how flat is flat when glueing panels, 20"x36"

[drobertson]

working on the cradle, and I kinda screwed up on drying I'm thinking, the panels are just a bit warped.  Other than this, is this normal or just my bad in drying?

[drobertson]

I'm thinking after seeing a previous post that the clamps and set up were marginal,, it seems to be a battle at best,,

[beenthere]

Side panels or the ends?

[giant splinter]

You will never have enough clamps ;D trust me, how many do you  need? ...... you need lots and fairly decent ones ..... try to find them used if you can.
Flat is FLAT! and then there is Dead Flat. So it can be flat difficult to flatten it out and might flat run you out of patience.

I hope you can get it close enough so it looks right, sometimes it works so give it a try. I Bet you can do it, you always do nice work so hang in there.

[Don_Papenburg]

A Vacuum bag and a dead flat table is slicker than a cat's whistle.  Also makes curved laminations a lot easier.

[WDH]

The type of clamps that you use can have a lot to do with it.  I use the Bessey K-body clamps, also called parallel clamps.  They clamp flat and dead square.  A little expensive, but worth every $ if you do much woodworking. 

[jdtuttle]

When you glue up panels you also need to pay attention to the growth rings. You should alternate the direction each board, one up next down etc.
Good luck with your project. I made on for my Niece's first child recently.

[LeeB]

Try putting it concave side down on a lightly damp towel or newspaper and see if it doesn't straighten back out. It may have indeed continued to dry after you did the glue up. If you had it a long time with one face on the bench top it may have dried more on the face up side than the bottom.

[woodworker9]

Try putting it concave side down on a lightly damp towel or newspaper and see if it doesn't straighten back out. It may have indeed continued to dry after you did the glue up. If you had it a long time with one face on the bench top it may have dried more on the face up side than the bottom.

This ^^^^^   Also, check your jointer (assuming you used one)  fence for square against the top.  Only place that matters is right behind the cutterhead on the outfeed side. You have introduced 1° of out-of-square to each board glued up. 

When using clamps, you need to alternate how they are positioned on the glue-up panel to equalize forces introduced to the panel.  First one on the bottom, next on top, then bottom, and so on, so on.......Alternating can even out the pressure of clamping.

Before giving up on the panel, take a damp cloth and wipe down the concave side.  In the summertime, I'll put a panel that has warped outside on the dewy grass, concavity down.  The sun will dry out the top side, and flatten it right out, often enough.

If nothing else works, you can rip the glue-lines apart, and look for the offending board(s), replace them, and glue it all back up again.  Inspect each edge joint with a known square to verify the edges are 90° to the faces.

Good luck, and most times, it can be saved.

Jeff

[1938farmall]

i always rip any board over 5" with cup (joint the cut & put back together if you like the grain).  most important is to have a flat table or cauls to work on and don't try to force the joints to match if it compromises the whole panel - plane/sand off the mismatch after dry.  all the fancy clamps in the world will not help if you try to force the wood. you can catch alot of problems when you dry-fit the pieces on the cauls before gluing.

[drobertson]

thanks guys!  I've done bout what has been mentioned,  the main issue is I dried it without proper stickering.  The planer did not take out the slight bow, so a few of the panels had a bow, maybe 1/8" or lil better.  I did get the jointer squared up, but man you guys that do this on a regular basis, hats off to you!  brutal, but fun,  thanks again,   

[red oaks lumber]

yup poor stickering will continue to haunt well after the fact. recut thru the glue lines and start over

[Hilltop366]

thanks guys!  I've done bout what has been mentioned,  the main issue is I dried it without proper stickering.  The planer did not take out the slight bow, so a few of the panels had a bow, maybe 1/8" or lil better.  I did get the jointer squared up, but man you guys that do this on a regular basis, hats off to you!  brutal, but fun,  thanks again,

When you say bow are you talking along the length of the board(s) or across the glue joints?

[drobertson]

Not sure if I read this right, but the boards are bowed, each end high and low in the middle if that makes any sense.  the planer makes an even thickness,  the board just has a natural bow that does not lay flat, which I think is due to a curve in the board that has dried that way.  the planner flattens but the board returns with a bow. edge wise they are parallel and the glue joints solid.

[Hilltop366]

I think I get it, Bowed from end to end like a banana, not edge to edge?

