock preparation is so important.

Mike

[Allan Speers]

Good to know, Kent. I think I'll make some cauls myself, as I have a lot of HM out back.

I like that idea of grooves for squeeze out, but how does that work with the packing tape over it? Any pics?

I assume you're cutting them with a 2" SQUARE profile, yes? - So then which grain-orientation is best for the cauls? Surely, one way is stiffer than the other, but too stiff is no good, either. What is working for you?

Last: When laying out your strips, do you make sure to alternate grain direction, as some folks suggest, or does that also not really matter much?

[Kent A Bathurst]

Good to know, Kent. I think I'll make some cauls myself, as I have a lot of HM out back.

I like that idea of grooves for squeeze out, but how does that work with the packing tape over it? Any pics?

I assume you're cutting them with a 2" SQUARE profile, yes? - So then which grain-orientation is best for the cauls? Surely, one way is stiffer than the other, but too stiff is no good, either. What is working for you?

Last: When laying out your strips, do you make sure to alternate grain direction, as some folks suggest, or does that also not really matter much?


ALso - you should take the time to look at the link MIke H included in his note. He did a bang-up job with BORG framing lumber. I was way gone around the mountain before I saw that - I went for the HM because I was royally ticked and frustrated with clamping and cauls and was bound and determined to put "paid" to that noise. WHich I did. But 8/4 HM ain't cheap, and is likely overkill.

Having said all that.............

Will post photos soon - tomorrow, hopefully.

I put the packing tape on, and then a couple months later realized the value of the grooves - just drug them across the TS. THe glue doesn't get up in there, so I'm not worried. In fact, I have advanced to a level where the packing tape never comes into play, but it is a good safety measure, and I would do it again.

Yeah - square profile - roughly 2". Get a slab of 8/4 and cut it for best yield. THere is no grain orientation issue. That stuff is stiff either way. And - the precise grain orientation likely varies from board-to-board, right? Depending on where in the log it came from, and how it went through the saw mill. Forget that issue entirely.

There is a lot of what I regard as hokus snake-oil about grain orientation and direction and cupping and what-have-you. Pretty much all nonsense to me [not picking a fight with anyone of a different belief system, guys.....back away from the keyboard].

I sequence the boards and orient them to get the "most pleasing" visual grain orientation. I often pay for bookmatched boards....so you can easily figger out how they go together. In any other case, I just try to get the grain aligned so it looks good - not stupid. Move them to different spots in the glue up, try both sides, flipping them back and forth...........The best presentation is not always easy - comes down to a judgement call - but the dumbest is readily apparent.

[Tom Morassini]

I use angle iron wrapped with packing tape for my cauls (thicker steel, not aluminum). Sure you won't get the added pressure in the middle of the panel that you'll get with convexed cauls, but for cutting boards and door panels they work great for me. You could always put some playing cards or whatever for spacers in the middle to add a little pressure in the middle. I haven't tried them on a large table or anything that big yet.

[Michael Stein]

ALso - you should take the time to look at the link MIke H included in his note. He did a bang-up job with BORG framing lumber. I was way gone around the mountain before I saw that - I went for the HM because I was royally ticked and frustrated with clamping and cauls and was bound and determined to put "paid" to that noise. WHich I did. But 8/4 HM ain't cheap, and is likely overkill.

Having said all that.............

Will post photos soon - tomorrow, hopefully.

I put the packing tape on, and then a couple months later realized the value of the grooves - just drug them across the TS. THe glue doesn't get up in there, so I'm not worried. In fact, I have advanced to a level where the packing tape never comes into play, but it is a good safety measure, and I would do it again.

Yeah - square profile - roughly 2". Get a slab of 8/4 and cut it for best yield. THere is no grain orientation issue. That stuff is stiff either way. And - the precise grain orientation likely varies from board-to-board, right? Depending on where in the log it came from, and how it went through the saw mill. Forget that issue entirely.

There is a lot of what I regard as hokus snake-oil about grain orientation and direction and cupping and what-have-you. Pretty much all nonsense to me [not picking a fight with anyone of a different belief system, guys.....back away from the keyboard].

I sequence the boards and orient them to get the "most pleasing" visual grain orientation. I often pay for bookmatched boards....so you can easily figger out how they go together. In any other case, I just try to get the grain aligned so it looks good - not stupid. Move them to different spots in the glue up, try both sides, flipping them back and forth...........The best presentation is not always easy - comes down to a judgement call - but the dumbest is readily apparent.

