Resisdence soldering or normal soldering whats the difference?

[Enterprisingwestern]

One unmistakable advantage of an RSU over a conventional soldering is the ability to extend pick ups on the side of a plastic frame, as in diesel locomotives which only pick up on 2 out of three wheelsets, and coach bogies with electrical contacts. The RSU doesn't build up a bank of heat and melt the surrouding area.

 

Mike.

[Izzy]

So far I have read nothing to convince me I need to spend a large sum of money on an RSU - a factor not mentioned - that will give me an advantage over a conventional iron. When I decided to try my hand at 2mm some years ago it was suggested to me that an RSU would be pretty essential to do anything in the scale. Having looked around at them and been balked at the considerable cost - never having used or needed anything past plain fixed wattage irons before, and with a simple Antex 15w iron to hand I tried that first. It is all I have ever used since in this particular scale, and I can't see the need for anything more, which would be to my mind overkill in terms of heat/power for the size of work.

 

Perhaps it boils down to how a particular individual works, their workspace, the scale they work in, and their current irons, ( I have a number from 15w -75w each with a range of tip sizes bought over several decades of use), which determines whether or not they give an advantage to someone.

 

Izzy

[JeffP]

Agreed.........but you say you were "balked at the considerable cost".

 

Now add up what you've spent on soldering irons........   LOL

[TheWeatheringMan]

So far I have read nothing to convince me I need to spend a large sum of money on an RSU - a factor not mentioned - that will give me an advantage over a conventional iron. When I decided to try my hand at 2mm some years ago it was suggested to me that an RSU would be pretty essential to do anything in the scale. Having looked around at them and been balked at the considerable cost - never having used or needed anything past plain fixed wattage irons before, and with a simple Antex 15w iron to hand I tried that first. It is all I have ever used since in this particular scale, and I can't see the need for anything more, which would be to my mind overkill in terms of heat/power for the size of work.

 

Perhaps it boils down to how a particular individual works, their workspace, the scale they work in, and their current irons, ( I have a number from 15w -75w each with a range of tip sizes bought over several decades of use), which determines whether or not they give an advantage to someone.

 

Izzy

Hi,

The fact that an RSU (commercially made) can be a large outlay was mentioned in my first post in this thread - hence my mentioning the potential to convert one from a battery charger at a considerable saving in cost.

 

Regards

[TheWeatheringMan]

A crocodile clip has several sharp contact points and does't give as much contact area as other methods and is therefore a point of higher resistance where you don't want it, something best avoided.

 

Much better would be some sort of small clamp with parallel jaws that gives a bigger contact area You could also solder or bolt the return lead (with an eyelet on the end of it) to the model. That works better in 7mm where the model has some weight and is more likely to stay where you want when working on it.

Hi,

Although this is true, in practise the use of a crocodile clip on the negative lead of an RSU does not effect its working in any way and was indeed the way the earliest units marketed made the negative connection.

The very fact that a crocodile clip has the sharp points actually makes for a more reliable negative contact whereas a flat (which it will not be if you think about it) clip cannot in most cases achieve such a good contact.

I have used such as a bulldog clip on occasions and when the RSU is powered I've heard a distinct 'fizzing' from the bulldog clip and felt the heat resulting - an absolutely deffinate sign that there is poor contact or resistance at that area.

No, of the two options the crocodile clip is the better in most situations.

 

Regards

[Izzy]

Agreed.........but you say you were "balked at the considerable cost".

 

Now add up what you've spent on soldering irons........   LOL

 

Yes, but it was done over time, decades, as the need for them arose, and long before RSU's even came into existence as far as I am aware. Besides, several posts indicate that conventional irons are still needed for much work. My point is the considerable extra outlay for the perceived advantage. I have no problem with spending out when I feel that I will gain something, just concerned with wasting money when I don't benefit. Obviously some feel they do gain, whilst others don't.

 

Izzy

[EKR]

Izzy it's like any other tool, the more familiar you are with it the more use you will make of it.

 

If you only make three or four kits a year then an RSU is a very expensive luxury, but then so is a high end chassis jig.

