About
I was born in northeast Iowa in 1980 as a first generation American citizen, my father’s family having lived in the Dutch East Indies (now Indonesia) and then Holland, and surviving Japanese POW camps during WWII. My father and grandfather were passionate outdoorsmen and I’d often watch dad improvise or repair his gear with scraps of leather and an awl. He taught me to hunt and fish, camp, and more, and I owe him for igniting the spark that led me to a passion. Learning from my father, I enjoyed tinkering with leather as a child, and continued investigating all he’d taught me about the outdoors. After high school, I completed nursing school, and have worked in the midwest as an RN since 2006. I spent three months living at Ryumoni Zen Monastery in northeast Iowa after college, and received lay ordination there in 2013.
My hobbies and passions are too numerous to list, but of late I’ve spent most of it with leather. In it, I found a medium that was accessible, rewarding, and fascinating. I’d tried drawing and others, but with leather I found the greatest ability to put my imagination in my hands. I’ve taken a keen interest in mycology of late as well. Many hours during fair weather are spent in the woods with Java, crouching with a camera next to some rubbery mass on the woodland floor that others would scarcely taken notice of. In the summer there’s more than I can eat, so friends and family get to (have to?) enjoy the bounty. I’ve done a bit of fungi cultivation at home as well, and have a great community of experts online who have graciously offered 1:1 guidance. Camping, fishing, hiking, emergency woodland survival, bushcraft, sewing, carving, and a host of other pursuits keep me busy.
Besides working as a registered nurse, I’m also currently an active contributor to the Leather Crafters and Saddlers Journal, where the entirety of my leather hardening article has been published, and many of my build journals will appear in future issues. I’m also a licensed ham radio operator, certified case manager, ordained Soto Zen lay practitioner, and contributing team member on the ‘Poisons Help’ Facebook community (now referred to by the ASPCA and several poison control centers) as well as several outdoors and related forums.
Jason F. Timmermans
The Shop
This is where the magic happens, a small room in my apartment in Iowa.
Oni is a demon in Japanese mythology. I chose this icon as a representation and a reminder to myself of the struggles I’ve endured along this journey, the discipline that guided me through them, and the strength I found in making friends with the demon. Would you like to know more?
I hope my legacy is the knowledge I’ve brought to my areas of interest through my work, my passion for growth and critical thinking, and my love for the natural world. To that end, all information offered on this website is free to be used, shared, copied, pasted, and further developed. No information is to be copyrighted, and please credit the author when appropriate. I’m banking on common decency to promote and maintain this knowledge as available to all.
I’ve chosen to add a donation link at the bottom of the site. Since this endeavor is self-funded, content is limited by my budget and time. All content on this site is made by myself and is offered freely without copyright. If you feel this project is of value and would like to contribute, your donation of any amount is deeply appreciated.
ONI 
your work on the skin really really interesting. nothing to do with all the crap of the tutorials on the web.Thank you so much for all the information. if you have a description of the complete process with stearin I’d like to see it
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Compliments. My 1st issue of leather crafters was fantastic.your quiver was beautiful.
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Hello Jason
I’m writing to thank you for your extremely useful article about hardening leather. With zero prior experience even in the basics of leather-working, I was able to produce a little two-pocketed belt holder for a phone and a tiny old-school planner notebook. I used your stearic + heat method, and without being particularly scientific or careful, it worked exactly as advertised. I used no thermometer, heated the already-shaped leather in the oven at its coolest setting (170 F), and immersed it as soon as the wax was completely melted. (It occurred to me that I could perhaps have melted the wax and heated the leather simultaneously in an oven at a known temperature setting. Because the leather, once immersed, had to be heated further, I decided that the stove-top was slightly simpler.)
Being such a novice, and limited to materials I could order online cheaply, I ended up with leather that I guess would be classified as suede. I formed it with water; once dry, it held the shape fairly well but was still soft and pliable. I decided that I wasn’t risking much (other than redoing the whole project with more appropriate leather), so I treated it with your method. The results, surprisingly, is a hard, smooth-surfaced leather, much more like shoe leather than suede.
I made a dummy phone and dummy notebook from scraps of recycled-plastic “lumber.” This worked very well for water shaping. I removed the forms when heating in stearic acid, guessing that heating the leather while on the forms would interfere with absorption. The leather shrank about 1/8 inch across 3 inches, and I really had to struggle to get the forms back in for hardening. (Leather remained pliable for about 15 minutes.) After hardening, the sleeve for the notebook was still just under size. Leaving the form in place, I inserted an 8-inch nail between the leather and the end of the form, and pounded it downward: this successfully stretched the leather enough to fit.
I tried removing the waxy residue with heat gun and rags, as you did; didn’t work for me. A much easier way, I found, was to buff the leather. I used a Dremel tool with a small cloth buffing disk, but i’m sure any buffer could work. The Dremel is especially useful because it is small enough to get into the seams.
Again, thanks for the rigor with which you approached the topic; it allowed me to improvise on a firm basis. And of course, thanks for sharing the information publicly. Feel free to incorporate these observations into your work/publications in any way you like.
BTW, I have also been practicing Zen, for nearly 45 years, initially in a Rinzai zendo, and now with a Soto group. Beginner’s Mind must have something to do with all this!
(Mr.) Kim Sorvig
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