Wet forming: how much curvature is too much?

[Leb]

Hi everyone,

I spotted this "leather basket-hilt" in the interwebs https://fencingclassics.wordpress.com/2009/01/08/leather-hilted-singlestick-britain-c-1900/
As far as I can tell, there are no visible stitches going across the hilt. I never tried wet-forming anything so extreme in the past (the closest thing was a flask, where I basically copied what this person did here: https://leatherworkingreverend.wordpress.com/2010/05/06/flackets-the-other-leather-bottle/ ), but thought I'll give it a go.

I made a prototype which is about 10cm tall, and has a top-view profile of an ellipse with major/minor axis of 12 and 10cm respectively. The leather is about 3.5mm thick, and soaked it in room temperature water (maybe I should heat the water a bit more?). When I try forming the leather, I can only get so far before getting stuck due to wrinkles, and I am not sure how to get rid of them without the "cutting triangles" technique. I tried "pre-forming" on a less aggressive shape, but that didn't seem to make a difference. When I had wrinkles on my flask project, I got rid of the wrinkles by using a "multi-step" approach - that is, I would press as much as I could before the wrinkles would prevent me from going further, let the leather dry, resoak, and then press again, which would usually deal with the issue. However, multi-step approach doesn't seem to work here.

I'd like to ask you opinion if you think this should be formable, and whether there are some crucial steps I am missing which prevent me from succeeding. I wonder, if rawhide forms differently to veg tan (perhaps it is possible to "boil" rawhide onto a shape?). I would also be interested in hearing some theories how the hilt in the first link could have been made. Perhaps forming on a half-sphere first, and then squeezing on the sides by hand to make an oval shape could be an approach?





The "top view" size is about 12x10cm (which I suspect is one more problem, I guess it should have less elliptical)

I am only able to form the first ~2inches before I cannot push my press any further with clamps or otherwise.



This is due to wrinkles forming


Now, perhaps I have left just a little bit too much excess leather, however, I wonder if this shape is in general too much for wet forming.

 

[garypl]

Have you thought about wet forming the upper dome section and then stitch the bottom cylinder to the dome?  Don’t know if this design would work for you, but seems it would give you a smooth surface all the way down.

Gary

[mikesc]

On the picture in your 1st link, I can see a stitch line going across the crown of the "dome" starting about 3 or 4 cm to the left ( as we look at the photo ) and slightly below the 9 o'clock position of where the stick enters the hilt..I think that the seam would continue across the crown of the dome and down the other side of the hilt, so that the hilt is maybe wet formed from one piece, but with a "split" which is then sewn up..Inside the dome part of the hilt you could have two hemispherical wet formed parts sewn together, with the seam at 90 degrees to the outer seam.This would be reinforcement.These two hemispherical parts could also continue on down to the wrist..and would incorporate ( via two holes ) the sewn in ends of the stick "tube"..

This stitch line over the crown of the dome part would not be facing many incoming blows, and so would not get damaged..

Edited September 19, 2019 by mikesc

[chrisash]

Your shape does not look the same you have a straight edge from the bell shape , whilst the picture shows the curve continuing into a much more bell shape, I assume the row s of stitching is just to hols on the banding close at the top and inside about a inch or so

Have you tried using Belly which may be more flexible and also some thinner leather and maybe two or more layers deep stuck together, In those days the sailors would have been experts on using leather, so it might have been made like PAPIER MÂCHÉ, small pieces lining around a mould and stuck over each other to build up the thickness and just a micro thin covering over the top

[Leb]

Thank you for the replies everyone.

@garypl stitching another section is certainly something worth considering, thanks.

@mikesc Do you mean these two stitches circled in yellow? Nice spot, I completely missed it, thinking it was just a scratch.
Having only these pictures to go with, I think the construction you describe is certainly possible. However, it still escapes me how the outer "dome" is seemingly made form a single piece of leather.

@chrisash Ah, very good point about the shape. The more gradual shape should help, and I do now see that it is more of a bell rather than an ellipse. Interesting suggestion regarding using very thin leather in multiple layers. I have just quickly thrown a ~ 1.5mm leather (so not that thin) to see what happens, and to my surprise it wrinkled more than the thicker leather. I'll need to try with some 0.8mm goats leather to see what happen. Regarding belly, I will keep this in mind, thank you. So far I have been using scrap pieces (not even sure anymore which parts of the hide are they...)
 

