Just to put the record staight here.
1. These were not poorly built !! All Dyna-tech frames were hand built by Raleigh Special Products Division.
2. The damage seen in the picture is a result of the chain dropping and jamming between the chainset and the chainstay, a fault of poor gear adjustment, not poor materials or manufacturing.
3. These frames were not brazed or welded, but bonded with special high temperature adhesive used in the areospace industry. Any attempt at using heat on the chainstay joint will result in destroying the bond of all tubes into the bb shell.
I am the Bikemeister
Just to bend the record slightly:
1: A common failure on these frames was the tubes separating from the lugs. A result of the bonding technique used not quite being the best.
I am not the Bikemeister, but I do remember this happening to the frames of a few friends BITD. That to me would suggest something being badly built or a technique being badly researched - or the wrong materials being used.
2: If that happened whenever a case of chain suck occurred I would have no frames left.
3: See 1 above. Don't think heat is the enemy here. Whether the adhesive used was developed for the aerospace industry seems slightly irrelevant TBH - just sales blurb.
I'm sure if the frame was taken a mile above the ground and flown at 700mph in an outside temperature of -50º it'd be fine - but that's not what it was built to do...
Anyway, sorry to see that Russell - good look searching a replacement!