Hello leather masters,
I have two questions about better edge finishing.
The first issue is making an edge on soft leather where two layers that are not perfectly aligned come together.
As an example, you can see in the picture below that a piece of soft leather was cut using a cardboard template.
The leather is supposed to be folded and sewn along the edges, with a zipper in the middle. Since the rounded edges were made with a round knife, they are not completely straight (picture below).
How do you best approach such details? Since the leather is too thin, sandpaper cannot be used. Is it best to cut the edge after the layers are sewn, or is there a better trick?
For example, how do you suggest finishing an edge like this where the leather is very thin, is it best to leave it raw, paint it, or is it best to heat treat it? The second question is about the edge, on dyed leather. In the picture below you can see that two pieces of leather are sewn together and dyed with Fiebing's blue paint (the edge was also dyed).
The edge was heat treated - a mixture of water and Water-Based Contact Adhesive, then rubbed with a cloth. However, there is a white line in the middle, which I assume is because the paint did not absorb into the glue. For example, how do you patch an edge where the paint does not adhere to the glue? On the lower part of the edge, you can also see that where the glue is (in the middle), the edge is not well polished/finished. How to approach this problem? Thank you for your tips and tricks! Have a nice day!
I recently had to cut a perfect circle of .5mm thick ostrich for the watch case that Phil has on his courses. Ostrich is very very soft. What I decided to do was to stick the leather down onto an adhesive Cricut mat and then using an NT circle cutter I was able to cut cleanly and accurately without any bunching up of the leather. Perhaps the same technique could be used in your particular situation.
I agree with Feather, it may be best to trim your edges after stitching. Or, make one side slightly oversize, then after stitching, trim to the side that was cut from the original pattern dimensions.
Don't be afraid to use some sharp scissors on soft leather, a round knife is designed for cutting thick or firm leather and may cause soft leather to stretch due to the friction from that big blade.
I've never heard of using contact adhesive and water to burnish an edge, this may be where the issue lies (if I understand correctly). Ideally PVA glue is one of the best glues to use when you glue two parts together which will be finished with a burnish.
I hope this helps!
For your mismatched edges, you may want to refine and adjust your round knife technique until you can get more smooth, consistent edges. Try starting with a square edge and then using lots of straight cuts to make a curved line. I've added a screen grab below of how the concept works. At the point you're at, stitching first and then carefully cutting the stitched product may be a less frustrating solution than trying to match those cuts then sewing together. Adding a simple gusset while the whole thing is inside out and then turning it back right side out may cover the edges enough to clean them up and add some volume back to the inside of the project if dimensions are going to be too small after sewing to the new, smaller curved edge.
For your dyed edge, it looks like you're using a much stiffer leather, likely a veg tan? You likely need to sand this down to remove the glue, possibly hit it with a crepe eraser glue removal bar, and then dye and finish again. Since you've finished the edge with water based contact adhesive, you may have enough stiffness from the adhesive even with chrome tan to sand, re-dye, and re-finish.
Good luck!