 

I use both a TCU & a RSU nearly daily so I think it was a great investment.

It's cost is less than a decent loco kit.

 

Only you can say what it's value is to you.

As someone who has had a workshop for over twenty years I have/ had tons of tools, but in daily use I found I used the same half dozen every day as they just did what I wanted. Familiar tools give familiar results.

[raymw]

Based on a toroidal transformer - easy to put on a few turns of thick cable for the secondary winding - I would guess a diy rsu would cost about £20.00 for the Tx, a fiver for the rod holder, a tenner or so for the foot switch, and make your own case. Of course, if you have to buy everything brand new, then you'd need to add the cost of cable, the case, etc. The rod holder and foot switch could be made, if the cost was a problem, or you liked a more basic diy approach, either way it's far easier to make than a temperature controlled soldering iron.  Using a simple wooden frame, and a length of piano wire, you can also use it for cutting expanded foam, straightening wire, electrolysis of water to produce 'Brown's gas' and other applications where you need high current and low voltage, (but then, I use a soldering iron for other uses, too).

[raymw]

I don't see anything in what i have written above can be disagreed with, unless it is thought it is possible to make a temperature controlled soldering iron easier than making a rsu. I'm not saying one is better than the other, I am saying you don't necessarily have to spend money on a 'brand name', but you can if you want to, of course.

[Siberian Snooper]

We seem to be getting to the point where this thread is going round in circles.

[Jol Wilkinson]

Based on a toroidal transformer - easy to put on a few turns of thick cable for the secondary winding - I would guess a diy rsu would cost about £20.00 for the Tx, a fiver for the rod holder, a tenner or so for the foot switch, and make your own case. Of course, if you have to buy everything brand new, then you'd need to add the cost of cable, the case, etc. The rod holder and foot switch could be made, if the cost was a problem, or you liked a more basic diy approach, either way it's far easier to make than a temperature controlled soldering iron.  Using a simple wooden frame, and a length of piano wire, you can also use it for cutting expanded foam, straightening wire, electrolysis of water to produce 'Brown's gas' and other applications where you need high current and low voltage, (but then, I use a soldering iron for other uses, too).

 

 

I don't see anything in what i have written above can be disagreed with, unless it is thought it is possible to make a temperature controlled soldering iron easier than making a rsu. I'm not saying one is better than the other, I am saying you don't necessarily have to spend money on a 'brand name', but you can if you want to, of course.

I think that your view that a RSU is easy and cheap to make is inaccurate and implies that the commercially produced ones are far too expensive.

 

While you can buy a toroidal transfer of ebay for about £20, a 100va rated one will cost about £35. As you won't know how many turns the primaries have, you will have to determine the secondary winding turns by trial and error to get the required output. 

 

To handle the current required you should use 2.0mm dia enamel copper wire, costing £8 from Maplins. You could use several parallel windings of thinner wire, but you would need four lots of 1.0mm diameter to give the same cross section of one 2.0mm diameter winding. About twenty five years ago I wound a RSU transformer using a  Maplins 100va transformer kit (no longer available). It was not at all easy to get the secondary windings neatly and firmly in place. That was winding them around the commercially made primary windings, I can imagine it would be even harder around a toroidal transformer.

 

The Radiospares metal cased footswitch used on the LRM RSU  costs £26.84 inc. vat, the cheapest plastic one from the same source is £13.48. The Graskop RSU footswitch looks like the Radiospares metal cased one as well.

 

A turned brass collet probe holder and handle, flexible high current silicon cased cable, metal case, mains lead and plug, etc. Yes you can make your own or cobble up something that you regard as every bit as good or even better, but the commercial producers have to supply components that are safe and fit for purpose in the hands of even the most inexperienced user. You can make your own RSU safely and relatively cheaply if you know what you are doing. Even then, given some of the suggestions that I have seen on the web as to how to go about it, then I would consider that they are unlikely to meet the needs of the modeller producing 2mm, 4mm or 7mm models as a commercially produce RSU designed specifically for that purpose.

 

Of course, no one that has made their own will ever admit it didn't work perfectly, for less than at least half the price of a "branded" item.    

