Leather "Curling-up" after tooling...

[SCOUTER]

Ok, I feel like this should be a "first post" question but I would like to know how you deal with "curl-up"- We rubber cement a piece of leather to a backing material (I use plexiglass) then case and tool. After the leather dries and is removed from the backing, a few days later it starts to curl slightly. I ASSume this is happening because I am only casing one side of the leather, but if I case the back of the leather how do I cement it to the backing? I have tried leaving it on the backing until it was bone dry but soon after I remove the backing a day or two later- Curling... Now to counteract the curling I thought of casing the backside after removal but the rubber cement makes this difficult to do. Thanks for any imput...

[bruce johnson]

Scouter,

It is going to be interesting to see how others respond here. I had a conversation about this a week ago with a guy, who was havng the same problem, and mentioned it had stopped. I really have not recognised a problem with this. Here's what I do. I tape the backs with carton sealing tape. I really don't think what you do to secure it makes much of a difference. I wet my leather with the case solution of choice. I have used water, water/lexol/dish soap, ProCarve, and now use the lexol/baby shampoo formula shared here a while back. I wet my leather, and case it at least 8 hours but usually overnight at least. I seal it in plastic ziplocks, and those XXL huge storage ziplocks are a big help now. I leave enough air in the bags to keep the plastic off the grain side of the leather. Next morning I tool as normal. I have done the longer casing for several years, and have found no matter whose leather I was using, the effects were just better.

What had changed with the guy who had the curling problem. He went from casing and tooling as soon as the leather returned "to color" or casing for an hour or two to casing overnight. The lexol/shampoo formula is not a quick case solution in my hands, and I told him I was overnighting it. He went back and tried some ProCarve and cased overnight, and said little or no curling too. We suspect that the casing level being equal through out the layers was the difference. If only the top layer is moist and it stretches slightly with tooling, then it stands to reason it is working against the bottom layer and curling over it. If the moisture is even, the compression is against the entire thickness. Some leather takes casing slower or faster than others. By giving it plenty of time, you minimize that effect.

[David]

I have a real easy solution for your problem....It is caused by that last little bit of moisture evaporating from your leather. My solution is to lay my piece face down on my workbench....My workbench surface is granite. I place a poly pondo board on top of it and then one of tandy's 12" square pieces of granite on top of that. I leave it like that until I'm ready to make my seat/binder/whatever. It comes out flat as can be.

Dave

http://www.theobaldleather.com

[steveb]

I have a real easy solution for your problem....It is caused by that last little bit of moisture evaporating from your leather. My solution is to lay my piece face down on my workbench....My workbench surface is granite. I place a poly pondo board on top of it and then one of tandy's 12" square pieces of granite on top of that. I leave it like that until I'm ready to make my seat/binder/whatever. It comes out flat as can be.

Dave

http://www.theobaldleather.com

yep - i use a version of this tech. and it works fine...i use a small weight and a piece of flat and smooth wood - rather than Dave's hi-roller setup..lol

[Duke]

I use blue painters masking tape to the back side to keep it from stretching. why the blue stuff? less adhesive, so it comes off easier. still holds good tho.I case overnight also, and tool the next day, and I make sure to use the bee natural pro carve. what happens is the solution helps to break down the cells of the leather and make them more soft and supple, hence easier to tool.yu can also leave your item to completely dry for a few days before removing the backing.good luck.

[SCOUTER]

Gentlemen Thankyou! I had a hunch that it was the residual moisture causing the problem... I guess with Bruce's method the moisture has fully penetrated the Leather and dries more evenly. In Al Stohlman's leatherworking manual, he states to case BOTH sides of the leather. I never tried that. Thanks again!

[Rawhide]

Here's how I do it.

I rubber cement a piece of Crescent (#201) illustration board (hobby lobby) to my leather. Put rubber cement on the board only. I use a hotel room card to spread the cement out evenly. Then I stick the leather to the board. Case, tool and let dry completely. If you let it dry why still on the board, it won't curl up on you. When it's dry, it's easy to peel the board away, because the cement is only on the board. Now the back of your leather is still open to receive water if you want to shape or mold it or re-case it, or whatever.

I got this idea from Peter Main.

Marlon

[Hilly]

Here's how I do it.

I rubber cement a piece of Crescent (#201) illustration board (hobby lobby) to my leather. Put rubber cement on the board only. I use a hotel room card to spread the cement out evenly. Then I stick the leather to the board. Case, tool and let dry completely. If you let it dry why still on the board, it won't curl up on you. When it's dry, it's easy to peel the board away, because the cement is only on the board. Now the back of your leather is still open to receive water if you want to shape or mold it or re-case it, or whatever.

I got this idea from Peter Main.

Marlon

You mean, when you pull the cardboard off the leather, all the cement STAYS on the cardboard??? How does the leather stick to it then? Do you have trouble with your edges coming up? I've tried cementing to xray film, and I think I prefer the tape method because the back of my project came off the xray film feeling like a rubber pancake

[Roger]

i have not really seen this problem either. i use a few drops of dawn dish detergent in water to case, bag it and try to let it sit at least overnight.

what i find interesting is..

i have only had an issue one tme with the leather getting stretched out of shape from tooling and it was a small piece of 3-4oz and heaviliy tooled.

i use nothing on the back of my leather and if i need a bit more moisture, i spray the back side where it's needed.

