Warping oak

[[email protected]]

Hi guys I'm new here and would appreciate some help . I've been charged with making a high end box from oak with a 10mm thick lid approx 450mm x 300 mms .despite using 4 year old oak which was previously kiln dried the lid warped .. I'm proposing inserting a piece.of t -section into the both edges of the box and gluing in place ..the first test I used expanding PU glue and the lid warped despite the 're-inforcement of a piece of 16mm x 3 mms steel. I feel that because the glue is flexible that it allows the warping . My question is this .. if I use cascamite is it flexible once.set ? .I'm very restricted on what I can do as the lid has to be 10mm thick solid oak made.from. 2 pieces and I can only frame the lid with oak 10mm x 12mm ! Any suggestions gratefully received!

 

[scooby]

All I can say is cascamite isn't flexible at all, it cures rock hard. Cant say if it will solve your problem, sorry.

 

[MikeG.]

Hi and welcome.

Cascamite is not flexible at all. It sets hard and stiff.

Tell us how you are getting to your finished dimensions for the lid. Timber isn't generally supplied 10mm thick, so how did you get down to that from whatever thickness it was when you got it?

In general terms, oak that thin is going to be a bit of a trial. However, with some nice quarter sawn and straight-grained dry stock, properly seasoned indoors, you'll have a chance. Inserting steel into the edge is an unusual approach. What are you trying to achieve? If it is simply to prevent warping, then it won't work........twisting, for instance, can happen with both edges remaining straight. Cupping will bend the steel. Steel and oak don't go well together anyway, as steel reacts badly to tanin, and you'll get staining, unless you are using stainless steel.

 

[custard]

There are lots of different designs for boxes, but as a general rule I use veneered ply for the top and bottom, and solid wood for the sides. This method solves at a stroke all the problems you're currently encountering.

I've made plenty of boxes like these using this basic method,

I'm not saying this approach is the best method or the only method, but I am saying it's predictable and doesn't spring too many surprises on you!

 

[Sheffield Tony]

I think a fundamental characteristic of working with wood is that you are using a material that will always move, in a well understood way, and sucessful designs build on that understanding. Breadboard ends or cleats on the underside are usual ways of keeping a thin lid flat. Quarter sawn wood is also helpful.

Gluing in metal, presumably across the direction of the grain, is likely to fail either by the glue breaking when the top expands, or the top cracking when it wants to shrink but can't. If you can fix the metal with screws in slotted holes, so that the top can expand and contract freely, but not cup, it should stand a chance of working like a breadboard end, maybe. It worked on old school desk lids, after all !

I see MikeG has beat me to it with cautions on oak+steel...

 

[woodbloke66]

Hi and welcome.

Cascamite is not flexible at all. It sets hard and stiff.

What Mike said. Cascamite sets glass hard - Rob

 

[Racers]

Breadboard ends will help a lot, if they can hold this in shape they should work for you.

Oak knot box by Pete Maddex, on Flickr

They are dowled with the outside one in slotted holes to allow for expansion.

Pete

 

[Yojevol]

This title caught my eye because I've been involved in saving a heavily warped oak table over the last few weeks (more of that later). I had the advantage of the oak being about 20mm thick and very old and dry. The wood was mainly cupped in the direction of the grain, so my solution was to make it flexible by cutting slots on the underside with the table saw blade. I then clamped it upside down onto a flat surface and filled the slots with oak strips glued in with Cascamite because, as Mike says, it's rigid.

I imagine you're making this box with a treasured bit of oak from your client. A solution could be, if you have a bandsaw, to produce thick veneers and use them to clad a piece of plywood. This may mean cutting the oak into a suitable size for your saw. Book matching may then be a possibility.
Brian

 

[transatlantic]

Breadboard ends will help a lot, if they can hold this in shape they should work for you.

Oak knot box by Pete Maddex, on Flickr

They are dowled with the outside one in slotted holes to allow for expansion.

Pete

That's a very nice looking box! ... I haven't seen bread boards used like that on one board. I've only seen them used on tables where there are multiple boards and the top is also attached to the rails.

In your case, the top is not attached, so I would have thought it would still twist?

 

[lurker]

OP, can I suggest you alter your forum name because you are asking to get bombarded with spam.
I am sure the moderators will help you fix it.

Welcome, by the way.

 

[Racers]

Breadboard ends will help a lot, if they can hold this in shape they should work for you.

Oak knot box by Pete Maddex, on Flickr

They are dowled with the outside one in slotted holes to allow for expansion.

Pete

That's a very nice looking box! ... I haven't seen bread boards used like that on one board. I've only seen them used on tables where there are multiple boards and the top is also attached to the rails.

In your case, the top is not attached, so I would have thought it would still twist?

It could wind but hopefully the ends are thick enough to stop it warping.

Pete

 

[Benchwayze]

FOR MIKEG...
For some reason I can't reply to your post in the WANTED section.
I can't send a PM either. I think this new 'format' for the Forum is throwing me!

I have a 1-1/2 Stanley Blue Chip that is lying around getting rusty! Some 'helpers' used it and left it in my utility room! I'll fix it if you want it.

Regards
John (hammer)

 

[MikeG.]

Kind of you John, but I've already bought one from someone else. If that goes wrong somehow, I'll come back to you. The offer is much appreciated.

For the good of your soul, though, you should sort that chisel out anyway. :lol:

 

[Benchwayze]

No Problem Mike,

My son had left the chisel out in the yard; it started to rain, so he gave it a quick wipe over and left it in the utility room. It's not that bad, but I'll have to give it some resuscitation .

I don't do much thee days, but I am still trying to keep the shop tidy! Some hopes!

Cheers and take care
John

 

[[email protected]]

Thanks for all the advice guys ... this is a very difficult project because it is obviously designed by someone who does not appreciated the way in which wood moves . At the moment it's all very hush hush so I can't attach any photos !. I have just received the prototype back today only to find that the cupping has lessened but the lid has now bowed left to right and warped front to to back popping the oak frame around the lid ! The problem is further exasperated by the fact that the lid sits inside the box walls when shut making any warping obvious. the oak for the next 12 boxes arrives tomorrow so I'll let you know what happens !

 

[marcros]

if the prototype is failing, then redesign it before making the 12. the client does not always understand what they are designing and the constraints.

 

[MikeG.]

Suddenly there are a dozen boxes!

I'm going to say straight out that this isn't a project within your capabilities, stoneways. Experienced woodworkers approach such projects cautiously, and that's with years of knowledge and experience to help them. If you try and build these yourself, it is going to go horribly wrong.

 

[custard]

I tend to agree with MikeG. You've sensibly tested the concept with a prototype, but now you're ignoring the lessons that the prototype is trying to tell you and cracking on with twelve more.

You say the lid nestles within the sides, making any warping painfully obvious, therefore common sense says forget solid timber and switch to veneered man made board for the lid. Basic veneering like that is pretty straightforward, but if you're not comfortable attempting it then either sub that part out or drop the project.

 

[Mr T]

I would agree with Mike G. and Custard. You may be getting yourself into deep water here. 10mm thick oak will warp, also are you making allowances for expansion and contraction of the panel. If the 10mm has been cut down from thicker stuff it needs to sit a while a bit over thickness before taking down to 10mm, but even then it's likely to move.

Good luck!

Chris

 

[MikeG.]

You may not be aware of the calibre of the advice you are being given here, stoneways. Custard is a professional furniture maker. Chris Tribe is a professional furniture maker and a teacher of fine woodworking. I've been a professional furniture maker. We've all been doing this for donkeys years. People pay good money to get the sort of advice you are being given, so I really would stop and have a good think before you go any further.