buffalo Posted October 14, 2012 Share Posted October 14, 2012 ...On the left are the four components to be 'sweated' together. The right most component is the four bits dry assembled. What worries me is that the faces of the two outer bits when tinned will make the channel formed by the narrower middle piece a too tight a fit when slid onto the frames. Is it just a case of going for it and cleaning out the channel after soldering or is there an easier solution. Ah, yes, I remember assembling this bit What I would suggest is to try to avoid tinning the outer pieces beyond the width of the inner one. It should be sufficient to just tin about 1 to 1.5mm around the bearing hole on the outer pieces. You really don't want to end up with any stray solder in the groove where the unit slides in the frames. Even then, be prepared for some tedious work with the tip of a scalpel blade cleaning out any solder that does end up in the groove. A piece of fine wet/dry folded back on itself so that it is double sided may also prove useful for cleaning up. Nick Link to post Share on other sites More sharing options...
tender Posted October 14, 2012 Author Share Posted October 14, 2012 Ah, yes, I remember assembling this bit What I would suggest is to try to avoid tinning the outer pieces beyond the width of the inner one. It should be sufficient to just tin about 1 to 1.5mm around the bearing hole on the outer pieces. You really don't want to end up with any stray solder in the groove where the unit slides in the frames. Even then, be prepared for some tedious work with the tip of a scalpel blade cleaning out any solder that does end up in the groove. A piece of fine wet/dry folded back on itself so that it is double sided may also prove useful for cleaning up. Nick 'Well, that went as well as could be expected, didn't it?' Always one to try something a bit different, (but i guess it's been done before on here somewhere) i remembered i had some solder paste at work, (the stuff you repair SMT components on PCB's) not that I'd ever used it, so i thought I'd give it a try (tried it on some scrap etch first) Just painted the smallest amount on both sides of the center layer with a tiny paintbrush, assembled and sweated as together with a hot iron (300deg C). Seems to have done the trick with just a bit of cleaning up in the groove with some brasso on the back of a scalpel blade to remove the excess flux. Thanks Nick and Miss Prism (Brasso) for the advice. Link to post Share on other sites More sharing options...
John_Hughes Posted October 14, 2012 Share Posted October 14, 2012 Yes, for sweating I'd go with the solder paint every time, as it's easier to get a smooth joint between the pieces. Of course, the easiest way of all is to use a resistance unit, but they're as rare as hens' teeth these days. Looks like the loco's coming on a treat - I wish I worked as quickly as you do! Link to post Share on other sites More sharing options...
Flymo748 Posted October 15, 2012 Share Posted October 15, 2012 Yes, for sweating I'd go with the solder paint every time, as it's easier to get a smooth joint between the pieces. Of course, the easiest way of all is to use a resistance unit, but they're as rare as hens' teeth these days. John, You may find that talk of the early demise of the Resistance Soldering Unit is greatly overstated. There were quite a number of RSUs being used at the Autumn Missenden Modellers Weekend just past. My own is now viewed as an essential modelling tool, and entirely complementary to a traditional soldering iron. It's one from London Road Models (no connection, etc...) and you can find the details at the bottom of the page http://www.scalefour.org/LondonRoadModels/various/components/ I know that LRM were still selling them on the stand at Scaleforum, only a couple of weeks ago. HTH Flymo Link to post Share on other sites More sharing options...
tender Posted October 16, 2012 Author Share Posted October 16, 2012 Looks like the loco's coming on a treat - I wish I worked as quickly as you do! Been under the weather (and duvet) last day or two so not much progress, just been preparing the frames for the hornblock assembly's. Will hopefully be back on the job tomorrow. John, You may find that talk of the early demise of the Resistance Soldering Unit is greatly overstated. There were quite a number of RSUs being used at the Autumn Missenden Modellers Weekend just past. My own is now viewed as an essential modelling tool, and entirely complementary to a traditional soldering iron. It's one from London Road Models (no connection, etc...) and you can find the details at the bottom of the page http://www.scalefour.org/LondonRoadModels/various/components/ I know that LRM were still selling them on the stand at Scaleforum, only a couple of weeks ago. HTH Flymo I did look these up, but quite expensive so will stick with the soldering iron of for time being. Link to post Share on other sites More sharing options...
