Horsetan Posted October 27, 2012 Share Posted October 27, 2012 ....ultrasonic bath today and all (most) of the soldering has taken on a dull grey coating, looks a bit of a mess. .... I'd be far more worried if the bits fell off in the ultrasonic bath. Seems like your soldering has been perfectly sound, so I wouldn't worry about it going grey - we all go grey eventually. Link to post Share on other sites More sharing options...
Jol Wilkinson Posted October 27, 2012 Share Posted October 27, 2012 Hello, I apologies if this is off topic but could you expand on the above please, as I was considering building my own? trustytrev TT, the articles describing diy RSUs usually suggest using a readily available transformer, such as used in a battery charger. They are usually rated at 12v but probably 5 or 10 amps. The secondary windings will therefore be of a lower gauge wire than used in the custom made transformers in RSUs like the LRM version. Higher output voltage = more windings, higher current means larger gauge wire. The voltage required to drive the current through the joint to be soldered is usually 2 - 3 volts. The current creates the heat, so something in the order of 30 amps is required. That's why RSUs have specially wound and hence more expensive, transformers. The other bits can be sourced fairly readily, but will be as expensive as the ones supplied in an RSU, if you make /buy the same quality. Jol Link to post Share on other sites More sharing options...
tender Posted October 27, 2012 Author Share Posted October 27, 2012 If it's just stopped being shiny I wouldn't worry too much, Shiny solder will oxidise a bit in time if you leave it. I'd be more concerned if there is any depth to the layer. . What was in the water? Sounds that there may have been too much of what ever it was. Did a plain water run last improve things? I would always do that any way if I've has a cleaning agent in the water to make sure there is no residue left on the model. Actually us more anal modellers would have cleaned all the solder of surfaces so this doesn't happen. Will Disaster averted I hope. I've given it a good scrub (the bits I could get at) with some Cif cleaner and another clean in the bath with just plain water and its not looking too bad now. I think it may have been residue from the solder paste I've been using in places. The bits where I've used Carrs yellow flux and plain 60/40 solder seem to be less affected. Actually us more anal modellers would have cleaned all the solder of surfaces so this doesn't happen. That sounds painful. How do you do that? we all go grey eventually. That happened some time ago. The Metal blackening stuff and low temperature solder arrived today so I'll be having a play with that on some scrap bits to see how the blackening turns out and solder on the sand boxes. Link to post Share on other sites More sharing options...
tender Posted October 27, 2012 Author Share Posted October 27, 2012 Will's suggestion of two-thirds of the distance from front axle to compensation pivot sounds right to me but I think your estimate is a little too far forward. A rough measurement on mine gives about 46mm between the axle and pivot, so the CoG should be just over 30mm behind the front axle. The driving axles are 29mm apart so the CoG should be just behind the rear driver axle. On mine, the side tanks are filled with lead sheet and there is some more in the boiler/smokebox, plus a little in the bunker. The CoG is actually about 1mm further back than the above, but it runs well enough and if I needed to adjust it there's still plenty of space for more lead in the boiler/smokebox. Nick Your perfectly correct Nick, I don't know my back from front. Should have read 'about 2mm behind the rear driver' Ray. Link to post Share on other sites More sharing options...
trustytrev Posted October 27, 2012 Share Posted October 27, 2012 TT, the articles describing diy RSUs usually suggest using a readily available transformer, such as used in a battery charger. They are usually rated at 12v but probably 5 or 10 amps. The secondary windings will therefore be of a lower gauge wire than used in the custom made transformers in RSUs like the LRM version. Higher output voltage = more windings, higher current means larger gauge wire. The voltage required to drive the current through the joint to be soldered is usually 2 - 3 volts. The current creates the heat, so something in the order of 30 amps is required. That's why RSUs have specially wound and hence more expensive, transformers. The other bits can be sourced fairly readily, but will be as expensive as the ones supplied in an RSU, if you make /buy the same quality. Jol Hello, Thanks for that Jol.I thought it might be something like that.I have a nice transformer from a micro wave oven I rewound the secondaries on some time ago.Having moved to DCC it is now redundant so I think I have found another use for it. trustytrev. Link to post Share on other sites More sharing options...