If that is the case then clamping was not the problem. My guess would be some stress in the wood, I had a problem with some birch the I was using to make cabinet doors and panels with last fall. If I jointed one side flat and then ran them through the thickness planer on the other side the boards would bow, to stop this I had to flip the boards over each time I ran them through the thickness planer and some of them I would have to re-joint one side partway through the process.

[beenthere]

This bow is one reason mentioned for jointing a face first, before running through the planer.

Now, is there enough bow to make the rockers out of them... ripping in strips and laminating them together?
;)  just jokin.. but the baby will enjoy the cradle regardless.. 

[drobertson]

This bow is one reason mentioned for jointing a face first, before running through the planer.

Now, is there enough bow to make the rockers out of them... ripping in strips and laminating them together?
;)  just jokin.. but the baby will enjoy the cradle regardless..

Yea, that's funny, and real true!  we laughed about that and just about made a rocker rather than a swinger, next project should go better, this is my first glue up, so, I am a rookie for sure,

[woodworker9]

Not sure if I read this right, but the boards are bowed, each end high and low in the middle if that makes any sense.  the planer makes an even thickness,  the board just has a natural bow that does not lay flat, which I think is due to a curve in the board that has dried that way.  the planner flattens but the board returns with a bow. edge wise they are parallel and the glue joints solid.

I am sincerely trying to help you, so bare with me.  There is a flaw in your approach to milling your boards, and unless you change your approach, you are never going to get different results.  I say this in the nicest way possible, with only intent on helping you get past this.

A planer DOES NOT flatten boards.  It is a tool for thicknessing, and nothing more.  A planer has a pressure bar and roller that push the wood through the machine, under the cutterhead, and out the other end.  A planer does nothing more than create lumber with an even thickness across the width and length of the board.  The pressure on your cupped board exerted by the planer temporarily flattens out the board for cutting, but when the board comes out the other end, that pressure is gone, and the board springs right back to what it was before.  If you put a warped, twisted board through a planer, you only get a warped, twisted board out the other end that is of even thickness throughout.

I wrote this in another thread about jointing, and it explains exactly how you need to change your approach for better results on your lumber; here it is, copied and pasted here:

For those that already know, just ignore my post.......

For those who are new to milling rough sawn timber, the procedure is as follows:

1.  Flatten one "face" along it's width by using the jointer first.
2.  Now, with the flattened face against the jointers fence, joint an edge of the board.  You now have a board that has one side flat, with a perpendicular edge.
3.  Now, to the planer.  With the flattened face down, run the board through your planer.  This creates a board of even thickness with both sides flat and parallel to       each
     other.
4.  Take this 3 sided milled board to your table saw.  With the jointed edge run against the fence, rip your board to your desired width.  Run this fresh 4th edge over the
     jointer.  You now have a board that is flat and square, and equal thickness throughout.  S4S.

Using your planer first is a mistake.  The board must be flattened before proceeding to your planer.

In an ideal situation, your jointer and planer are of equal capacity in size.  If you work with wide boards frequently, you need to have the capacity to both joint and plane the width you are using.

If I need to flatten a board wider than my 16" jointer, I use a hand plane to do it.  My planer has an 18" capacity.   At some point, I plan on finding 24" capacity in both.  Nice to have the capacity for wider slabs, if you do that sort of work.  I do.

Jeff


By joint your boards with a face down over the jointer first, you will create one flat side to your board with no cup, warp, or twist.  Now, run that same board flat side down through your planer, and you will have a straight, flat board of even thickness of your choosing.

It is also very important to remember to remove an even amount of wood from each side of the board.  In other words, if you remove approx. 1/8" flattening one side, remove the same 1/8" using the planer on the other side.  Once you have a flat board of even thickness, if you need to reduce the thickness of that board, say from 7/8" down to 3/4" final thickness, you should proceed by making sure you alternate sides when running it through the planer.  One side first, then flipping end for end, paying attention to grain direction, and remove the same amount from the other end.

By removing all your material to thickness a board from one side, you will introduce a moisture content difference to this board, even if only temporarily, and it will surely most likely bend on you.

I hope this helps.  I'm much better at teaching this in person than I am at getting the words right in a long post like this.

