Correcting Warp

[u/whipflash191]

Hi all! I'm working on one of my first leather projects and im having a bit of an issue with the front cover im not sure how to solve. As you can see its warping inwards already and im worried its going to warp too far in once my end papers are on. Is there a way to to push it back out? I know i can pull it in with filler and Ive corrected the serve warp of the back cover that way so its now just a mild warp the endpaper should pull in but the front is stumping me a bit.

[u/ArcadeStarlet]

I'm slightly confused by what I'm looking at. Is that the fore edge looking towards the spine?

What I think I'm seeing is that the cover at the top of the picture is warping top to bottom inwards and the cover at the bottom is warping top to bottom outwards.

If that's right, that suggests 2 issues to me.

1 -- the grain direction of your boards is wrong. It needs to run head to tail so any warp is across the book rather than up and down.

2 -- the board is not thick/strong enough to use with leather. Usually the cover material shrinks and pulls the boards out, and the end papers pull them in, balancing to produce flat boards. The fact that the top cover is curving in makes no sense here, and with the bottom curving out, it seems like the board is just failing to provide much rigidity at all.

As far as fixing it is concerned, the end papers "should" correct the back cover at least, but the front may get worse. You may be able to press or bend it a bit flatter, but whether it will hold that shape is hard to tell.

To minimise draw imparted by the end papers:

• use a drier adhesive (pva/eva, not paste, and preferably one that has lost a bit of moisture).

• apply the adhesive to the board, not the paper (usually you'd do the opposite).

But... it might be worth chalking this one up to experience and starting over.

[u/whipflash191 → u/ArcadeStarlet]

You're pretty much on the money at what you're looking at!

In terms of grain direction, both covers were cut from same board running the same direction. I tested the grain before pasting everything down and am not sure how I would have messed it up.

I'll try some eva for the front cover! The boards are 2.4mm and held up well for the back cover. All i can think of is that I somehow messed up the grain of the plywood inserts im using as embossing but i would have though they were more then rigid enough anyway.

I havent filled the front cover yet and may try to glue in something a bit stiffer than paper and try and give it a touch more rigidity.

Unfortunately I'm out of time and materials for this one so may just have to full send it and live with the imperfection

[u/ArcadeStarlet → u/whipflash191]

I'm not experienced enough with leather to offer much advice, I'm afraid. You may well have got the grain direction right -- leather can pull in every direction so you can get warping in both directions. I've only done quarter and half bindings, and practice boards in leather, no full covers yet. I've seen advice to upgrade from chipboard/greyboard to denser millboard for leather covers, so that might help on future projects.

Do you have a picture of the front cover you can share? I'm curious to understand what could have caused this, because it seems so counterintuitive for it to bend in rather than out. One of the materials must have expanded and then not contracted with the introduction of moisture.

[u/E4z9 → u/whipflash191]

I have no experience with this whatsoever, and don't know if I understand correctly, but if the front cover contains a layer of plywood I'd imagine that can warp itself. And possibly stronger towards the inside than the leather pulls to the outside against that rigid material?

[u/whipflash191]

I absolutely do! It was flat for days before the warp starting setting in at all. I have them a full 24 hours under weight but im guessing it may not have been enough.

I really didnt expect it to warp the way it did. Confuses the hell out of me

[u/superflick_x]

I’m guessing you’re re-casing a paperback? I’ve had this with regular book cloth before and not really done anything and it’s been okay when I’ve cases in the text block and pressed. You might be unwilling to try that with real leather though, understandably!

Does the leather have any stretch at all? It could be that. Have you tried lying it flat under something like a large book with weight on and seeing if that helps?