Castle Posted October 27, 2012 Share Posted October 27, 2012 Hi All, I think at least some of us now have a mental picture of Trev putting a brass kit in a microwave with the flux and solder, putting it on the 'build' setting and putting the timer to 5 minutes. Makes a change from a 'shake the bag' model kit! Is this the future of kit building? Sorry, wrong thread. I'll get my coat... All the best, Castle Link to post Share on other sites More sharing options...
trustytrev Posted October 27, 2012 Share Posted October 27, 2012 Hi All, I think at least some of us now have a mental picture of Trev putting a brass kit in a microwave with the flux and solder, putting it on the 'build' setting and putting the timer to 5 minutes. Makes a change from a 'shake the bag' model kit! Is this the future of kit building? Sorry, wrong thread. I'll get my coat... All the best, Castle Hello, That is nothing even the lights at the local power station dimmed when I switched it on and that is nuclear. trustytrev. Link to post Share on other sites More sharing options...
Will L Posted October 28, 2012 Share Posted October 28, 2012 That sounds painful. How do you do that? You clean off excess solder with a variety of scrapers, files and abrasives. My favourite scraper is a fairly heavy craft knife with a strait blade with the point ground off and turned into a chisel. Actually at its best once its stopped being very sharp as you don't cut yourself so much. There is also an official tool for the job. Some people grind scrapers out of worn out files. Files can be used but the solder will tend to clog up the cut. The best abrasive is a good fibre glass brush, like this and this which will take thin layers of solder off brass all by themselves. This is how you recover etch detail lost under a layers of errant solder, but large blobs need paring down with the scraper first. . You need lots of refills with the propelling pencil type but they are best for small details and will get closer to corners. The string wound ones need wearing in before they become really effective. They are better at cleaning up wide open spaces and can also be used to get the solder out of a clogged up file. With either type, keep the unsupported length of glass fibre as short as possible because they break off if you don't. Not that they won't break off anyway, but nothing like so much. The broken off bits will stick in your fingers, and various other places if your not careful. Glass fibre proof skin would be nice, but isn't available. Sometimes it is necessary to suffer for one's art. When these things are wielded with skill and dedication, your brass kits will show practically no visible solder. Once cleaned up and defluxed properly an unpainted kit will stay bright shiny brass for years. But only the really anal bother on the inside and underneath where nobody else will ever see. Will Link to post Share on other sites More sharing options...
Jol Wilkinson Posted October 28, 2012 Share Posted October 28, 2012 I have some scrapers made from hacksaw blade ends by John Hayes of MRJ loco building article fame. They are the blue items shown in the photo, now twenty years old and still going strong. The edges are ground back at an angle of about 45 degrees to create a cutting tool profile. They are left and right handed, for different situations. The "hooked" version is for getting into corners behind beadings or other raised parts. Simply run the tool along the joint where the solder need removing and it is scraped/machined off. The red and yellow items are etch tag chisels, used with the 2oz hammer for cutting out parts from etch sheets. If there is just a bit too much solder, and it is the free flow 144 deg. variety, then I have found it easiest to "spread the solder over the surrounding are using a liquid flux. The layer of solder is so thin that it can then be polished of with a glass fibre stick. Jol Link to post Share on other sites More sharing options...
tender Posted October 28, 2012 Author Share Posted October 28, 2012 Thanks Will, Jol. Obviously more to this soldering business than first meets the eye, live and learn. Link to post Share on other sites More sharing options...
tender Posted October 28, 2012 Author Share Posted October 28, 2012 Used the 100deg solder for the white metal sandboxes. Wasn't sure what temperature to set the iron to but 180 deg seemed to give good results without melting the white metal. Tried out the Carr's blackening fluid on the removable bits followed by a waft (or two) of matt black from a spray can. Maskol was used for keeping the paint out of unwanted areas i.e. the grooves in the rear wheel carrier. Can't remember who put me on to this, (I'm sure I read on here somewhere) but thanks whoever you are. Final check on the main chassis now to make sure I've not missed anything before doing the same to that. Ray. Link to post Share on other sites More sharing options...
