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| DIY fixed steady for a lathe: CQ9325 10 x 18" (250x450mm) |
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| andyf:
Hi Pekka, The rods in the long tube look mechanically stronger (50 daN / mm2) than those on the left (38 daN) but it looks like those on the left don't need as much heat. I'm not sure about the flux in the blue container, because there is no temperature range showing, but the flux in the white container looks like it might be OK. But if the Rothenberger rods and fluxes are made to match one another, it might be better to rely on those. As to actually doing it, there are folk on here much more experienced than me, and you would be better taking advice from them. As a novice, I have done some silver soldering (brass to brass and steel to steel), and it all turned out OK. Some was even done with a small butane/propane torch like the one shown on the blue container, which didn't really deliver enough heat, and which took far too long though it did work in the end. Search Madmodder for "silver soldering" and you will find demonstrations like this http://madmodder.net/index.php?topic=4958.msg55323#msg55323 Andy |
| PekkaNF:
Thank you all. A lot of my brazing stuf is a "souvenir". The rods on the picture are from Paris, went there for a few days with my newly wed wife. Had to find a hardwarestore and found those. White flux was sold to me to braze copper pipes with phosphoros bronze and it is liquid. Paste is probably from Holland, that is even oder...I don't remember seeing temperature rating. OK, I think I have eneough to give it a try. Just few more questions: * Do I fabricate the parts ready before brazing or do I just cut arms (shoes) and tips to rough size and finnish after soldering? I'm most likely using a key stock, brazind does very little to properties. * Does part relative position matter? Using a heart (I have some firebricks and an "insulator" palte) I think I could prepare tha parts as instructed before, stand them up (bronze tips up) with some mild steel wire and heat them up as a lot. Although this probably would heat the tips easier than the arms. If I put the smal tips down, arms are easier to heat, but tips will be touching insulator.... Thank you very much, Pekka |
| John Hill:
Pekka If it was me I would roughly form the parts and finish them after brazing, the pieces may move a little and if you do the finishing after that is a chance to correct things. It might be best if you can lift the pieces, especially the biggest pieces, clear of the bricks. Maybe you can lay them on nails or some scraps of steel, this will allow the heat of the flame to go under the work as remember you have to heat it right through for the solder to flow throughout the joint. I had another look at your posts and I think the challenge you will have will be to get the pieces hot enough. It might be quite difficult with that little torch but if you build your hearth like a little cave you might be able to do it. Good luck! |
| andyf:
Hi Pekka, If you stand the arms upright with the tips on top, it will be difficult to get the solder to flow into the joint. This isn't like soft soldering, where you get the job hot and then touch it with the solder. If you can lie the job flat with flux applied in and on top of the joint, put a piece of solder on top of the joint and then apply the heat from below, the solder should liquify and then flow into the joint with capilliary action aided by gravity. Like John, I think it would be a good idea to roughly form the parts and finish them after soldering/brazing. The force of the gas jet might blow a small piece of bronze out of position, so the easiest way might be to cut each steel arm roughly to length and solder/braze a long piece of bronze to it, then cut the tip off to the correct length afterwards. This would help in positioning the parts, but bronze is a good conductor of heat so you might not be able to get a long piece hot enough. Andy |
| AdeV:
Going back a few days.... --- Quote from: PekkaNF on May 28, 2011, 02:38:46 PM ---Circular "deep" hole milling manually :wack: I had to mill central hole manually just to see if it is a PITA claimed to be. I can conform it is - least with this piece. Does anybody knows how to make it less painful experience. --- End quote --- The only thing I'd do differently to the way you've done it; I'd have used a roughing cutter, rather than a smooth endmill/slot drill (speaking of which - there's no significant difference between the two, when cutting "on edge" like you are. I suppose in theory the 4-flute endmill would need a slower feed than the 2-flute slot drill, to prevent clogging, and the former would give you a nicer finish. A roughing mill, on the other hand, has serrated edges, which allow you to chew through the metal much faster than with a regular end mill (using a 12 or 16mm roughing cutter, I'd be taking 1/2" deep cuts in Ali, at whatever feed rate "felt right". Obviously, you have to cut the hole undersize, and finish off with a proper end mill (or slot drill, if you run it fast enough), to leave a smooth edge. Have a look on eBay for roughing cutters; or drop me a line if you fancy a couple of 12-16mm ones, I have a few spares. |
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