R A Watson Posted October 17, 2012 Share Posted October 17, 2012 I can recommend a R S U for most uses imaginable, mine is permanently on the end of the bench and plugged in at all times as the control switch (foot switch) works on the incoming power lead and the unit is not live until the switch is operated. It certainly save the time spent searching for the correct size iron and then waiting for it to come up to working temperature. The last time I spoke to L R M the situation was that they build to order and don't carry stock due to the large and fluctuating cost of the transformer component. Sorry to digress but felt I must continue the missionary work to convert more people to this form of working. Link to post Share on other sites More sharing options...
John_Hughes Posted October 17, 2012 Share Posted October 17, 2012 Yes, my RSU's from the good folks at London Road as well - very useful it is too! Link to post Share on other sites More sharing options...
chrisf Posted October 17, 2012 Share Posted October 17, 2012 I bought one at the York show three years ago. The decision to do so was almost instant, based on their abundance which was at the time akin to that of rocking horse droppings, and was a case of 'can I afford not to get one?'. I am still exploring exactly what it will do but my mindset is to use it unless a conventional iron is required. I endorse the remarks of the last two posters. Chris Link to post Share on other sites More sharing options...
tender Posted October 17, 2012 Author Share Posted October 17, 2012 Lots of recommendations for RSU's so I guess I'll have to put one on the Christmas present list. Are these suitable for building PCB trackwork as well? That would make the expense more justifiable. Back to the build and some advise required. The picture shows the hornblock assembly and frame cutout. In the center top of the axle block is a 0.4mm datum hole which lines up with the datum hole in the frame (directly above). Unfortunately the hole in the frame hasn't etched through so I'm now waiting for a 0.4mm drill to arrive (among other things) to drill it through. The instructions say 'Use a short length of 0.4mm wire , slotted through the axle box datum holes to locate it, check it sits vertically and solder into place.' So the question is, how vertical does it have to be, just by eye, or is something more precise required? Ray. Link to post Share on other sites More sharing options...
Kempenfelt Posted October 17, 2012 Share Posted October 17, 2012 Ray, Looks like you're making good progress! Just a quick observation, that hole above the hornblock cut out is only suppose to be half etched. This is to give people the option of opening up the hole to fit hornblocks. Or for those who want to build the chassis rigid, they can do without having to worry about holes in the frames that they will then have to fill (if so inclined). I'd be surprised to hear of under-etching on Chris's products as his quality control to me at least would appear to be second to none. With regards to a 0.4mm drill bit you'll find it a very useful tool in your armory, it's probably my most used drill size, however I would advise getting more than one! Alternatively you can always open then hole out to a size for which you do have a drill bit (and wire) available. Good luck with the rest of the build! Paul Link to post Share on other sites More sharing options...
jjnewitt Posted October 17, 2012 Share Posted October 17, 2012 So the question is, how vertical does it have to be, just by eye, or is something more precise required? I use an engineers square if at all possible to do this kind of job to get the hornblocks square to the top of the frame or whatever is parallel to the horizontal axle centres. Not so easy in this case as there are the curved splasher parts but there maybe other areas you could use. I don't think you can be too carefull when it comes to putting together chassis. If the hornblocks aren't square to the chassis then there will be changes in the vertical axle centres as they move. While we're only talking about fractions of a mil it all help. Sometimes it's only fractions of a mil that cause a heap of problems! Link to post Share on other sites More sharing options...
buffalo Posted October 17, 2012 Share Posted October 17, 2012 ...So the question is, how vertical does it have to be, just by eye, or is something more precise required? How long is a piece of string? In theory it should be absolutely vertical and both sides should be perfectly matched and all should be parallel. In practice, as near to vertical as you can get it. If you can get a square in there to check, then do so, but often its not practical to do that because of the frame shape, so you end up doing it by eye. One suggestion would be to tack solder one side in place as near to vertical as you can manage, then use a steel ruler or other straight edge to align the other side on the first one. Tack the second one in place, check, adjust if necessary, then solder up fully. Nick ps. Paul is right, you'll need more than one with these small sized drills, I usually buy them in tens... Link to post Share on other sites More sharing options...
John_Hughes Posted October 18, 2012 Share Posted October 18, 2012 While a good variety of small drills is certainly essential (plus spares, as mentioned!) I usually find myself reaching for a reamer if I need a hole to perfectly match whatever's going to be pushed through it. A set of decent small reamers isn't particularly cheap, but it will repay the cost several times over in sheer usefulness. Link to post Share on other sites More sharing options...
