Need Evaporator Design Help

[NDB]

Our barrel stove arch burned through after 6 years of use. So, I need to build a new arch.

We have less than 30 taps, but they produce well, so we are looking at a 2’x3” pan which should cook off at least twice as fast as our previous pan. My wife wants a flat plate for pre-heating sap, heating water for tea/coffee/hot chocolate. We’re also thinking of two pans instead of one ; a 1’x2’ finishing pan and a 2’x2’ boiling pan. The reason for going with the smaller finishing pan is that my wife occasionally is the one to finish and she can’t lift a larger pan off the evaporator.

I’d like to build an angle iron frame arch with a hotplate at the front of the arch and then a 2-3” step between the finishing pan in front and the flat boiling pan in back. I’d like to do this so I can gravity feed from the boiling pan to the finishing pan as necessary. What are the pros and cons of having a stepped arch? We’ve typically only had enough sap to do batches that finish with 1-1 ½ gallons of syrup, because we don’t collect enough sap to keep an inch of sap in the bottom of a pan much larger than a 2x3” flat pan. With the stepped arch, my thinking is that I can fill the finishing pan from the boiling pan as I add water to the boiling pan to keep it from scorching. That’s my thought anyway. Will that work? My wife’s not too keen on adding water to a pan that we just spent hours boiling all the water away, but is that the way others finish with a larger pan?

I was thinking of getting a glass front door from an old wood stove at a junk yard for the doors to the arch. Will that work on an arch? Does it get too hot for that much glass? Would I be better off making my own door and putting a smaller glass in it? What’s an ideal door size? I could use the Vogelzang door from my old evaporator but it’s smaller than I’d like.

I could run the stack straight out the top of my arch but wondered if I should make a base stack to transition to the planned 8” stack. Any ideas? If I go with the base stack, what gauge steel should I use considering this is the hottest area of the arch?

Should I make a 45° ramp from the firebox to the area under the back pan (as shown), taper to the stack or just make it go straight back? Which will do a better job getting heat to the pans, especially since my arch isn’t going to be very long?

Thanks for your help.
Neil