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View Full Version : Small heat treat furnace: Source?



strokersix
08-01-2012, 11:03 PM
Looking for a small furnace, say 6 inch cube or so. I want to quench and temper tool steel and harden precipitation hardening stainless. I googled knife making and found some but interested in source suggestion and/or experience from others. Occasional use only. I'm comfortable with using a torch and colors but would like more control over the process.

Duffy
08-01-2012, 11:55 PM
You might try the ornamental glass hobby. That is bead making and glass firing of metal.
I was given a small electric furnace, (so I dont know its actual cost.) It is literally one brick, on edge, for each side, with a separate refractory lid and bottom. It is three settings and a maximum temp of about 1800*F. It plugs into a standard 110V outlet, and is equipped with a thermocouple and temp. gauge. There is no fine temp. setting, but maybe that could be added. Inside dimensions are about 7x7x4 inches. It comes up to temp. in about ten minutes, weighs about ten pounds and sits on ANY surface.
It looks like it should cost about a hundred bucks, but you know what hobby supply prices are like!

macona
08-02-2012, 12:04 AM
I have a little vulcan. Works great.

http://www.dentsply.com/en/solutions/us/prosthetics/fixed/vulcanŽ-furnaces/

flylo
08-02-2012, 12:10 AM
I just bought a batch of dental furnaces I think for dentures as well as shakers, vacuum pumps,etc. I have 2 rd door furnaces witha square oven abour 6x5x2"h. The gaude goes up tp 3000 deg, I ran it up to 2000 deg in just a few minutes. I also have a Jelenko jell fire that all digital. It plays a few notes while dropping down a flace to put your object then retracks it back up inside. It's a little larger but I didn't know how to program it so I called the company & they want to buy it. All these have vacuum also. So maybe look for dental furnaces. I can e-mail a picture if you wish.

CCWKen
08-02-2012, 01:41 AM
If Evan is up to it, he may post pics of the one he built from scratch. I can't seem to find the link to his previous post but as I recall, he used hand wound Nichrome wire coils bedded in alumna-ceramic and surrounded by fire brick. A temp controller can be had for less than $50. Add a solid state relay to fire the coils and you're all set. Timer optional.

bobw53
08-02-2012, 05:51 AM
Look for pottery kilns. and also welding rod drying ovens.

yul m6
08-02-2012, 08:22 AM
I have been looking for a heat treatment furnace, and have narrowed my research to this Olympic kiln that goes to 2350 degrees costing $445 shipped
http://www.ebay.com/itm/Olympic-model-HB86-small-kiln-great-for-ceramic-pmc-glass-and-metals-/320931021039?pt=LH_DefaultDomain_0&hash=item4ab8fac0ef

I plan to add a ramp and soak electronic controller from automation direct for $100.
http://www.automationdirect.com/adc/Shopping/Catalog/Process_Control_-a-_Measurement/Temperature_-z-_Process_Controllers/1-z-32_DIN_Size_%28SL4824_Series%29/SL4824-RR

Add a thermocouple and the whole project comes in for less than $600.

rowbare
08-02-2012, 09:59 AM
There is an optional programmable controller available from that seller for $100. It might be less trouble to go that way. Here is a link to the controller they use: http://www.bartinst.com/KILN/3key.html

bob

rkepler
08-02-2012, 10:35 AM
I have an Olympic kiln that I use for HT, it's an older version of their model 129. For HT you definitely want a front load model - top load would be impossible (can you imagine reaching in there through 2200 degF bricks?) The Bartlett RTC 1000 controller is the one to get as it will let you anneal difficult materials with a cooling ramp. If at all possible get a 220V machine and Kanthal elements - I have a 120V machine that's maxed out on a 20A circuit and it has trouble getting the temp up to 1800degF if not isolated with a warm fiberglass blanket, even then it's an hour to get there.

lazlo
08-02-2012, 10:57 AM
You can buy a Paragon knifemaker's furnace for around $1,000:

http://usaknifemaker.com/paragon-xpress-km18-furnace-w5-5-xd18-xh4-25.html

They're very simple to build though -- some refractory bricks from the local pottery supply, a length of Kanthal wire for about $40, and a PID controller off Ebay for $40.

davidwdyer
08-02-2012, 04:38 PM
You can get used burnout ovens used in jewelry making. They work OK.

lazlo
08-02-2012, 05:17 PM
You can get used burnout ovens used in jewelry making. They work OK.

The Vulcan furnace (that Macona mentions) are dental burnout ovens. A friend has one, and it's very nicely made. Works great.

I have a Moore heat treat oven (no idea if it's the same Moore -- I doubt it), and the previous owner had replaced the original analog controller with a PID controller that he wired a goofy twin voltage setup: 110V controller/contactor with a 220V heating element. It was simple enough to replace the whole controller with a 220V Omron PID unit.

In other words, "dead" pottery kilns, muffle furnaces, dental/jewelry furnaces are a great find, and they're very easy to fix.

gzig5
08-02-2012, 07:05 PM
I picked up one of these off CL for $300, new unused. bigger would be nice but saved a ton of time not building my own, and so far it's done everything I need for making cutting tools and reamers.

http://www.riogrande.com/Product/Rio-PMC-Kiln-with-Nine-Program-Controller/703117

strokersix
08-02-2012, 09:18 PM
Thank you all for the suggestions. This will give me some direction.

Evan
08-02-2012, 09:37 PM
This is what I built.

http://ixian.ca/pics9/furnace21.jpg

http://ixian.ca/pics9/furnace18.jpg

http://ixian.ca/pics9/controller2.jpg

http://ixian.ca/pics9/controller9.jpg

uncle pete
08-02-2012, 10:24 PM
For what it's worth.
Around 1974 I worked at a coal testing lab. They happened to buy 4 brand new 220v muffle furnaces while I was working there. Even at that time, the non computerised controllers were more than accurate enough to produce lab quality results. Maybe? there's a few dealers around that specialise in used lab equipment? Brand new today from a proper lab equipment supplier? (that is if you wouldn't need some special damn licence to buy from them due to the bastard illegal drug producers) would I think be probably be expensive. But I really have no idea for sure. Either way, it might be worth a shot to check out. Ideally you'd want a atmosphere controlled furnace, Ideally we could all afford one too.

Pete