7mm Finney7 A3/A4 Corridor tender build.

[mickoo]

Next up on the bench for instruction photos is the A3 / A4 corridor tender.

The kit builds into either variant and the instructions will guide you though how to make the necessary changes for the A4 version. The tenders were all originally fitted to the A1/A3 class, however when the A4's came on stream the tenders were modified to work behind those engines, and remained so for the rest of their lives.

For this build I've opted for the original A1/A3 guise, if for nothing else other than it's the rarer (significantly shorter) of the periods and seems less modelled.

A quick clean up of the major parts, forming the cant rail and turn in curves results in a pretty quick build, like the streamlined non corridor tender built recently there are limited castings as yet, however it's pretty obvious where they go from the instruction drawings The objective of the photos is to try and show in 3D those areas that are best visualised by photos than deciphering 2D drawings.

I've skipped the chassis for now as the streamlined one is near identical except the rear steps and vacuum pipe fitting, that sub assembly will be built for the photos but there is no need to build the full chassis for this current task. The full chassis will come later so that the whole kit can be eventually displayed at shows.

Only a couple of photos so far.





It doesn't take long to get to this stage, with cleaning and tack soldering, about six or seven hours, the tank top is only temporarily fitted to brace the sides for cleaning; I also still need to add the left side hand rail and both side lamp irons and it's easier to solder those in with the tank top out of the way.

Enjoy

MD

 

[mickoo]

Moving onward and a reasonably productive day results in the tender insides all but finished.

The coal space folds up like a dream, someone really did their math and trig homework here, I thought the streamlined one was good but that was a more simple hopper, the corridor one has a dropped slope to the sides which makes the etch net a touch harder to work out.

Unlike the instructions I opted to build the whole inside as one piece, having also built the outside as one piece; there's nowt wrong with the instruction method, it works very well but doesn't suit my personal build style; the point being, it doesn't matter how you make it, it'll all still fit in the end if you take care.

Front ¾ view, still to fit (non castings) are the vent breather pipes, small stubby coal rail on top of the corridor roof and division plate.



From the side.



Clearly showing the dropped slope section on the coal space sides, there's a few bits of solder to finally clean off but overall it's good for the ball.

Test fitting into the main body.



As one would expect from it's pedigree it all fits where it should.



The corridor roof is just overlaid on the curved cant rail side, once finally fitted it springs in underneath into a recess so that the side sits on top of the corridor roof. The corridor roof is a nice etched part with proud ribs, at the end are small holes for the tabs for the stubby coal rail, during bending these can create small stress areas and the camera has picked them up wonderfully They're barely visible to the eye and only when the light catches it at certain angles, but that is the nature of bending such items.

The show as creases but are in fact gentle changes in curvature, a quick whizz with a #6 Swiss file and sanding sticks will reduce effect; the area is also matt black which will help as well.



Rear ¾ view, again showing the stress marks from the slots in the corridor top, more care during bending would help, not polishing to a mirror finish and choosing a different angle would also help as well

Front end tomorrow and the rest of the little pieces to close it out.

MD

 

[simond]

It's a bit like looking at those photos of rocket scientists building satellites.

I try, I really try, but I never get my models so crisp, sharp and antiseptically clean!

Brill.
Simon

 

[mickoo]

It's a bit like looking at those photos of rocket scientists building satellites.

I try, I really try, but I never get my models so crisp, sharp and antiseptically clean!

Brill.
Simon

I'll take some pictures tomorrow of the inside and underside of the tank and hopper, it'll make you feel a whole world better

The trick is to solder from the inside or if you do it on the outside, somewhere where you can clean easily, around the steps or handrail knobs would not be a good place

Other than the lift rings, the hopper lift ring brackets and breather pipe flanges, the soldering iron has not touched a single outside surface; a lot of the kit has been designed with hidden solder points which helps a great deal.

The lift ring pads were bent up and tinned only on the underside of the flat top part, not the bit that touches the sides, no need as the top fixing is more than sufficient, then a dab of flux on the hopper side, hold the part in place with tweezers and then hit it with a big tipped iron at 400°C, a good trick is to add a dab of solder to the iron tip first, it'll act as a heat transfer medium and you'll get the heat in much faster. You'll see and hear the flux spit and sizzle and that'll be it, part soldered. The only bit you have to now clean is the top of the bracket, which is flat and easily accessible.

The breather pipe flanges were tinned and the hopper placed on it's side with the flanges in place, then I just breathed on it with the micro flame about 2 - 3" away, I make three passes, each about 2 seconds long with say 3 -4 seconds between. The first warms the metal and then during the respite expands outward, the second brings it to near melting point and then expands out and the third just flashes over almost instantly and solders the part. Sometimes the solder will pop and flick the bit out of place, that's annoying but a fourth pass will allow you a few seconds to either whip it off the model or nudge it into place, of if you think it's going to happen (small parts usually do) then hold it in place with the point of a pair of tweezers.

Everything is soldered with 150°C solder, I've some 188°C but mainly use that for frames or large structural parts and I can never get on with 100°C at all, except maybe as a filler for valance to footplate edges.

