You Can Fuse Leather
Some time back, I showed some leather I bought to a friend who doesn't sew. I went on and on (while she politely listened) about how I dislike gluing stiff interfacings to bags and bemoaning the fact that you can't fuse interfacing to leathers. Her response was, "Why not? Don't you think they use high heat during the tanning process? I bet you could fuse it if you wanted to." Then she changed the subject.
From the mouths of babes-or at least non-sewers-came a great "Aha!" moment. So I took some scraps of leather and some standard craft fuse and had at it. Sure enough, it worked like a charm! I did likewise with tailors' canvas and got good results that stuck (pardon the pun) as well.
How to do it
To fuse interfacing to leather, I use a silk organza press cloth and a heat setting somewhere between wool and cotton. Press down (not too hard) for 10 seconds and-voila! It's fused, and it gives just the right firmness without being unwieldy. The picture above shows a bag that I fused, sitting on the same leather in its un-fused state. As you can see, the fusing doesn't have any adverse effect on the leather. Test first on a scrap, of course, but don't be shy. I have fused successfully on cowhide, lambskin, pearl finish, metal finish, plain finish, and suede.
The moral of the story is, Go for it!