makeshift oven wont heat past 1700

C

Clarence

Joined
Dec 26, 2009
Messages
4
i guess i shouldn't be too surprised that my first attempt at maming an oven to heat steel doesnt heat the way i want it to. i can get 44o stainless to orange hot about 1700 degrees, but would like to get to about 2300 degrees.

my setup is as follows:

i used firebrick to create an oven area with dimensions of 4.5in w X 8.5 h X 18 deep. i made a chimney at the back that i can seal offby putting a brick over it. the front opening is 4.5 X 8.5 and i dont have a door for it. i am using propane to heat it at 18 psi.

can anyone recomend changes to help me get hotter temps. i want to go to 2300 or 2350.

best,

Clarence
 
Cover your chimney and cover the door hole so you have just enough room to install and remove your steel. Or put your steel in and cover the door completely with brick. That should increase your temp quite a bit.

Keep at it & welcome to Bladeforums. If you have questions, just ask!!

Also, if you fill out your profile, you may find that another maker lives close enough to visit. It's amazing how much you can learn by visiting another makers shop.
 
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Welcome to the forums.
A lot depends on the materials and manner of construction. A good info site on forges and burners is"
http://www.cashenblades.com/info/gas_forges.html
and
http://forgegallery.elliscustomknifeworks.com/

If you have soft firebricks, and are trying to heat up a nearly 700 cubic inch chamber that is open on both ends, you better have a big burner. Since you said the operating pressure was at 18PSI, I'm guessing it is a venturi burner. That combo won't work very well.

If you are using hard fire brick....good luck ever getting it above the current temps without a lot of changes.

A layer of refractory insulation and a coating of ITC-100 will help a lot. Making a back door cover and adding a front port that is only 3X3" will also help.
Make sure the burner is capable of supplying the needed amount of heat. What size burner tube (pipe) is it made from? Is it entering at a tangent? Is the orifice the right size? etc.?

I'm not sure why you are heating stainless in this forge, but if it is for HT, the results will be poor at best.

Welcome again,
Stacy
 
You could use any of the high carbon steels with your oven and get good results, for new makers 1084 is highly recommended. You only need about 1500 F. Decarb will be a big issue with stainless. This way you can use your over and make some knives.
 
Deweyknives said:
I thought the same thing, but that was'nt the question. :D:D
Click to expand...

I don't own a gas forge and I never dealt with stainless at all but... a friend of mine has one and he told me that it is so hot he only finds it suitable for stainless blades. He just eyes he temps by the color of the steel.

Why are not gas forges like this (propane) suitable for HT stainless?

Mikel
 
it seems that i need a blower of sorts.. i am gonna go set something up now and will get back to you. thankyou for all the help so far

best,
 
Clarence said:
it seems that i need a blower of sorts.. i am gonna go set something up now and will get back to you. thankyou for all the help so far

best,
Click to expand...

I read someone was using a hair drier as an air source. Maybe that could help your endeavor.
 
well i scrounged a shopvac that can be used as a blower, it will be here this evening. in the mean time i am trying to set up some pipes to merge the air flow with the propane. see image below. if any of that looks scary let me know. i would hate for you guys to read about me in the paper. :)

the last photo is my failed attempt at drilling my brick to fit the pipes. :D i think i can get that ready before my shopvac gets here.

Best,
Clarence
IMG_2737.jpg

IMG_2738.jpg
 
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I don't know crap about ovens but... just in case... please, record on video the first time you fire that "thang'" up.... It may be a lot of fun.

As a side note, try to remote-fire it up... we don't want to lose a forum member.
Mikel
 
Don fogg has an excellent example of a propane forge on his web site. I'm no expert but I think your air supply line may be too small. I have a two inch pipe with a squirrel cage blower attached. Between the blower and the elbow where the gas line enters I have a gate valve to regulate air flow. Make sure the air is first thing going before you try to start the forge and the last thing you turn off when you are done.
I have to agree with the other guys, using this kind of setup is less than ideal for stainless but would be fine for simple carbon steels.
 
Don fogg has an excellent example of a propane forge on his web site. I'm no expert but I think your air supply line may be too small. I have a two inch pipe with a squirrel cage blower attached. Between the blower and the elbow where the gas line enters I have a gate valve to regulate air flow. Make sure the air is first thing going before you try to start the forge and the last thing you turn off when you are done.
I have to agree with the other guys, using this kind of setup is less than ideal for stainless but would be fine for simple carbon steels.
 
Mike -- about the steel... i am using 440C which has 1.2% carbon vs 1084 which has between .8 and .93% carbon.. will the 440C deplete faster or something?

And thank you for the direction to Don Fogg. i am constantly rereading his plans trying to get all i can out if them. i saw a picture of your oven/forge on your "Welcome to the Shop" page on your website. does it have a blower? is it propanes fired?

By the way, your knives are stunning!

Best,
Clarence
 
Thank you for the compliments. The forge is propane with a blower and the kiln is elec. The kiln I have much more control with when it comes to heat treating. The 440c requires that control that an elec. kiln offers. Whereas the forge can get the 1084 to an austenizing temp(nonmagnetic) then quench. The 440 requires a presoak I believe around 1200 then ramp up to 1950 to 2000 and hold, this is going to be tough with a propane forge.
 
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