Heat treating oven VS gas forge?

[Ian Sayers]

I am fairly new to knife making and so far all of my experience is in stock removal. I want to move on to forging and I plan to use gas, but I'm wondering what advantages there are to having a heat treating oven in addition to a gas forge. Can someone help me understand the cons of using a gas forge for everything, and the added pros of having a heat treat oven?

I'd also appreciate a little insight into the advantages of open end port forges vs forges with solid doors... I assume that with open ports I can heat longer pieces of metal and billets with welded-on handles, but I'm sure I'm missing the fine points if not the fundamentals...

-Ian

Edited September 27, 2015 by Ian Sayers

[Frosty]

If you're new to knife making then you need more experience to heat treat by eye. A heat treat oven takes the guesswork out of it no matter who you are. One of the guys in our club recently got a liquidation sale ceramic kiln rewired as a heat treat and mokume oven.

If you're burning any fuel you MUST have an exhaust or it's going to be choked out. You want to keep the doors in a gas forge as closed as possible without creating back pressure that effects the burners. A gun (blown) burner is less susceptible than a naturally aspirated burner but MUST have an exhaust port none the less.

And YES that's a fundamental.

Frosty The Lucky.

[Steve Sells]

forges and ovens are not the same thing anyway, they do not always cover the duty's of the other one.

[PValBlanc]

More specifically, the atmospheres are different within a heating electric kiln and a gas forge, leading to different kinds of oxidation/decarburization issues, and as such, different solutions. I am not well versed enough in gas forges to elaborate on that, but there is another big point of difference.

You can heat treat virtually any steel in a controlled kiln. With any type of forge, maintaining the precise temperatures for the necessary soak times (of multiple hours) for proper treatment of stainless or other forms of highly alloyed steels is next to impossible. As such, if you plan on using mostly carbon tool steel, the forge will do fine. But the kiln would be an essential for higher tech steels. 

With a bit of mcguyvering, you can use a good heat treat oven for a bunch of other stuff too: burnout (for lost wax casting), enamel, mokume, melting for copper alloy brewing... And so on. 

I hear gas forges are pretty versatile too, but again, not my area of expertise, not yet anyway.

Hope this was of help! 

 

[Charlotte]

The summer I worked in the tube mill running annealing furnaces they the same building housed the stainless heat treating units.   They had special dip tanks and high sophisticated heat control, temperature baths  and ;;;; the heat treating was done in an electric furnace when every other heat in the plant was high pressure natural gas.

[phabib]

A few years ago I put together a very simple heat treat oven for a friend who needed to make some transmission parts he couldn't buy.  I used firebrick, some kaowool for a quick shell, two 220V heating elements I picked up cheap, and a digital temperature controller from a surplus store.  I don't think I had $50 in the whole thing and it worked pretty well.  You had to set the temperature each time you needed a change to ramp up or down but for one off, it wasn't bad.