FBinNY 

Here's a catch-22 to think about.

If you had simply started a new thread describing your problem, you would have received multiple answers, possibly linking back to this thread.

However, having found and resurrected the thread, one must wonder if you had bothered to read through it before rudely asking folks to redo what's already been done.

That said, if you have a similar, but alightly different problem that wasn't addressed here, feel free to ask.

Duragrouch

Well said. Firm, educational, but not rude, well done.

I liked your comments in post #6. People just don't know how rims used to be put together. The cheapie aluminum rims on my early '00s Dahon, have the exact same line, exactly opposite the valve hole, as it should be. But it just occured to me, that these are single wall, so no double wall for an insert to tie the two parts together. I'll have to take a close look next time the tire is off, my guess is it's welded and smoothed on the inside, and come to think of it, was probably the same on the outside, but brake wear (getting significant on these old wheels) probably wore the outside weld away. Food for thought. I'm babying the rims, using just the rear brake more, but the end of life for these is within sight.

I enjoy your posts and knowledge.

FBinNY 

These cannot be welded, since you can't weld a rim leaving a bead on the brake track.

Actually, aluminum rims are typically welded without adding material. The hoop is formed slightly overlong, then the joint area is heated and compressed together, simultaniously fusing the joint and bringing the rim to size. Excess metal flows to the side, and ground or machined smooth later.

If the rim has a visible joint, it's hollow someplace to accept 2 pins in the corners that form tire seats, or with a strip in the "false bottom".

Duragrouch

The weld process you describe sounds very much like welding a bandsaw blade; A good bandsaw like a DoAll typically had a welder on it, and a tiny grinding wheel for finishing it.

A technology of recent decades is "stir friction welding", IIRC, used on the recent VLJs, Very Light Jets, private and commercial jets smaller than the original Learjet 23. This results in a high-strength weld, without a detrimental heat affected zone. I have no clue if this has been applied to bike rims, but it would be a good application.

I'll look for those pins or strip inside the rims. But I don't recall, and there is no telltale spot weld or staking on the outside. I vaguely recall on my rims on other bikes of higher quality, seeing the outside sidewall area, that if I looked close, appeared to have been "dressed" after a weld of some sort, just the tiniest bit imperfect flatness versus the rest of the rim. Not these cheap rims, they have that part-line all the way across on the outside. But there's gotta be something holding the pieces in alignment. I'll look next time I have a flat.