Optimus 535 cracked vaporising tube.

I have recently acquired this cooker and the large and rapidly getting larger flare up let me know there was an issue with the left hand burner! On further investigation I found the crack in the vaporising tube where it joins the top chamber. It looks like it has been bent slightly at some point hence the crack.I also found the plug underneath so I could test run the right hand burner. It goes really well. Pump works great, enamel is really good so keen to fix the other burner. Haven’t done any brazing so would be grateful for any pointers from those experienced in burner repair. I’m in NZ so if anyone knows what brands of brazing rod available here to use? I’m thinking clean it up and MAAP gas torch? Thanks for looking. Cheers

 

I’ve done a bit of silbrazing on those kinds of burner cracks, and there’ll be threads here on those repairs, but the maestro of silbrazing repair is @presscall. Do a search here.

Two words of advice: cleanliness and cleanliness! Also, practice on some copper or brass rod first.


Cheers

Tony

 

As @Tony Press said, if the burner is clean the repair is quite simple. Just flux the crack and braze it.

Not sure what’s available in your country but I used some Castolin rods with 45% of silver that melts at 680C circa if I remember…

These rods are coated with flux, but I added on the area some more borax flux as well… these rods flows very easily and well.

I cleaned the burner with an ultrasonic washer, but they can be cleaned in any way… after the brazing it’s enough to boil the burner in water for some time to remove the flux.

A mapp torch is ok, I used a simple butane torch anyway.



Nicola

 

I’m no expert, but with the help of other members here tackled a similar problem last year.

Some of what is in Pinhole leaks in 111T burner may be of use in your repair.


-R

 

I’d the same issue with an Optimus burner here:

 

Thank you all for your responses. Some great information there. I have a pretty good idea about what I need to do now. It actually looks like someone has tried to weld it in the past as there is a bit of splatter about place. Cheers

 

Make sure you straighten it up before you braze.

Good luck.


Cheers

Tony

 

I got it straight today and went to buy some brazing rods. Seems there are a lot of options for % of silver. Does more silver have a lower melting point? What % Ag would you recommend? Sorry for all the questions, just don’t want to ruin it. Cheers

 

45/50% of silver is good.

 

I used a filler with something like 30% silver on my 111T - melting point 720-765C on the basis that should I ever need to decoke the burner by heating it would be better able to withstand the process.


-R