Tempering in a convection oven

[Bailey Knives]

So my wife wanted to upgrade the appliances and I didn't, so we compromised and upgraded the appliances. A new convection oven is due here later this week, and the first thing I thought of is how it is going to effect (affect? I can never remember which one) my tempering. Does anyone else use one? Is the temp set on the oven accurate to the temp in the oven? I know they are supposed to cook faster, but do they do it at a consistent temp? Thanks in advance.

 

[i4Marc]

I use a convection oven for tempering. No mine is not accurate but it is steady. I use a rack type thermo to guage the temps as the dial is way off. It does hold a nice steady temp once I dial it in. I get the oven going before I start heat treating to give the oven plenty of time to come up to temp and dial it in. Take the old oven you're replacing and move it to the shop!

 

[zhyla]

Some (all?) convection ovens can operate like a normal oven. So you could just not use the convection option in that case.

The thermostat control is the same with or without the convection so it shouldn't be much difference other than the actual temperature setting. On my oven if you punch in 400 F with convection it sets it to 365 F or something like that to compensate for the "cooks faster" aspect.

 

[Andy Lewis]

Take the mystery out of it whatever your heat source. Roll the steel up loosely in lightly crumpled foil and bury a type K TC right next to your edges while your at it. Twist ends tight and ease up on your temp. Take notes. Too much effort to be guessing at this step.

Always enjoy your thoughtful work Matt. Great stuff over the years.

 

[timgunn1962]

Search on Ebay for "TM902C". Buy the cheapest one you can find including delivery. It should be under six bucks. It's a Type K pyrometer with a 3' glass-fiber-insulated bead-type thermocouple that is thin enough and flexible enough to go through the door seal. It's degC only, but it's not like you need to do the conversion in real time and in your head, so that should be no problem. As said above, this takes the guesswork out of the equation.

The lightly crumpled foil should work fine. The other way of evening out any temperature fluctuations is to bury the blade and thermocouple in a tray of dry sand. Either method will slow the heating to temperature somewhat, so you'll need to allow longer in the oven to get the time-at-temperature.

 

[Bailey Knives]

I have a bunch of oven thermometers that I use now. I guess I will just have to do a conversion between the oven setting and the actual temp. I was hoping I could just set it and forget it. For as old as our oven was it was only of 10 degrees from the actual temp.

 

[tattooedfreak]

Do a test first, put an oven thermometer in and do an hour at your normal temp. Convection ovens are more efficient than conventional ovens due to the fan vice heat radiation, it will also give you more even heat. The only real effect it will have is quicker heating of your oven and whatever is inside it. It wont affect your temper as long as you ensure your temperature is even at the heat you want.

 

[J. Hoffman]

My oven can be used as a convection or conventional. I used an oven thermometer to check the temps. In conventional mode, the oven reading was little off from the thermometer. In convection mode it was right on. I figure if I have two readings that are the same they are correct. I always temper on the convection setting.