Thread: Fix cupping...what IS cupping?

Okay, I have a nice strop that if you're looking at the part you strop on, we will call that the front. Well, the very edges "fold" or curve towards the back.

Is this a problem or could it become one? How can you fix this?

'Tis a vintage Illinois.

As I've heard it, cupping is when the edges rise up, so when you strop only the toe and heal make contact. Regardless, it can be fixed. If the strop is dry or stiff, rub in a little neatsfootoil. Then, on the back of the strop, take the smooth part of a glass bottle and give it a good rubbing. I do this with slack in the strop and press the bottle in firmly (to take up all the slack). Run it back and forth a bunch, and see what it does.

My TM cupped from leaving it in the bathroom (humidity, I guess) and this flattened her out.

Rick,
Cupping is where the edges are higher than the middle. When pulled taut this does not seem to go away and as mentioned the razor does not make full contact with the strop. I have found that with many cupped strops if held a bit slack the weight of the razor does flatten it a bit and you may then get full contact.

What you describe is more of a "crown", like the crown in a road. The center is high, the edges are lower. This I find flattens easily under stropping pressure even with a taut strop.
I prefer this myself and actually ship my strops with a slight crown to counteract, or delay any tendancy to cup. Over time the crown seems to go away but can be coaxed back with a little pressure from the fingers on each side of the strop.

Tony

Does your Vintage Illinois have a handle or is it the square cut leather at the bottom?

Lynn

Originally Posted by Tony Miller

Rick,
Cupping is where the edges are higher than the middle. When pulled taut this does not seem to go away and as mentioned the razor does not make full contact with the strop. I have found that with many cupped strops if held a bit slack the weight of the razor does flatten it a bit and you may then get full contact.

What you describe is more of a "crown", like the crown in a road. The center is high, the edges are lower. This I find flattens easily under stropping pressure even with a taut strop.
I prefer this myself and actually ship my strops with a slight crown to counteract, or delay any tendancy to cup. Over time the crown seems to go away but can be coaxed back with a little pressure from the fingers on each side of the strop.

Tony

Yes, this is a crown. Not cupping.

Originally Posted by Lynn

Does your Vintage Illinois have a handle or is it the square cut leather at the bottom?

Lynn

Handle.

Thanks Rick. The old strops with handles don't normally cup or crown as much as those that are held by hand and those either cupped or crowned where you are holding them at the flat base of the strop. I have also rarely seen what you are describing in the old 2 1/2 inch wide strops, but definitely easier to remedy as described than cupping. I have never seen any strop intentionally crowned and it would be pretty hard to do this when sending in either a flat box or with one lightly rolled in a box for shipping. I would also be surprised to see a strop hold a crown for any period of time if curled for that effect when new. Never say never...........

Lynn

Rick, give the 50 lap hand rubbing a try a few times over the next couple of days. That will impart some skin oil into it and may help flatten it out and soften it up a bit. Some of those vintage strops have been laying around with no TLC for a long while.

Originally Posted by Lynn

...I have never seen any strop intentionally crowned and it would be pretty hard to do this when sending in either a flat box or with one lightly rolled in a box for shipping. I would also be surprised to see a strop hold a crown for any period of time if curled for that effect when new. Never say never...........

Lynn

Hi Lynn,

I have never seen one that I knew to be intentionally crowned, but the way the leather is shipped or stored plays a big part. Ideally, the hides would be flat, but they are usually stored rolled-up in cardboard boxes ready for shipping with the area and type of leather marked on the outside.

Hides that are rolled rough side inwards, depending on how you cut strips out of them, produce strops that either curl towards the back on the long dimension or the sides on the short dimension - both a sort of crown, really. When I order I always specify the hide to be rolled in this way - it lessens the chance of wrinkles on the face side, too.

The problem ones for me are those that are rolled with the fair face inwards - these cup in one or the other dimension and the compression on the fair face leather sometimes leads to wrinkles, especially near the middle of the roll. I haven't had many rolled like this, most seem to come from europe and are tanned a bit softer so often the problem goes away after unrolling.

In a large concern I guess the strips are cut from the hides and stacked ready for handles and hanging gear to be added, so the pressure of the stack and being laid flat often conteract gentle cupping or crowning problems.

Just what I have experienced though!

Regards,
Neil

Thanks Neil.

I totally agree on the storage and rolling them up definitely playing a part. We actually hang all ours as soon as we make them up and then ship in flat boxes so that they are not rolled. I guess anything actually can cause them to cup or crown as they are a natural material. I normally hang the ones I use all the time, but do store the vintage and other strops in a closet flat. I have never seen one of them cup or crown yet although I know occasionally people will see this. I pulled out a couple of my vintage strops with no handles and did see a little cupping down where I hold it with my thumb in the middle of the strop, but the entire strop did not cup as a result.

Appreciate the insight,

Lynn

how about using some olive oil... i just built myself a cowhide strop and the leather is stiff and rigid and after i lathered it up and left it overnight it cupped.... so i tried rubbing a wine bottle on the back and that did not make it very flat still i dont get full contact with the razor... will taking some olive oil into my palm and then massage it firmly into the face of the strop for say.. 50 laps and then take the bottle for a spin on the back make this go away ? is it worth the try?

thanks alot .