air-o-lite window restoration

[rdg51]

I have checked the archives and do not see many posts on this topic. If there is one, kindly refer me to it.

I have a 48 Spartanette with Air-o-lite windows. They had a mitered corner which appears to have been soldered on the inside after the window was installed.
How do I reproduce this?

If welded or soldered (the new stuff for low temp alu repair is 350degrees) after seals and glass are in would the seal not melt?
If done first, won't it be impossible to get glass in with seal seated on three fixed sides?

I am waiting for a sample of the VTS repro seal, but I suspect from comments here that it is not a perfect replacement. Any ideas on how to make it work well would be appreciated.
Thanks
Rob

[tintent]

Use J-B Weld.