About to attempt my first hamon and need a bit of advise

B

Black cat

Well-Known Member
Blade length 7"
Total length 12.5"
Steel 1095

I have a feelng my Paragon Evenheat kiln might not be accurate.
How should I go about testing the accuracy of the temperature ?
My first thought is to use some sort of high temp oven thermometer but I have yet to find an accurate one at a decent price... Any thoughts?

Fast quenchant: I want Parks50 but I think I would have a better chance of finding a unicorn in my part of the world. I do have canola but I dont know if that's good enough to get a good hamon ? Any alternatives ?

What can be used for clay ? I have some containers of high temp refractory mortor for my forge build... I dont see why that wouldnt work well. Thoughts ?

Also considering torch softening the spine after the temper.
I tried this before with another blade but not sure if I did it right.

How hot do I have to heat the spine with the torch, glowing/red or just get it hot ?
 
Is your Paragon not digitally controlled (is it analog...with a dial instead of the touch pad?) I would think the least expensive way to test it would be with a forge type pyrometer..... I have instructions here: http://www.caffreyknives.net/forge_pyrometer.html

Canola oil should work.....just make sure you pre-heat the oil to 120-130F.

For the "clay" I've had good luck with simple "furnace cement" that I've purchased from local hardware stores. Opinions will of course vary, most folks have their favorite based on experimenting and the results from it.

I'm a bit confused when you say you're considering "softening" the spine with a torch. If the "clay" hardening works out correctly, there's no need for that.....the spine/areas covered in "clay" will not harden. That being said, softback drawing with a torch is more complicated them most realize/understand. With steel it's all about time AND temp.....such and such a temp, for a given amount of time. Those who use a torch, and just go to the point of "get the back blue" simply are not doing much....all that will do is create a very thin tempered "skin" (generally .010" or less thick), leaving the interior of the blade just as hard as it was before. In order for a "softback" draw to actually work as most intend, it takes time and concentration. Placing the blade in some type of fixture, with the edge in either water, wet sand, or something that will keep the heat from "bleeding" into the cutting edge is what I consider a necessity. Its not uncommon for it to take 30+ mins of heating with a torch to get the intended benefit. I've had a large number of folks over the years who have showed up at my shop to test for their JS...... and their blades have broken during the bend test.....all were supposedly "softback" drawn. But after having them walk me through their process(es), and looking at the broken pieces of blade(s), its obvious that all they achieved is the "tempered skin" that I mentioned earlier. Anyway, based on you post, I thought an explanation such as that was in order.
 
Ed has it right on and his forge pyrometer is easy to build and very inexpensive did I forget to say very accurate.
 
What was I thinking (must be one of those days lol) The HT with clay makes a soft back (face palm).
my Paragon has a digital rampmaster controller but I tend to suspect it's not accurate enough to do a hamon on 1095 but I could be wrong.

The pyrometer! Good idea, I followed those instructions to make one for my forge but it's not installed yet. I thought those give you a ball park on temperature, didnt realise they are also accurate (thats a good thing).

How would I test the paragon with that, just open the door and slip the thermocouple inside ? Wouldn't that give an inaccurate reading ? The only other way I can think of is too drill a hole in the Paragon.

On the "softback with a torch" I guess I wont have to do that to this blade but the info helps, I see now where I went wrong last time.

I'll give standard furnace cement a try.

Thanks!
 
How would I test the paragon with that, just open the door and slip the thermocouple inside ? Wouldn't that give an inaccurate reading ? The only other way I can think of is too drill a hole in the Paragon.
Click to expand...

Yes, you're going to have to put a hole somewhere (if none is already available). You want to leave the existing thermocouple in place, so you have something to compare with/judge by. Ideally you'd want the thermocouple of the pyrometer as close as possible to the existing thermocouple. The good part is that once you get things figured out, you can always plug the hole with kawool or the correct temp furnace cement, with no ill effects. (I've done this several times to check the accuracy of heat treat ovens)

Unless there is some reason to suspect otherwise, I've always found Paragon ovens to be the most accurate. In the case of doubt, it's always best to prove it to yourself. Its unlikely that its going to be to the single digit degree accurate....heat treat ovens generally have a +/- a given percentage that is used to describe their accuracy. For example, the better ovens guarantee 2-3% accuracy..... that would be a 40 degrees variance for 2%, and a 60 degrees variance for 3% at 2000F.

I once had one of the "less expensive" ovens, and after going nuts, trying to figure out why it seemed to vary wildly, and going through the oven's user manual many times, I finally called the company and explained my problem.....they told me that there was nothing wrong with the oven.....the "standard" for their ovens is 5-7%, meaning that 140-150 degree variance from the set point was totally acceptable.......that oven is now owned by someone else. :)
 
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two things that helped me out was
* Less heat- use the lowest aust temp you can for your steel. I go down to 1450° for W2 and W1
* Less Clay- use a thin layer, you don't need that gobbed up thick layr of clay. It should be thin..with practice you can practically draw on the blade with your hamon..
then.....
* After practice you don't even need clay, just time and temp control..You will get crazy active hamons that way..
oh and the other "less"...
* Less etch, more polish..don't etch the fire out of your blade, polish it more..
 
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EdCaffreyMS said:
Yes, you're going to have to put a hole somewhere (if none is already available). You want to leave the existing thermocouple in place, so you have something to compare with/judge by. Ideally you'd want the thermocouple of the pyrometer as close as possible to the existing thermocouple. The good part is that once you get things figured out, you can always plug the hole with kawool or the correct temp furnace cement, with no ill effects. (I've done this several times to check the accuracy of heat treat ovens)

Unless there is some reason to suspect otherwise, I've always found Paragon ovens to be the most accurate. In the case of doubt, it's always best to prove it to yourself. Its unlikely that its going to be to the single digit degree accurate....heat treat ovens generally have a +/- a given percentage that is used to describe their accuracy. For example, the better ovens guarantee 2-3% accuracy..... that would be a 40 degrees variance for 2%, and a 60 degrees variance for 3% at 2000F.

I once had one of the "less expensive" ovens, and after going nuts, trying to figure out why it seemed to vary wildly, and going through the oven's user manual many times, I finally called the company and explained my problem.....they told me that there was nothing wrong with the oven.....the "standard" for their ovens is 5-7%, meaning that 140-150 degree variance from the set point was totally acceptable.......that oven is now owned by someone else. :)
Click to expand...


I'm going to try this, it sounds like a good idea too me. Those tutorials also really help! I tried to reply before and it just didn't seem to want to post my reply.
 
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