 

Yes the commercially produced RSUs are an expensive tool. So is a loco chassis jig as well as many other "specialist" tools. I wouldn't be without my RSU and the same applies to my Unimat lathe, GW rolling mill, Minicraft 12v drill, Badger airbrushes, compressor and spraybooth. I could make models without them and none get as much use as my Antex TCU soldering iron, but they all enable me to make better models more easily than I could without them. 

 

[EKR]

The OP has already made his decision and was looking for a compelling reason to change his mind.

There is no compelling reason.

 

An RSU will do lots of small tasks faster, speeding ones workflow. 

How much his time is worth is up to him.

[TheWeatheringMan]

 

Of course, no one that has made their own will ever admit it didn't work perfectly, for less than at least half the price of a "branded" item.    

 

Why is it necessary to make such a sweeping and inaccurate statement.

 

The RSU that I reconstructed from a battery charger as described earlier works in every way just as well as some of the commercial versions and a damm sight better than at least one other commercially offered one that a friend has - he has even asked me to build him one like mine so he can get rid of the one he owns - he is a 7mm modeller by the way and has used mine regularly in preference to his bought unit. The problem with this is that although i'd be more than happy to do so for him, the battery charger I used is no longer available it seems and an alternative dual voltage item now seems overpriced an of course therefore almost wipes out the advantage of the conversion on cost grounds - although the likely better working should still be obtained.

 

As I said in my original post, when the first suggestions of making such a conversion were published there were several self appointed experts who maintained this would not work.

Subsequent events have shown that provided one uses a battery charger up to the job (not a cheap market stall offering but a decent item from the likes of Halfords or another motor factor) then such a conversion not only saves money over a commercially sold unit but WORKS PERFECTLY WELL and in some cases BETTER than a bought in unit.

 

I am well aware that such a conversion is not for everyone but for those that have done one the pleasure of using a piece of equipment that has been produced by oneself in immense.

 

Incidently your costings are based on one of the most expensive sources - there are several other suppliers of components that can be used - I sourced my components from another major supplier and acheived a considerable reduction on your quoted prices - an example being the footswitch, which cost just over £20 (twenty) less than you quote. All of the components I incorporated in my conversion have stood the test of time in regular use by more than one modeller.

 

I am sure more modellers would be able to benefit from the advantages, and there are plenty as has been pointed out by others, of an RSU, when they are aware of all the facts regarding such conversions.

Of course as has also been pointed out, an RSU will not replace a conventional soldering iron (mine certainly hasn't) but the two together gives the modeller the best of both worlds.

 

Regards

[Enterprisingwestern]

We seem to be getting to the point where this thread is going round in circles.

 

https://www.youtube.com/watch?v=tjRJHnrPNtU

 

Mike.

[Jol Wilkinson]

Why is it necessary to make such a sweeping and inaccurate statement.

 

The RSU that I reconstructed from a battery charger as described earlier works in every way just as well as some of the commercial versions and a damm sight better than at least one other commercially offered one that a friend has - he has even asked me to build him one like mine so he can get rid of the one he owns - he is a 7mm modeller by the way and has used mine regularly in preference to his bought unit. The problem with this is that although i'd be more than happy to do so for him, the battery charger I used is no longer available it seems and an alternative dual voltage item now seems overpriced an of course therefore almost wipes out the advantage of the conversion on cost grounds - although the likely better working should still be obtained.

 

As I said in my original post, when the first suggestions of making such a conversion were published there were several self appointed experts who maintained this would not work.

Subsequent events have shown that provided one uses a battery charger up to the job (not a cheap market stall offering but a decent item from the likes of Halfords or another motor factor) then such a conversion not only saves money over a commercially sold unit but WORKS PERFECTLY WELL and in some cases BETTER than a bought in unit.

 

I am well aware that such a conversion is not for everyone but for those that have done one the pleasure of using a piece of equipment that has been produced by oneself in immense.

 

Incidently your costings are based on one of the most expensive sources - there are several other suppliers of components that can be used - I sourced my components from another major supplier and acheived a considerable reduction on your quoted prices - an example being the footswitch, which cost just over £20 (twenty) less than you quote. All of the components I incorporated in my conversion have stood the test of time in regular use by more than one modeller.