[Rawhide]

Hilly,

It will stick. And stick well enough to tool and prevent stretching. I've done it on several projects. Just be sure to let the cement dry to a tacky state. Also, the more coats you put on, the tackier it will get. I usually put on two coats and that's plenty enough for it to stick.

Give it a try.

Marlon

[JRedding]

I guess I'm the odd man out here I don't case leather to tool it, I've tried it but just never loved the results. I've experimented a lot and came up with different conclusions that work for me. The leather we get today is not the same as it was back in the fifties , sixties , or probably the seventys, I hung out in the old Newton Bros. shop here as I'm sure many of you have the old local saddleshop, the leather they dealt with back then was harder than a jailhouse door, it wouldn't mold to shape without hot water, and it wouldn't tool without casing, thirty or forty years later the EPA has forced the tannerys to re-invent the process several times since most of the literature people are referring to was written. It's kind of a case of nothing stays the same and the changes in the tanning process have definately changed the behavior of leather. I don't case to tool because I don't feel todays leather is so hard I need to for it to accept it. As everybody knows casing allows the moisture time to penetrate and even out throughout the thickness of the leather, thus the back becomes as formable as the front making it easier for the leather to stretch. By leaving the back as dry and hard as I can it retains some of it's own rigidity helping it hold it's shape. Something like moistening it and then taping it to try and control it except without all the extra steps. I tape small projects made out of lighter weight leathers and then moisten from the top down and have little to no stretch, but leather in projects like that have almost always been leveled on the back that's a different thing. Leather being a product of nature has a knit all it's own that holds it together, once it's been leveled the knit of the fibers has somewhat been destroyed it no longer has a top and a bottom it only has a top and a middle once it's been leveled, and it no longer has near the ability to hold itself together that it once had. Taping and scrimping on the moisture as much as possible really helps me control the stretch on leveled leather. In a nutshell you're not tooling deep enough you're into the bottom layers of a piece of leather if the surface you're working with isn't so hard you have to case it to be able to tool it why do it ? I've just had my best results by trying to get the moisture in the portion I'm working with and leaving the portion I'm not alone as much as possible. I'm sure others have drawn different conclusions and as long as it works then it's a good conclusion this is just my approach.

[pete]

Fascinating! So you just maybe run a dampened sponge over the belt as you are working that area?

pete

[JRedding]

Fascinating! So you just maybe run a dampened sponge over the belt as you are working that area?

pete

Pete, I use a spray bottle instead of the sponge and I wet the whole piece pretty well I like to carve wetter than I tool just because it's easier, by the time you've finished carving it's dried enough to tool , that kind of depends on the size of the project but that's the basic idea. then you can just spray it a little bit to keep the moisture consistant. It's just a practice deal learning to read the leather, some leather seems to return faster than others and here it varies from summer to winter, you have to feed it a little different in August than you do in January but once you've learned the look and feel of what you want it's not so hard. I just don't beleive there's a formula that's correct and always works well, like you can take any brand of leather of any weight , and at any climate and case it for a set amount of time and it's going to hand you back the best results possible to be tooled. Learning to read the leather and make adjustments for what you've got at hand will make a lot of leather give you good results as opposed to just treating it all the same, and wondering why one piece is so agreeable and the next isn't. Casing is pretty much a set formula, you're going to case it long enough it balances the moisture throughout it's layers, I just think it may have worked better when all the leather was tanned with basically the same process in every tannery and it was a lot harder leather than we see today.

[BillB]

My experience over the last 40 years is a mix of all the comments already in this thread.

The quality and the tanning of the leather has changed over the years for better or for worse. :mellow:

I have cased, quick cased and not cased at all. When I case the leather, I let the moisture penetrate and equalize through out the thickness of the leather. I then allow the leather to dry until the surface and the back have returned to their natural color, but one can still feel the coolness of the leather caused by evaporation when it is held to ones face cheek. Some folks call this reading the leather.

I have also found that leather, a skin, is held in natural tension by the fibers, as previously stated. When one cuts the fibers on the tooling surface, that natural tension is broken, it is further disturbed by tooling, remember we are not removing material but compressing it. That compression set up a new tension in the leather. Depending on the thickness of the leather and the depth of the tooling and the size of the design in relation to the leather (tooled versus not tooled) has a lot to do with the amount of change I impart on the the original piece of leather whether that be in size (length or width) or its ability to lay flat.

Since leather is skin, I have also found that the dyeing process can also impact this problem. Skin likes to have natural oils in it to stay flexible. Dyes are solvents that first must suspend the dye to transport it to the fibers. It must then replace the natural oils in the fiber so that the pigmentation of the dye is transfered into the fiber. It then must evaporate to lock the pigmentation in. This process tends to remove all oils from the fibers and changes the tension in the leather/skin. Have you ever used a cleaner on your hands to remove the dye stains and ended up with rough and cracked skin? Same process. Putting oils back into the leather will help resolve the condition the dye process has created, but not the change the tooling process has done.

I guess that is why well tooled leather is still an Art or Craft. It is impossible to replicate with a standard process or by machine.

Lets hear it for all those Artist and Craftsmen/folks/people that are out there. :D

Have I now :deadhorse: