Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers with NON EPA-Certified Models Only => Home Made => Topic started by: beeman on September 02, 2011, 08:30:51 PM
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still building stove getting closer though i would try some pic . please be nice it is based from shaver desine allmost all is from salvage thanks for all the help
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that is so cool ;D have to try another
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one more mind you learning to weld is easer than this comp stuf :bash: but cant stay in the old days good to learn
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if we have a winter like the last one the stove will be grand , snowed in for 3 days
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Looking good!
Did you space your burn chamber up from the bottom of the water jacket so water can flow all around?
Have you checked for water leaks inside the burn chamber and on the outside tank seams?
I put about 5 to 8 PSI of air on mine and then sprayed all the seems with concetrated window cleaner.Worked like a charm :thumbup:
Keep up the good work
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That looks great beeman. I got my first one together(OWB) 5 years ago and leak tested it by putting 10 psi air to it and letting it set all night. It's the only one so far that had no leaks. I've built a couple since then and haven't been so lucky. My gasser I'm building (been a work in very slow progress for 5 months) I filled with water, plugged everything off, then turned the water back on (I think around 45psi or so) and found 2 leaks that did not show up with the air test.
What diameter combustion chamber do you have and how long?
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built my homemade out of propane tanks 2 years ago....
tested mine to 60 psi air...then checked with soap and for bubles ,all good left overnight to be sure all good .sprayed all welds with black antirust paint and played around with the air that was in the tank (tried shooting stuff,that thing hold a LOT of air).
hard to check for leaks with water in the summer because condensation unless your patient or filling it with warm water.
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built my homemade out of propane tanks 2 years ago....
tested mine to 60 psi air...then checked with soap and for bubles ,all good left overnight to be sure all good .sprayed all welds with black antirust paint and played around with the air that was in the tank (tried shooting stuff,that thing hold a LOT of air).
hard to check for leaks with water in the summer because condensation unless your patient or filling it with warm water.
60psi? Homemade tank, remind me to stay wayyyyyyyy the heck away the next time you try that!
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mober if you were testing your tank with that much air, i hope both ends of your stove were "belled" ends if you had a square end on one end you sure put a lot of strain on the weld..way more than you likely should have
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mober if you were testing your tank with that much air, i hope both ends of your stove were "belled" ends if you had a square end on one end you sure put a lot of strain on the weld..way more than you likely should have
if he didn't he's lucky to be posting here... That's a lot of psi
im like the others i wouldn't go over 8-10
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have done some pipe welding before so i had the guts to do it....
3 passes and it was all good ....
my first plan was to make it pressurized boiler thats why i tested it higher...
bought the expansion tank pressure relief valve make up water automatic water fill air seperator ...
the whole shabang for pressuirized boiler but after reading a lot on this site i decided the pros for pressurized is not worth it since non pressurized works just fine.
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built my homemade out of propane tanks 2 years ago....
tested mine to 60 psi air...then checked with soap and for bubles ,all good left overnight to be sure all good .sprayed all welds with black antirust paint and played around with the air that was in the tank (tried shooting stuff,that thing hold a LOT of air).
hard to check for leaks with water in the summer because condensation unless your patient or filling it with warm water.
The company that sells steel 100 gallon fuel transfer tanks at TSC(4 years ago) pressure tests their tanks for leaks @ 50 psi. Their burst pressure is much higher than that. If my memory is correct, those tanks were only 10 gauge. I've built make shift accumulators(air over oil) for a silage defacer out of quarter inch square tube that runs at 2750 psi, and they are still working fine after 8 years. 60 psi wouldn't scare me at all if I welded it, but it might make me a little nervous not knowing who welded it and how they did it. I like pressure testing with water and compressed air. If the tank is full of pressurized water (45 psi), you will find any and all leaks. Using compressed air on all moist seams will pinpoint the leak, then you mark it, grind it, weld it, and then refill and retest.
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you built someting out of 4 inch square tube and pressurized it with a flat end on it?..ok that flat end was only 4 inches square now take that flat end and put it on a 36 inch pipe. that pressure is now trying to equalize over a much bigger and weaker area, you are looking for trouble. i will give you the benifit of the doubt (because i don't know you) and say your welds are good and strong enough to pull the ash can right up from hell but if that big flat surface starts to yeild and push outwards in the center, your weld on the flat edge could very well tear from teh direction the metal is going to try and go no matter if it was 3 passes or ten. you ever look at a blank flange on a pipe (you know, the flat end that bolts on) they are usually 4 times thicker than the pipe itself, there is a reason.
take a look at one of them portable air tanks, they are safe to use at over 100 pounds PSI (and likely tested at 5 times that) and are about 1/8 of an inch thick...now you build one the same size and thickness and weld in flat ends, fill it with water and then add air and see how many psi you get in it before the ends buckle or you have complete failure...i would bet (hell i know!) it will be way before 100 psi
flat ends on a pressure vessel are a NO NO and any OWB being tested should be tested with air over water
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All I know is that a 30 gallon steel drum can't take more than about 10PSI. ;D The bottom bulged out and it rolled over on it's side. Much more and the bottom would have blown right off.
