View Single Post
  #2  
Old 02-10-2020, 04:07 PM
crystallographic crystallographic is offline
MetalShaper of the Month October '14 , April '16, July 2020, Jan 2023
 
Join Date: Dec 2010
Location: Western Sierra Nevadas, Badger Hill, CA
Posts: 4,390
Default

Quote:
Originally Posted by sandmanred View Post
Starting design on a new motorcycle gas tank. I want to make more or less this shape. I want the outer ridges but I might suppress the ridge down the middle a bit. I've got basic hammers, dollies, stump, sandbags and e-wheel to work with. Looking for thoughts on where to run the seams on this part of the tank?

This image show most of tank, the portion that's out of sight will mostly be open tunnel. The ridges will smooth to almost nothing at the tunnel opening.


If I were in my first year of metalwork, I would make it from 3 pcs, left center, right, and use the two "shoulders" as my seams, putting them on top, but making sure that the part edges were rounded a little bit to meet, so the weld was not on a sharp, but on a little rounded surface. (gives more support against distortion whilst tacking)
With more experience in shaping and having a way to work your 3 peaks evenly, I would make in two halves and weld along the center. Far too laborious with hand tools, though, so doing the 3-piece would be plenty enough work.
__________________
Kent

http://www.tinmantech.com

"All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919.
Reply With Quote