PenrithBeacon Posted October 18, 2012 Share Posted October 18, 2012 ... I'd be surprised to hear of under-etching on Chris's products as his quality control to me at least would appear to be second to none. ... I don't think the holes are intended to be anything other than half etch. Regards Link to post Share on other sites More sharing options...
Jol Wilkinson Posted October 18, 2012 Share Posted October 18, 2012 Lots of recommendations for RSU's so I guess I'll have to put one on the Christmas present list. Are these suitable for building PCB trackwork as well? That would make the expense more justifiable. Ray. Ray, To clarify the situation on London Road Models RSU's. John Redrup may now have sold the last of the latest batch. He now has to invest in a new batch of cases, which represents a considerable investment. Following problems with the coating on some of the last lot (returned to the supplier), John is reviewing an all stainless steel case. For an update on availability and to express interest in placing an order, LRM can be contacted at lrmenquiries@hotmail.co.uk. Do not expect an immediate reply within minutes, as he may be taking the kids to school, in the workshop or somewhere else where the pc isn't located. The late Mike Grey, designer of the LRM RSU, described what he called Offset Resistance Soldering in MRJ 82, for building rivet and ply track. There is no reason why the same technique couldn't be used with pcb sleepers. Basically, the underside of the rail would be tinned, aligned on the fluxed sleepers and then RSU probes applied to each side of the rail (in the web) above the sleeper. The current passing through the rail heats it locally, melts the solder and creates the joint. Jol Link to post Share on other sites More sharing options...
tender Posted October 18, 2012 Author Share Posted October 18, 2012 Just a quick observation, that hole above the hornblock cut out is only suppose to be half etched. With regards to a 0.4mm drill bit you'll find it a very useful tool in your armory I don't think the holes are intended to be anything other than half etch. While a good variety of small drills is certainly essential (plus spares, as mentioned!) I usually find myself reaching for a reamer if I need a hole to perfectly match whatever's going to be pushed through it. A set of decent small reamers isn't particularly cheap, but it will repay the cost several times over in sheer usefulness. Ok, consensus seems to be that the half etch holes are meant to be that way. I'll just drill them through a bit further to take the end of the wire for location. Have ordered a bundle of small drills - looks like i'm going to need them. I already have a set of broaches 0.7-3mm and a 3-4mm and have already found them invaluable. Never knew such a thing existed until i started reading the various posts on this forum. Picked these up from Eileens at the Manchester show the other week. I use an engineers square if at all possible to do this kind of job to get the hornblocks square to the top of the frame or whatever is parallel to the horizontal axle centres. Not so easy in this case as there are the curved splasher parts but there maybe other areas you could use. I don't think you can be too carefull when it comes to putting together chassis. If the hornblocks aren't square to the chassis then there will be changes in the vertical axle centres as they move. While we're only talking about fractions of a mil it all help. Sometimes it's only fractions of a mil that cause a heap of problems! How long is a piece of string? In theory it should be absolutely vertical and both sides should be perfectly matched and all should be parallel. In practice, as near to vertical as you can get it. If you can get a square in there to check, then do so, but often its not practical to do that because of the frame shape, so you end up doing it by eye. One suggestion would be to tack solder one side in place as near to vertical as you can manage, then use a steel ruler or other straight edge to align the other side on the first one. Tack the second one in place, check, adjust if necessary, then solder up fully. Putting a steel rule across the bottom of the wheel springs seems to be parallel with the the top of the frame (which is a bit inaccessible due to the splashers) so I'll use that as a reference for an engineers square to get the axle blocks vertical. The square lines up nicely with the vertical sides of the axle box cut outs in the frame so should be ok. Ray, To clarify the situation on London Road Models RSU's. John Redrup may now have sold the last of the latest batch. He now has to invest in a new batch of cases, which represents a considerable investment. Following problems with the coating on some of the last lot (returned to the supplier), John is reviewing an all stainless steel case. For an update on availability and to express interest in placing an order, LRM can be contacted at lrmenquiries@hotmail.co.uk. Do not expect an immediate reply within minutes, as he may be taking the kids to school, in the workshop or somewhere else where the pc isn't located. The late Mike Grey, designer of the LRM RSU, described what he called Offset Resistance Soldering in MRJ 82, for building rivet and ply track. There is no reason why the same technique couldn't be used with pcb sleepers. Basically, the underside of the rail would be tinned, aligned on the fluxed sleepers and then RSU probes applied to each side of the rail (in the web) above the sleeper. The current passing through the rail heats it locally, melts the solder and creates the joint. Jol Thanks for that, I'll get an email off to John Redrup to find out what the situation is. Ray. Link to post Share on other sites More sharing options...
tender Posted October 18, 2012 Author Share Posted October 18, 2012 A useful bit of progress this evening, I was suprised how quickly it went together once i got started. I've been ticking off the bits in the manual as I complete each section so hopefully I've not forgotten anything. In the absence of an ultrasonic bath any suggestions for cleaning out the flux from all the corners before they become inaccessible when the rest of the bits are assembled? Ray. Link to post Share on other sites More sharing options...