I have to ask. I have tried to figure it out, but what does BORG stand for??

[scott vroom]

I have to ask. I have tried to figure it out, but what does BORG stand for??

BORG refers to either of the 2 infamous big box stores Home Depot and Lowes. Borg is also the name of the inhabitants of a futuristic cube shaped space ship whose only purpose is to assimilate all cultures it encounters. I guess some folks along the way drew a parallel between the Orange Big Box Home Depot, the Blue Big Box Lowes, and the space peoples? I dunno.

[Britt Lifsey]

I have to ask. I have tried to figure it out, but what does BORG stand for??
I've heard both Big ORanGe store which leaves out any blue ones and Big Old Retail Giant.

[Sam Murdoch]

There is a lot of what I regard as hokus snake-oil about grain orientation and direction and cupping and what-have-you. Pretty much all nonsense to me [not picking a fight with anyone of a different belief system, guys.....back away from the keyboard].

I sequence the boards and orient them to get the "most pleasing" visual grain orientation. I often pay for bookmatched boards....so you can easily figger out how they go together. In any other case, I just try to get the grain aligned so it looks good - not stupid. Move them to different spots in the glue up, try both sides, flipping them back and forth...........The best presentation is not always easy - comes down to a judgement call - but the dumbest is readily apparent.

No fight here - I completely agree. Technique/method goes a loooong way to alleviate issues. I go for the best look at the outset. Never been bit by that preference.

[ken masoumi]

I use angle iron wrapped with packing tape for my cauls (thicker steel, not aluminum). Sure you won't get the added pressure in the middle of the panel that you'll get with convexed cauls, but for cutting boards and door panels they work great for me. You could always put some playing cards or whatever for spacers in the middle to add a little pressure in the middle. I haven't tried them on a large table or anything that big yet.
That's what I use for small boards,works very well but for wider boards I use a combination of wooden cauls & angle irons.

[Pat Barry]

I went for the HM because I was royally ticked and frustrated with clamping and cauls and was bound and determined to put "paid" to that noise. WHich I did. But 8/4 HM ain't cheap, and is likely overkill..
What is HM? Hard Maple?

[Michael Stein]

Big Old Retail Giant.

I like that one, makes sense now...

Thanks yall! Sorry for the hijack on my first post :o

[Kent A Bathurst]

What is HM? Hard Maple?

Yep



1010101010

[Mike Schuch]

When I glue up panels I always use dowels. Not so much for strength but for alignment. I have an old Davis and Wells horizontal boring machine which makes well aligned dowel holes quick and easy. Of course with door panels I have to think ahead enough to not put a dowel too close to an edge that will be milled with a panel raising bit... BUT you only make that mistake once! :rolleyes:

If I do a good job of jointing nice straight boards clamping pressure is minimal... as it should be. With minimal clamping pressure I have not had any problems with the entire panel bowing.

I actually have 3 and a half of these clamps that I have never purchased pipes for (they use 1/2" pipes instead of the usual 3/4" of the rest of my pipe clamps use.) I got all 3.5 of them off Craigslist for $20 and couldn't pass them up. Someday I look forwards to seeing how well they work on panel glue ups without using dowels.
311168

http://www.leevalley.com/us/wood/page.aspx?p=65573&cat=1,43838

[Kent A Bathurst]

I like that idea of grooves for squeeze out, but how does that work with the packing tape over it? Any pics?

Allan - this is from a build sequence for a table top. Shows everything in its place pre-glue up, and then the process. Best story on the cauls and my accessories that I have.


Cauls in place. You can see the grooves for squeeze-out

Note the cradles they sit in. this gets them at the correct min height off the table for the c-clamps.

Note the holders for the 3/4" pipe. Sections of 1" PVC, snapped in place, Ply scraps to build a base to match the height of the wood.

311200


Grooved and taped blocks for the ends.

311201

C-Clamps in position. I want to know I have everything in place, so I don't have to stop and go running around mid glue-up.

311202

Boareds on the cauls - aligned over the grooves.

311203


Glued and clamped. NOtice that [for the most part] the pipe clamps alternate above and below the wood. COunteracts any bowing tendency.

