Sievert burners flame profile

I have been brazing a boiler this week. I am using a Sievert propane standard type burner and mostly a cyclone burner.

Can anyone help me identify where the hottest part of the flame is please? With the standard burner I assumed it would be in line with the centre of the torch, but found much better results working at the edge of the flame? The cyclone burner is more central, but as I can't see the flame how far away from the work should it be? I recall from school days that the flame can be quite cold if you are inside the blue bit - ie too close. Any advice great fully received, thanks

John,

the hottest part of the flame of the standard burner types is at the tip of the blue part of the flame. The cyclone burners are really good for working on round parts as the flame wraps around round parts to surround the area with flame which is hottest at the surface of the round component.

You get a feel for things as you gain experience. If you are trying to braze anything that has a large mass give it plenty of time to heat up and try to conduct your brazing/Silver soldering out of any wind or draughts. It is surprising just how much heat can be lost due to wind.

Bob.

Thought the cyclone got its extra heat from doing away with the blue cone therefore anywhere in the flame should be the same.

I get a 1/2 inch long visable flame out of mine, if it disappears inside the tube I know I've got another gas blockage to clear.

Flame touching the work seems best.

Hi John,

If you can't see the flame, view it against a dark background.

A cyclone flame still produces a blue zone and the hottest part of the flame is at the tip of that blue zone. The whirlwind type gas flow produced in this type of burner creates a blue area that is circular in nature.

Keith