Hi All, My Ditmar 531 suddenly leaks from Preston loop... So I did silver alloy brazing and test. It was burning good few minutes but leaks again... I want to know another way to repair it. Does someone give me advice? Regards, YOSH
That looks like the solder alloy has molten or was not soldered correctly. The Preston loop gets very hot, so maybe you could try another kind of alloy with higher melting point? I can't imagine that apart from hard soldering there's another way to repair the vaporizer. Or could it be that the tube is heavily corroded so that another hole near the first one has occurred?
Hi Martin, I used silver solder that melting point is Ce 745 degrees. And the leak was happened same point... YOSH
If all else fails and another vaporiser can not be found, you could replace the whole loop with a thick walled brass or steel tube of the correct size. (perhaps even a loop from another vaporiser) High temperature silver solder should work well enough on the ends of the tube where they fit into the vaporiser as it does not get quite so hot there.
@YOSH I would: 1. Clean the whole area, at least 10mm wide around the leak; 2. Clean the inside of the Preston tube (use thin wire); 3. Abrade the area where the hole is; 4. Reapply your braze (high temperature) to the area surrounding the hole. If you have some brass sheet you might consider brazing a patch over the leaking area. Cheers Tony
@phaedrus42 , @Tony Press Thank you for your advice. I will try clean and solder again. If it not work well, use brass sheet. Cheers, YOSH
