RMweb Gold Donw Posted January 4, 2015 RMweb Gold Share Posted January 4, 2015 If your 75watt Iron is one of those Weller ones where the tip is held in by a screw you can try making tips from copper or brass rod. Yes it will corrode but a quick pass with a big file and re-tin. If you make tips from bits of scrap rod it doesn't matter if they get filed away and you can easily make special shaped tips for awkward to reach spots. I do think the clips add to the model. Will it show up that other models are lacking them? Regarding tinning I do miss having a moleskin, a pass over with a torch a dab of solder and a wipe with a moleskin left a nice thin tin coating. One of the items in my armoury is a microflame unit. A very small very hot flame not cheap though. Don Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 4, 2015 Share Posted January 4, 2015 "I have a 75 watt iron, which I find oxidises quickly and is a problem to keep clean. Any suggestions anybody? " Many soldering irons run far too hot for us - they are designed with continual use on production in mind. The simple expedient of turning the power down slightly should help considerably; I use a Variac but a lighting dimmer/switch will do just as well. I always plug my soldering iron into my Variac, rather than the mains, because my 80W Solon and 40W Antex irons run too hot even for 'ordinary' 60/40 188C solder but I can also use these, and my 25W and 15W irons, on 145C solder. David Link to post Share on other sites More sharing options...
puddlejumper Posted January 4, 2015 Share Posted January 4, 2015 When I use my RSU I tend to use soldering paste which is sold by C&L in a hypodermic syringe, not that cheap but it goes a long way if just used for detailing, and this way you can control the amount you use and it saves you tinning all the parts. Also I have to admit to using my RSU to solder a seam about 3 inches long with good results, with no sparking or humming at all . Now a lot of folks will frown on this admission but it worked for me, although I do not make a habit of this practice. Chaz I notice that you have the same compressor that I have, what do you think of it? I would not be without mine. ATB, Martyn. I exclusively use the Carrs solder paste when using the RSU, in fact I can't remember the last time I used ordinary solder!! I have recently built one of Jims lowmacs and it was built using only the RSU, lots of spot soldering but looks ok. Will try and post some pics of it if any interest?? 1 Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 4, 2015 RMweb Premium Share Posted January 4, 2015 Any chance you could post a photo of your Antex 80W? - include a hand (or something) in the photo to show the size. Chaz Here you go Chaz. Link to post Share on other sites More sharing options...
3 link Posted January 4, 2015 Share Posted January 4, 2015 (edited) Crumbs, look at the size of that! No wonder you keep burning your finger tips . Martyn. Edited January 4, 2015 by 3 link Link to post Share on other sites More sharing options...
RMweb Gold Donw Posted January 4, 2015 RMweb Gold Share Posted January 4, 2015 (edited) It may be 12ins but I would'nt use it as a rule :nono: Don Edited January 4, 2015 by Donw Link to post Share on other sites More sharing options...
RMweb Premium 2ManySpams Posted January 4, 2015 RMweb Premium Share Posted January 4, 2015 Crumbs, look at the size of that! No wonder you keep burning your finger tips . Martyn. Possibly overkill for some jobs but I found the Antex 25w somewhat lacking when attaching large bits of brass together. It does mean you can get in and out quickly. Link to post Share on other sites More sharing options...
3 link Posted January 4, 2015 Share Posted January 4, 2015 (edited) It does mean you can get in and out quickly. I bet it does Matron . But seriously I agree it does have a place in 7mm modelling, I also have an iron that size. I now have one of the Antex solder stations, and most of the time I use quite a fine tip on it. If I cannot get enough heat into the job I'm doing with the temperature wound right up, I just change the tip for something a little more chunky and that does the trick. My original Antex iron was over 25years old before it finally died, when I phoned them up at Antex they said because I was a loyal customer I could have 30% off my new iron, result. Martyn. Edited January 4, 2015 by 3 link 1 Link to post Share on other sites More sharing options...