 

I am sure more modellers would be able to benefit from the advantages, and there are plenty as has been pointed out by others, of an RSU, when they are aware of all the facts regarding such conversions.

Of course as has also been pointed out, an RSU will not replace a conventional soldering iron (mine certainly hasn't) but the two together gives the modeller the best of both worlds.

 

Regards

Well, we could continue this discussion, but clearly we have different views on how a RSU should be designed and constructed.

 

Regrettably, any suggestion that it is possible to produce something from commonly available items - such as a battery charger - will potentially lead those that don't appreciate what is involved into making something that isn't always fit for purpose. Those that advocate such an approach don't always provide sufficient details as to what they used and why. 

[TheWeatheringMan]

Well, we could continue this discussion, but clearly we have different views on how a RSU should be designed and constructed.

 

Regrettably, any suggestion that it is possible to produce something from commonly available items - such as a battery charger - will potentially lead those that don't appreciate what is involved into making something that isn't always fit for purpose. Those that advocate such an approach don't always provide sufficient details as to what they used and why. 

Hi,

Whilst I do agree with what you say here in that the conversion articles have been, in some cases, lacking in details that should really be included, I would point out that when I offered my first post in this thread together with the photos, I very clearly said that if there was interest in such a conversion I would describe what I did.

Had I done so I would have included FULL details of the work involved so that anyone contemplating doing the same could, with variations to accomodate differeing componets, virtually use the post as an instruction leaflet.

However almost nobody seemed to be interested in more information so I did not take it any further.

 

As to how an RSU should be 'designed and constructed' there is clearly a very wide scope for variation - as is proved by the fact that the very unit that someone is biased to is the same unit that my 7mm friend finds unsuitable for his needs!.

 

Regards

[runs as required]

Thanks everyone for a cracking good read (a really enjoyable escape from the chore of addressing Christmas Cards assigned by SWMBO).

 

I've just been on line to check the price of the LRM RSU: £175.

Maybe I shall stick to the staedily accumulating rage of soldering irons that started with the gas stove one 'Uncle' Vic shewed me how to use in 1947. He was a badly burnt RAF  'Guinea Pig' who made the most beautiful scratch built 4mm LT&S tanks.

 

.....back to the %@#*% card writing....

 

dhig

[Jol Wilkinson]

Thanks everyone for a cracking good read (a really enjoyable escape from the chore of addressing Christmas Cards assigned by SWMBO).

 

I've just been on line to check the price of the LRM RSU: £175.

Maybe I shall stick to the staedily accumulating rage of soldering irons that started with the gas stove one 'Uncle' Vic shewed me how to use in 1947. He was a badly burnt RAF  'Guinea Pig' who made the most beautiful scratch built 4mm LT&S tanks.

 

.....back to the %@#*% card writing....

 

dhig

Or the Swanage Models version - £145.

 

For those that want more power there is a probe equipped American Beauty model, $568 (£362). That's in the USA, I can't find a UK price. That is just the starting point, they do a 1.8 KW version for $1084 which should suit the needs of the most demanding 7mm modeller   

[raymw]

I deliberately do not give instructions wrt mains electrickery stuff on an open forum - it is a question if you are capable in sorting things out for yourself, or if you haven't a clue and need finely detailed point by point instructions.  There are suppliers of components, other than Maplins or RS, or ebay, and before I wrote my approximate prices I checked their on-line prices.  Fwiw, when I built my multi-purpose unit, which would most likely be too involved for those who want to buy rtr, I purchased four, unused, 12V toroidal transformers, rated at 85A secondary, in a sensible metal case, for £60.00 including delivery from ebay (that's £15.00 each). These were apparently surplus to a 12V lighting installation. 

 

Anyway, it doesn't bother me in the least what others do, (unless it effects me - selfish or what?) but it does annoy me when folk appear to pick an argument, without thinking that others may be right in what they say.

