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[kjw58]

Just wondering what you guys feel is the best type of steel to use for the fire box and water jacket for a  owb ?  Is mild steel the best ?  And at least 1/4"  thick  ?  How about the best welding process,  stick,  mig  ?   Any suggestions  ?   Thanks

[willieG]

i used stick on mile steel..thats what i have to work with on heavier metal...my pipes are 3/8 to almost 1/2 inch and at thetime i built mine i hade to work in position as it got heavier. Stick i am good at, i have weldedi n teh field for over 39 years

i have good stick welders..high amps and long duty cycles..for me there was no choice

there have been many  arguments about stainless steel..many for andmany against, i used mild steel..my reasons were cost..availability, and of all the boilers i have seen in old farm housed right up to chemical plants i work in...they are all boiler plate (hence the name) and lined with refractory and or fire brick

plus..i figured if i had to crawl in there and weld up a patch, i got lots of mild steel around..so far i haven't had to make any and this is winter 9

use the welding procedure you like the best..but make sure if you  mig it you have a machine that can pour the heat and penatration and a long duty cycle

when i welded mine i used a 200 amp portable. my next one i will be building in my shop i have a 600 amp 3 phase bullet in there. (electricity is cheaper than gas)   and i have an overhead crane so i can keep all my welds flat for speed

good luck with your project
kwwp ua poatwed on progress

[kjw58]

Hey  thanks for the reply Willie
 I to have heard the stories about steel or stainless and I am thinking mild steel is the way to go!  I to am more comforitable welding with a stick welder,  I have a portable Miller Big 40 that runs great and I have a overhead crane in my shop.  I'm just try to get some feedback from some guys who have already tackled building a owb.  This web site is great,  the wealth of information on here is unbelievable. thanks again

[rosewood]

 kjw58 ,steel is by far the best heat transfer for a firebox, stainless is to unpredictable, will crack from sudden temp changes.high heat,cold return water. i used stainless jacket''304 grade'' and steel firebox . stainless for jacket has its benefits, rust #1, cleaner water, no build up of minerals. down side ..cost  whatever you decide, get as thick as you can on firebox, and water jacket if you go with steel.  and go big on water capacity!

[rosewood]

 as far as welder, if u can weld stick good, u can weld with a mig even better ! took me 4 water leak tests on firebox to jacket, with stick and 1 pass to water tight on tank with mig.  much cleaner welds and alot faster. if you have access to mig than get it ,youll be happier!