chaz Posted January 4, 2015 Author Share Posted January 4, 2015 (edited) "I have a 75 watt iron, which I find oxidises quickly and is a problem to keep clean. Any suggestions anybody? " Many soldering irons run far too hot for us - they are designed with continual use on production in mind. The simple expedient of turning the power down slightly should help considerably; I use a Variac but a lighting dimmer/switch will do just as well. I always plug my soldering iron into my Variac, rather than the mains, because my 80W Solon and 40W Antex irons run too hot even for 'ordinary' 60/40 188C solder but I can also use these, and my 25W and 15W irons, on 145C solder. David So if I were to use this ploy with my 120W iron it would become a practical piece of kit? I suppose the idea is to limit the top temperature, thus reducing the oxidation problem, whilst retaining the bigger heat reservoir of a bigger iron? Chaz PS - just Googled "Variac" as I know nothing of these - they are seriously expensive for a piece of kit with limited use (for me). I suppose the dimmer switch will do the job much more cheaply. Something like this? http://www.amazon.co.uk/Mercury-350-109-DMR-1-Dimmer-Switch/dp/B000LAU04K/ref=sr_1_1?ie=UTF8&qid=1420386932&sr=8-1&keywords=dimmer+switch Edited January 4, 2015 by chaz Link to post Share on other sites More sharing options...
chaz Posted January 5, 2015 Author Share Posted January 5, 2015 Bit of a hitch last night. I decided to take a break from those clips and move on. Next step is to add the headstocks. Tinned them and the underside of the body and then attempted to solder them on. With the side overlays in place the body constitutes a sizeable mass of brass - a big heat sink. I put the RSU on 100% but it had very little effect and solder did not flow. Something wrong - I have fitted a new carbon rod (they do get gummy with the solder flux) and will try again later today. I don't really want to resort to the butane torch as I fear the detail work on the ouside near the corners will be at risk. WTS Chaz Link to post Share on other sites More sharing options...
Pete Harvey Posted January 5, 2015 Share Posted January 5, 2015 (edited) Use a hot air gun Chaz one with the clip on deflectors then you can just heat specific areas. Edited January 5, 2015 by Pete Harvey Link to post Share on other sites More sharing options...
Simond Posted January 5, 2015 Share Posted January 5, 2015 Chaz I've never known my RSU to fail - cruddy electrodes, poor earth, broken wires, but even doing great big (70') blacksmith coaches in brass, never seen a problem. HTH Simon Link to post Share on other sites More sharing options...
chaz Posted January 5, 2015 Author Share Posted January 5, 2015 Chaz I've never known my RSU to fail - cruddy electrodes, poor earth, broken wires, but even doing great big (70') blacksmith coaches in brass, never seen a problem. HTH Simon I am sure you are right Simon. Will have another go tonight otherwise..... Time to break out the 120W iron then? ....that may well be plan B Use a hot air gun Chaz one with the clip on deflectors then you can just heat specific areas. It's a thought Pete, but I don't have one so will have another go with the kit I have got - that could be a useful fall back though. Thanks chaps - it will not defeat me! Chaz Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 5, 2015 Share Posted January 5, 2015 So if I were to use this ploy with my 120W iron it would become a practical piece of kit?Yes, I would certainly expect it, and I would be surprised if it did not.I suppose the idea is to limit the top temperature, thus reducing the oxidation problem, whilst retaining the bigger heat reservoir of a bigger iron?Spot on; that's it exactly!Just Googled "Variac" as I know nothing of these - they are seriously expensive for a piece of kit with limited use (for me).I completely agree, Chaz. I only have mine because I intercepted it on its way to the scrap metal recycling skip! They're very useful if you want a supply of AC between 0 and 250V (not necessarily for model railways). I suppose the dimmer switch will do the job much more cheaply.Yes, and just as effectively.Something like this? http://www.amazon.co.uk/Mercury-350-109-DMR-1-Dimmer-Switch/dp/B000LAU04K/ref=sr_1_1?ie=UTF8&qid=1420386932 Just so!David Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 5, 2015 Share Posted January 5, 2015 Talking about RSUs and the return connection to the model, I do use the crock clip quite often; sometimes I clip the crock to the vice that is holding the larger part. However, most of the time I use this base plate: It's bit of a non-picture really but it shows the thick wire that my second-hand RSU came with connected to a sheet of 0.7mm brass that is stuck to a piece of contiboard with impact adhesive. I made the connection using the end of a redundant pin from a broken 13A plug that I soldered to the back of the brass before sticking it down; the wire enters the contiboard through a hole at the end and the terminal screw is reached through a hole underneath the contiboard. The whole lot sits on four little stick-on rubber feet to stop it skidding about the bench. Hope this gives some inspiration. David Link to post Share on other sites More sharing options...