Also - look closely at the pipes - you can see the PVC snapped on teh pipe - these are spacers to keep the black pipe out of the damn glue.

311204

End blocks in place. I had a problem once, where everything came out great except at one end -- not flat at the joint. Stopped that noise.

311205

Good photo of the glue squeeze out running through the tunnels.

311206


I have one card scraper assigned to glue squeeze out. It doesn't have to be really sharp, and it doesn't have to be clean.

311207

[Kent A Bathurst]

OK - could not get the entire photo sequence in above..

Change to a good card scraper for a few minutes.

311208



Now, then - You are looking directly at where the glue line is. Where's Waldo?

My point is simply this - if you have the right methods, attention to detail, and focus, you don't need biscuits or dowels or nuttin' to get a near-perfect glue joint alignment. Those boards were dead-nuts in line.

For top-end show surfaces, I only glue one joint at a time. They all come out like the one you have seen here.

311209


THe cradles for the cauls are made from scrap whatever-was-handy. THis one looks like 3/4" ply scraps.

311210


Same with the bases for the pipe clamps. Looks like I used some QSWO scraps for the end clamping blocks.

311211

[John TenEyck]

I wouldn't claim that all my panels come out so good that it requires nothing more than a card scraper to get perfect, as Kent's are, but mine generally come out well. I've found the most important thing is to get all the joints not only to fit together well but at a perfect 90 degrees so they don't squirm during clamp up. This sounds obvious but do you know if yours really are that good? Well, if you stack up all the boards for the glue-up it becomes crystal clear.

311228

When they stand up like this, they are. Any joint that's not will make the panel tip one way or the other. When the joints are perfect, glue up is pretty easy, and I generally need nothing more than finger pressure or a gentle wrap of a rubber mallet to flush the boards as I pull up the clamps.

311229

After removing the clamps:

311230

Note I'm gluing 4 boards, too.

John

[Keith Weber]

I'm trying to decide if I should get some kind of panel clamp. Either 2 of these:

http://www.rockler.com/damstom-38-in-panel-clamp...


Allan, just to point out what might not be obvious to everyone, those Rockler clamps that you linked do nothing in terms of keeping your boards from lifting relative to another like a caul would. They give the illusion that they'd be doing something because of the bar that sits on top of the glue up, but that bar does nothing more than provide symmetry and clamping pressure in the normal direction. I'd rather use a pair of K-bodies or Jorgensons than those.

I have a set of Frontline clamps that are awesomely great for this purpose, but they're priced on the ridiculous side, and you'd better be planning to visit Australia if you want them because Frontline won't answer your e-mails or phone calls if you don't live in Australia. I just about gave myself a heart attack hauling 6 of them through 3 airports to get them to my shop -- a task I would never want to repeat, no matter how nice the clamps are.

[Andrew Joiner]

I use the rubber mallet method like John. Simple and fast. The trick is to clamp one end of the glue-up tight with all faces flush, first. Then work your way to the other end like this: Barely tighten the next clamp so you can pound the faces flush. When flush, tighten and move on down the panel. I've done panels of 7 or 8 boards this way, but if the boards are long you have to work fast. Titebond Extend is my favorite glue for this.

Pipe clamps work fine for this. There is no need for any "panel clamps".

[Allan Speers]

Allan, just to point out what might not be obvious to everyone, those Rockler clamps that you linked do nothing in terms of keeping your boards from lifting relative to another like a caul would. They give the illusion that they'd be doing something because of the bar that sits on top of the glue up, but that bar does nothing more than provide symmetry and clamping pressure in the normal direction. I'd rather use a pair of K-bodies or Jorgensons than those. .


Wow, thanks. That's one seriously misleading ad / product.

[Allan Speers]

[QUOTE=Kent A Bathurst;2403572]Allan - this is from a build sequence for a table top. Shows everything in its place pre-glue up, and then the process. Best story on the cauls and my accessories that I have.......


VERY nice tutorial, Kent. Thanks.

[Chuck Hart]

I would start here:

http://www.highlandwoodworking.com/woodnews/2010april/cauls.html

[Allan Speers]

A new question regarding cauls:


I couldn't tell from Kent's pics, but in that Henderson tutorial Chuck Hart linked, above, he is clearly using cauls both above and below the stock.

Wouldn't it be better to have straight supports underneath, and just put the curved cauls on top?

