In Need Of Advice On Hardening Scales

[insanityprelude]

Hi everyone.

To start wit I'd like to say that I've found this forum a great source for info, tips and inspiration for my other projects.

Right then, down to business.

I'm having a go at making some scale armour from my offcuts (ranging from 4 to 6mm)

I'll be thonging them onto a suede backing (patterns done just waiting for the suede to arrive) but before I can do that I'll have to harden them.

I've soaked leather in warm water then dried it while making bracers & lame for a paldron but nothing to harden it

Reading around I was thinking of oven baking them as per Marc Carlson's method (part E) as it would be easier to control exposure and it seems easier for a first attempt.

My main worry is that given the amount of time they'd need to bake that they might curl as I wouldn't think pressing them into shape would let them bake them properly.

It's either that or soaking them in hot water (sorting them into batches by thickness first) then pressing them between baking trays and allowing the scales to dry completely.

So basically i'm after a bit of input on what you think would be the best method for hardening batches of scales, I've also got a few other questions that will ultimately require experimentation but I'd like to hear some opinions on anyway.

1) If i was to bevel the edges would they curl?

2) As you can see from the above picture i haven't got any holes punched yet. should I do that beforehand (making them larger to allow for shrinkage) or after on the now tougher leather?

3) In a similar vein a few of the edges need neatening (a few stray fibres that I'd usually burnish away). Should I do this before/after or will the heat cause them to shrivel away?

Thank you for your time

Ben

[RuehlLeatherWorks]

What I typically do for hardening leather is to pre-soak the leather in the hottest water that you can get from the tap. While that is soaking, put some water on the stove and heat it to 190 degrees (about 87 Celsius). When this temperature is achieved, adjust the heat until the temperature is maintained (Just to be sure).

Place the soaking leather in a sink (make sure the drain is open) and pour the water from the stove over the leather. You can see the leather turn darker and start to shrink a bit. When the edges of the leather become a darker color than the body of the leather, stop pouring water over it and remove it from the sink. I typically sandwich the leather between two hand towels at this point, but it's not necessary. I do it because it absorbs water but still traps the heat. Once the leather sits for about a minute between the towels, remove it and it should be the consistency of rubber. This is where you want to subtly shape the leather to any shape you want. Once it dries entirely, it'll hold that form.

Now, if you want to dye it, make sure that it is entirely dry BEFORE dying it. After you have it dyed, you need, need, NEED to oil the grain of the leather, otherwise it will crack when placed under pressure. These cracks usually aren't more than just surface cracks, but they could develop into larger cracks as time progresses.

Once the scales are hardened, dyed, and oiled you can start stringing them to the backing. You may want to drill holes with a power drill rather than a leather punch at this point, though. These scales will be HARD!

I've used this technique several times with great success on bracers. In fact, I just finished a commission using this technique and they turned out great!

[insanityprelude]

Thanks RLW.

I'll try some experimenting tomorrow to see how much water it takes for a few then go from there..

I hadn't heard of cracking after dyeing before. I was planning on oiling anyway but its great to know.

Yes I think a power drill would be apt in this case.

[RuehlLeatherWorks]

It's not so much that it's the dye that cracks it. The leather is just so hard at that point that it's brittle. Even after oiling it, you have to be careful because there's places where the leather will absorb more oil than others, drawing it away from the surface, which leaves it brittle. From the reports I've read, the original technique was to submerge the leather in simmering water (Just below the boiling point) and then remove it wihen the edges changed color or when the leather stopped producing bubbles. Once this was done, the leather would be placed under a layer of straw, which is a very useful for insulation. This allows the leather to dry the moisture, while maintaining the heat.

[radar67]

I recently used the simmering water technique. Once the water started to form small bubbles (not boiling) I submerged the leather for about thirty seconds, removed, formed and let dry. It is hard as a rock. I could literally knock someone out with it.

[hivemind]

Alternately, get some beeswax, then get a used crock pot from goodwill, put the wax in, when it's fully liquid, start stuffing scales in. Leave each one in until it stops bubbling, then remove it with some tongs, and give it a little shape with your hands (wear gloves, they're hot), then let them cool. Hard like wood. Don't leave them in long enough to scorch, experiment with scrap first.

[insanityprelude]

Right I'm back.

RLW I'll definitely use your method next time I do a bracer or another large project but the amount of water I'd get through to harden the scales would take ages.

Radar I'll try your method on a bit of scrap with my time off but I'm unsure how consistent it would be and I thought it might be a bit too hot but I won't know unless I try so I'll experiment.

Hivemind I'd thought of using wax but hadn't taken it any further due to cost and that it didn't seem that authentic. Thinking about it though given that the scales would be flat, deforming under heat wouldn't be such a problem. saying that I'm sure I've seen a small bar of beeswax lying around so I'll try it if i can find some.

Yeah it seems my oven doesn't go low enough so I might end up using immersion after all. Looks like I'm off to town tomorrow to try and get an old steamer

[RuehlLeatherWorks]

I came up with a good way to do scales using the immersion technique that won't burn the crap out of your hands! Pre-drill all your holes and use an old metal coat hanger to dunk each scale. Sure it'll take a bit to do each scale individually, but it's better than pouring them and you won't have to find a way to get them off of the bottom of the pan when they're finished! This will also prevent scorching which sometimes happens when leather makes contact with the bottom of the pan as it sits on the stove.

