How to Lay out and square-cut a 24 inch Propane Tank

[SeenRed]

I need some advice from more experienced fabricators than I...

I'm trying to build a 24" x 46.5" RF patio smoker, with a square FB (I already purchased a set of Frank's plans to fit this build) out of a propane tank I picked up cheap. The tank is 24" diameter by almost 11 feet long - more than enough to build 2 patio smokers with these dimensions - and if the 1st build goes well, I plan on doing it again with the other end of the tank.

What I haven't figure out how to do yet: how to measure, mark out, and square-cut the tank on the FB end. The opposite end of the tank is bell shaped, and I don't know for sure how to get it measured and laid out accurately, and then make the cut on my mark so that the FB end is nice and square.

The tools at my disposal for this task are: All the common shop measuring and layout gear (rulers and tapes, chalk lines, levels, carpenter's squares, combination squares, speed squares, etc.); angle grinders w/ cutoff wheels; sawzall w/ metal cutting blades; 50 amp Chinese plasma cutter (the thickness of the tank is 1/4", which is near the limit of this plasma cutter's capability).

FYI, I have already safely flushed the tank out, and have rough-cut it in half, so propane tank safety is not my issue.

I'd really appreciate insight from any of you who have done this...thanks in advance!

Red

[hogaboomer]

You can use a wrap around, or a contour marker. They show both in this video:

[Dirtytires]

Lay a carpenter square over the bell and an mark the tank at a random length, let's say 12 inches. Do this for at least 4-8 points around the diameter of the tank. You can then use these points as a standard starting point to find the center of your tank. Once you felt the center marked, connect the dots around the tank with a piece of masking tape and use that as your cut line.

It doesn't have to be perfectly cut as your weld dad will cover much of the error, if needed.

[SeenRed]

Lay a carpenter square over the bell and an mark the tank at a random length, let's say 12 inches. Do this for at least 4-8 points around the diameter of the tank. You can then use these points as a standard starting point to find the center of your tank. Once you felt the center marked, connect the dots around the tank with a piece of masking tape and use that as your cut line.

It doesn't have to be perfectly cut as your weld dad will cover much of the error, if needed.

There it is! I knew there must be a fairly simple method of doing it…seems obvious now that someone explains it. Thanks brother, that’s just what I needed.

Red

[Barrion2018]

Thanks for sharing the info/video hogaboomer!

Being brandnew to this, I have very limited tools. Not saying I'm going to order everything in the video, but I did see 2 or 3 tools I would like to get to make my life easier.

Thanks again!

[SeenRed]

You can use a wrap around, or a contour marker. They show both in this video:

Not sure why, but I don’t see the video…

Could you repost a link? Sounds like a videos I ought to see.

Thanks!

Red

[hogaboomer]

Sure, here you go.


https://www.youtube.com/watch?v=QolQsRcS0WM

[SeenRed]

Sure, here you go.


https://www.youtube.com/watch?v=QolQsRcS0WM

Thanks! Some cool tools in that vid.