Heat Treating Oven

[Gliden07]

I was reading a post asking some questions about this subject. I didn't want to hi-jack the post but had some questions too. Why does everyone want the TAP control vs the Cheapie 3 button? When you heat treat do you put knife blanks in as oven is heating or after its heated? When doing "Stepped" heat treats do you take blanks out as oven cools or heats, and (i assume) once it get to set temp that's when you start timing the blank? Obviously never had a heat treating oven, these are questions I've really wondered about though.

 

[EdCaffreyMS]

Speaking just for myself, the TAP controller is the easiest controller to program/use that I have ever seen. Plus the fact that they have android/IOS apps, mean you don't have to "babysit" your oven if it's not in the same place you are as it's being use (my oven are in the hot shop, and unless I'm there, I have to set approx timers on my phone.) My pargon ovens have the Sentry 2 controllers, and EVERY time I have to do anything with them, I have to drag out the manual and reference how to do things.

The only time I use my heat treat ovens is for stainless steels, that require ramping/holding during heat treat...... and when doing that, I place the blade(s) in a cold oven, then start the program. and let it run. Once the oven reaches temp, that is when the actual program/time(s) start.

When it comes to heat treating any steel that doesn't require the ramp/hold recipe, I don't use the ovens, as I far prefer the salt tank, or torch if I differentially heat treat.

I'm sure there are others here that have far more knowledge of heat treat ovens use than me......

 

[KenH]

That TAP controller is really sexy and I'd LOVE to have one rather than my cheapie 3 button. BUT - the 3 button does everything I need. I do mostly AEB-L and sometimes carbon steel, and use oven 99% of time. Make that 99.9% of time for HT'ing, and a separate PID controlled oven for tempering. If you need many different recipes for HT'ing the TAP would be worthwhile. The 3 button version (on my EvenHeat) holds 4 different custom recipes that are selected with up/down arrows and that's plenty for me. If I do need something else, it's very easy to change as the selections are made.

On the advice of Hoss and Larrin (father 'n son) who are extremely knowledgeable I allow oven to stabilize at temp before putting cold blade in oven. If using a pre-quench soak per Hoss's recommendation for AEB-L the foil wrapped blade is soaked at 1725F, quenched between plates for cooling. Then AFTER oven is stabilized at austizing temp the foil wrapped blade in put into oven for final austizing heat.

My understanding is an oven should be stabilized at temp prior to putting blade into oven, Especially for carbon steel to prevent excessive scale build up. The longer metal is in oven above 1200F range the more scale (and de-carbon?) will form.

Ed is LOTS more knowledgeable knifemaker than I am, Ed has forgotten more than I will ever know. The above is my understanding from reading with Hoss, Larrin, and a few other folks.

Ken H>