Happy woodworking, and keep at it.  Before long, it will come as second nature to you, once you understand why you are doing each step.

Cheers!

[POSTON WIDEHEAD]

I enjoyed reading this Jeff. 

[red oaks lumber]

i just glued up a 25"x72" bench top. started flat ended flat i never needed a jointer just used my planer like i always use making furniture. the old saying you can't make a silk purse using a sows ear. same with using crooked or bowed wood and expect good results. seems kinda funny how it all comes back to proper stickering of lumber.

[woodworker9]

I enjoyed reading this Jeff. 

I'm glad.  I've learned so much from you guys and this forum about sawmilling over the past 10 years that I'm just happy that I can share something I know from my profession.

Attempting joinery with stock that isn't straight and flat is frustrating and can make a lot of people give up.  Learning a process that makes it all much easier will keep everybody making sawdust.  The work is difficult enough without fighting the wood....

[woodworker9]

i just glued up a 25"x72" bench top. started flat ended flat i never needed a jointer just used my planer like i always use making furniture. the old saying you can't make a silk purse using a sows ear. same with using crooked or bowed wood and expect good results. seems kinda funny how it all comes back to proper stickering of lumber.

In a perfect world, where every board dries perfectly flat and every stack is stickered just right, everything gets a whole lot easier.  I've learned in my career that this isn't the norm.  I completely agree with you that we can do a lot to end future headaches by stacking, stickering, and drying our lumber the proper way.  That is definitely a huge lesson that can be taken from this thread.

However, I also know from practice that not every single board that isn't straight needs to go in the woodstove.  I've met a lot of professional woodworkers all over the country who don't own sawmills, and are limited in timbers to what is available in their area, and they make do with rough sawn wood that isn't always straight and flat.  Following the procedures I outlined gives a solution to 98% of the boards in the stack.  Some are just destined for the stove, no matter how nicely we treat em'.

I've been mostly a reader of this forum for over a decade, and I put my 2 cents in where I feel I can help somebody out.  I agree completely, and have read here often enough, that the biggest push around these parts is to get people to sticker their stacks properly.  Most end-user problems are avoided when this is done.  I'll let the "Sticker Police" who know drobertson better than I get all over his case for that.  I'm just trying to help him solve the problem he has right now.

For what it's worth, I never, ever, ever (did I say NEVER?) mill any rough lumber by just using a planer.  I always use a jointer first.  It's just a simple way to guarantee great results.  If you don't own a jointer, you can use a planer sled in a planer to achieve the same thing, or you can use a hand plane first to flatten one side.  Even the straight boards in a stack can have a few small waves in them, and they can, and will, show up in the finished product.  If you're making a kitchen table for your own personal use, or a new workbench for the shop, it hardly matters at all.  But, if you're building a $7500 dining room table for a client who's purchased 12 pieces from you already, and expects absolute perfection for his/her money, then it'd better be right......that is, if I want to stay in business.

Two different extremes to consider.....

[drobertson]

the planer sled is what I had in mind from the get go when I saw the results just did not know how to go about it.. after years of machining steel, to heat treat to the grinder I know all to well about warping of stock,  and shimming to make flat.   I will learn this wood thing, because I love it,  thanks you guys for the input, and patience with a rookie,  again hats off to the folks that share the craft with grace and knowledge.  david

[red oaks lumber]

drobertson
i wasn't pointing fingers towards you, just emphasing the results of less than perfect stickering.
ww9
i feel the biggest push is proper lumber handling and i also know you wouldn't be one of my customers. there are customers that are picky and then there are customers that are unrealistic. maybe you should change suppliers if 98% of the lumber has to be jointed to make it usable. 

[Andy White]

drobertson,
I know the frustrations you are having with those panels. Shortly after getting my mill and kiln up and running, I would try to recover every board from every log. Soon I learned, that it is easier to edge glue narrower boards that are straight and flat , than to try to salvage a wide board. The cabinet project I am finishing now, really drove that home! Hand tools only, and you have to have every thing perfect. The stickering and stacking, with weight will give great results,  if you  know the limitations of the wood. Now I will cut the heart wood from all my lumber before stacking and drying. Those wide boards look good, but seldom give good results after kilning.


  

  

  

  

 

This is my observation, and your mileage may vary. 8) 8) 8)   Andy