Do I need a fan in my oven?

[corybarta]

I built a 6 foot tall by 4 foot wide by 2 foot deep oven with 4 burners at the bottom. The digital oven temp gage reads 400 degrees but the parts only get around 325 degrees. I am using an infared temp gun to check the parts. If I need a fan should I mount it down by the burners or clear at the top.

I have a fan that turns 1550 rpm's, I am thinking about putting it in and hooking up a switch to it so I can turn the rpm's down, just like on house lights, that kind of a turn knob switch. will this work. thanks guys

[corybarta]

also will I still need venting holes, one at the bottom and one near the top with a fan.

[VPC]

Careful with the infared temp gun.It will give false readings on anything that has a shine or gloss.Try taking your readings from different areas on the part.As far as vents my large oven has none.Fan circulates air through the oven in a closed system.Circulation will make for a more even cure.You will be less likely to have hot spots.

[tavo1765]

Go with the fans facing horizontal.

[jtagger19]

what do hot spots do or looks like ?
I don't have a fan in my 7x4x5 oven and it works fine

[corybarta]

I put a fan in yesterday and the thing got so hot it quit working, after it cooled down it would run again. I drilled a 1/4 inch hole in the side of the oven an inserted the shaft and put the fan on the other side. It worked fine until it got hot then quit. I had it at full operating speed. I think I have it to close to the burners. I might mount it on the top of the oven this time. Actually the oven does work fine without the fan. I have found out that I have to bake everything longer to make it work rite. thanks

[overcoat]

Originally Posted by corybarta

I have found out that I have to bake everything longer to make it work rite. thanks

Before or afting fitting the fan?

[corybarta]

before the fan, the fan will run until it gets to hot and it shuts down. I am going to weld a longer shaft on the fan so I can keep it farther away from the oven.

[Popeye]

If you add a second fan blade on the shaft outside of the oven it will act like a heat sling and the motor will run MUCH cooler.