Chromexcel. One of my favorites, and probably my single favorite if I had to choose one. The picture above gives some idea of how long the formula has been around (and this journal is full of different trials and doesn't even contain the original, standardized recipe). Whether because it's right, or because we're just terribly stubborn, we've left the processes and formulas for many of our leathers largely unchanged. We have had to substitute some of the components that were traditionally used in small quantities - whale oil was replaced with another marine-creature derived oil, one that's more available and not controversial.
Chromexcel, or CXL as it's written in the building, is a combination tanned leather that undergoes at least 89 separate processes taking 28 working days and utilizing all 5 floors of our facility. Needless to say, it's complicated. For any tannery, the chemistry that transforms salted or cured hides into leather often requires a degree of "cooking." By cooking I mean there are slight variations that must be managed and corrected from lot to lot. This arises from the fact that we're taking many component parts, putting them through a multitude of steps, all the while trying to achieve an end result that is as uniform and consistent as possible. There are additional complexities in that we're taking hides and materials that are naturally occurring - that each hide is in itself unique in that it came from animal as a byproduct of the meat industry is just a single example in a long list. Retannages are derived from tree barks, dyes and stains are derived from naturally occurring pigments, and it's all mixed and applied using heat, steam, pressure, hands, and time.
The process starts when the hide deliveries come in from one of our domestic suppliers - brined, with the hair on, and folded and packed on pallets. We inspect the shipments, "side" the skins (meaning we cut them in half, as we run half hides not whole hides), and then stage them for dehairing, bating, pickling, and tanning. Dehairing is achieved in large cement mixer type drums, where we actually use a solution to "burn" the hair off all the way to the follicle. Once we begin this process, and continuing through all the processes that follow for the next week or so, we've created a perishable product and started an extremely time sensitive chain of events. A power outage, for example, during dehairing would be very bad - there's nothing to prevent that burn to continue and digest the hide along with the hair (yes, it has happened - think Jell-O).
After dehairing the mixer is "limed" (actually re-limed at this point) to manage the reaction and then drained and washed. All of the water that we use, we treat. We have a fully functioning, EPA compliant, City of Chicago monitored, effluent treatment plant. And, being responsible and ethical producers, we take that very seriously.
After dehairing comes lime fleshing, where the back of the hide is scraped of any unsavory bits. This also serves to open up the hide for the next processes - bate, pickle, and tan. Bating and pickling is the initial preservation step, and serves to prepare the hide for the actual base tannage. In the case of Chromexcel, this is a chrome base, achieved using chrome salts. This is done through lots of what many would think is complicated chemistry demanding specific concentrations, temperatures, run times, and pH levels. This is an around the clock process - our expert mill and mixer operators work shifts all week long beginning Monday morning and ending Friday. At this point, we now have hides that are considered "wet blue," due to the characteristic blue color that all chrome tannages initially have. The process up to this point is not unique, other than our specific formulations, and the many of tanneries around the world are utilizing similar methods.
This is where it starts to get interesting. Wet blue hides are sorted for initial quality so that the proper "selections" are made - for grain character, weight/thickness, scratches, scars, brands, etc. Next comes retanning, and it's where the secrets begin. Specific and proprietary mixes of bark extracts and natural agents are used to give Chromexcel, and many of our leathers, its heavy vegetable retannage. The benefit of combination tanning comes from the specific attributes that both chrome and vegetable tanning impart. Generally, chrome tanned leathers yield soft, supple, and durable leathers, while vegetable tanned leathers are round and full feeling, patina well, and are easy to coax into shapes using heat and moisture.
The next step is "hot stuffing" - that is, the impregnation of the hides with oils, waxes, and greases that are solid at room temperature. Stuffing is achieved through the use of steamed mills, and is the process that is responsible for the "pull-up" of this leather. Pull-up is the temporary displacement of these oil and wax blends that cause a lightening of the leather. Our philosophy that you need to use the best components to make the best leather is particularly evident in this department, where we create blends using products like food-grade beef tallow and cosmetic-grade beeswax.
Now that we have the canvas ready, we can start the finishing process. Chromexcel receives several hand-rubbed coats of aniline (non-pigmented) finish - this type of dye application allows for even staining of the hide
For the most part, the leather is complete at this point, and it's ready to be sorted, graded, packed, and shipped. The last step for Chromexcel is coat of Neatsfoot Oil, so when people ask me how to condition this leather, that's always my first recommendation.
There are many varieties of Chromexcel at this point - Wooly, Beaufort, Cavalier, Plainsman, Huntsman, Kudu, and Horsefront, to name some. All have been developed with specific uses and attributes in mind, but all share many of the same processes and formulas as the original formula, and all are made by the same skilled and experienced craftsman. I say it all the time, and I can't say it enough - ultimately the quality of our product relies on our tremendously capable employees.