Thanks Wayne
Have you seen any discernable difference in gas production between the slightly different diameter fire tubes? Or have you experimented with fire tube thickness? I just sent you a pm before I saw you had posted here. I have access to a 11" pipe 1/2" thick and was wondering if that would work for a fire tube in the toyota
Good morning Marcus.
In most cases when I build something it is not what may be best but what I have available to me.
I think a 11 inch diameter pipe would work out OK by tuning the unit with the proper choke plate .
1/2 inch pipe is heavy and I can’t give much advise on that . The heaviest I have used is 1/4 inch and I think most of the time 3/16 inch ,
A 1/2 inch fire tube will serve as and give somewhat of a flywheel effect but may be too much . It will take longer to get fired up and running .
The expansion rate for 1/2 inch material is going to be a lot different than the materials that are welded to it so not sure how it will affect welds .
3 /16 x 12 inch pipe seems to be fairly common and can easily be cut down to whatever diameter you want .
Well I’ll keep looking. I don’t want to deviate from the recipe to far on a first build till I have the basics down and learn the system and how to operate it
Marcus, Around here sign companies have a lot of bits of pipe usually 12" diameter and 3/16" wall. Some of the guys on the forum or in-person thought that 3/16" worked well for them. The only comment I remember was that they thought it might take a couple of minutes more to come up to temperature. I don’t recall anyone trying to use 1/2" wall pipe.
I have some lengths of bridge piling here in Michigan. This is spiral welded pipe formed from flat coil stock and rolled into a helix and welded. There is a weld bead on the outside so there is some fitting involved for welding fins to it. I’m not certain of the diameter. I can check if there is interest.
I thank you very much for the offer, I found a piece to work with and started a build thread 
