7mm Jan's 7mm Workbench

simond

Western Thunderer
I use my (home brewed) RSU lots, mainly, but not exclusively for adding details, including adding whitemetal to brass by tinning the brass first with "normal" solder, then a drop of lowmelt, loads of flux and a quick blat of heat from behind, it melts, joins & refreezes very quickly - similar approach to Raymond.

I do use solder paint with it, but I'm equally likely to use ordinary cored solder wire, possibly cut into tiny pieces, along with a drop of flux.

I think there was an article about building RSUs, possibly 20 years ago in the Gazette or MRJ?. I bought a Maplin transformer kit, which provides a 240V primary, plus iron cores. This is connected to the mains via a suitable push button, with a neon indicator, and a 2A fuse in the plug. I wrapped my own secondary from approx 2mm varnished copper wire, and it works fine. I only ever use it on "max". The whole thing is mounted in a steel box, and sits on the floor under the bench. I slip my slipper off, and press the button with my left big toe.. other digits are available. It is fully isolated, and the case & ground pin is earthed - this is important!

I did use an ally ground plate, it's ok, but gets dirty and is an effective heat sink. I now have a brass plate on top of a bit of MDF on which my smaller bench vice is mounted. This is used occasionally (thus the vice is also an earth), and is also an effective heat sink, but the simplest & best approach IMO is to fix the ground wire to the model, somewhere inconspicuous.

I also use a 25W Antex, and a ruddy great 80W Weller thing. The latter is my normal tool of choice for any heavy soldering, but the mains lead is irritatingly short.

I guess it's down to taste, but I find it to be a useful weapon in the armoury. (And I'm building in 7mm)
Best
Simon
 

adrian

Flying Squad
Lovely Adrian, i'm surprised the heat from the 80W didn't buckle the etches..
Thanks - to be honest I've found them less likely to buckle with the larger iron. I use solder cream and so using the 80W I can be in and out in a fraction of a second so it never has time to heat up the rest of the etch. With the smaller iron it takes longer to get the joint up to temperature meanwhile the heat is dissipating throughout the etches.
 

oldravendale

Western Thunderer
It just goes to show - different techniques suit different people.

I've heard of - in fact knew until his recent demise - someone who built an etched brass wagon using the RSU and no other means of soldering. He was a good builder and it was just to prove a point, but it can be done. Nevertheless he continued with his traditional method most of the time, using a hot stick.

For myself, building 7mm kits, (and it's a very personal thing) I use an Antex 50W soldering station for almost everything, but I have an RSU which has it's uses from time to time. I'd rather not be without it. I normally attach the wire directly to the model, or occasionally may use a crocodile clip, although the contact is not as good or reliable. Very occasionally I use baking foil which gets rid of the heat sink problem. I use it quite often for white metal as it's sometimes easier to get in from behind, and if that's the case do exactly as described by simond. The trick with that, to my mind, (and it's counter intuitive when handling white metal) is to use the RSU on maximum output. A "blip" on the foot pedal is usually all that's needed, but with experience (make sure you practice this first!) you can actually see the solder flash but your reactions have to be perfect. In fact any problems I've had with white metal have usually occurred because I've forgotten to adjust the temperature of the Antex, although even there a large hot bit and quick in and out is often better than a low temperature over time approach.

However, I reckon this is another of those threads which proves how different techniques can be used to create fundamentally similar items. I'll bet that we could put our finished models side by side and not be able to tell the difference, so is there truly a "best" way? I think not. I started by using a small iron and 70 degree solder, and despite the warnings of the gurus it's still stuck together and no-one has looked at the van concerned and said "well, you should have used a higher temperature solder". Discussing techniques with different people over time has lead to my current preference for high heat and short dwell time, and that does it for me apart from making (usually) perfectly strong joins.

And right now I'll admit that I can't show you any examples because house move has meant time in the workshop is very limited. But normal service will be resumed at some time in the future.

B
 

Dikitriki

Flying Squad
I've always thought that you were either in the microflame or RSU camp. Me, I'm in the microflame camp. I periodically find my RSU and think I ought to give it another go....then I reach for the soldering iron:)

Richard
 

oldravendale

Western Thunderer
Oh yes, forgot about microflame. I use mine about as often as the RSU, which doesn't tell you how often but is a reminder that it's another useful tool/technique within the arsenal.

B
 

simond

Western Thunderer
Ah yes, a selection of Naked Flame Devices from "micro" to "macro" are ranged within easy reach of the SimonD workbench. Very useful for unsticking the bits I stuck on wrong...