Wizard of the Moor Posted October 19, 2012 Share Posted October 19, 2012 In the absence of an ultrasonic bath any suggestions for cleaning out the flux from all the corners before they become inaccessible when the rest of the bits are assembled? http://www.maplin.co.uk/electronic-solvent-cleaner-30056 Does what it says on the tin. An ultrasonic cleaner is a good investment, though. Link to post Share on other sites More sharing options...
Nigelcliffe Posted October 19, 2012 Share Posted October 19, 2012 In the absence of an ultrasonic bath any suggestions for cleaning out the flux from all the corners before they become inaccessible when the rest of the bits are assembled? Toothbrush and scrub with CIF cleaner (or any other kitchen cream cleaner). Then scrub in water. I used this for years before getting an ultrasonic cleaner. - Nigel Link to post Share on other sites More sharing options...
John_Hughes Posted October 19, 2012 Share Posted October 19, 2012 Well, I just pop the work in the dishwasher, though I know that that idea gets a few raised eyebrows on here! As long as I use the cheapest sort of tablet - without rise-aid or the other fancy stuff - it does the job just fine and seems to leave no residue at all. Link to post Share on other sites More sharing options...
tender Posted October 19, 2012 Author Share Posted October 19, 2012 http://www.maplin.co.uk/electronic-solvent-cleaner-30056 Does what it says on the tin. An ultrasonic cleaner is a good investment, though. I guess switch cleaner will do the same thing, think I might have a can somewhere. Toothbrush and scrub with CIF cleaner (or any other kitchen cream cleaner). Then scrub in water. I used this for years before getting an ultrasonic cleaner. - Nigel Will give the CIF a try for now. Well, I just pop the work in the dishwasher, though I know that that idea gets a few raised eyebrows on here! As long as I use the cheapest sort of tablet - without rise-aid or the other fancy stuff - it does the job just fine and seems to leave no residue at all. Is that with or with out the dishes? I don't think I'd get away with that one. I've noticed that ultrasonic baths can be had on ebay for about £20, said to be suitable for jewellery etc. are these any good and what cleaning fluid would you use? Most fluids on ebay seem to be seaweed based! Link to post Share on other sites More sharing options...
RMweb Gold Happy Hippo Posted October 19, 2012 RMweb Gold Share Posted October 19, 2012 And if you are too mean to spend a lot of money on a resistance soldering unit: http://www.girr.org/girr/tips/tips1/solderer.pdf Which shows you how to build your own. Regards Richard Link to post Share on other sites More sharing options...
Mike G Posted October 19, 2012 Share Posted October 19, 2012 Which shows you how to build your own. Have to say I'd hand this over to a qualified lechy to do. I really would not trust myself with this electrickery stuff. Each to his own. Mike Link to post Share on other sites More sharing options...
45609 Posted October 19, 2012 Share Posted October 19, 2012 Have to say I'd hand this over to a qualified lechy to do. I really would not trust myself with this electrickery stuff. Each to his own. Mike Mike, I wouldn't even trust you making me a cup of tea without me watching what you were doing.... Link to post Share on other sites More sharing options...
John_Hughes Posted October 19, 2012 Share Posted October 19, 2012 I guess switch cleaner will do the same thing, think I might have a can somewhere. Will give the CIF a try for now. Is that with or with out the dishes? I don't think I'd get away with that one. I've noticed that ultrasonic baths can be had on ebay for about £20, said to be suitable for jewellery etc. are these any good and what cleaning fluid would you use? Most fluids on ebay seem to be seaweed based! With a light run - glasses and suchlike. SWMBO knows all about it and hasn't objected once. I just pop the item in the cutlery caddy and away it goes. Ultrasonic baths were the 'big thing' for loco painting in North America back in the 70s, but they seem to have rather taken a back seat recently. I've never found them necessary myself, but some other people swear by them. Link to post Share on other sites More sharing options...
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