What happened?

[Ledbeter36]

So I have a bunch of cheap leather from Argentina that I was using to try new designs, build prototypes, practice carving and just try new things in general. So I was making a holster back piece and didn't like the way the water based dye was going so I decided to rinse out as much as I could and go with a much darker color to cover since it's not that important. Once wet I just put it in the oven on lowest setting like always because I wanted to hurry up drying and didn't care if it was hard. I checked it several times and the outer edges were drying and the center was still darker.  Then a short time later the center turned very dark and heavy wrinkles in the skin. I had a piece do this that I knew had been in contact with baby oil before but this hasn't had any oil on it as far as I know. Is my oven heating up more than it should? Or does it mean it had to of come in contact with some oil or chemical. It didn't feel that hot when I removed it. I just want to make sure I don't do this to expensive leather. I'm not experienced enough to know for sure. Any help or ideas is appreciated.

[ConradPark]

That is what rapid drying does to leather. It's not so much the heat as the moister content or lack of. I grew up with my parents running a shoe manufacture business, and we are talking full blown machine production capable of hundreds of pair a day. There was machines that wet formed the uppers of the shoe by pushing in a plastic or wooden last between the leather and the shoe bottom, and to hurry up the drying process the shoes were then put into giant drying 'ovens' and they where hot! However, they also had steam pumped in to keep a certain moister level to avoid the leather to shrink too fast and dry and crack. And the shoes had to air dry regardless for the end part, too cool down and to 'level' out naturally. And most of the leather used was chromed tanned (that has actually better resistance to this kind of treatment.)

Basically, in my experience the quickest way to hurry up the drying at home, is to let it air dry above a warm oil/water radiator or similar and to remove it before it turns too dry and let it air dry for the final part. I always do it this way after tooling leather, to make it ready for coloring in like five to ten minutes, instead of having to wait until next day.

[Ledbeter36]

2 hours ago, ConradPark said:

That is what rapid drying does to leather. It's not so much the heat as the moister content or lack of. I grew up with my parents running a shoe manufacture business, and we are talking full blown machine production capable of hundreds of pair a day. There was machines that wet formed the uppers of the shoe by pushing in a plastic or wooden last between the leather and the shoe bottom, and to hurry up the drying process the shoes were then put into giant drying 'ovens' and they where hot! However, they also had steam pumped in to keep a certain moister level to avoid the leather to shrink too fast and dry and crack. And the shoes had to air dry regardless for the end part, too cool down and to 'level' out naturally. And most of the leather used was chromed tanned (that has actually better resistance to this kind of treatment.)

Basically, in my experience the quickest way to hurry up the drying at home, is to let it air dry above a warm oil/water radiator or similar and to remove it before it turns too dry and let it air dry for the final part. I always do it this way after tooling leather, to make it ready for coloring in like five to ten minutes, instead of having to wait until next day.

Thank you, so your saying I should never let a wet form stay in until completely dry rather remove it near the end and let it finish drying on its own. I've noticed every leather reacts somewhat differently to being heat dried. I've had some that dried completely in the oven and it didn't Matter but this is the third time I've seen this reaction. So no more full drying under heat.