Yew Swine - how to unbend a bookcover...?

[Dokkodo]

My girlfriends Pa is a musician, photographer and and poet, and he recently collected a bunch of his works into an anthology and bound a lovely one off book containing them all.

He did his research and came up with a pretty good plan, having found a luthier selling a 5mm thick cut of yew large enough to make both A3 front and back covers, he bought the wood and glued it good and proper to some 6mm birch to stabilise, and had the title and graphic lazer cut in and bound the book.

however, upon treatment (osmo i think), it went boing in quite a big way. front and back covers are cupping quite drastically. He isnt toooo bothered, he says he quite likes the fact it looks like its trying to open itself. But also would prefer if it was flat, so i said i'd ask.

I think he tried leaving some weight on it, i suggested lots for an extended period, but i dont know if that would ever work completely and i don't really know what else to suggest. the birch ply seems not to be helping at all. he said he had tried wetting the cupping face just to see what happened and it straightens out, which i guess youd expect, but then bends back once dry, which i guess youd also expect...

so, any advice? will the book be bendy forever?

 

[NazNomad]

Flip the back cover over so they both bend the same way?

Fit a clasp to the book, assuming the covers can be pushed together?

 

[Rob Platt]

hes not made a sandwich and that looks why its bent It probably needed a balancing veneer on the inside
all the best
rob

 

[mrpercysnodgrass]

Rob is right, it will need to be veneered ( something straight grained ) on the inside with the grain at 90° to the front cover.

 

[swb58]

Won't it need something more substantial than a veneer on the inside?
To try and rectify the situation I'd have thought that whatever is applied to the inside now will need mechanical strength to to stop the curvature. The yew has found its happy state regarding humidity, keep it in the garage?

I'd be inclined to plane off the plywood and start again.

 

[Droogs]

The face and the backing veneer should be the same thickness with the grain running in the same direction. the "sandwiched" core should be at 90Deg to this and this allows the 2 faces to then counter each other and the board will sit in equillibrium.

So basically, looking at the picture, take the cover off and plane away the current ply and replace with 3mm ply. I say this as the yew does seem to be a little thick and just putting on a backing veneer would make the book exessively unweildy.

hth

 

[Dokkodo]

Thanks! I have relayed the info. As we suspected, short of unbinding the book and starting again, not much to be done.

 

[LBCarpentry]

Id just be grateful it wasn't you who did it for him and get back to yer coffee and cake haha!

 

[CHJ]

Looks like He's basically made a large Hygrometer. Assuming (I know one should never assume) the boards were flat to start with then placing the book in a sealed plastic bag for a while to let the two woods reach equilibrium in moisture level may flatten them again.

If it works placing the book in a storage sleeve case may prevent it curling again a it would discourage the Yew from drying out quicker than the inner leave.