All the parts are burnished with a soft fibre brush in the flat after cleaning up the cusps and punching the rivets, though I forgot to do the tender front so they'll show up with a slightly duller finish which is a trial to see if it helps the photography; really shiny models are the devil to photograph and show details for instruction photos.

Previously I'd clean the model every couple of days, the streamlined tender was every day, maybe twice, this tender has been cleaned a dozen times and more in just two days and is cleaned immediately I've finished used the iron at 400°C, that hot solder spatter starts to go green in a matter of hours. Cleaning is a quick squirt of Cillit Bang and general loose scrub with a ½" paint brush, no more than ten seconds or so and then a liberal wash in warm water. Drying is with a good quality kitchen paper towel roll, it's much stronger and leaves less fibres than say plain old bog paper, more a blotting function than wiping.

That all there is to it.

At the end of the day you really don't need it this clean, it just looks nice in the photos and on the stand for one or two shows, if your soldering is neat and smooth, then once painted no one will ever know. The streamlined tender is starting to tarnish now after a couple of months so it'll go into primer shortly, the B1 being nickel silver looks as clean and bright as the last day it was washed a couple of months ago; NS is a much better material to clean and keep clean.

MD

 

[simond]

Cheers Mick,

Interesting: I think the key differences in our techniques are:-

Solder - I use cored electrical solder for everything except whitemetal. I should experiment with lower MP solders.

Flux - following a discussion on the G0G website, when things were less fraught (but involving the key participant of the current debacle) I experimented with home brew citric acid flux. Citric acid crystals are available from home-brew shops, Wilko & the W3 for most reasonable sums. The detailed proportions in the mix seem to be fairly irrelevant but I make up a saturated solution in deionised water then add about half as much again of iso-propyl alcohol. This works very well, and doesn't go green, ever, it does however go sticky, but washes off without scrubbing; might be worth looking at.

I'm less brave with the gas torch. I do use one, and a homebrewed RSU. I might use the torch a bit more. The IPA in "my" flux occasionally catches fire if using the torch. This is not normally dangerous, but can be surprising!

Cleaning - I give my models a toothbrush-and-Shiny Sinks treatment after every modelling session, usually followed by 10 minutes in the ultrasonic bath. I tend to avoid the glass fibre brushes, as the only sensible place to use them is on the moon (the fibres wont float in the air, 'cos there isn't any, and they won't stick in your fingers 'cos you're wearing a space suit) so that kind of polishing is rare. A dozen times in two days, and I'm pretty sure my models would be almost a bright and shiny as yours!

Thanks for taking the time to explain.

Best
Simon

 

[Dan Randall]

The IPA in "my" flux occasionally catches fire if using the torch. This is not normally dangerous, but can be surprising!

I tend to avoid the glass fibre brushes, as the only sensible place to use them is on the moon (the fibres wont float in the air, 'cos there isn't any, and they won't stick in your fingers 'cos you're wearing a space suit)

Nice one Simon - your comments have just brightened my Sunday morning.


Regards

Dan

 

[Dikitriki]

Just to advise that Finney7 will be selling a new range of tinted glasses to aid viewing of Mick's models at shows

Richard

 

[mickoo]

Simon,

Why are you using flux with multicore solder?, it's already self fluxing and should only really be used for electrical work or tinning your iron, it's actually very good for that.

The flux in multicores is horrible stuff and most (all?) multicore solders these days are lead free, which makes them a witch at flowing. Many years ago we were tasked with moving all of our leaded solder from the workshops to comply with the new regulations, I kept my 500g reel of leaded multicore locked away and use it when I need it for those really difficult delicate repairs I would never use multicore on a model.

Some of the modelling solders still use traces of lead, which help it flow better, or seem to, not sure if my 150°C has lead in but it flows nicely when used with Safety Flux.

It did take me a while to find a solder that I get on with and I think mine is Carrs, but annoyingly I cannot remember and it is getting low so I will need some more and don't want to go through the same testing process again. Once I do find out, I'll buy a kilo of the stuff so that I never have to worry again

I only started using the blow torch recently so am still experimenting, I do need one with a much smaller flame, I've got two, both of indeterminate heritage (Ebay) and both have a flame about 25 mm long which whilst quite small, isn't small enough. I can get a 5-10 mm flame on a good oxy welding set, so it should be possible to achieve the same or better on a smaller butane torch

MD

 

[JohnFla]

Mick have you looked at a Chefs blow torch the flame can be reduced considerably.

 

[mickoo]

John,

I hadn't

Ideally it needs a flame 10 mm long or so, the ones I have are good for general model making but seem a bit too cumbersome for micro work and I'm sure the jewellery trade must use some even smaller.

I tried researching the Proxxon flame length but to no avail

MD

 

[SimonT]

I would recommend the Iroda Solder Pro 120. Use it for modelling and lighting the barbie. The flame is adjustable from 10-25mm. I hardly use my RSU now.

Simon

 

[mickoo]

Just to advise that Finney7 will be selling a new range of tinted glasses to aid viewing of Mick's models at shows

Richard

I'll see if I can bring some of the welding drapes we have in the trailer repair shop at work, they might work a bit better.