R A Watson Posted October 28, 2012 Share Posted October 28, 2012 With regard to tools for removing excess solder I purchased some "wax carving tools" which come in several shapes in an exhibition special deal of six for a fiver some time ago and they are very good as both scrapers and chisels. Whilst I use the Birchwood Casey Black for Brass rather than the Carrs product I find that a quick swim in the sonic bath helps to stop the reaction and the formation of crystals in later life. Also a useful by product of the blackening process is that solder will not adhere to treated surfaces and if you treat the bits of valve gear etc that you do not want to be rendered immovable before assembly life will be much easier. Wally Link to post Share on other sites More sharing options...
ozzyo Posted October 29, 2012 Share Posted October 29, 2012 In the meantime DISASTER. I dumped the chassis in a ultrasonic bath today and all (most) of the soldering has taken on a dull grey coating, looks a bit of a mess. It does clean off with a bit of a scrape but I'm never going to be able to get at all the nooks and crannies. Does anybody have any idea what's caused this? I'll try and get a picture up later on, it's a bit beyond my iPhone camera. Ray. Hello Ray, I've just bumped a topic to near the top in kit and scratch building that may help you with some of your problems with using an ultrasonic cleaner. Depending on the flux that has been used and the cleaning solution, you can get a white deposit, this can be unboiled off flux.This should be cleaned off then into the USC again. The red / orange topped Cilit Bang is a good pre-cleaner. Acid based. It may seem strange that an acid based cleaner should be used when most of the fluxes that we use are acid based, but it does work as long as you clean it off with fresh water, I don't think that you answered a question about what your using in your USC to clean your set of frames, if you did, I'm sorry I must have missed it. OzzyO. PS. put a photo of your new USC up on here if you would, please. Link to post Share on other sites More sharing options...
tender Posted October 29, 2012 Author Share Posted October 29, 2012 Hello Ray, I've just bumped a topic to near the top in kit and scratch building that may help you with some of your problems with using an ultrasonic cleaner. Depending on the flux that has been used and the cleaning solution, you can get a white deposit, this can be unboiled off flux.This should be cleaned off then into the USC again. The red / orange topped Cilit Bang is a good pre-cleaner. Acid based. It may seem strange that an acid based cleaner should be used when most of the fluxes that we use are acid based, but it does work as long as you clean it off with fresh water, I don't think that you answered a question about what your using in your USC to clean your set of frames, if you did, I'm sorry I must have missed it. OzzyO. PS. put a photo of your new USC up on here if you would, please. Hi OzzyO. Many thanks for bumping the USC topic, useful stuff there. http://www.rmweb.co.uk/community/index.php?/topic/53956-ultrasonic-cleaners/ After my initial problems the frames were given a good clean with CIF followed by a rinse in some IMS. My attempts a blacking with Carr's blackening fluid we not that successful either. Grey and blotchy, seems the fluid lost effect shortly after contact with the frame. Pushing it around with a brush didn't have much effect on the untreated parts. I found rinsing off the expended fluid with water, drying and starting again with fresh fluid was the only way to get the whole frame treated. After this another rinse in the USC with plain water and then a spray with matt black aerosol paint. Having such a wide dispersion it is difficult to get paint into the corners without flooding the rest of the frame so several fine coats were given from different directions. Think I'm going to have to put an airbrush on the shopping list. There's a few spots that might need touching up and I need to remove the Maskol from the hornblocks once the paint has hardened off, hopefully they won't be gummed up with paint. Ray. PS OzzyO - the USC that I have access to at work looks similar your old one but quite a bit bigger, enough for two O gauge locos complete with tenders. Link to post Share on other sites More sharing options...
tender Posted October 30, 2012 Author Share Posted October 30, 2012 Decided to go with the plunger pickups following Buffalo's advice on preparation. The sprung contacts seem quite smooth in operation so hopefully will be ok. Next was to assemble the Gibson wheels inserting the crank pins before quartering in the chassis. However I've hit on a problem, the countersink on the screws (crank pins) supplied foul the axle boss of the wheel before it is fully home with a result that the pin is being pulled off square when exiting the other side. Couldn't get the camera in close enough to take a meaningful picture so hope the description is ok. Looks like a visit to the workshop to mill a bit off the boss to get the pin to seat properly. Edit - name correction for plunger advice Link to post Share on other sites More sharing options...
