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Post by peterl78940 on Jun 26, 2010 20:58:21 GMT -5
as I understand it, we're not supposed to use brass in the boiler or the pistons/valves/cylinders because of de-zincification, but then the book says to hold the copper boiler parts together during silver soldering with small brass screws... ... I have been searching for bronze screws, but it seems that the only ones available are silicon-bronze and only is sizes too large for this use (#6-32 was the smallest I found). has anyone else thought about this, another alternative is copper rivets, which are readily available (at least they used to be from Small Parts Inc), are there down-sides to copper rivets that folks can share from experience ? thanks, Pete Lawrence. ps, my Pennsy 0-4-0 (in F scale) will be on display next month at the Western Engine and Model Expo, in Vallejo, CA, check out www.wemeshow.com if you might be interested
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Post by dickr on Jun 27, 2010 12:10:27 GMT -5
My book says copper rivets, pg 141, but I used brass screws (2-56) because I had them. They are totally covered with silver solder and then some. I assume you are talking about the Penn A 3 A dickr
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Post by kwoodhands on Jun 28, 2010 17:20:54 GMT -5
I have bronze 3/48 screws 1/8",3/16 and 1/4" long. If I recall I got them from either Mc Master Carr or Wholesale Tools.Pretty sure it was the former.I can't help with the rivets, no real knowledge here.
mike
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Post by trainlarry on Jun 30, 2010 20:18:42 GMT -5
Pete,
Using brass screws to hold parts together while siver brazing a boiler is OK, because the screws are not part of the structural assembly of the boiler. If the screws do corrode in time, they will not cause a failure of the boiler. Most times, the screws will be brazed over also. Don't be afraid to use brass screws for this application. Copper rivets would work just as well, except for peening them over where space is limited. Threaded bushes brazed into the boiler should be phosphor bronze. Most external threaded fittings on a boiler are brass, like valves and water gauge glasses, and they would be subject to de-zincification over time. It is the threads that usually show signs of corrosion, and so the threads should be checked at least yearly. There seems to be no problem using brass for cylinders, steam chests, pistons, and cylinder heads, and many commercially available locomotives in all gauges use it, as well as many scratch-built designs, such as the 3/4" scale locomotives designed by Kozo, and featured in this forum.
Larry
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Post by mike44 on Feb 18, 2019 19:29:26 GMT -5
My book says copper rivets, pg 141, but I used brass screws (2-56) because I had them. They are totally covered with silver solder and then some. I assume you are talking about the Penn A 3 A dickr You can make a threaded rod from solid electric wire and thread it 3/48 easily. I threaded a few 6" or so lengths of wire and cut off what I need. The rods have no head so I leave about 1/16" on either side of the part and peen them over like a rivet. Flat work is simple, just place the part on an anvil or solid steel surface and peed away. Round parts like a boiler I have a 12" x 2" round steel piece I install in the vice with 6" or more sticking out beyond the jaws. I place the shell over the steel round and peen the rod from the outside of the shell. This works well. What I forgot to mention the parts are installed temporarily with steel 3/48 pan head screws. I remove one screw at a time and replace it with the copper rod. If the rod is installed without first using a screw the copper headless rod can't be removed . Once in a while you may have to adjust something before hard soldering , that's why I use the screws first. Threading copper wire is easier than other metals, I wish it would machine that easy. I believe it took less than 5 minutes to thread about 15" of wire. Don't worry if the wire is not completely straight, it will still work fine. mike
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