This is not our workshop.....it's too clean ...just a photo off the web.

What I like about this shot (also grabbed off the web) is that the guy welding is in shorts, T shirt and sandals, on a carpeted floor.



Even better there appears no means or ingress or safe egress, clearly a photo shoot, but if you're going to sell heavy industrial products to the industry, at least make some effort to look like you've complied with the regs

MD

 

[mickoo]

I would recommend the Iroda Solder Pro 120. Use it for modelling and lighting the barbie. The flame is adjustable from 10-25mm. I hardly use my RSU now.

Simon

I hadn't considered gas soldering irons with the tip removed, fairly sure we have a couple of those at work so will go and experiment

I've a gas barbie, turn on valve, push red button, barbie lit. Saves loads of time that is better spent drinking ale , but do respect those that chose coals or other combustible products .

MD

 

[simond]

Simon,

Why are you using flux with multicore solder?, it's already self fluxing and should only really be used for electrical work or tinning your iron, it's actually very good for that.

The flux in multicores is horrible stuff and most (all?) multicore solders these days are lead free, which makes them a witch at flowing. Many years ago we were tasked with moving all of our leaded solder from the workshops to comply with the new regulations, I kept my 500g reel of leaded multicore locked away and use it when I need it for those really difficult delicate repairs I would never use multicore on a model.

Some of the modelling solders still use traces of lead, which help it flow better, or seem to, not sure if my 150°C has lead in but it flows nicely when used with Safety Flux.

It did take me a while to find a solder that I get on with and I think mine is Carrs, but annoyingly I cannot remember and it is getting low so I will need some more and don't want to go through the same testing process again. Once I do find out, I'll buy a kilo of the stuff so that I never have to worry again

I only started using the blow torch recently so am still experimenting, I do need one with a much smaller flame, I've got two, both of indeterminate heritage (Ebay) and both have a flame about 25 mm long which whilst quite small, isn't small enough. I can get a 5-10 mm flame on a good oxy welding set, so it should be possible to achieve the same or better on a smaller butane torch

MD

Mick

It's leaded multicore, and I use it because old habits... I use it for everything except white metal. It is, as you say, very good for electrical work.

As I said before, I ought to experiment more.

I've quite a stash of lead free and agree that it's horrid stuff to solder with (free gift when site closed & stores were cleared) when I work out how to use it, or indeed, what to use it for, I'll let you know. Don't hold your breath. Meanwhile leaded is the better option.

Do try the citric acid flux, it seems very good.

My blowtorch is a black cooks' one that looks a bit like the Proxxon. Cost about a tenner from the local cook shop. Works well, and can also light the barbie now the built-in igniters are getting a bit inconsistent.

Best
Simon

 

[mickoo]

Simon,

The flux sounds interesting, mind I've now got about ten years of safety flux stashed away, I'm only 2/3rds through my first bottle in four years and recently bought two more...well you never know, always there for a rainy day

I'm getting better with the torch but a smaller flame one would also be much better for detail work, I found on this tender that even the big tip at 400°C wasn't touching the doubled up full thickness laminates, though I'm beginning to suspect my iron isn't as hot as the read out displays so maybe a new lead and iron are in order, the base unit'll be ok I reckon.

Anyway, just for you, solder



Cillit Bang does a lovely job of turning it all dark grey for you to see easier, which explains why I work very hard to not have any outside as it looks a witch!

With the interior in it was time to put the front in, it all folds up nicely and adding the little details to the top and bottom are often easier when it's in it's component parts and before the final build. Several bits had to be soldered from the outside so it's a bit messy in places, hmmmph




From the side.



There's a large white metal casting across the rear for the dog leg roof on the corridor as well as the scoop dome and water filler pipe but these are still in production so not fitted yet. The division plate will be fitted tomorrow along with the fittings at the front, water valves, hand brake stand and water scoop stand, finally some beading along the side and down the front and then front handrails, I'm not looking forward to bending the half round beading around the front at all

As is my usual want I bent something, usually I get away with it, but this time it was the corridor roof right at the rear by the dog leg, flicking the water off after cleaning it clipped some cutlery on the sink nothing I can do about it, once half etch is bent you're knackered, all you can do is straighten the best you can and move on, once the white metal part is in I'll have a better idea of how to repair it, a thin smear of Milliput before painting should cover up most of my recent visit from Cap'n cock up and his merry crew. It doesn't look as bad as the photo makes out but it's still blinking annoying

Right some wine, paella and a movie now me thinks

Enjoy.

MD

 

[simond]

Looks ok, Mick, if you need Milliput, I'll be surprised.

All you need is a big sign saying "don't touch", and the Vice President of the USofA...

Best
Simon

 

[oldravendale]

See, Mick. That's the down side of keeping on keeping on cleaning the damn thing.

Brian

 

[phileakins]

Or not doing the washing up first ....

 

[Yorkshire Dave]

Just to advise that Finney7 will be selling a new range of tinted glasses to aid viewing of Mick's models at shows

Bling it on....