Make Your Own Low Cost Evaporator-- part two

OK, back to the evaporator. You will use the fuel tank to make a firebox. I used one thats vertical. Cut the top half or third off with a torch or a metal cutting blade for your circular saw. Pull it out away from the buildings and burn off any left over fuel oil that's in it. Now that the top of the tank is open you can weld the angle iron around the inside of the tank making a lip for the pan to sit on. Also weld angle iron across the little frame you just made. Put it flat side up and tack it to the bottom of the frame. This will give the pan extra support when full of sap. Cut a door in the front. Weld a frame around the hole with angle iron. You can weld hinges to the door and add a simple latch, if you want. Now flip the tank upside down and cut 3, 3 inch by 3 inch square holes in the bottom. Save the pieces you cut out. Weld a couple of short pipe pieces, an inch long or so, to both ends of the tank. Make sure the pipe is the right size to firmly hold the rebar you found and let it slide back and forth. Heat and bend a 90* angle at the end of the rebar for a handle. Slide it through the pipes. Now weld the pieces you cut out onto the refer. Weld them so that when the rebar is pushed all the way back the holes are covered up and when it is pulled out the holes are open. This will be your draft control. On the end opposite the door cut a hole for 6 inch stove pipe. We found a steel collar with a 6 inch inside diameter and welded it over the hole. Next find a fire grate. You can make one out of the left over angle stock if you have any. Then line the inside with fire bricks. The bottom row can sit on the edge of the grate and just stack them up. Now for the pan. You will need to buy the stainless steel sheet from a machine shop or something. I got mine from a friend who worked a machine shop. I think it cost about $150-200, but it was several years ago. Always make the pan LAST. You will need to make it to fit the frame you made on the top of the tank. Depending what you scrounged up, every one will be different. Measure what the pan needs to be. Take the steel to a metal fabrication shop. They will bend, cut and weld it up for $50 or so. Have them cut a hole in the front right corner towards the bottom and weld in a treaded collar. You will put a gas valve here to draw off the syrup. We also welded to steel handles at the back of the pan so it can be drained better. I think the pan will be 3x5 or so when your done. It should be 3 inches or so high. You want to remeber when making the frame that it sets on, that the pan should sit 3/4 to 1 inch down itnto the firebox. We have a gravity tank feeding our pan. It has a valve that we control the flow to equal the amount boiling off. The first year we let in the pan cold. The back third of the pan would never boil. We realized that we were losing a lot of heat up the stove pipe. We got some 3/4 inch copper tubing and coiled it around the stove pipe all the way down to the pan. We added a brass valve with a compression fitting near the pan and a threaded end at the top. Then we had the sap flowing through the hose into the copper and coming into the pan hot. Now the whole pan boils front to back and it saves a lot of time.

I'm sure I made this sound more confusing than it is. If you have any questions feel free to ask.