[Keith Weber]

A new question regarding cauls:


I couldn't tell from Kent's pics, but in that Henderson tutorial Chuck Hart linked, above, he is clearly using cauls both above and below the stock.

Wouldn't it be better to have straight supports underneath, and just put the curved cauls on top?

You have to balances the forces on the top and the bottom to get a straight panel. So, if you want to use cauls top and bottom, you need to:

A) use identical cauls so that the forces balance out top and bottom, and
B) clamp the cauls together so that it is separate from the workbench.

If you clamp it as above, but use a straight support underneath (that's made similar to the caul, but without the curve), then the top caul will bend a cup into the top of your panel. You could use a straight support underneath, and a caul on the top, but that lower, straight support would need to be much stronger and rigid than the top caul to resist the cupping tendency - say, by using a 2" x 4" x 1/4" wall rectangular steel tube (on edge) as your lower support.

If you only wanted to use a top caul, you could get away with that if you clamped your whole setup to a rigid and flat bench. Your vertical clamps would go from the underside of the workbench to the top of the caul. The downside of this is that you cannot move the panel until it dries. Again, your workbench would need to be much beefier than your upper cauls so that the caul does not cause flex in your workbench.

The easiest and safest way would be to just use similar cauls top and bottom.

[Robert Engel]

Wood will do what wood will do, no matter how you clamp it. After you take the panel out of clamps it will go the way it wants to go. That's why stock preparation is so important.

MikeThis is exactly correct. I don't use them I just try to prepare the stock as uniformly as I can and glue it up as soon as I can.

Couple tips:
1. If using a jointer, edge them with alternating faces to cancel out any 90 error. If doing by hand, plane two boards facing for same purpose.

2. If you plan on hand planing the panel, make sure you have determined the grain direction is all the same prior to gluing. There's nothing worse than finding out two boards have the grain running opposite ways and you're stuck with scraping or sanding.

Sometimes reading the grain is almost impossible (and if you think you got it right, you find out later you didn't) dependingon the wood in which case I will actually (gently) try taking a test shaving just to be certain.

3. I'm a big fan of bagging in plastic bags during after each milling especially when the weather is changing.

I glue my panels based on grain direction and orientation (sometimes they conflict) but hardly ever on the alternation growth ring method.
Although theres nothing wrong with that, it will not cancel out cupping.

I never use cauls you shouldn't have to if your stock is straight and uniform.
If the stock is warped then you need a spline or biscuits.
I just put slight pressure with clamps and feel the joint use a soft hammer to adjust.
I usually clamp each joint at the ends till the glue is set.

Try them out and let us know how you do.

[Allan Speers]

You could use a straight support underneath, and a caul on the top, but that lower, straight support would need to be much stronger and rigid than the top caul to resist the cupping tendency - say, by using a 2" x 4" x 1/4" wall rectangular steel tube (on edge) as your lower support.


That's exactly what I was thinking. Use a straight bottom "caul" with steel rail reinforcement. Then you don't have to worry about the top & bottom cauls being perfectly matched, you'd always get a dead-flat result. I'm going to try this first, and see how it goes.


BTW - Clamping directly to the assembly table has another negative: No place for the glue to run out.

[Kent A Bathurst]

That's exactly what I was thinking. Use a straight bottom "caul" with steel rail reinforcement. Then you don't have to worry about the top & bottom cauls being perfectly matched, you'd always get a dead-flat result. I'm going to try this first, and see how it goes.


BTW - Clamping directly to the assembly table has another negative: No place for the glue to run out.

I always use the cauls top and bottom - one pile of cauls, interchangeable. No issue about dead-flat result - - the cauls are identical, the C-clamps are applying the same force equally to the pair, they came out of the same species [heck the same stick from the same tree] - and they react the same to the force.

I think you might be overdriving your headlights here............

On the flat table-top - - glue mess on the underside, plus - the required table top dimensions will vary with the size of the workpiece, no?

But - hey - if the flat table top gets you where you want to go, tee it up!!

One thing I did not emphasize in my earlier posts -- I use primarily QSWO. SOme of it is really big $$$. WO has deep pores. Any glue that gets smeared on the surface will fill those pores, and inhibit dye absorption. So - it is a critical step - and a non-trivial step - to get the glue out of there. I decided the best way to do that was to keep the damn glue out to begin with.