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general rule of thumb is if you use a flat end on a pressure vessel it will have about 30 percent more force on the flat end than on the pipe itself...yes the presusre is the same (50lb psi is 50lb psi) but it accumulates on the flat surface. think of a hydraulic cylinder with a bore of say 3 inches..add 1000 psi and it may lift 3 or 4 tons now take a cylinder with a 10 inch bore and the same 1000psi and it may lift 100 tons..same pressure but more square inches to push on...when you test your OWB ith a flat end on it you are essentually pushing on the flat end the same as a hydraulic cylinder...the bigger the bore the more pressure you exert on the flat surface. that is why your oil barrel bulged (failed) and an OWB with a flat end will burst or warp long before the same rounded side walls will give way
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I agree with Willie whole heartedly.You don't want to over pressurize a flat sided tank with to much psi.I charged my tank with 8 to 10 psi.I accidentally got her up to 15psi as i was looking at something else ,and my sides popped out ,and scared the crap out of me. ;)
I welded reiforments from the tank side to the burn chamber,and if i hadn't done that I am sure my 5' long flat side would have ended up bell shaped.
5 to 10 psi is more than sufficient to check for leaks.At the pressure you will hear the metal still try and move from the stress.
Unless you are an experianced pipe,and or steam fitter and know hydraulic pricipals of tanks.Then built it as such I would stick with a lower psi to check it.We sure would hate to hear how you launched your wood burner across the yard. :thumbup: (ok not really that far but you get the point)
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general rule of thumb is if you use a flat end on a pressure vessel it will have about 30 percent more force on the flat end than on the pipe itself...yes the presusre is the same (50lb psi is 50lb psi) but it accumulates on the flat surface. think of a hydraulic cylinder with a bore of say 3 inches..add 1000 psi and it may lift 3 or 4 tons now take a cylinder with a 10 inch bore and the same 1000psi and it may lift 100 tons..same pressure but more square inches to push on...when you test your OWB ith a flat end on it you are essentually pushing on the flat end the same as a hydraulic cylinder...the bigger the bore the more pressure you exert on the flat surface. that is why your oil barrel bulged (failed) and an OWB with a flat end will burst or warp long before the same rounded side walls will give way
3"=3.53 tons
4"=6.28 tons
10"=39.27 tons
Pressure will not accumulate or build up more on the flat ends of a cylinder. Because of its inherent design, the metal on the ends will move more, and because of the stress associated with that movement it will fail first.
With all the respect that's due to you Willie, I don't buy into your rule of thumb(30%?) for flat ended pressure vessels. The force will be equal over every square inch of the inside of the vessel.
Speak to a metallurgist as I have. 36" ductile iron well pipe @ .375 wall thickness with virgin .375 ends welded properly(two passes inside and out) with 80000 tensile strength wire will barely move(ends) at 45 psi. You will be shocked at the pressure it will take before the ends eventually fail.
I agree with you all about low pressures being used for open systems to check for leaks. Every winter I do many fabricating projects, including building power units,manure pumps, booster pumps,manure applicators,knife-in applicators, etc. I understand what metal is capable of, and more importantly what it is not capable of.
A portable air tank(.125 wall thickness) with a flat end(.125) properly welded on will not fail at 100 psi. That is fact.
The flat end of the 4" square pipe measured 3.5" square(I.D. of 4" is 3.5).
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marty, i am sure you know more of metal and what it may do or not do than i and i am in no position to argue with you about more pressure on the end of the vessle. perhaps i should say that the flat end of a vessel will take 30% less force than the rounded ends (and this may still be wrong) but i do know that a flat ended vessel of any kind can not take the same pressure as one with cylinderal ends unless the flat end is made stronger with bracing or perhaps thicker flat ends and heavier welds
they make pressure vessels this way as it is the cheapest because there is no need to strengthen the ends to take the stress of the metal trying to push round to make "all things equal"
i dont know much about metelurgist stuff but i do notice that when i work in the chemical plants and they bolt a blank flange on a pipe (no matter what size the pipe) the blank flange is always way thicker than the pipe wall. the flanges are reated for certain max. pressures like 150...300..and upwards, each being thicker as the rating goes up. i will agree that if your man told you after welding your flat end on the well pipe and it would (i belive he said) "barely move" than i would agree with him. but where i work if it "barely moves" it will eventually fail.
a lot of folks here that build their own OWB come here for pointers and help and like to read many other posts and a lot of them (you may not be included here) are "back yard welders" that are self taught and hit their welds with a hammer to test them not xray or bend test them as you and i may do. so with that in mind i personally will never tell a guy to pressure test his stove with air (unless he first filled it with water) and i would never suggest any pressure over a 8 or 10 pounds as that should show up any leaks in a 24 hour test period.
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Willie-
You and I are on the same page where testing procedures are concerned for leak checking an open system home built OWB. 'Nuff said.
Marty
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Yea as Willie said, 60 psi isn't comparable to some things, but a lot of folks who come on here are "back yard welders" to make them think it's safe to run psi that high is misleading, there is a huge difference in someone who understands welding and someone who says, "yea I can weld, I welded in
shop class in highshool" lol
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agree