After a further forty-eight hours, however, the black colour penetrated the pelt, andtannage was complete.
Reactions of Neradol D with Iron and Alkalies A special characteristic of Neradol D tannage is the sensitiveness of the latter to the action of iron and alkalies.
These figures correspond closely to those obtained by the analysis of leathers tanned with vegetable tanning materials, and this proves the similarity between the Neradol D tannage and a vegetable tannage in their chemical aspects.
The tannage completed, the leather must be well washed in running water to remove excess of synthetic tannin and then dried.
This combination tannage seems to be assured of a great future; especially may a combination tannage of iron salts and Ordoval G eventually entirely replace chrome tannage.
In all cases rapid tannage was observed yielding firm and soft leathers of light brown colour and varying degrees of swollenness.
No tannage No tannage By the condensation of their sulphonic acids, it may be demonstrated experimentally how the tannoid properties of nearly every member of the series are intensified.
The tannage is commenced by paddling in a spent handler liquor (4 deg.
The tannage is closely analogous in theory to the chrome tannages discussed in Part III.
The tannage of sealskins depends upon the size of the skins, the purpose for which they are intended, and whether they have been split or not in the limed state.
This assists in making the tannage permanent, on account of secondary changes discussed in Section III.
A typical case is that of "semichrome leather," in which a vegetabletannage is succeeded by a chrome tannage.
Some leather chemists regard the tannage as differing essentially from the vegetable tannages.
Type 1=, which may be compared with Type 1 for sole butts, is a tannage of about 5 months.
A soft and mellow tannageis the more important, inasmuch as the leather is not heavily stuffed with grease in finishing.
The tannage is also mellow, on account of the softness and pliability required; no acids are consequently employed, and no material which is liable to yield sour liquors.
In the wet work for the preparation of skins for tannage much the same general principles and methods are embodied as in the case of hides, but with appropriate modifications.
The hides are rounded before tanning into long butts or backs, and the tannage is commenced in suspenders (18 deg.
The light chrome tannage results, further, in yielding a leather which has great tensile strength, and it is not surprising to find that chrome harness and chrome picking bands are highly thought of.
The use of combinations of vegetable and mineral tannins has lately increased, and it is possible that the blending of the two classes of materials may produce an ideal tannage for certain classes of leather.
This is the nearest approach to the pure oak bark tannage of former days, and, if carefully regulated, is a great improvement on the old method.
Either the one bath or two bath tannage (described on p.
A very goodtannage for the production of a mellow and plump leather is that of pure gambier, the colour produced forming a good ground for brown shades.
Where light, fancy colours are required on the finished leather, this tannage must be completed by placing the skins in a tepid bath of sumach.
The tannage completed, the acid salts in the leathers are neutralised with borax, and after the leather has been washed in warm water it is ready for dyeing.
This tannage produces a white but somewhat thin and empty leather, and the fat-liquoring must, therefore, be filling and softening.
The tannage of dressing hides differs slightly from that of sole leather; the liquors must be mellower and contain less insoluble matter, in order to obtain the necessary pliability, and a good, clear colour on the grain.
Gambier can be used to advantage in keeping up the strength of bark liquors in the tannage of sole leather and hastening the process, while it may be used alone for the tannage of boot upper leather and dressing hides.
Sometimes a better tannage is given to goods of fair quality, in which they are, perhaps, started in the drum and finished in layers, slightly better materials being used all through, and a longer time taken to complete the tannage.
The tannage is carried out in much the same way as for goat skins, the goods being started in old acid bark liquors; the general tannage consists of sumach and bark.
The fact that an aldehyde tannage takes place seems to have been first discovered by Payne and Pullman, who took out a patent in 1898, covering formaldehyde and other aldehydes used in alkaline solutions.
It must consequently be removed together with the hair, wool or bristles before tannage begins, but as it is very thin compared with the corium, this matters little.
His peat or humic acid tannage was patented by him about 1905, and is now worked on a commercial scale.
Currying with animal oils is a second tannage in itself; the oils oxidize in the fibres and produce aldehydes, which are well-known tanning agents; and this double tannage renders the leather very strong.
In making alum combinations it must be borne in mind that alum leather will not glaze, and if a glazed finish is required, a fairly heavy vegetable tannage should be first applied.
The tannage occupies from 2 to 8 days, and the goods are then stuffed in a ventilated drum with greases or soap.
Consequently, the liming is longer and mellower; puering, bating or some bacterial substitute always follows; the tannage is much shorter; and mellow materials are used.
Some manufacturers finish the tannage with a mixture of sumach and oak bark; this treatment yields a less porous product.
In proportion to the thinness of the skin treated, the processes are more rapidly finished and less complex, the tannage is a little lighter, heavy materials such as valonia being used sparsely if at all.
The tannageof seal skins is now an important department of the leather industry of the United Kingdom.
As a leather for bookwork when tanned with a pyrogallol tannage it is soft and kind to the touch, having few equals and no superiors.
The section of the leather trade to which this Handbook relates is that concerned in the manufacture of light leathers tanned with a pale tannage preparatory to being dyed.
The tannageof bookbinding leathers must be a mellow one, and must not be carried too far, as we have found in many cases the cause of decay in tanned leather has been the fact that the leather was overloaded with tannin.
Pure sumach is the tannage we would most strongly recommend for high class bookbinding.
Ninety to one hundred days are required to tan bark leathers, while the chrome tannage is very quick and on the average requires only about three weeks.
There is also a tannage made from minerals that is called chrome.
The above tannageis what is called vegetable tannage.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "tannage" in a variety of sentences. We hope that you will now be able to make sentences using this word.
