Process: Fillet Brazing
The fillet brazing of each join has to be done carefully to ensure an even distribution of heat to the area being brazed which is the key to achieving strong and tidy fillets. We apply the same procedure to all the main joins which is as follows:
- We apply flux to the join; the flux prevents the molten brass from reacting with air.
- We preheat the tubes being joined so that the whole joint is heated evenly. If one tube is thicker than the other, then that tube is heated more. The flux turns to a clear glassy liquid once it has reached the required temperature and we can begin to add the brass..
- Firstly we do a ‘tinning’ pass, which uses capillary action to suck molten brass into the join to ensure a good internal fillet and a very strong joint..
- After the tinning pass the frame is removed from the jig and the join reheated. Once up to temperature the main fillet is laid. Careful heat control and application of the brass ensures an even sized fillet that is strong and also easy to clean..