new guy with ????

[454nova]

Hey ya'll

Ive been powder coating for a few years now. I use a modified Grieve NB-350 oven for curing but now have the need for a larger oven. I plan to build one like many people have on here: A 6x4x4 with many of the same concepts people have used. However I have one question about a recirculating fan. I see some people use Induced Draft fans for furnaces from Grainger. I also would like to use one, but what CFM should it be rated at? There is one rated at 216 CFM and I have no idea if thats good or bad for an oven of this size. Any information would be great. Anyone have a fan they would recommend? THanks

[JTW37]

I use a squirrel cage fan. Follow the link to have a look at it. My oven is 3x3x6 and it seems to move the air pretty good. You don't want it to turbulent or it will blow your powder off.

http://www.surpluscenter.com/item.as...tname=electric

[ed_denu]

I use one of the Dayton high temp blowers like these:

http://www.electricmotorwarehouse.com/dayton_blower.htm

If blowing the powder off the part is a concern, just add a switch and only turn the fan on after the powder has flowed out.

[FigureLLC]

we used grainger part no. 1tdu9 for a 5ft tall oven. works great. you need very little flow, as it doesn't take much movement to stabilize the temperature.

where the duct exhausts into the bottom of the oven cavity, we used a 2x10in or so floor register, like you'd find in a house. i wasn't real sure about the flow either, so i figured i could use the built-in louver to restrict it a bit if necessary. i considered controlling the speed of the blower, but the blower shaft has heat slingers on it to prevent heat from transfering to the motor, and if those aren't turning fast they can't do their job. so i wanted a way to control flow with the blower running at full speed.