#11
|
|||
|
|||
The difference between using a gas fluxer and dipping the rod into flux makes a big difference to the quality of the fillet. The gas fluxer adds consistency and control through adjustment of the flux flow rate. When I was an apprentice I used to make BMX frames from Reynolds 531 tubing. All of the joints were either silicon or nickel bronze welded using a gas fluxer. I also made 4 or 5 Jaguar D-type chassis using the same process. What the gas fluxer allows is for you to eliminate one variable - inconsistency in fluxing - and lets you carry on concentrating on your fillet. Hence the quality of the fillet is considerably better over the "dipping the rod in flux" method. Dipping the rod on flux is hit or miss affair at best. Who knows how much or little flux ends up on your rod - it's always a gamble. That's not to say it doesn't work, because it clearly does... It's just inconsistent. The key to nice welds is always consistency. Eliminate the variables and you have greater control.
Last edited by Stretch; 05-02-2015 at 02:36 AM. |
#12
|
|||
|
|||
It could make a big difference if the way you applied flux before was deficient. Frequently you don't dip the rod in flux, you apply flux to the surface of whatever your'e brazing. Building a bicycle with lugs, where braze is drawn into a joint via capillary action, practically demands doing it that way.
__________________
Matt |
#13
|
|||
|
|||
Matt, your are right about brazing requiring a different technique to silicon bronze welding. It's more like silver soldering in that respect. Brazing typically involves a thin, smooth surface finish, which is 'sucked' into the joints via capillary action. Silicon bronze welding typically leaves a large fillet with a consistency not too dissimilar to an aluminium weld. This is where the gas fluxer really shines
|
#14
|
|||
|
|||
Hi Matt,
What's the difference between silver soldering, brazing and silicon bronze welding. Yesterday I was silver soldering( I always though silver soldering and brazing was the same) a template and I noticed that the bead was more "put on the place" instead of sucked into the joints.
__________________
Richard |
#15
|
|||
|
|||
Richard
So, welding is where the filler material, if any, is the same as the base material. Brazing (and I've always used the terms brazing and bronze welding interchangeably, perhaps incorrectly) is using a different filler material than the base material, with the further distinction that brazing is at temps 450 degrees C and above, and below that temperature is soldering. edit: there are a lot of Matts here, hope I'm the one you wanted though I reckon you'd get approximately the same answer!
__________________
Matt |
#16
|
|||
|
|||
Hi Matt,
My question was for the other Matt but that's allright. The most important thing is , I think , that we can give each other the information that we are searching for. The difference between welding and brazing( mothermaterial/ different filler material) I understand but in the post from Stretch he describes brazing as a way that the fillermaterial is sucked into the jionts. Is this an action that doesn't occur when silver soldering?
__________________
Richard |
#17
|
|||
|
|||
No, it should be the same with silver soldering or any soldering, think of a soldered plumbing junction.
If the material isn't flowing into the joint there is likely not enough heat.
__________________
Matt |
#18
|
|||
|
|||
As Matt says, silver soldering will have a capiliary effect similar to that of brazing. Where people get a little confused is when they describe silicon bronze welding as brazing. If you tried flow silicon bronze like you would on a brazed tube, you would end up with what's called 'copper exclusion.' This is where the copper de-alloys itself from the bronze because it's been over-heated. It's a fairly common mistake when learning.
Silicon bronze welding will have little capiliary action if applied correctly. Sure, it sticks to the tube in much the same way, but it forms a proper bead with 'stacked dimes', similar in appearance to an aluminium tig weld. Welding temp was very critical in order to 'stack dimes'. Too hot and the bead's surface flattens and smooths out the dimes. Too cool and you end up with little craters where you dab the filler rod in! I wish I could show you some of the pictures of the chassis and frames I made as an example, but that was 30 years ago, well before the digital age!!! Cheers, Matt (Stretch) |
#19
|
|||
|
|||
I get a little confused now. Why is it called silicon bronze welding. I thought that welding meant that the filler material should be the same as the mother material.
__________________
Richard |
#20
|
|||
|
|||
Yes it is confusing! The terminology is a little tricky. Yes, technically welding is the fusing of two very similar materials. I guess it's used to differentiate between the capiliary method and the bead method.
|
Thread Tools | Search this Thread |
Display Modes | |
|
|