If you have been waiting, well here it is. Part II to the drain 'tank' rust repair.
I left off with the removal of the existing rusty metal. This piece, which acts as a 'drip rail' to keep moisture from the fan and fresh air vents. It had to be removed to get access to the bad metal. Here it is removed on the VM welding bench.
Once the old rusty metal is removed, take a pattern off the existing piece(s) using cardbboard. If the old sheetmetal overlaps, try to drill out the spotwelds. When you install the new metal, [like you see here] it should be installed in the same way it was taken out.
After the new sheetmetal has been installed, the firewall had to be patterned and installed.
Here you can see the piece being installed. When welding, be sure to weld in short runs. This will limit the warping. You can see each run from each of the heat marks. Of Course, during the install, I did hammer and dolly the weld seams to keep the metal straight.
Now the piece is installed. I did not weld in the holes to show you. After welded in, it will give the effect of a spot-weld like original.
Install your old driprail if its usable. I opted to weld in the larger holes. Since you wont see the piece, asthetics wasnt a worry for me. When this piece is installed as you see it, each seam will need to be sealed so water/moisture wont pass through to the fan and fresh air vent. If done properly, it should work as new.
Now that all the pieces are back in place, coat the inside with POR-15 to seal it tightly from moisture and remove the thread of rust in the future. This will add another 10 - 15 years to your Chevy.
Let the POR-15 dry, then replace the outer tank skin. Good as new.
I did find a replacement skin from Danchuck, but each side was $175.00 each. Pricey. Total cost of this work; $20 worth of 18 ga. sheetmetal, and about 8 total hours to complete.
Now get out there and build!