water jacket size?

[rdzracing]

I'm building a boiler out popane tanks & was wondering what i should have for space between the outer and inner shell.

 

[rdzracing]

anybody? is this a trade seceret?

 

[taxidermist]

Most users on here dont have OWB so we dont know what size it should. You could ask someone who lives by you for some help if they have built OWB before.

 

[bigburner]

don't think there is any trade secret, the pro's here worry about giving advise because of liability and then there is the gassification crowd that think that the OWB user is a second class wood burner. Me, I like homemade. Use the internet and look threw as many boiler sites as you can, lots of those guys will show cut-a-way etc. Look at the refractory and keeping the fire directly off the water jacket, that allows temps to go higher. Post some pictures.

 

[stee6043]

don't think there is any trade secret, the pro's here worry about giving advise because of liability and then there is the gassification crowd that think that the OWB user is a second class wood burner. Me, I like homemade. Use the internet and look threw as many boiler sites as you can, lots of those guys will show cut-a-way etc. Look at the refractory and keeping the fire directly off the water jacket, that allows temps to go higher. Post some pictures.

Hah. There is nothing second class about a responsible wood burner whether inside, outside or on the moon. I think the vast majority of the users here would agree.

Throw a tire and a bag of garbage in your wood burner....well....that's when you become second class.

 

[jebatty]

Keep in mind that if your fire is in the inner tank which is surrounded by water in the outer tank, the entire firebox is surrounded by a shell that is at a much lower temperature (generally not more than boiling or 212F) than the fire. This works to prevent the fire from getting as hot as it could with a different design (fire separated from the water jacket), and also usually results in significant creosote formation on the walls of the firebox and possibly dripping down, as well as incomplete and inefficient burn due to the low temperature and resulting smoke and creosote up the stack, plus other design related issues. Think through your design very carefully with a goal of maximizing the temperature at which the fire will burn and then extracting that heat to the water. This often is done with fire tubes and sometimes with water tubes, depending on design.

Like most people I know, I admire do-it-yourself and innovative efforts at design. However, the engineering and design of today's efficient wood boilers is getting pretty difficult to beat. I've used both the traditional OWB and now have a gasification boiler. I never would go back to the old style OWB, and although I am quite a do-it-yourself kind of person, I never would attempt to home-build what I would hope to be an efficient wood burning boiler.