 

I guess it's a fundamental difference in approach based on the serpent in one of GBS's plays - “You see things; and you say ‘Why?’ But I dream things that never were; and I say ‘Why not?’”  (never read the play, but JFK oft' misquoted the text)

[PGC]

Yes, but it was done over time, decades, as the need for them arose, and long before RSU's even came into existence as far as I am aware. Besides, several posts indicate that conventional irons are still needed for much work. My point is the considerable extra outlay for the perceived advantage. I have no problem with spending out when I feel that I will gain something, just concerned with wasting money when I don't benefit. Obviously some feel they do gain, whilst others don't.

 

Izzy

 

My posts indicate that for me, I prefer to use a conventional iron to tin the items before using the RSU. That's not the same as having to use a conventional iron - if one uses solder paste or cream, there's no need for the use of a conventional iron, and RSU can suffice.

 

One area that I've seen worked but not tried myself is soldering copper clad track. One puts a small dob of solder cream on the line of the rail, lays the rail, holds the rail down with RSU, uses second probe on the copper clad, presses the foot switch, hey presto.

 

Phil

 

 

Phil

[Graham Hughes]

 That's not the same as having to use a conventional iron - if one uses solder paste or cream, there's no need for the use of a conventional iron, and RSU can suffice.

 

If you use solder paste or cream you can melt it with a dab of a hot iron just as well as with an RSU.

 

I don't think anyone is questioning what you can do with an RSU. It is pretty clear that it does all that is intended of it and many people are very happy with it and find it preferable to an iron. Some people seemingly find it easier to become accomplished at soldering with an RSU than a conventional iron which, as I posted earlier, is probably reason enough to buy one if that is something that is a factor. Although I suspect that might be down to the proliferation of myths and falsehoods surrounding the "black art" of soldering as Adrian mentioned earlier. Soldering is really very simple.

 

The question some of us are wondering (mostly, it appears, those who already feel comfortable soldering with a conventional iron and have developed the requisite skills to use it effectively)  is the converse of your comment: In what situation is there a need to use an RSU where a conventional iron can suffice? (Not just suffice, but do the job entirely satisfactorily) So far I have not seen anything described as an advantage of an RSU which I don't already do with a conventional iron and in pretty much exactly the same way, bar the means of applying the heat.

 

I started watching this thread with interest as I wanted to know what I was missing out on by not having an RSU. My conclusion is that, for me, I can stop feeling I really should be using one and continue with my trusty iron. With forty years experience of soldering with an iron I am now reasonably confident in my abilities to solder with it. I can now rest easy knowing that I don't have to learn a new technique and invest a sizeable sum in new kit and that having an RSU would not enable me to do anything I can't do perfectly well already. I can concentrate on improving my more deficient skills in other areas of model railway building.

[Jol Wilkinson]

If you use solder paste or cream you can melt it with a dab of a hot iron just as well as with an RSU.

 

I don't think anyone is questioning what you can do with an RSU. It is pretty clear that it does all that is intended of it and many people are very happy with it and find it preferable to an iron. Some people seemingly find it easier to become accomplished at soldering with an RSU than a conventional iron which, as I posted earlier, is probably reason enough to buy one if that is something that is a factor. Although I suspect that might be down to the proliferation of myths and falsehoods surrounding the "black art" of soldering as Adrian mentioned earlier. Soldering is really very simple.

 

The question some of us are wondering (mostly, it appears, those who already feel comfortable soldering with a conventional iron and have developed the requisite skills to use it effectively)  is the converse of your comment: In what situation is there a need to use an RSU where a conventional iron can suffice? (Not just suffice, but do the job entirely satisfactorily) So far I have not seen anything described as an advantage of an RSU which I don't already do with a conventional iron and in pretty much exactly the same way, bar the means of applying the heat.

 

I started watching this thread with interest as I wanted to know what I was missing out on by not having an RSU. My conclusion is that, for me, I can stop feeling I really should be using one and continue with my trusty iron. With forty years experience of soldering with an iron I am now reasonably confident in my abilities to solder with it. I can now rest easy knowing that I don't have to learn a new technique and invest a sizeable sum in new kit and that having an RSU would not enable me to do anything I can't do perfectly well already. I can concentrate on improving my more deficient skills in other areas of model railway building.