 

 

Edited September 19, 2019 by Leb

[Matt S]

Is it possible that the main "basket" is in fact rawhide, rather than fully tanned leather? It looks pale (compare with the edge trim) for a 110-year-old piece of russet veg-tan. The description mentions it being "stiff and hard as plastic" which I would say is a closer description of rawhide than wet-formed veg-tan. I have some very limited experience of working wet rawhide (mostly soaking and flattening dog chews) but the stuff seems far more supple when wet than any tanned leather I've tried to wet-form.

[RockyAussie]

I have not done anything quite with so much stretch and it does say that the leather was boiled which also I have never done. I think your thickness is getting a bit much but for the little it is worth I will say how I would try to do it. Leave the leather soak in hot water with detergent in it for a half hour or more. If you check up on how staking is done in the tanning process you will see a somewhat pointed stick that the hide is repeatedly pulled down over and with a fair bit of effort this can stretch  a hide a lot in any given area. By working the centre outward you should then only need to work on broadening the point out to give you the more dome shape you are wanting. 

[Leb]

@Matt S It does look like rawhide, doesn't it. I think I'll just have to order some rawhide of different thickness and see what happens.

@RockyAussie Thanks for the tips, I guess the detergent acts to break up the membrane proteins to some extent to make the leather more pliable (and I suppose lubricates the leather to help with pressing?)

Edited September 19, 2019 by Leb

[robs456]

12 hours ago, Leb said:

maybe I should heat the water a bit more?

Yes, definitely. even your link says it's made with boiled leather. Boiling the leather will change the leather (on a molecular level?) and makes it very pliable and will dry hard as, well plastic.

12 hours ago, Leb said:

I can only get so far before getting stuck due to wrinkles

You need to make cuts, as many as you can up to the point the form begins, all around. If that makes sense?

 

[mikesc]

Quote

Do you mean these two stitches circled in yellow? Nice spot, I completely missed it, thinking it was just a scratch.
Having only these pictures to go with, I think the construction you describe is certainly possible. However, it still escapes me how the outer "dome" is seemingly made form a single piece of leather.

Nope :)..I saw those / that line, but I think that is just "damage"..I mean this line ( the arrow points to the line, the line ( fine dark line with a slight curve to it, it goes around "the back"* ) itself is just above the slightly curved line I have drawn in red ) I think this line is a seam ( could be glued onto another "composite" shape underneath as I described above, made from thicker leather ) I think that this "seam" ( I don't think it is a scratch ..Goes right over the "crown" of the dome and down to the edge of the hand guard )..or at least to the edge which is covered by the "binding"..Obviously there is some sort of reinforcement structure under the top cover of thin layer ( the top layer , outer layer, is thinner than you are using, and thus more flexible ) You can see this from the line of stitching which goes right around the circumference of the hand guard about 1cm or so away from the inner edge of the reddish leather binding strip..This "ring" of stitching would be holding the inner heavier leather construction ( two hemispheres on stitched together with a ring of leather around their base ) to the outer "shell"..the outer shell is made from one piece, wet molded, but with a "split across the dome and down the back side which we cannot see..we can only see the "blind" end of that seam..where I have shown..

Made that way..simple

* you might have to "zoom" the image a bit to see the line I'm talking about.

Edited September 19, 2019 by mikesc

[mikesc]

Btw.."cuir bouilli" despite what Wikipedia and other "sources" say..is not the French Translation" of "boiled leather"..Boiled leather is the English translation of the French phrase, the French phrase existed first..The original phrase is French, which was badly written in French ( modern French can be very "contextual", and sometimes quite "pidgin", old French even more so ) and translated to English..The "boil" refers to the bubbles that leather gives of when immersed in water of any temperature ( trapped air )..veg tan leather will do this "bubbling" in cold water or warm water ( veg tan leather is "porous" and the trapped air in the fibres escapes on immersion..However in boiling water , veg tan leather will instantly distort, shrink and be useless..Do not "boil" leather..Do not put it (unformed leather ) into water that is any hotter than you would be comfortable bathing in..and even that is a bit too hot..having formed the leather, you can then immerse it in water at around 55°C** ( depends on the leather ) briefly..when it comes out it's structure ( leather contains collagens, these are often mis-described as "plastic", like in the linked page ) will be altered..and it will be harder..

