Can I use this Muffle Kiln to HT my 1095 steel?

J

JimDiGritz

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Oct 18, 2021
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I'm currently using a DIY forge made from some insulating fire bricks and a MAPP gas (methylacetylene, propadiene and propane) blow torch. It works however the MAPP gas is expensive and I can only eyeball temperature.

I also then need to use the kitchen oven to temper, and obviously this is unpopular with the wife.

I noticed that many more established knife makers use electric forges like the Evenheat - however they all look very expensive - £1,000+ and I've no intention of making 5-6 blades simultaneously so don't need the large dimensions... plus my workshop is pretty small and a compact size is preferred.

So after looking around I came across this:

According to the blurb it can hold a temperature (within 1-2deg) from 20c/68f to 1130c/2066f and the heating volume (without the crucible) seems large enough for <12" knives (I don't make swords or machetes)
s-l1600.jpg

I've actually found one online new for £200.. am I missing anything obvious... it seems big enough for a knife, can get to the right temperatures for Normalizing, HT and Tempering.

Thanks

Jim
 
This seems very small. The dimensions appear to be exterior dimensions, the internal height is likely around 100mm/4" or less, just enough to fit the crucible.
 
Hubert S. said:
This seems very small. The dimensions appear to be exterior dimensions, the internal height is likely around 100mm/4" or less, just enough to fit the crucible.
Click to expand...
Good spot, I had missed the dimensions the crucible itself is OD(1″=25.4 mm): 60mm(td) x 47mm(bd) x 80(h) mm so this won't be big enough....

My question still stands - would an electric muffle kiln work for knife HT?

I can find quite a few pottery kilns like this https://www.ebay.co.uk/itm/284501920971?hash=item423da2cccb:g:OOQAAOSw8PRhdY7V

Just making sure that as long as the interior dimensions are sufficient that regardless of whether it's a muffle kiln, electric melting furnace or a pottery kiln it should work!!
 
That is not a kiln in the sense we use. It is a melting pot for melting gold and silver. It won't work for HTing a blade. The term kilon is probably a Chinese mis-translation.
 
It is designed to melt things, not to evenly heat them.

You insert a graphite crucible and that is heated by the coils. The crucible transfers the heat t the metal and melts it. The heating would likely be uneven if the crucible was not filled with metal to melt.

Placing a blade in without a crucible would be very dangerous.

Despite the glowing chart of attributes, these are pretty basic melting pots and unlikely to have the tolerances and accuracy stated.

As already said, the chamber inside the crucible is roughly 3X1".

Could you use one to HT a 1095 folder blade - probably.
Would it be a good choice for HTing 1095 folder blades - probably not.
 
Stacy E. Apelt - Bladesmith said:
It is designed to melt things, not to evenly heat them.

You insert a graphite crucible and that is heated by the coils. The crucible transfers the heat t the metal and melts it. The heating would likely be uneven if the crucible was not filled with metal to melt.

Placing a blade in without a crucible would be very dangerous.

Despite the glowing chart of attributes, these are pretty basic melting pots and unlikely to have the tolerances and accuracy stated.

As already said, the chamber inside the crucible is roughly 3X1".

Could you use one to HT a 1095 folder blade - probably.
Would it be a good choice for HTing 1095 folder blades - probably not.
Click to expand...

Thanks, this is really helpful.

As a beginner I'm still learning and whilst not trying to find the holy trinity of cheap, quality and small I thought that perhaps this was an option.

I just can't afford a high end unit like the Evenheat - here in the UK they are about $5,800

https://www.brownells.co.uk/HT-1-HE...1-Heat-Treat-Oven-EVENHEAT-KILN-INC-100004956
 
JimDiGritz said:
Thanks, this is really helpful.

As a beginner I'm still learning and whilst not trying to find the holy trinity of cheap, quality and small I thought that perhaps this was an option.

I just can't afford a high end unit like the Evenheat - here in the UK they are about $5,800

https://www.brownells.co.uk/HT-1-HE...1-Heat-Treat-Oven-EVENHEAT-KILN-INC-100004956
Click to expand...
Why you don t make one , the cheapest possible way and the simplest at the same time and would work better then many factory oven like that one from 5800 $? The only drawback is that you can't harden several knives at the same time.

Tube furnace

Well I found and I watched this video clip on You tube , this guy is genius ......:thumbsup: Forced me to do some research about this kind of furnace .What I found so far tell me that this is prefect HT furnace for me .One or maybe two blade can be HT at once but that is all I need .To...
bladeforums.com bladeforums.com
 
Stacy E. Apelt - Bladesmith said:
It is designed to melt things, not to evenly heat them.

You insert a graphite crucible and that is heated by the coils. The crucible transfers the heat t the metal and melts it. The heating would likely be uneven if the crucible was not filled with metal to melt.

Placing a blade in without a crucible would be very dangerous.

Despite the glowing chart of attributes, these are pretty basic melting pots and unlikely to have the tolerances and accuracy stated.