Graham,

 

it really depends what you mean by "satisfactorily". I have found that I can fit items more easily and cleanly in many case with an RSU, than with a soldering iron.

 

For example,  smokebox wrappers, splasher tops ("wrappers"), cab roofs, handrail knobs, coach door ventilators, sprung buffer bodies, handrail knobs, cab beading, a curved running plate onto a valance on an assembly jig. In fact anything that needs to be held in place while you solder it. Take a splasher top, you can tin it, locate it in place and while applying light pressure with the probe, solder it. I find that easier than holding it in place while applying the soldering iron, you effectively have another hand.

 

Clearly there are occasions where an RSU doesn't do the job as well as a soldering iron, such as running a seam along the inside of a valance or soldering a folded w-iron. When I start assembling a kit I invariably use only the soldering iron. As it gets towards completion, the iron is used solely to tin the items I fix in place with the RSU.

 

On of the major benefits is the fact that the heat is applied within the joint and so I don't get any solder on or alongside the item I am soldering in place and which then requires cleaning up. That's why I find it a worthwhile tool.

 

Jol

[Adrian]

Take a splasher top, you can tin it, locate it in place and while applying light pressure with the probe, solder it. I find that easier than holding it in place while applying the soldering iron, you effectively have another hand.

 

 

That's what wooden sleepers were invented for! I have half a dozen bits of wood I use as holding pieces for soldering. So in the case you cite of splasher tops I would use a wooden sleeper on the outside of the splasher top holding it in place on the splasher side. I would then apply the iron to the inside of the joint, the solder follows the heat so forms a nice fillet on the inside so minimal cleaning up on the outside. A can do the job without needing the extra hand, Simples!

 

So as usual it comes down to how you use the tools you have. As I and others have acknowledged some people find RSUs a bonus and that's great, however it is not guaranteed to be "the solution", it does not always "do lots of small tasks faster". A conventional iron can do small details just as well as an RSU but different people find different ways to work which may tip the balance one way or the other. 

 

If someone is undecided then it is worth testing one but just be prepared to stick it on eBay if you don't get on with it.

 

However in one respect I concur with Jol's statements, do not consider one built from a battery charger unless you have suitable qualification in power engineering and transmission. You are effectively creating a short circuit in using an RSU and even 2mm copper wire gets quite warm and toasty on a high power setting. Unless you very very carefully select the battery charger you will significantly overload the transformer, and mains electric is not something to be taking chances with. As I have said when we were building the Cherry Scale Models units in the 80's we looked at various off the shelf transformers, including battery chargers. Nothing available was suitable and we had to get the transformers custom built.

[PGC]

If you use solder paste or cream you can melt it with a dab of a hot iron just as well as with an RSU.

 

I don't think anyone is questioning what you can do with an RSU. It is pretty clear that it does all that is intended of it and many people are very happy with it and find it preferable to an iron. Some people seemingly find it easier to become accomplished at soldering with an RSU than a conventional iron which, as I posted earlier, is probably reason enough to buy one if that is something that is a factor. Although I suspect that might be down to the proliferation of myths and falsehoods surrounding the "black art" of soldering as Adrian mentioned earlier. Soldering is really very simple.

 

The question some of us are wondering (mostly, it appears, those who already feel comfortable soldering with a conventional iron and have developed the requisite skills to use it effectively)  is the converse of your comment: In what situation is there a need to use an RSU where a conventional iron can suffice? (Not just suffice, but do the job entirely satisfactorily) So far I have not seen anything described as an advantage of an RSU which I don't already do with a conventional iron and in pretty much exactly the same way, bar the means of applying the heat.

 

I started watching this thread with interest as I wanted to know what I was missing out on by not having an RSU. My conclusion is that, for me, I can stop feeling I really should be using one and continue with my trusty iron. With forty years experience of soldering with an iron I am now reasonably confident in my abilities to solder with it. I can now rest easy knowing that I don't have to learn a new technique and invest a sizeable sum in new kit and that having an RSU would not enable me to do anything I can't do perfectly well already. I can concentrate on improving my more deficient skills in other areas of model railway building.

