Now with the two halves trimmed and shaped correctly, we smoothed out the crown where the two meet up, to make a nice weld joint.
We made a filler strip to go underneath the seam- this serves two purposes: first, it absorbs heat, which is very important when welding aluminum sheet. Second, it distributes the stress when you weld it to each half from the underside, so that your seam down the center doesn't have to absorb all the stress and vibration.
strip tacked to one half, then the tacks were ground down so that the second half could mate up flush with the this one- you don't want a gap down the center to fill in.
Welding the top seam
Done- in retrospect, we should have taken the few hours to metal finish all the shrinker marks on each half, because now it will take TWICE as long to finish them without disturbing the weld. It may just need to be ground down flush, we are not sure yet.....
A little more shrinking to add some curve to the lower tank edge, along the main "bulge" on each side.
BAM! We also took a few minutes to add the nice detail of a tank badge recess, by using a metal hammer form and just pounding it in with a plastic mallet, no wizardry involved!
On the bike- you can see the shrinker marks more clearly here, not a big deal, just will take a lot of filing and wet sanding, because we intend to go for a mirror finish on these pieces.
Starting the tunnel.......