Acid dyes on leather: experience or resources to share?

[Ifutzwithfire]

I’ve seen several mentions of acid dyes (such as Jacquard brand, or the house brand from Dharma Trading Company) on leather, but none laid out a clear and complete method for the process used. In the past I have used these dyes on textiles such as wool and silk fabrics, yarn, and spinning fiber so I know the process for those well- basically the dye powder is mixed with water and an acid (citric acid is great as it adds no smell like vinegar will), the dye is applied to the material, and then the dyed material is heated to set the dye either by heating the dyebath in a pot on the stove, or by wrapping it up in a packet which is then steamed. If the amount of dye to material is correct, when the item is rinsed afterward there will be minimal color runoff; this is called an “exhausted” dyebath.

But putting leather in a pot on the stove or steaming seems like a risky thing, or at least one that requires extra steps, so I’m hoping to find someone who has experience with it. I’ve reached out to Dharma but not yet heard back. I know there are other brands and types of dyes available that are designed especially for leather, but I’m specifically looking for information on acid dyes. I’m not sure if it matters whether I’d be using them on veg or chrome tanned- if it matters I’d love to learn more about how and why, and maybe that will help me narrow down my choices.Right now I’m just trying to figure out what potential exists for this combination of material/technique, and once I figure that out I can start coming up with ways to make use of it.

[alfredleatherworks]

I have no experience using acid dyes on leather, but I know that simmering leather in a pot is going to harden the fibers and that’s not going to turn out well unless you want to make leather armor.

Tanneries do use heated dye drums, but the temperatures are kept low to prevent the leather from hardening. Typically, this is done through heated air passed through the drum as it turns, so the heat is minimal and not direct on the leather or the liquid. 

I’d be interested to hear what Dharma says in a reply to you, or what you discover in any experimentation.

[Ifutzwithfire]

I did hear back from them. Apparently in most cases people applying the acid dyes to leather are using them more as a stain, and not heat-setting to create that permanent chemical bond of dye to substrate. The rep did tell me that in this kind of application, most colors will sort of settle in and become resistant to crocking if allowed to sit for a couple weeks. A sealant afterward is almost always going to be a good idea, and exposure to any moisture or solvent will probably make them bleed (so don’t go dipping a brush back into your jar of clear coat). 

I’m still going to do some experiments with heat-setting through various methods. Obviously the leather will most likely require some treatment afterward to rehabilitate it, but I think that’s reasonable enough. I’m also contemplating some applications that are more controlled, not a full immersion or covering the whole surface, so getting that to exhaust may be achievable with a shorter duration of heat, or a localized application of it. The chemical bond requires a certain temperature to be achieved so it still has to get just shy of boiling, but I’m convinced there’s a way. Just a matter of finding it.

[chuck123wapati]

15 hours ago, Ifutzwithfire said:

I did hear back from them. Apparently in most cases people applying the acid dyes to leather are using them more as a stain, and not heat-setting to create that permanent chemical bond of dye to substrate. The rep did tell me that in this kind of application, most colors will sort of settle in and become resistant to crocking if allowed to sit for a couple weeks. A sealant afterward is almost always going to be a good idea, and exposure to any moisture or solvent will probably make them bleed (so don’t go dipping a brush back into your jar of clear coat). 

I’m still going to do some experiments with heat-setting through various methods. Obviously the leather will most likely require some treatment afterward to rehabilitate it, but I think that’s reasonable enough. I’m also contemplating some applications that are more controlled, not a full immersion or covering the whole surface, so getting that to exhaust may be achievable with a shorter duration of heat, or a localized application of it. The chemical bond requires a certain temperature to be achieved so it still has to get just shy of boiling, but I’m convinced there’s a way. Just a matter of finding it.

 

As a modern human, I'm always falling into a rabbit hole trying to reinvent some wheel too lol. Most times it becomes a waste of time and money on my part. But hey, sometimes it's fun and works great! But I have to say, folks have been experimenting with this stuff for thousands of years to come up with the leather dyes that work. 

I wish you all the luck, and post some pics of your success.

Ps. You can't make an archery target in a kids' wading pool out of torn-up boxes and a gallon of Elmer's glue. It never dries out and gets real stinky!! Total cost of the materials plus the dump fees was about 60 bucks. The butt-chewing from the wife was priceless.