(And occasionally for sorting something that needs a serious bit of heat input, like the boiler and 3-lamination smokebox of my Dukedog)

Not usually my first choice for assembly. I'd probably grab the RSU...
Best
Simon
 

Lyndhurstman

Western Thunderer
My apologies for not being clear enough - this was that sort of thing I was alluding to Resistance Soldering because unfortunately quite a few people use this as the "reference" material for resistance soldering when I consider this to be quite misguided information.

For example from that site

Sorry but that is quite frankly laughable - as a definition it is so far wide of the mark it's ridiculous. Soldering is a simple mechanical process so we are not persuading, there is no urging or prevailing to be done, we are not trying to reason with the metal and convince it to stick to another component. "frequently dissimilar"???? I would suggest that 99% of the time it is similar metal, either two etched brass components, or nickel silver. Dissimiliar occasionally when adding whitemetal components - although I have yet to see any one demonstrate the addition of whitemetal components with an RSU - although happy to be proved wrong. Finally what's with the stick together at room temperature bit? Sorry but that definition is more applicable to using a bit of superglue than soldering.


A little bit of background might be appropriate then. I first came across RSUs in 1984, at that time Lord Gretton (Stapleford Park Miniature Railway) turned up at my Dads with various Japanese built HO Brass American Locos and amazed at the detail and being curious as to how they could build them we started investigating. This led to an article on Resistance Soldering and getting information from NorthWest Shortlines (my Dad was importing Sagami motors from them at the time). So in 1985 my Dad commissioned a batch of transformers from a firm in Nottingham and I built a batch of 25 RSUs - at the time we couldn't find an affordable electrical foot switch to cope with the current so we used a pneumatic foot switch from RS. These were sold under the Cherry Scale Models banner - check the Guild archive Volume 9 issue 8 Autumn 1985. We sold it as the "Hot Spot Soldering Unit". They were all built by me as my Dad was an electrical numpty - he once put up a shelf in the workshop and there was a wire in the way so he just cut it out. Bob Moore turned up at lunchtime for their usual Saturday business meeting (in the pub!!) wondering why he wasn't answering his phone! Guess which wire he'd cut!!
View attachment 66529

I subsequently "acquired" a London Road Models RSU. Quite frankly it sat on the workbench gathering dust because there was nothing it could do that wasn't far easier and quicker with using a standard Weller iron. I have since upgraded to an ERSA RDS-80 and this was money well spent and the RSU went up on ebay. For example this 2mmFS cattle wagon was built using the RDS-80 LNWR Special Cattle Wagon - Cherry Clan

So my apologies for the long reply - but it's safe to say I have had a go with an RSU and it's not for me - as they say your mileage may vary.

In reply to your comment I would respond with find a silversmithing course at a local college and give it a go. I did and learning how to silver solder in my opinion is invaluable.

Hi Adrian

I'm very grateful for your input here. It's true that we look at the experience of others as gospel, and act accordingly. I know I'm guilty of this. Which is why I always work under the umbrella of "personal enlightenment" .

It seems to me - as someone who can get solder all over the place - that an RSU would help to produce better work for me. But having spent a fair few years wielding a Weller for The Government, I'm pretty good with the smaller stuff, it's just the larger irons seem to amplify my inadequacies!

Cheers

Jan
 

Lyndhurstman

Western Thunderer
Hello Chaps
All this is wonderful stuff, and the variety of means and methods gives me a lot of food for thought; I must admit that a microflame tool holds appeal - anything that doesn't have a lead to irk gets a boost to the rankings!

I've looked at upping the bit size on the 40W, but there doesn't seem to be anything meatier than the one I have, so an upgrade in wattage is looking likely. When funds permit...

Thanks again

Cheers

Jan
 

farnetti

Western Thunderer
I'm a fan of the 'lots of heat very quickly' school of soldering. So tend to use flame and RSU with an Ersa as back up.

Occasionally resort to 24 hour Araldite or Loctite 480 when parts are too small (and they haven't pinged off into the ether first).

Probably the best soldering method is the one you feel comfortable with. I am quite keen to try out some silver soldering but always found it a bit of a dark art, but maybe with the flame?

Ken
 

Lyndhurstman

Western Thunderer
I'm a fan of the 'lots of heat very quickly' school of soldering. So tend to use flame and RSU with an Ersa as back up.

Occasionally resort to 24 hour Araldite or Loctite 480 when parts are too small (and they haven't pinged off into the ether first).

Probably the best soldering method is the one you feel comfortable with. I am quite keen to try out some silver soldering but always found it a bit of a dark art, but maybe with the flame?

