Welding/Structural Question

[drg]

I'm looking at J4500s to purchase.

Is there any way to inspect these welds without disassembling the interior ?

Yes, here's one way, but I'd say that it's pretty uncommonly done outside of very critical, high load areas such as aircraft wing support structure or engine mounts.
The procedure would also add to the cost of the project.

https://unixray.com/radiographic-inspection-of-welds/

[luvrbus]

Those were added for flexing ,it was cheaper than buying the flex bar that runs the length of the bus 45 ft long buses flex a lot fwiw ,I had the 3 inch  solid flex bar under the bays you can find all the recalls and service bulletins on the DOT report for that bus and there are a lot of them