I fillet brazed my first frame and from somewhere ( I cannot remember where) I was advised to use a specific grade of brazing rod.

This rod was I believe 'low eutectoid', I cannot remember the exact terminology. The important property of this rod was that it turned from solid to liquid over a larger temperature range than normal braze and in this temperature window it was semi- runny and therefore easier to form into a fillet.

Maybe this is common knowledge and what everyone is using? I have done quite a bit of googling on fillet brazing recently and have not come across any mention of this type of braze material.

I bought some of this rod and with no instuction, just a few hints gleaned from I cannot remember where (pre-internet days) I found it pretty easy to do half decent fillets. Even the first one I ever did would have been OK. In fact I just did a couple of practice joints and then built the frame, below are my two practice joints.

I still have a load of the rod left over, if you need any more info on it I will have a dig around and see what I can find.