Best way to know what your leather's "change" temperature is to put small pieces of the leather that you'll be using very briefly ( 5 to 10 seconds max ) into water that is heated, begin with water at 50°c..then raise the temp of the water in 5°C steps until the leather comes out harder ( it gets harder the more it dries out after ) , but not distorted..test ..every time you use "new leather" or leather from a different part of the hide as it varies across a hide.

*Example "kick" is "coup de pied"..literally a "hit of foot".."gust of wind" is a "coup de vent"..a "hit of wind".."coup d'état".."hit of state" etc.

Another example..French "Le cuir pleine fleur"..literally in English.."the leather full flower"..true meaning in English.."full grain leather" ..another English "split"..the French "croûte de cuir"..which literally would be "crust of leather"..which would make you think that you were buying "full grain***" as the crust is usually the outermost layer, whereas a "split" is an inner layer, split from the outer full grain layer..

Translating literally "word for word" , especially from older manuscripts of "contextual" languages is not a good idea at all..that way lie errors and misunderstandings.

There used to be a site ( in French IIRC ) about experiments in "cuir bouilli", I think it is offline now, I'll try to find it, or ( if it is offline) see if the IA has any pages . There may even be translations of it by someone who knew what they were reading.

**those who still work in Fahrenheit can convert it

***grain is the same word in English and French, it came over "intact" from French into English via the Norman ( "northman" ..Vikings ) who inhabited the Northern part of Modern France..William the Conqueror was a Viking descendant..not a Gaul.He had more in common ancestry with us Celts..Dublin being the capital of the Viking world for a long time. Lot of red haired Normans ( like my mate Guy ) lot of red haired Irish, like my athair / dadaí ( btw note where "Dad" and "Daddy" come from, they are Gaeilge words ) .. Irish and Normans were / are a Viking / Celt mix. Dark and or fair /red..Welsh ( more Celt, less Viking) are darker.

Edited September 19, 2019 by mikesc

[Leb]

@mikesc Thank you for the clarification (and for the French lesson!), I think the way you describe the construction (with a "split") makes sense to me. By the way, I have learned the hard way about boiled leather  some time ago, that's why I used "boil" Unless rawhide behaves differently, I don't believe it was truly boiled.

I wish there was a good picture of the inside of the basket - I thought the lower line was just there to hold the brown rim (but I can almost convince myself there is a slight "dent" so it's possible the brown leather covers and holds an inner quarter-sphere leather shape you were describing)

[chrisash]

One thing i have found wet forming is that using a kitchen vacuum machine, by placing the wet leather over a form inside a vacuum bag it appears to me a much better fit around the mould that just placing with a press down mould on its own

If you stop the vacuum just before it completes its cycle, you can really shape the leather through the bag and then continue the vacuum to its limit

[mikesc]

Quote

using a kitchen vacuum machine

I'll bet that goes down a storm with the CFO , unless you have a machine reserved for leather.

[chuck123wapati]

6 hours ago, Matt S said:

Is it possible that the main "basket" is in fact rawhide, rather than fully tanned leather? It looks pale (compare with the edge trim) for a 110-year-old piece of russet veg-tan. The description mentions it being "stiff and hard as plastic" which I would say is a closer description of rawhide than wet-formed veg-tan. I have some very limited experience of working wet rawhide (mostly soaking and flattening dog chews) but the stuff seems far more supple when wet than any tanned leather I've tried to wet-form.

good thoughts indeed I was thinking maybe the leather was made from parts of an animal that already are shaped similar, many cultures used the male genitalia of animals for bags or pouches. 

[Tugadude]

15 minutes ago, chuck123wapati said:

good thoughts indeed I was thinking maybe the leather was made from parts of an animal that already are shaped similar, many cultures used the male genitalia of animals for bags or pouches. 

Actually that is possible.  I posted a seamless dice cup on here a while back and asked folks how it was done.  It was one piece, seamless.  The consensus was that it was  likely made from leather derived from a bull scrotum.