PenrithBeacon Posted October 30, 2012 Share Posted October 30, 2012 I note that you haven't fitted the hind axleboxes Link to post Share on other sites More sharing options...
buffalo Posted October 30, 2012 Share Posted October 30, 2012 ...However I've hit on a problem, the countersink on the screws (crank pins) supplied foul the axle boss of the wheel before it is fully home with a result that the pin is being pulled off square when exiting the other side... Yes, a common problem with Gibson wheels. I usually trim a bit off with a scalpel. The plastic is soft and it takes less time than setting up the mill. Nick Link to post Share on other sites More sharing options...
tender Posted October 30, 2012 Author Share Posted October 30, 2012 I note that you haven't fitted the hind axleboxes The hind axle boxes are a different type, these can be seen separately in an earlier photo. Here they are fitted in the frames with the rear wheel set (without the retaining wire). Link to post Share on other sites More sharing options...
PenrithBeacon Posted October 30, 2012 Share Posted October 30, 2012 ... Next was to assemble the Gibson wheels inserting the crank pins before quartering in the chassis. However I've hit on a problem, the countersink on the screws (crank pins) supplied foul the axle boss of the wheel before it is fully home with a result that the pin is being pulled off square when exiting the other side. Couldn't get the camera in close enough to take a meaningful picture so hope the description is ok. ... I had that problem too, I countersunk the back of the boss and used a .85mm drill instead of the recommended .75 Regards Link to post Share on other sites More sharing options...
tender Posted October 31, 2012 Author Share Posted October 31, 2012 Yes, a common problem with Gibson wheels. I usually trim a bit off with a scalpel. The plastic is soft and it takes less time than setting up the mill. Nick Setting up! I just set the depth of a 3mm end mill to the height of the spokes and wiggled the required part of the wheel hub under it. Only took a few seconds. Crude but effective, and don't tell the H&S guys. I had that problem too, I countersunk the back of the boss and used a .85mm drill instead of the recommended .75 Regards Doesn't that make the screws a loose fit, my wheel were pre-drilled and the crank pins (screws) cut themselves in. I did countersink the back a bit for the head of the screw. I also put a spot of Locktite on the thread as I don't want them unscrewing when I put the crank pin nuts on. Don't know if this is common practice or not? Ray. Link to post Share on other sites More sharing options...
buffalo Posted October 31, 2012 Share Posted October 31, 2012 Setting up! I just set the depth of a 3mm end mill to the height of the spokes and wiggled the required part of the wheel hub under it. Only took a few seconds. Crude but effective, and don't tell the H&S guys... Fair enough, but I was including summoning up the courage to go out to the garage in this cold/wet weather as part of the setup time Nick Link to post Share on other sites More sharing options...
tender Posted October 31, 2012 Author Share Posted October 31, 2012 Fair enough, but I was including summoning up the courage to go out to the garage in this cold/wet weather as part of the setup time Nick Guess I should come clean, this is my milling machine http://www.proxxon-direct.com/acatalog/MICRO_miller_MF_70.html and it sits on the bench behind my desk in the office at work, nice and warm. Ray. Link to post Share on other sites More sharing options...
Will L Posted October 31, 2012 Share Posted October 31, 2012 Guess I should come clean, this is my milling machine http://www.proxxon-d...ller_MF_70.html and it sits on the bench behind my desk in the office at work, nice and warm. I'm still not convinced that trimming the hub back around the crank pin hole with a scalpel isn't quicker. Will Link to post Share on other sites More sharing options...
tender Posted October 31, 2012 Author Share Posted October 31, 2012 I'm still not convinced that trimming the hub back around the crank pin hole with a scalpel isn't quicker. Will Your probably right, but knowing me, less risk of slicing the top of my finger off. Assembled the wheels tonight along with the coupling rods. Couldn't understand why there was stiffness at certain positions when rotating the wheels. On closer inspection I realised that despite the locktite on the crank pins one had pushed back and was fouling the chassis. I had just screwed on some sleeving to hold the coupling rods in place but seems there was enough grip to undo the crank pin part way. So, how do you stop the crank pins unscrewing when you tighten the nut up against the crank pin bush? Ray Link to post Share on other sites More sharing options...
buffalo Posted November 1, 2012 Share Posted November 1, 2012 ...So, how do you stop the crank pins unscrewing when you tighten the nut up against the crank pin bush? A drop of Loctite 243 (thread lock) on the last mm or two of the thread as you screw it in. Make sure there's none left on the thread that protrudes from the front of the wheel. Other Loctite formulations and maybe some cyano glues may also do the job. Nick Link to post Share on other sites More sharing options...
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