When to oil?

[mcguyver42]

Hello, I've been at leathercraft for a few years now, but I don't have a lot of hands on unfortunately.  I'm really struggling with being able to evaluate leather for proper suppleness/ oil content?  I am making a briefcase for my son.  I selected a 6-7 oz veg tan side from my leather collection.  It's a Tandy hide, probably Brazilian grade C, not terrible looking, not been oiled since I have had it.  I rolled it out on my bench and had to weight both ends to hold it down while cutting out my pieces.  My scratch awl didn't make a very convincing groove or line to follow; it was very shallow, almost like a light cat scratch and I had to look at it from different angles to see my cut lines.  I had to make 4 or 5 passes with a reasonably sharp round knife.  My knife would get stuck, and I had a few skip offs.  I ended up pulling it towards me, and even using it like a strap cutter.   My big pieces were still wanting to curl up by an inch or more, even after laying out on the bench for a few days.   I had a disaster of a dye up and pretty sure now that I should have oiled my leather.   I'm wondering if some of the above should have been clues that this hide needed oil?  What do you guys look for when you are evaluating a hide for it's overall condition and usability?  Do you have some tests that you make on the leather, or do you just know by feel and sight?  How does temper figure in there?  Is firm temper leather just dryer leather?  Thanks in advance,  Guy

[fredk]

It does sound a bit like your leather is too dry and hard. Does it feel and act like cardboard? A good sharp knife should slice through the leather easily; not like a  'hot knife thru butter' but easily with a little bit of effort. A scratch awl should almost cut the surface

Mix some, very little, NFO with hot water and a few dribbles of washing up liquid soap. Then apply some of that in big swathes across the leather using a sponge. Not too much, too much NFO is bad. Allow that to soak though for 24 hours, see how the leather feels after that. If it still feels stiff and hard apply again, allow it to work for 24 hours and repeat until the leather is almost pliable, Stop then and allow the leather to rest and the NFO to work for a few more days

Assessing the temper of leather does come with experience. I once got stiff as a board leather from Tandy. I managed to get a discount as it was like a sheet of masonite/hardboard but I knew I could oil it and rejuvenate it. Firm temper is often a measure of how the leather was tanned. I have belly leather that is as floppy as cloth and some which is as stiff as thick cardboard, neither is too dry

[mcguyver42]

It seemed like the leather was reasonably pliable.  I just rolled out the rest of the hide on the bench for a look at it.  Possibly it may feel a little light for the size but I'm not sure.  What does the soap do?  I gave it a very heavy oiling with olive oil a few hours after the dye up.  The next morning I gave it another very heavy oiling, and then two more heavy oilings.  It didn't soak the oil up near as fast on the last oiling or two, and I was able to rub it in circles and even out the blotchy dye job some.  Still it came out much darker than the intended light brown, and the pieces are curled.  I didn't mention this before because the curling was already very evident, and I didn't want to add variables that may not apply.  There were some spots on the leather from the workshop.  I tried 3 of the methods that are well agreed upon by members here.  (Alcohol, 50/50 lemon juice and water, oxalic acid)

 

 

[mcguyver42]

[mcguyver42]

[mcguyver42]

[mcguyver42]

The first backside picture is of the really curled up piece.  The other 2 backside pictures and the 2 grain side pictures are from the side that the pieces were cut from.  I really appreciate your input.  I think the project is a flop at this point.  I'll go ahead and build it for the practice, but I shure would like to learn from this.  Thanks

Edited May 10, 2023 by mcguyver42
misspell causing unclear meaning

[chuck123wapati]

what you will learn is that leather will form to whatever shape you make it form to, by the time your done making your briefcase it will be flat and not a flop. Just keep going. 

[dikman]

Could be a feature, to ensure it doesn't go floppy when made?

As Chuck said, keep going, at the very least it's all experience. Working with leather is a bit like shooting black powder, there's an element of unpredictability involved.

[Burkhardt]

The soap will act as a lubricant slightly. By handling and making what you are will loosen it up and make it pliable and the oil will work in deeper. Eventually you'll have to add a conditioner to make it last but the more you work it the better it will get. Just do it in baby steps don't force it. Another reason not to dye it first is that it will make it stiffer. You can take about any leather that lays flat and dye it and it will curl up and become stiff.