As already said, the chamber inside the crucible is roughly 3X1".

Could you use one to HT a 1095 folder blade - probably.
Would it be a good choice for HTing 1095 folder blades - probably not.
Click to expand...

Not wanting to labor the point, but at the moment I'm using a blow torch to HT my blades - so not sure how much less accurate this type of 'kiln' would be compared to what I currently do which is getting the blade past non-magnetic 'plus a bit' - I'm also aware that even with moving the blade around and angling my blowtorch in the fire brick I'm still ending up with hotspots in the steel...

I'll keep looking - just not sure what the key/minimum specifications I need!
 
Natlek said:
Why you don t make one , the cheapest possible way and the simplest at the same time and would work better then many factory oven like that one from 5800 $? The only drawback is that you can't harden several knives at the same time.

Tube furnace

Well I found and I watched this video clip on You tube , this guy is genius ......:thumbsup: Forced me to do some research about this kind of furnace .What I found so far tell me that this is prefect HT furnace for me .One or maybe two blade can be HT at once but that is all I need .To...
bladeforums.com bladeforums.com
Click to expand...
Thanks!

I hadn't considered a DIY oven - I'd be concerned with electrocuting myself - but I'll watch that video now!!
 
I have HTed carbon steel blades in a forge for nearly 60 years l. Using a magnet and a well trained eye it can be done with good results. Even though I have HT ovens, I still do some blades in the forge. I l prefer the forge for Japanese blades and W2. The trick is to have a low ambient light level so you can see the real color of the blade.
Is it the same as a HT oven - NO ... is it going to give a properly hardened blade - YES.

A small home built forge with a 1.5"/40mm ID muffle pipe will HT 1095 pretty well. If you make it PID controlled, it will do it quite well.
A simple forge should cost around $100 to build. With some scrounging abilities, maybe half that. PID control will add another $100. You can start with the forge and add the PID control system later.

There is a section in The Stickys about my two-stage PID controlled forge setup. There is also plenty of info on building a basic forge.
 
Thanks for all the advice, I guess I'll stick with my firebrick & MAPP gas torch forge for now.

This seems to be one of those odd specialist areas where the price of something seems unrelated to the time and material costs! After watching the really interesting videos on DIY electric ovens with PIDs I've got a parts list of maybe $300, and the build time seems to be only a few hours.. yet a purpose built version is £1,500 minimum... Compare this for example to a 2x48 grinder - the parts alone add up to $400 and I yet can buy a custom made one for $600 - supply and demand I guess!!!!

I'm not an electrician and I draw the line at half arsing a 3kw oven, but it's awfully tempting given the price disparity!!!

Jim
 
$300??? Good Luck!
You can build a DIY HT oven for $400-500. It won't likely be the same oven as a commercial one, though.

One thing you are paying for in a commercial oven is experience and engineering. Few DIY builders have either one. The other thing you get is customer service and tech support. If an Evenheat doesn't work right they will help you fix the problem or replace it. IF your DIY oven doesn't work "Who yo gonna call?"
 
Stacy E. Apelt - Bladesmith said:
$300??? Good Luck!
You can build a DIY HT oven for $400-500. It won't likely be the same oven as a commercial one, though.

One thing you are paying for in a commercial oven is experience and engineering. Few DIY builders have either one. The other thing you get is customer service and tech support. If an Evenheat doesn't work right they will help you fix the problem or replace it. IF your DIY oven doesn't work "Who yo gonna call?"
Click to expand...
Fair enough, I paid $500 for a small purpose built belt grinder because making my own would cost almost as much. I'd happily pay $800 for a small hobby kiln but it looks like a minimum $2,000 investment....

I'm not disagreeing with you - I'm just surprised at the big jump in cost from my bricks 'n blowtorch setup! ;)
 
1) A blacksmiths hammer is $50. A power hammer is $5000-$8000. They both move metal. It is just that one does it more efficiently.
2) A torch will HT a carbon steel blade. A HT oven will also do it. One is just more accurate.

Lots of practice with a hand hammer will make perfectly fine blades.
Lots of practice with a a torch and some firebricks will get you good HT results.
Both are a matter of practice and skill level.
 
Stacy E. Apelt - Bladesmith said:
1) A blacksmiths hammer is $50. A power hammer is $5000-$8000. They both move metal. It is just that one does it more efficiently.
2) A torch will HT a carbon steel blade. A HT oven will also do it. One is just more accurate.

Lots of practice with a hand hammer will make perfectly fine blades.
Lots of practice with a a torch and some firebricks will get you good HT results.
Both are a matter of practice and skill level.
Click to expand...
You're absolutely right, my first knife was made with only hand files and a hacksaw - I HT it with an old spluttering Butane torch!

I'm not trying to find a shortcut, however I'd like the option at some point of trying some stainless steels and at that point maybe an oven will make sense!!
 
Always remember that sending blades out for HT is far cheaper than doing them yourself.

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