Can I add a blower to a homemade evaporator without using pipes inside?

[Pibster]

I am in the process of building an evaporator similar to the DavyJones design, roughly 2'x3'. I was wondering if I could add air by attaching a small blower to the front without installing an internal manifold to distribute the air. Would the boil rate improve with just a blower? I have searched this site for plans but it seems that most AOF is done on larger evaporators and not the smaller hobby type that I am building. Thanks for any suggestions.

[smokeyamber]

I have seen pictures of folks using house fans in front of the open door so I guess you can force air anyway you can think of. I ran my air in via an old exhuast pip with holes drilled in it, pipe went under the grate and for a blower I use an old JennAir blower. My goal was to have air from below to help and it seemed to work last season. Air from the front would help, but I wonder how it would affect your front of pan boil ? The great thing on a homemade rig is you can just try it and change it on the go with no worries about hurting any shiny stainless... :D

[Gary R]

If you have an ash door, guys will put air under the grate. Many will use 3"-4" furnace pipe. This blows the heat up. It does burn more wood, but it runs hotter and boils faster. Just about anything can be used.

[Pibster]

Sounds like it might be worth giving it a try. Thanks.

[jluckay]

i put a small fan on my ash door. i cut a slot & welded the fan directlly to the door. i did put a sliding pice of sheetmetal between the fan & door as a damper. i did this by grinding a relief on the fan housing befor i weled it on. the air from mine bounces off the removable ash pan & is forced upward. works great for boiling or even getting you fire started.

[maple flats]

Air under the fire speeds the boil but does little to increase efficiency. You will boil somewhat faster but will burn more wood in the process. If you can manage it, install air under and over the fire. This requires high pressure air to create turbulance above the fire. This greatly increases the burn rate and efficiency. High pressure blowers aren't cheap, but I would suggest if you can't afford a high pressure blower this season, install the piping and use a squirrel cage blower for 1 yr which will give some improvement. Then get a HP blower for next to maximize the AOF.

[Pibster]

Would some exhaust pipe filled with holes work for distributing air inside the firebox or would the heat just ruin it?

[Bucket Head]

Yes, the heat will destroy it- unless its wrapped with the high temp. insulation. Search the homemade section and you will see many photos of how air-over manifolds are installed. But if your just looking for a very effective and inexspensive boil enhancer, just put the blower on the ash box so the air is under the grate. You'll be surprised with how much that helps out. I think air-over would be better for a larger rig. Do you have any plans on expanding anytime soon? You might want to think about a larger rig so your ready to go when you add taps in the future. When it comes to sugaring, it really pays off to plan well in advance.

Steve

[maple flats]

The heat would quickly destroy anything short of cast iron or insulated pipe over the fire, but my underfire portion is just a piece of 4" 24 ga stove pipe with 3 rows of 3/8" holes drilled every 2 inches for the depth of the firebox. This piece of pipe has been in for 3 seasons now. Mine enters the rear at floor level and goes forward until 6" from the front. The 3 rows seem to distribute the air well. Realize that I also have a manifold system over the fire and only a small portion of my high pressure air is directed under the fire, far more goes over the fire. High pressure blowers are not high volume. If you will be using a low pressure blower the first year, just design some sort of air flow regulation and experiment.

[seclark]

How would 3" black pipe hold up for a A.O.F. setup,it is a lot thicker than tail pipe plus I have a lot of it hanging around which is also a plus.As far as a blower,I have been using a cheap electric leaf blower with a plain dimmer switch for A.U.F. and so far it has worked.Just wondering what others think or have used.

[smokeyamber]

My current setup uses exhaust piping with holes in it, run under the grates. I did warp the grates last season, but the pips is just fine and looks no worse that before I started. Key thing I think was that the pipe did get buried a bit in ash that protected it and since it was running air most of the time it was kept relatively cool. So my vote for the ultra cheap setup is still exhuast pipe :lol:

[maple flats]

Under the grates is good, over the grates requires protection from the intense heat. Your 3" black pipe will last a good long time under the grates. Heat will not be their eventual destroyer but rather wood ash if not completely removed after the season. The ashes will be caustic and anhydrous. The moisture they attract in the off season will even eat thru 3" black pipe in several years.