 

There is no one situation where an RSU is the only tool you can use, nor is there one situation where only a conventional iron can suffice. Whether it be the manufacturers of RSU's or the snobbish attitude of users that have created the myth about RSU's I know not, but the popular myth that an RSU is better than a conventional iron is rubbish.

 

In the same way that a PC and a MAC, or an estate car and a car based van do the same thing but in different ways, RSU's and conventional irons also do the same thing but in different ways. Personally, with irons (certainly not computers, give me a PC any day!), I like both because, as Jol says, there are times the RSU makes life that much easier when doing certain features, such as the smokebox wrapper I did last night. Perfectly soldered and no cleaning up. Easy!

 

My advice - if you don't feel the need to buy one, and you're happy with your iron, don't waste your money on an RSU. I would suggest, if you can, you find an RSU and try one, but I do realise that's a logistical problem. Perhaps one of the RSU manufacturers could start an RSU hire scheme for those who want to try one but not spend the money unless they think it's worthwhile.

 

As always with tools, it's horses for courses. Hope that helps a little bit.

 

Phil

[TheWeatheringMan]

That's what wooden sleepers were invented for! I have half a dozen bits of wood I use as holding pieces for soldering. So in the case you cite of splasher tops I would use a wooden sleeper on the outside of the splasher top holding it in place on the splasher side. I would then apply the iron to the inside of the joint, the solder follows the heat so forms a nice fillet on the inside so minimal cleaning up on the outside. A can do the job without needing the extra hand, Simples!

 

So as usual it comes down to how you use the tools you have. As I and others have acknowledged some people find RSUs a bonus and that's great, however it is not guaranteed to be "the solution", it does not always "do lots of small tasks faster". A conventional iron can do small details just as well as an RSU but different people find different ways to work which may tip the balance one way or the other. 

 

If someone is undecided then it is worth testing one but just be prepared to stick it on eBay if you don't get on with it.

 

However in one respect I concur with Jol's statements, do not consider one built from a battery charger unless you have suitable qualification in power engineering and transmission. You are effectively creating a short circuit in using an RSU and even 2mm copper wire gets quite warm and toasty on a high power setting. Unless you very very carefully select the battery charger you will significantly overload the transformer, and mains electric is not something to be taking chances with. As I have said when we were building the Cherry Scale Models units in the 80's we looked at various off the shelf transformers, including battery chargers. Nothing available was suitable and we had to get the transformers custom built.

Your last paragraph contains factual errors that are very wide of the mark.

Firstly you are not producing a 'short circuit' with an RSU - the carbon probe acts as a point of resistance (giving the unit its name) and effectively 'uses' the current in exactly the same manner as a conventional light bulb or an electric fire.

Secondly you are not doing anything with the mains current which is isolated from the soldering probe by the fact that the mains is on the transformer primary winding and the soldering probe is fed from the secondary winding.

Thirdly, the use of the unit does not cause undue heating of the battery charger transformer which is built to withstand considerable mistreatment in its intended field of use.

As I have said in a previous post, I have used my RSU to solder the rails (code 100) to pcb strips on an exhibition layout that involved continuous operation of the RSU for twenty second intervals over a period of aprox thirty mins while we did the work - very little heating of the transformer resulted which proves beyond all doubt the durability of the RSU as such a job a far beyond the normal use the a modeller would subject an RSU too - I am more than happy to demonstrate this application to anyone.

Fifthly, no knowledge of electircal design is needed to undertake such a conversion for oneself - all that is necessary is the same common sense that is applied to handling the electrics within our hobby as a whole.

 

Whilst as a former commercial supplier of RSU's I understand that you would not wish people to build their own but to buy a ready made unit but it is wrong to make statements that are not correct to put people off doing a worthwhile and relatively easy build.

The fact that many people have very sucessfully done such a conversion proves beyond all doubt that it works and all the reasons that are sometimes given why it wont work dont alter the fact that it does.

Remember that according to the rules of aircraft design the bumble bee cannot fly - problem is nobody has informed the bee and so he keeps on flying !.