Simond Posted January 5, 2015 Share Posted January 5, 2015 David That is rather nice. I compare it to my own efforts (1.6 mm aluminium with a 4mm banana socket and a 4" Record vice affixed thereto) and think, mmm, his looks nice AND functions..., whereas mine merely functions. Actually, the aluminium is a pain, it needs cleaning every 5 minutes. Next time, brass... Best Simon Link to post Share on other sites More sharing options...
raymw Posted January 5, 2015 Share Posted January 5, 2015 It's been a long time since i knew about such things, but I think the 'light dimmer' will chop the waveform, producing harmonics, and may not work too well with a transformer, if thinking of using it with an rsu, but will be good enough for a mains soldering iron. I use a pencil sharpener to trim the end of my rsu carbon rod, followed by a rough filing of the tip, to remove the flux inspired insulated crud. I build on a plate, similar to David's, but I used some stainless steel sheet, and screwed a piece on the back edge, to be able to wedge round stuff against, and small magnets can stop bits blowing around on the flat surface, 1 Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 6, 2015 Share Posted January 6, 2015 I would only use the lighting dimmer on resistive loads, such as soldering irons (and incandescent filament light bulbs); inductive loads, such as transformers, may heat undesirably but I cannot see why you'd want to reduce the power to an RSU, as it already has several power settings (you may use any pair of output sockets). Thank you for your kind comments, Simon. The brass does get a quick scrub over with wire wool once every Preston Guild but that's only because I think it's starting to look a bit scruffy! David Link to post Share on other sites More sharing options...
chaz Posted January 6, 2015 Author Share Posted January 6, 2015 It's been a long time since i knew about such things, but I think the 'light dimmer' will chop the waveform, producing harmonics, and may not work too well with a transformer, if thinking of using it with an rsu, but will be good enough for a mains soldering iron. I use a pencil sharpener to trim the end of my rsu carbon rod, followed by a rough filing of the tip, to remove the flux inspired insulated crud. I build on a plate, similar to David's, but I used some stainless steel sheet, and screwed a piece on the back edge, to be able to wedge round stuff against, and small magnets can stop bits blowing around on the flat surface, No question of using it with the RSU, which has four output sockets. Choosing two of the four controls the output. No, I would only want the dimmer for use with a big soldering iron where the waveform is irrelevant. Chaz Link to post Share on other sites More sharing options...
chaz Posted January 6, 2015 Author Share Posted January 6, 2015 Talking about RSUs and the return connection to the model, I do use the crock clip quite often; sometimes I clip the crock to the vice that is holding the larger part. However, most of the time I use this base plate: RSU_Baseplate.jpg It's bit of a non-picture really but it shows the thick wire that my second-hand RSU came with connected to a sheet of 0.7mm brass that is stuck to a piece of contiboard with impact adhesive. I made the connection using the end of a redundant pin from a broken 13A plug that I soldered to the back of the brass before sticking it down; the wire enters the contiboard through a hole at the end and the terminal screw is reached through a hole underneath the contiboard. The whole lot sits on four little stick-on rubber feet to stop it skidding about the bench. Hope this gives some inspiration. David Interesting device that obviously works - I had wondered whether such a plate would just form an excellent heat sink. I have a large sheet of nickel silver and plenty of chunky bits of MDF which could be pressed into service. I'm inclined (if I make one) to include a couple of "fences" set at a right angle against which parts can be set. Do you not lose some of the heating effect in the "joint" between your plate and the model? Chaz Link to post Share on other sites More sharing options...
Adams442T Posted January 6, 2015 Share Posted January 6, 2015 Interesting device that obviously works - I had wondered whether such a plate would just form an excellent heat sink. I have a large sheet of nickel silver and plenty of chunky bits of MDF which could be pressed into service. I'm inclined (if I make one) to include a couple of "fences" set at a right angle against which parts can be set. Do you not lose some of the heating effect in the "joint" between your plate and the model? Chaz I'm thinking of doing something similar and I think a back angled support coupled with a front 'bench-hook' type arrangement might work well. I presume the brass, being 0.7 mm wouldn't drain much heat anyway. Apropos of an earlier exchange, it reminded me of a late friend who had been a metallurgist during the war, and who in retirement repaired clocks, even going to the extent of casting brass to 17th C ingredient mixes just to 'get it right' for the clock in hand. He took great delight in showing me one day how tinned brass could be wiped until there was no apparent tinning visible then soldering the two pieces together. They formed a virtually unbreakable bond. Sam said that it was a common, but great, error to assume that there was any strength in the bulk of solder in a joint. Time spent cleaning and matching mating faces, with as little solder as possible used in the joint was Sam's watchword. Something I have endeavoured to follow ever since! Link to post Share on other sites More sharing options...