Ken

Hi Ken,

Thanks. After making a mid-range Horlicks of the fix of solebar to body with the Antex 40W last night, I'm probably going down the flame route too . If for no other reason than to take it apart and start again!

Cheers

Jan
 

Rob Pulham

Western Thunderer
I'm probably going down the flame route too

HI Jan,

I pretty much use the flame for as much as I can get away with. I only resort to the iron if I can't use the flame for any reason. - You just need lot's of clips and self locking tweezers to act as heat sinks to stop bit's already added from falling off.
 

Scale7JB

Western Thunderer
Hi Jan,

I had a thought whilst I was building last night, and recalled the photos you had posted.

Having a look again now, the brass that you seem to be soldering looks awfully yellow and tarnished. Are you cleaning up the area that you are soldering with some glass paper or a scratch brush. In all honesty and without doubt a 40w will be more than enough for what you're doing, but the metal does need to be clean..

JB.
 

Lyndhurstman

Western Thunderer
Hi Jan,

I had a thought whilst I was building last night, and recalled the photos you had posted.

Having a look again now, the brass that you seem to be soldering looks awfully yellow and tarnished. Are you cleaning up the area that you are soldering with some glass paper or a scratch brush. In all honesty and without doubt a 40w will be more than enough for what you're doing, but the metal does need to be clean..

JB.

Hi JB

Thanks for your input. I agree - the brass does look tarnished. I did pretreat the area with a fibreglass brush before applying both flux and solder, but I'll do double on the other side.

As a newbie to this size of working, I'm erring toward thinking that part of the problem is that the expanse of the body - basically a 100mm x 60mm sheet of brass) is taking the heat away from the seam too quickly. And if i recall (I'm in Shropshire on a weeks holiday at the minute...) the Antex doesn't have anything more than an 1/8" screwdriver bit to it.

Cheers

Jan
 

Lyndhurstman

Western Thunderer
.. But It's Watt You Do With It That's Important

Shropshire is a-fixed firmly in the Rearviewmirror. I have come back to work to find the Draper 60W waiting for me. Having girded my loins (other junctions are available...) I took the plunge:
IMG_3797.JPG
Smooooth.... lots of heat at the tip, and a nice flexibility to the lead made short work of my fear, and served to render the previous effort (more reminiscent of a pigeon with a bad case of Montezuma's Revenge) into something s bit more pleasing to the eye - and a darn sight more structurally useful!

I still have doubts about whether there's enough room left between the back of the solebar and the bufferbeam hole to be able to fit the whitemetal boss of the buffer housing in without modification of the later, but Doubt Dispelled is a Step Forward - and A Moment For Pleasure.

Thanks to you all for your support.

Peace

Jan
 

Lyndhurstman

Western Thunderer
A Short-lived Warm Spell
The euphoria of previous posts was extremely brief. After no more than two evenings radiance, a brief flare of activity is over: the Draper is cold and dead. Forensic footling (that probably rendered the guarantee invalid) has identified the expiration of the element. To say I'm hacked off is STBO. It was all going so well..

I've tried to restore some kind of progress via the 40W Antex, but - despite switching to solder paste and introducing blocking efforts to try and restrict the thermal diaspora - I'm back to looking for portable oomph.
IMG_3821.JPG
Above: Evidence of Ex-Lax utilised in affixing the corner and bracing plates.
 

jonte

Western Thunderer
A Short-lived Warm Spell
The euphoria of previous posts was extremely brief. After no more than two evenings radiance, a brief flare of activity is over: the Draper is cold and dead. Forensic footling (that probably rendered the guarantee invalid) has identified the expiration of the element. To say I'm hacked off is STBO. It was all going so well..

I've tried to restore some kind of progress via the 40W Antex, but - despite switching to solder paste and introducing blocking efforts to try and restrict the thermal diaspora - I'm back to looking for portable oomph.
View attachment 67185
Above: Evidence of Ex-Lax utilised in affixing the corner and bracing plates.

'Thermal diaspora' ......This is well over my head, Jan, but all looks very neat.

May I wish you more power to your ......Antex-y thingy!

Jonte.
 

Lyndhurstman

Western Thunderer
'Thermal diaspora' ......This is well over my head, Jan, but all looks very neat.

May I wish you more power to your ......Antex-y thingy!

Jonte.
Hi Jonte

Thanks. I think my increased verbiage is inversely corellated to my progress! Basically, using the smaller iron, I'm trying to corral the heat into the area that needs it, which would result in a better environment for joint and joiner.

Cheers

Jan
 
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