Raleigh SBDU 753 fillet brazed frame Super Rare

I see that this incredibly rare SBDU 753 frame is up for auction again. I did consider bidding on this last time it was for sale...it would have been a superb addition to my collection. All of the details and information about the frame is correct and I'm happy that it's a genuine SBDU frame even though it doesn't have an SB prefix frame number.Many SBDU frames didn't have an SB prefix number though other marks and frame details can confirm authentication. I had requested more information and photos about the frame from the seller which I am more than happy that it's a genuine SBDU...it is a stunning and very rare frame which would build into a beautiful Time Trial machine.
Unfortunately the the seller confirmed my suspicion about the frame which has basically rendered it useless..it has been POWDER COATED....OH DEAR...

https://rover.ebay.com/rover/0/0/0?mpre ... 4311693945

What's wrong with the frame being powdercoated?

In other news £30 for a Huret Eco rear mech WTF we used to have bags full of those in the shop

Because Reynolds 753 is a heat treated tube it has to be brazed at much lower temperature using a high silver content filler rod. Also as it is of Lugless construction so save the additional weight of lugs so it is weaker than lugged 753 frame, relying solely upon the filler material plus some small gussets at the headstock for strength. This type of 753 fillet brazed frame was only really suitable for smooth time trial riders.
The seller has ruined an incredibly rare frame constructed at a lower temperature and then had it placed into a high temperature Powder Coat oven..
A Recipe for Disaster...I have seen first hand the damage to a frame that had been repaired using silver content filler and then powder coated... it was not a pretty sight.
If i was to buy this frame I would like to ride it in anger and don't fancy it falling to pieces beneath me.... really it's only suitable for a frame collector to hang on the wall..... what a shame...

But surely the temperature used to melt the silver filler rod during frame construction, 600 degrees C or so, must be higher than the temperature needed to melt the powder coat?

Failed to sell again.
Should have painted it red.

The only SBDU Raleigh's that sell for big money are red and strangely they are all sold by the same vendor.

Indeed: feels like the OP’s claims need a bit of fact checking. A cursory google suggest powder coat only needs 200 deg c or so: would that really harm a brazed frame?

Also, plenty of rigid mountain bikes were made using fillet brazed construction - including 753 - and are tough as old boots.

I’d agree with this & should have been painted properly...

I would NOT feel confident riding this knowing the silver solder has been messed about with due to temperature changes & metallurgical changes due to temp changes itself...... certainly not worth the asking price now..... certainly would need some NDT testing whether MPI or ultrasonic testing to fully check on voids & joint areas....

There's a certain irony in powder coating 753 frames.
The (only?) selling point of 753 was light weight.
The weight saving was small, maybe 200g.
This frame is rare because it tried to save even more weight by not having lugs.
To keep weight low they had wafer thin paint, my 753 Time Trial literally had one coat which had mostly flaked off.
A thick powder coat will probably negate any weight saving.