Blower size

Hi Everyone, I have a 2x4 flat pan on a block arch and was using a small desk fan for under grate (or is it through the grate?) air. I'd like to do something that will up the amount of air being pushed in. I'm thinking about a squirrel cage blower that I could set in front of the air intake on my arch. I'd like to power it with an extension cord and it would be nice to be able to adjust the air flow. I'd rather not spend a great deal but....Does anyone have any ideas to help me get what I want? What size blower? Motor size? Rheostat wiring? As you can see this is not my area of expertise! Any help will be appreciated. Ted

I have a 2x6 and ordered a squirrel cage blower off amazon. I had a plenum built. you can see some pics in my photo page. I basically replicated the Grimm woodsaver blower you see on the leader website.

Ted,
Sound like you have the right plan. You wount need a lot of cfm's for this size arch I would maybe look for a 75 cfem blower. Motor size would be a fractional HP like a 1/4 hp or maybe smaller. Check Grainger on line or maybe craigslist ?
Make sure if using a electric cord it is on a GFS breaker and that there is not as tripping hazard around the arch. About any thing that will move air will allow you to make more heat. Doesn't mean you will increase your boil rate, that would need to be checked as a before and after test. Also you will have a hotter fire and burn a little more wood. You can adjust the air flow on the output end of the blower with a adjustable gate/damper/restrictor which can be simple to elaborate.
Ahhhh yes more fire!!
Regards,
Chris

That is what we did with our arch, putting the blower in the front where the draft door was on bottom of arch door. We adjust the air flow with a flat section or sheet of furnace type pipe and it has worked well to adjust our air flow. The blower blows the air under our grate system. Got the furnace pipe and sheet of furnace type at home depot.

So for specifics, go with a 75 cfem blower with a 1/4 hp motor. As I said earlier this really isn't my area so if I go to the hardware store and ask for the above they will know what I'm talking about? Is there any way to use a dimmer switch to control the air flow? Also want to say thank you for the safety (tripping) reminder. Ted

Ted,
Hardware store may not have a thing for you, but you can try. Most of these types of blowers are a industrial type and Grainger or McMaster Carr might be better places to shop on line?
Ok just looking at McMaster Carr these may be too pricy at $300 for about the smallest. 1/16 hp.
How about a small 2 gallon Sears shop vac? They have a blower feature opposite the suction side and produce quit a bit of air for nor much jing? May be a little noisy?
Regards,
Chris

I think a blower like Grainger's Dayton 2C647 at $76.80 would be better. It has a 134 CFM at 0" SP (restriction) which when the air inlet /outlet are full open is what you'd get. Then put a damper on the inlet to adjust air flow, not the outlet. It will work either way but is easier to make a adjustable flap to open or close as needed and it seems to stay in place better. A flapper damper in the duct leading from the outlet to the arch tends to adjust itself more than one on the inlet side. Google a Dayton 2C647 for full performance info, and this one is USA made.

A shop vac! That's brilliant! I've got a 10 gal. 3hp shop vac! I just tried it out. It blows pretty hard. It might be too much. I wonder if I fastened the hose to a larger diameter hose and made it longer would that slow it down? I do like the idea though. Getting some use out of an item that was in the shed long, long forgotten is very appealing, and free! Any ideas to slow the air down? Thanks. Ted

Don't know if this is suitable, but the price is right at $18.59 shipped, and it says it's 75 CFM. I think I might give one a shot myself. Been meaning to get some forced air into my lil 2x3.

http://www.amazon.com/Replacement-Fi...el+cage+blower

I have done the shop vac thing and it did get the fire nice and hot but it is loud and annoying. That lasted about 20 minutes before I unhooked it. Don't know how well it would stand up to running for 12 hours straight. Can't imagine that you would get too many hours out of it before it ceases up on you. Restricting the air going in might help slow it down. Or, put a hole or a "t" in the output line before it goes into the evap. to slow down what is going in (release some pressure before it gets to the fire)

I see you have 3x10 arch same as mine & I am puting AOF how many cfm blower should get Thank You Marty

Hey Flats, I didn't see your post earlier. That may be the better way to go. The shop vac is incredibly noisy and old so probably wouldn't work for long. I'm not much of an electrician so I'll talk to my son (he's the smart one) and see if he can help. I appreciate the idea. Thanks, Ted