Building a Big "Beast"

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allan

Member
Jan 6, 2008
95
EUP of MI
Well, my brother-in-law likes my homemade "garnlike" boiler that I made a couple of years ago which is approximately 3000 gallons so he want to build a bigger one for himself. He has a 7 foot diameter tank by 21 feet long. I think that the tag says it holds 5000 imp gallons. I think we will use 6-inch pipe for the exhaust pipe and a 16-inch pipe for the reaction chamber and maybe a 42-inch pipe for the firebox. I believe that there will be approximately 100 feet of pipe for the heat exchanger. Depending what the exhaust temperature is, we could add a tubulator in the last pass. I'm a little worried about condensation forming in the last pass if I used multiple smaller pipes for the last pass since it is so long. I added one to mine this year and it seemed to reduce the temps at least 100 degrees at the exhaust. Also, I want to maybe build on Tom's idea about bringing in air to the front of the unit in two places for the primary and secondary air. Still thinking about how to do that. I love the simplicity of these units. Any ideas?
 
Sorry, no help from me, you're way past me in the idea dept.from the sound of your project! but some pictures along the way of your build would be cool!
 
a friend of mine has got his hands on a six thousand gallon tank that we were going to cut in half and build two three 3000 gallon units. have you ever thought of using stainless pipe for the heat exchanger/exhaust? i was wondering if would transfer heat faster with less passes? very nice job on your first build by the way.
 
SS might bring up some difficult corrosion issues in an open system.

It sure would be nice to have an easy way to clean the tubes, and/or a swirl design like woodgun uses.
 
Hello Allan, That tank is huge, 7' tank holds 287.9 gal per foot. 21'= 6045.9 gal. what i'm doing with mine is preheating the intake air off of the second pass with a muffler looking box , you could come off there with 2- 4 or 5 " pipes to hit your intake. that sould make the intake air temp around 4-500* you will need a large blower wheel and maybe 2hp. motor. mount your motor on the back and condensation should not be a problem. just my thoughts. these things are awesome !!!


Larry
 
Stainless can corrode.

Do not know if there would be an issue with dissimilar metals.

Perhaps more significant is that it not a very good conductor.
 
big...???? wow 6000....? how much wood do you think it will take to keep it up to temp?say 140.. start 190 finsh..? i would love to see in side pics?
i build a stainless indoor 4 years back and am looking to build a garn typ in the next year ...:)..good luck brent
 
SS can cause galvanic action just like having copper inside of a steel tank can. The pipe is so thin that even SS is a far better conductor than the still water and the soot on the inside of the pipe. All SS units have issues also -beyond my paygrade.
 
Hey guys,

When I was in the process of building mine I too looked at going the ss route. I talked to a local guy that deals in 310 ss which is good for high heat but a 4'x10' 10 gauge was 2300.

Was also looking at using ss well casing for flues. That too was @50/ft- 6". This was 4 ys. ago. Problems= SCC stress corrosion cracking.
 
My boiler was built in 1936, I can't say how many years it was in service or weather it has been re-tubed. when I found it it looked just liked it had had been installed yesterday. Guess my point is ---- It's just big and heavy. I would buy the heaviest gauge tube that I could and not worry about exotic materials. I can speak to SS owning an ICE production facility in my younger days. It is wonderful stuff, but can be your worse nightmare at the same time. Cracking was our issue ans also certain types of acid eat right on threw it. [pin holes]
 
Let a little condensation mix with creosote in a ss chimney liner. Shortens the life dramatically. Been there. Got respect.
 
Thanks for all the comments. I used A53 pipe in mine and when I looked at it after a year, it was identical to when I built it. If you have a good hot fire, it does not build up any creosote in the pipes.
 
EUP of MI said:
Well, my brother-in-law likes my homemade "garn" boiler that I made a couple of years ago which is approximately 3000 gallons so he want to build a bigger one for himself. He has a 7 foot diameter tank by 21 feet long. I think that the tag says it holds 5000 imp gallons. I think we will use 6-inch pipe for the exhaust pipe and a 16-inch pipe for the reaction chamber and maybe a 42-inch pipe for the firebox. I believe that there will be approximately 100 feet of pipe for the heat exchanger. Depending what the exhaust temperature is, we could add a tubulator in the last pass. I'm a little worried about condensation forming in the last pass if I used multiple smaller pipes for the last pass since it is so long. I added one to mine this year and it seemed to reduce the temps at least 100 degrees at the exhaust. Also, I want to maybe build on Tom's idea about bringing in air to the front of the unit in two places for the primary and secondary air. Still thinking about how to do that. I love the simplicity of these units. Any ideas?
Owning a garn 2000 and wishing it had more storage I can't wait to see the pictures of this build.
 
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