Hood question

[Adkandy]

I'm building a steam hood for my 2x6.It will sit flush on rear pan but I want it cantilevered over front pan.I only have 1 hole in my roof too exhaust the steam.Ive seen pics of these hoodsets with just 1 exhaust in rear section.My question is how big of a hole between front and rear section?I'm afraid if I cut it too big I'll get steam blowing out of rear section into front?Any thoughts are appreciated.

[maple flats]

Just a guess but I'd think about 1/4 of the steam going up the steam stack would be from the syrup pan. Figure the area of that stack divide by 4 and make an opening between them that size. (3.14 x radius squared). However on all 3 hoods I made there was no partition between the front and pack, the partition ended at the bottom of the front hood. That worked good too. My current hood (factory made) is 2 parts, a 3x5 flue hood and a 3x3 syrup hood, they are bolted together and do have a full partition on both, but I then have 2 steam stacks of 15" each.

[Haynes Forest Products]

You need some structure to keep the hood strong. Like Maple Flats my home builds were open as much as possible from the syrup/finish pans into the flue pan are where my stack is. Getting the water vapor to evacuate your shack in an orderly fashion is like herding cats. There are so many variables and I think that once your rig is up to running temps and your incoming air is regulated your hood will be at its best.
Once you get a good hot hood and the steam is causing a natural draft and you replace the exiting air with some open windows you will be happy. once my rig is up and running I can take all 4 of my access panels off and you can see the clear air rushing in and up the steam stack.

[Sugarmaker]

adk,
Are you going to put a preheater in the rear hood? if so I would suggest two hoods. Make the front one 16 inches wide by 16 inches long (assuming your front pan is 24 inches sq?) and set it towards the back, center of your front pan. Right down on the pan! Use a 6 inch stack for that one. You wont have any steam in your sugarhouse, and you can then build a preheater for your back pan and gain 15% production rate, plus be able to add a damper to control that rear hood steam flow.
Cantilevered hoods are pretty much just for show. and generally less than 50% effective, IMO.
Regards,
Chris

[Adkandy]

I will be adding a preheater,the 2 hoods will be attached,I just wanted the front raised up so I can keep a close eye what's going on,this is my first 2 pan rig so it's new too me,I previously had a continuous flow flat pan.This is a drop flue 2x6.Ive already got rear hood almost done.Is that why your saying build front one 16 in wide so you can see around the edges?Thanks for help,I appreciate it.

[Haynes Forest Products]

my back syrup hood is very functional without it itys foggy. Now once again it only works when the rig and shack are warm. I have hinged side curtains that flip down and contain the pan area when its cold. The smaller the hjood the better your preheater will work. people make the mistake of looking in the pan and commenting that "there ain't much steam in the hood. and then I pointed out that when it goes from clear to white fog is the real heat zone.

I will admit that my confidence level is very low so I'm always walking the entire operation lifting covers checking valves and if I can glance over the edge and see the different syrup pan levels and colors I know things are OK.

[Wanabe1972]

This is my first attempt to build a hood and preheater. I just needs the stack thimble and LEDs installed in the front hood a drill the front channel so the condensate can get out.17488

[maple flats]

Looks good. A damper in the flue hood is important when you have a pre-heater in the hood, then adjust the damper so steam just starts to escape the seams and loose fit spots, and leave it there, that will give you the best performance from the pre-heater.

[Sugarmaker]

I will be adding a preheater,the 2 hoods will be attached,I just wanted the front raised up so I can keep a close eye what's going on,this is my first 2 pan rig so it's new too me,I previously had a continuous flow flat pan.This is a drop flue 2x6.Ive already got rear hood almost done.Is that why your saying build front one 16 in wide so you can see around the edges?Thanks for help,I appreciate it.

Yes then you can then see into all front compartments with the smaller front hood, which I think is important. But it will draw out all the steam from that pan.
Regards,
Chris

[Adkandy]

Thanks alot for the pointers everyone it's much appreciated.

[Haynes Forest Products]

Dave Maple Flats
Putting a dampener in the steam hood will get you more heat to the pre heater but wont it cause less or slower evaporation because of the increase in Barometric pressure. I was under the impression that lower temps on the surface allows for the water molecules to leave the liquid faster. If I'm rights isn't there a trade off.

[maple flats]

No, that is the normal practice. The damper will not have the ability to create a pressure buildup, so you gain boil by putting hotter sap or concentrate into the inlet float box while losing no boil due to back pressure. Doing the back damper in the hood will give you a bigger gain than if you don't have a damper. Now, if you were actually able to creat a pressure buildup in the hood, there might be a slight loss of evaporation, but no hoods fit tight enough to do that.

[Haynes Forest Products]

Thanks I have never seen a dampener used on the steam hood but that's because I hang around a bunch of Cheese heads.

[Wanabe1972]

Does anyone have a suggestion for inexpensive lights I can use in my hoods? My electrician friend told me the one I was going to use won't work. Thanks Jeff

[mol1jb]

I would think a LED rated for a bathroom install would have the best chance for success

[Haynes Forest Products]

First it needs to withstand the heat. The lens needs to be high heat glass or plastic. The light fixture, bulb, socket and housing will be on the outside so moisture isn't that big of a deal. In reality one of the driest places in my shack is on the hood. You want to dry your gloves put them on my finish pan hood. Cut a hole in the hood and plop a shop light over the hole.

[Cjadamec]

I would suggest either these lights from amazon (https://www.amazon.com/gp/product/B01MZ9TDGX/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1)or

these lights from bees lighting. (https://beeslighting.com/maxlite-led-cooler-light/p/RL-4818U-40)

I have 3 of the ones from amazon in the picture below.

[BRL]

I am going to try these in my hood. I think someone on here has tried them.
https://www.amazon.com/Strip-light-Waterproof-Flexible-White/dp/B00DUSL78I

[Wanabe1972]

I have several shop lights already so I will try this. I just hate to cut another hole inthe hood but I guess if I want light I'll have to cut. I tried those waterproof strip LEDs on another project and found the ones I used were not nearly as water proof as they claimed. Thanks for the input from all. Jeff