raymw Posted January 6, 2015 Share Posted January 6, 2015 Do you not lose some of the heating effect in the "joint" between your plate and the model? Yes, and no. Yes, some heat will be transferred to the plate - but does it matter, no. Assuming we are soldering a couple of brass sheets... The heat is generated wherever there is resistance in the circuit. The resistance will vary during the soldering process. There is a fair bit of misunderstanding of the soldering process using an rsu. If you start off, with the highest resistance joint between, say, the sandwich of brass, flux film, solder bead, flux film, brass, then that will alter, to the resistance of a liquid soldered joint. The highest resistance will then be elsewhere, but the idea is to remove the current, once the joint is made. The temperature of the 'working plate' does not effect the joint resistance between that and the brass sheet (much), so if that resistance is low, then little heat will be generated there. Of course, in practice, it is unlikely that the highest resistance will be at the solder joint interface, in particular if you are soldering a seam, or large area, since the two brass sheets will be electrically connected anyway, either by the previously soldered area, or by fortuitous touching of the two brass sheets. In that case, most resistance will be at the tip of the carbon rod, and that is where most heat will be generated. (The effective heat, however, depends on how fast the heat is moved away). It helps, if between your 'working plate' and the brass sheet workpiece, you have a good contact - hence my use of stainless steel as a work plate, and the sometime use of magnets. Also it needs far less cleaning, and no chance of soldering small pieces to it. Aluminium, brass, nickel silver, etc, will form an oxide/high resistance coating over time, and will need cleaning, (s/s is a bit better) and they are non-magnetic, so not as easy to ensure a good connection (apart from the pressure of the carbon tip). Of course, you could have a sheet of steel below the thin working plate, if you want to use the magnet clamping idea. If you just use ordinary mild steel as a work plate, then you will be forever cleaning it. Now, going back to the variac/dimmer/rsu - it depends on the rsu that you have. Many folk build their own, it is not exactly rocket science. Often, a car battery charger transformer, or other relatively high voltage secondary voltage is used, then a light dimmer must not be used to reduce the voltage (at least not the type illustrated). Also, Weller, and others make soldering irons running at 24V, via a transformer, and for those a light dimmer would be unsuitable, too. There are all sorts of folk reading these forums, and I would not want them to be misled, and generally, if I see something ambiguous, then I will try and clarify. Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted January 6, 2015 RMweb Premium Share Posted January 6, 2015 I use a a piece of galvanized steel sheet as my earth plate and wrap it aluminum baking foil and ditch it when it gets manky. I use magnets to hold bits together. 1 Link to post Share on other sites More sharing options...
chaz Posted January 6, 2015 Author Share Posted January 6, 2015 Confession time.... I think this mistake elevates me to this week's dozy p*ll*ck! Returning to my bench to paint some bridge abuttments - see my Furness Valley topic - I suddenly realised that I have probably tinned the headstocks and underside of the wagon body with 60/40 resin cored. I had a reel of that handy for restoring the soldering iron tip and I must have reached for it rather than the reel of 145. I don't know what the melting point of 60/40 electrical solder is but it's obviously way above 145! Later on I will clean most of it away with emery to get a flat surface (it didn't flow very well - and that didn't set alarm bells ringing - is there any hope? ) and re-tin with 145. I will let you know how I get on. Chaz Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 6, 2015 Share Posted January 6, 2015 "I had wondered whether such a plate would just form an excellent heat sink"Not really, for all the reasons given above (saved me from writing it all out - thanks!)."Later on I will clean most of it away with emery to get a flat surface ..." I would 'warm up' the components with a bow torch and then just wipe away the molten 183 with a tissue; no need to re-tin, just carry on from there. David Link to post Share on other sites More sharing options...
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