[RockyAussie]

11 hours ago, Leb said:

@RockyAussie Thanks for the tips, I guess the detergent acts to break up the membrane proteins to some extent to make the leather more pliable (and I suppose lubricates the leather to help with pressing?)

The detergent makes the water wet. It allows the water to soak in to the fibres more fully and thus become more supple. Belly leather will give you more stretch for sure and I have seen seamless shoe uppers made from it. What I am saying is that you need to do a lot of stretching and softening before trying to mould to shape. In this post I did awhile back you can see I formed a fairly tight and high handcuff pouch. Note that at the bottom of the top mould there is a relief groove that allows the leather to grip more as the top goes down and give the leather somewhere to swell into and resist back pulling and wrinkles as it dries.

The end result of the waste to cut off on these in the end came down to just over 3/8" (10mm). Too much extra can require bigger wrinkles to try and accommodate and is why @robs456 says to V cut the leather I believe.

[robs456]

9 hours ago, RockyAussie said:

and is why @robs456 says to V cut the leather I believe.

Yes.

[chrisash]

17 hours ago, mikesc said:

I'll bet that goes down a storm with the CFO , unless you have a machine reserved for leather.

Hi Mike

They do not come in contact with the leather, I think the vacuum machines are about £30-50 in the UK see this example

https://www.amazon.co.uk/Automatic-Sealing-Preservation-Starter-Compact/dp/B07NVM339R/ref=asc_df_B07NVM339R/?tag=googshopuk-21&linkCode=df0&hvadid=309920218458&hvpos=1o5&hvnetw=g&hvrand=3907504002454057720&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9044854&hvtargid=pla-680497445189&psc=1

They just suck out the air and seal them up to keep the vacuum also benefit it keeps food fresher and if you freeze them they are a lot more compact (food that is) to store away

[mikesc]

I Know they don't come into contact with the leather Chris, I've got two ( one for me and one fro the kitchen, which although I do the cooking in our house, the CFO still chunters about using "les trucs de la cuisine pour des bricoles".."kitchen things for DIY". I've learned that rational explanation is to no avail, the chuntering may lessen, but the looks and the "roll eyes" do not abate..So..I bought two :)

Co-incidentally , they are on sale again this coming week at our local Lidl..€29.00..I like them, lets me cook and then bag a few portions of "whatever" to go in the freezer for if I'm going to be getting back from somewhere late, I can just phone to say " look in the freezer and in the 3rd drawer down, to the right, you'll find 3 portions of "X" labelled..take them out, defrost them, reheat 2 and don't wait for me to arrive before beginning eating"..Lidl never have enough bags for them when they are on sale, and being French Lidl, the bags are not stocked all year round, and other retailers here charge an arm and a leg for bags..I'm stocking up on various sized bags next week..if they had any bags delivered other than the ones in the box with the machines..I keep thinking that I ought to make a bigger machine ( they are pretty easy ) ..but never got a round to it..Lidl don't sell roundtoits, so I'd have to make one from scratch..if I have enough left.

[toxo]

I don't know why no one has suggested multi layers. Layers of thinner leather will be much easier to form and of course you don't have to stop at 3.5mm if the idea is to protect the hand.

[mikesc]

Quote

I don't know why no one has suggested multi layers. Layers of thinner leather will be much easier to form and of course you don't have to stop at 3.5mm if the idea is to protect the hand.

Multi layer..is what I was describing in my post of yesterday at 01.14...and my post before that one.

[toxo]

16 minutes ago, mikesc said:

Multi layer..is what I was describing in my post of yesterday at 01.14...and my post before that one.

What I'm suggesting Mike is thinner layers covering the whole thing being more mouldable. Each layer drying before the next. When thick enough just trim and cover with the binding.

[mikesc]

Ah..lots of thin layers each molded to that complete shape..could work, but they'd all have the same outside and inside dimensions, so how would you Matryoshka* ( матрёшка ) "Russian doll" them into each other to glue them up ?

* yes I know..verbing nouns weirds them

[toxo]

Once dry, the next layer is easier to mould by virtue of the "bloc" being bigger and the moulding radius greater. I would suggest Gorilla glue between  the layers because it needs damp to work and I can absolute vouch for the join having had to separate two pieces of leather after a mistake. Had to cut the leather, easier than the glue