attic fan in kiln

[kelLOGg]

Has anyone used an attic fan for circulation in a kiln? Seems like the bearing lubricant would take the heat since an attic is comparable to kiln temperatures.
Bob

[pineywoods]

Bearings aren't the only concern. I built a solar kiln for a sawyer up the road. He bought plastic box fans from wal mart. The blades melted and fell off.  We also found that the fans last a lot longer if you leave them running all the time.

[James P.]

kelLOGg, I have 5 attic fans I bought new several years ago for a kiln. I have yet to build a kiln but I am hoping they will do the job. The only thing concerns me is they aren't enclosed motors and the moisture will have a negative effect in short order. The price for them is a lot cheaper than a true kiln fan . Plus kiln fans have alot higher cfm and HP from what I remember. I hope someone with some experience using them will post their results.

[solidwoods]

Bearings aren't the only concern. I built a solar kiln for a sawyer up the road. He bought plastic box fans from wal mart. The blades melted and fell off. 

Now that's funny

The atic fan should have a temp rating on it if not check Grainger for the model # and check the spec info on it.

[davemartin88]

Has anyone used an attic fan for circulation in a kiln? Seems like the bearing lubricant would take the heat since an attic is comparable to kiln temperatures.
Bob

I have a small (4'x8'x8') solar kiln using two solar powered attic fans for circulation. Been in use for about 3 years with no problems, fan is metal so nothing has melted! They were expensive but so far, so good.

[solidwoods]

In my kilns I use furnace squirrel cage fans.  They are rated for high temp.
We can get them from the scrap metal yard.  They allow us to remove them from a furnace, they charge $.10 per pound for the fan.  I can check it with a VOM to see if it has a short, also I check the fan for excess spindle play.
If we get the fan home and its bad, the scrap yard will buy it back for $.05 per pound.
I have the fans mounted on a piece of plywood with a hinge that has a quick release hinge pin. a few times per year , I take them down and oil the bearings.
Also these type of fans are typically 3 speed so I run them on high speed.
But they are not reversible, and they are more trouble to clean (kiln fans get caked on dust real easy).
jim

[kelLOGg]

Well, thanks for all the feedback. I got 2 attic fans from Amazon.com - all metal with re-oilable bearings. Built a box to house them and this week I will put them in the kiln and be back on the "air".

I also got baseboard heaters installed to get the temp to ~135 -140*. The kiln is full of 7% MC white oak. I will reheat with the new heaters to kill possible bugs and empty the kiln.