[insanityprelude]

I had a chance to muck about yesterday with immersion, getting the water to about 80-82 then putting them in until the edges darken. I do like the thickness if left in for longer but they tend to distort. If it was something larger on a form it would be fine but as they want to be flat not so much.

I came up with a good way to do scales using the immersion technique that won't burn the crap out of your hands! Pre-drill all your holes and use an old metal coat hanger to dunk each scale. Sure it'll take a bit to do each scale individually, but it's better than pouring them and you won't have to find a way to get them off of the bottom of the pan when they're finished! This will also prevent scorching which sometimes happens when leather makes contact with the bottom of the pan as it sits on the stove.

I will probably give that a go as I've been using a pan with a removable steamer plate sort of thing that keeps them off of a direct gas I would think that keeping them suspended would be better. I'll just have to experiment with the holes.

[John D]

The advice I would offer on "hardening" your scales all depends on what you want to accomplish with the finished product. If you want to simulate metal go with the water hardened methods outlined above and pull them out just as the edges turn color. You will end up with very firm--and as already noted--very brittle scales. If you push the water temperature much beyond 180 you will end up with lots of deformity and have very hard, very brittle, and mostly useless leather on your hands. Yes that is the voice of experience.

Wax is certainly an option. I do not recommend it personally as there is little evidence that wax was used for more than water proofing in historic contexts. Yes, it certainly can be used to harden leather, not arguing that. But wax hardened leather has a tendency to lose shape and soften in hot weather. That is also the voice of experience. And yes, it is also possible to play with formulaes of wax, and ratios of wax with other things to overcome that.

Here is how I harden my leather today and I use all these methods depending on the end result I am looking for:

1: heat water to ~172 to 178 degrees. Soak leather until it stops emitting bubbles, pull it out, and shape it. Let it air dry

2: warm water (hottest you can get out of the tap), and mix in uncolored and unflavored gelitin, soak leather until it stop emitting bubbles, pull it out, and shape it. Let it air dry.

With #2 you can also do much the same thing with:

* rabbit fur glue (from memory and not precisely what it is called) which is basically a variation of the gelitin "glue" above

* wood glue and water (search internet for recipes)

* "craft white glue" (search internet for recipes)

NOTE: by recipe I mean ratios of glue to water.

Option #3:

* room temperature to slightly warmer water

* soak leather until all bubbles are done emitting from the leather

* put the leather in or on a former

* place in a fruit rack and with very controlled temperatures and lots of checking, ensure that it dries as rapidly as possible without cooking above the burning temperature of the leather

IMPORTANT NOTE: I do not use an oven (gas or electric) as they tend to be over warm. Much more than ~182 degree F and you risk burning the flesh and ruining your hard work. Mind you I am not all that patient, I want methods that I can setup, walk away, forget about it over several hours, and then come back and not have completely ruined work. Your mileage will vary.

Each of the above methods has slightly different results. I find I like the wood glue results a little better for what I am looking to make. It is a mostly period form, and if you used water proof/resistant glue the end result will handle heat, humidity, and even rain well.

IMPERATIVE NOTATION:

Leather once dried out will over time become brittle. You will want to either seal the leather to prevent loss of moisture, or, you will want to oil the leather as suggested to give it "food" for long life. After oiling to feed your leather, you will want to coat it with wax or some other sealant to keep moisture from working its way into the leather. If you end up with lots of water damage often times pieces can be remolded, but not always.

It is my hope that by end of February I will have completed an experiment with the above methods and offer some mildly scientific observations about what each method does to the leather, and what the resulting product looks like.

Beyond all else, start with any of the advice I have read so far (not mine mind you) and they will all work. Take time to experiment and learn. Oh, and be willing to share your findings moving forward.

Best regards,

John

[Matty]

I came up with a good way to do scales using the immersion technique that won't burn the crap out of your hands! Pre-drill all your holes and use an old metal coat hanger to dunk each scale.

Do the metal coat hanger thing with several scales, evenly spaced, enough to easily fit in your pot. Or make a long metal trough just large enough for your scales, line them up on hangers, pour boiling water into your trough, wait for it to cool to 190 or whatever you need. Dip, remove, hang to dry, all on one rack. As long as you're not getting excessive shrinkage it will work. If you don't want to hang dry, dip fewer pieces at once and remove from the hangers to dry.

[douglais]

All good stuff, but I think that many of the temps are on the high side. I'd hover between 175 and 180. That will give you some time to get the leather out of the water when it starts to change color on the edges. It's a process that's extremely sensitive to time and temperature.

Once you get above 180, the edges start to curl within less than 30 seconds, and they curl rapidly. When it dries it will be brittle, and not take dye very well.

At 175, you can leave the leather in for over 2 minutes or more, without damage. When it dries it may still have a little flex to it, but still be stiff. Shrinkage and distortion are minimum, and it accepts dye just fine.

Below 170, the cuir bouilli doesn't happen.

I'd drill before hand, and immerse a few at a time, so you can keep an eye on them, and keep your temp steady. You can shape them by hand after they've been out of the water for 5 minutes.

Stick a vegetable steamer, or some kind of screen in the pot, as the leather will scorch if it touches the pot bottom.

The rabbit skin glue sounds fascinating, as it would eliminate the problem of softening in the heat or the rain. If you use some kinda glue, what would you do about waxing or oiling the leather? Would it absorb oil or wax?

Also, would it still accept dye? Or would you need to dye it before you harden it?