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| Bernd:
Tim, I like that parts box idea. Reason being I never seem to finish one project before I start another. Then I have parts laying all over and can't remember which one goes were. Bernd |
| spuddevans:
Well I got a few moments in the workshop this afternoon, so I got a little more done on this. I have to admit that I had been kinda putting off the silver soldering as that is something new and unknown to me, but this afternoon I decided to have a go. So getting out the citric acid I made up some pickle, then I mixed up some flux (tenacity 5 if my memory serves me right) and got out the SS and blowtorch. Rather than try my first joint on a real part I took some scraps of brass, drilled some holes and used some 4mm brass rod. It wasnt as bad as I thought it was going to be. It took a couple of attempts but I got there in the end. Feeling elated from this I made a start on soldering up the eccentric straps to the con-rod to the little con-block. I had read about how it is good to have a slightly slack fit when soldering, I now know from experience the value of this. I had decided to try and solder the whole assembly in one go, and so had cleaned and fluxed both holes ( one in the eccentric strap and one in the con-block ) and both ends of the little rod, and put them together. Applying the heat to this, first of all gently to evaporate the water in the flux, then with a bit more heat. It was while this second phase of heating that there was a sharp "crack" sound and the con-block decided that it would violently leap at the wall and bounced off, landing quite neatly on the floor directly underneath the rest of the assembly. I guess that there must have been a bit of water/steam/gas that had got trapped until it heated up enough to propel the block off the rod. Taking this as a sign, I decided to solder one end at a time, and it worked out much better, if a little longer to do. Then I attempted to do the 2nd eccentric assembly. I gave soldering both ends at once another try, but this time drilled out the holes to a slightly larger diameter. This seemed to work much better except that just when the solder started to flow, the con-block (I'm not sure that is the right term for it, but I've used it enough for it to stick :dremel:) started to move a little off the rod. :bang: This is them after being quenched. Those of you who are not completely blind will see that there is approx 2.3mm height difference between the 2 assemblies. I dont know if there would be enough adjustment to compensate for this, or whether it would be better to re-flux and then reflow the solder and just push the 2 pieces back together? :scratch: (any and all thoughts would be welcome) Anyway, I have learnt that silver soldering is not all that hard, but that I do need to practice a bit more. Also learnt that you need to get the workpiece much hotter than I originally thought would be needed. I did notice that when heating up the joint, the flux 1st of all will evaporate the water in it, going white, then it darkens to the point of looking a bit black (perhaps I am burning the flux? ) then it goes clear and you can see it cleaning the metal, then the solder flows. Does all that sound about right to you guys who are experienced with SS? Tim |
| NickG:
That's how I remember it Tim, Looks like you have good joints there. I haven't done it for a long time but remember getting a nice thin tidy ring flash around then thinking, ... I better put a bit more on, and a bit more for good measure and it ends up a messy joint! I know some of the guys use thin wire and wrap a bit around the joint to keep it a neat fillet, never tried that myself but it sounds logical as that must be about the right amount of solder. Nick |
| spuddevans:
--- Quote from: NickG on November 22, 2009, 01:16:13 PM --- I know some of the guys use thin wire and wrap a bit around the joint to keep it a neat fillet --- End quote --- That's how I did it, seems easier for a beginner like me :thumbup: Tim |
| bogstandard:
Tim, When I do joints as you have just done, I invariable put a 'stopper' at each end, a bit of metal or firebrick resting against them. That usually stops the 'blow apart' that is caused by the water in the flux turning to steam, and the joint acting like a piston in a cylinder. The correct gap for all silver soldered joints should be about 0.002" (0.05mm) clearance. Tenacity 5 is the latest flux and is designed for stainless, and you will be very hard pushed to make it lose it's properties. I think the brass would melt before you need to worry about it. I have recently changed over to that for all my silver soldering work. For your already soldered bit, stand upright, and gently warm up the centre rod until the solder melts, then just push the bit down until in the correct position, then let the assembly fall over, while still heating, press the two parts down onto whatever it is standing on to get the both plates level with each other. Use a bit of metal, not your fingers. :lol: If you do it right, and don't overheat it, you will find it will be just fine without any further flux. Another string to your bow, nicely done. John |
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