My 7mm dabblings

[Steph Dale]

Mick,
For blackening I use diluted Birchwood Casey Gun Blue, which I rub on with a cotton bud. Make sure the parts are cleaned (small ultrasonic bath) to ensure even patination. The 'fluff' you describe is likely from contamination; it's not something I've faced before.
Once parts reach the level of patination you require drop them immediately in to a bath of warm water. Leave them there for an hour or so to ensure the blackening chemical are well and truly stopped, dry and then burnish with nothing more than toilet roll; this will remove the excess blackening, but leave the patination behind.
If you find you have a spotty or uneven coating this will tend to be from the blackening solution reacting too harshly - either too long in the solution, or the solution to strong, in which case it will flake off. Re-applying a weaker solution with more rubbing from a cotton bud and then rinsing will tend to solve the issue.
i hope that helps!
Steph

 

[Rob Pulham]

Hi Mick,

I tend to polish metal black with a cotton bud - it's abrasive enough to polish without removing the underlying blacking.

 

[mickoo]

Cheers, I have Carr's 'metal black for steel' and applied with a cotton bud, I probably didn't apply it for long enough (5 mins) and only rinsed briefly once it had gone dry.

I'll try again and take a photo of the discolouration I got, I say fluff but it's more like it's been sprayed with matt, not a sheen any more.

I burnished with very worn emery and a soft comm polishing stick which are obviously still too abrasive

 

[OzzyO]

Before applying the blackening clean the metal with meths.

 

[mickoo]

Ok, small update, working on the front end brakes, just a few pull rods to add and join the leading transverse brake rod with some insulating material, thin plasticard top and bottom I think, I can only do that on the last assembly really, or try and work out some sort of sliding section that can be slide between the two parts to join them up. It needs something as it's all a bit sloppy right now.

The photos.

Front end brakes showing dummy pull rod behind leading wheel



Ragstone layshaft and bearings fitted in place, the nickle silver pull rods are mine, a bit thick just to get the forked end, there are other (neater) ways, but under here this'll have to do , just need to add some dummy pull rods to the brake cylinders and hand brake linkage to finish off.





Photo showing inner chassis sliding under layshaft dummy pull rods.



Inner chassis in place, the two pull rods do not touch as the ones linked to the transverse linkage can become live if the pull rods each side of the wheel touch on tight curves.


Front view showing layshaft.


Overall side view with Ragstone axle boxes and spring castings.


Somewhere along the line there's a slight measurement issue with the spring hangers, they are about 1½-2mm too long and the snubbing block hangs too low in relation to the frame arches and axle box, it's a simple case of cutting the drop link rod from the anchor bracket, drilling a 1mm hole in the bracket and then rejoining.

On this side it's all glued with two part epoxy, just as well as the photo has highlighted a couple of the brackets that need adjusting to line up correctly, on the other side it was all soldered, stronger but a lot more fiddly, I've still divided on which is the best way to attach these small parts so this'll be a trial model in that respect.

I don't know where the 1½ -2mm discrepancy comes from, as all the parts measured individually all measure up perfectly, but altogether the snubbing blocks end up too low, still, I would rather they were too long than too short, trimming them back took no time at all

 

[alcazar]

Which are the snubbing blocks? Not come across that before.

Is that layshaft soldered in place? On the last but one photo, the far end looks to have dropped?

 

[mickoo]

Snubbing blocks are the blobs on the end of the spring drop links, that may not be the correct term but they look like some sort of resilient type of mounting. If they're not then they effectively just become very thick washers.

The angle of the shaft is correct and all the pull rods line up. Because the layshaft centre is higher than the leading brake block pull rod pivot then the rod between the two has a down ward slant to it. I'll post a snap shot of the relevant part of the GA that'll explain it shortly.

Addendum, image of brake shaft and pull rods attached.

 

[alcazar]

Thanks.
Reading other posts on here, it appears that some of my problem may be that I'm using a gun blue PEN, not the liquid.

I was assured that it was better by the gunshop guy that sold it me.........maybe for guns, but not, apparently, for model locomotives: absolutely no chance of diluting it.

 

[Dog Star]

Mick,

I feel that I have seen that image before... and if that is so then the prototype is one of the early builds where the water scoop mechanism is a large lever rather than a screw thread.

 

[mickoo]

Thanks.
Reading other posts on here, it appears that some of my problem may be that I'm using a gun blue PEN, not the liquid.

I was assured that it was better by the gunshop guy that sold it me.........maybe for guns, but not, apparently, for model locomotives: absolutely no chance of diluting it.

Well if it makes you feel any better, I'm using Carrs metal black for steel and you basically have to submerge the item in the stuff for it to blacken and none of this wash with water afterwards as it'll never get black enough.

I did find though that even after the first pass the axle and rims started to rust again, so this time they are super black after cleaning back...again... I do think that some of it is the flux (Bakers fluid) I'm using, even though it's no where near the wheels when soldering the inner chassis I'm beginning to suspect the fumes give off by soldering in the general area are so aggressive that they are attacking the blacking.

So for the last few pieces of work on the inner chassis I've taken the wheels and axles off and stored well away from any soldering to see if the rusting comes back.

 

[mickoo]

Mick,

I feel that I have seen that image before... and if that is so then the prototype is one of the early builds where the water scoop mechanism is a large lever rather than a screw thread.

Graham, that's correct, the drawing is for the GN 8 wheel coal rail tender, however, cross reference with other photos and information show that the brake shaft and linkages appear to match the rest of the LNER 8 wheel tender fleet, certainly Gresley and Thompson and the layshaft arrangement matches photos of Tornado and Blue Peter, but then being preserved there is no evidence that these follow as built tenders, certainly not Tornado

What is as yet undetermined is the brake cylinder arrangement, this drawing shows two vacuum cylinders, being as the Peppercorn locos have steam brakes, then it may be that the tenders followed suit, unlike previous 8 wheel tenders in Gresley and Thompsons days, Peppercorn pacifics did not swap tenders. Being as I really don't need to model that aspect it's not too much of an issue, though I do concede, some sort of light block needs to be added in there somewhere I think.

NRM do GA's for most 8 wheel tenders so one could get the required info, though I'm told the A1 tender drawings do not exist and they used Gresley patterns for the non corridor example on Tornado, could just be wild hearsay

 

[Steph Dale]

I did find though that even after the first pass the axle and rims started to rust again, so this time they are super black after cleaning back...again... I do think that some of it is the flux (Bakers fluid) I'm using, even though it's no where near the wheels when soldering the inner chassis I'm beginning to suspect the fumes give off by soldering in the general area are so aggressive that they are attacking the blacking.

It is. If you think about it the vapour concentrates the acid as well as giving more energy. I too use Baker's fluid, but anything that's been on the workbench gets a wash in hot water at the end of every modelling session; so far no real problems with the stuff. I also make sure the soldering iron bit is well coated with solder before turning off the iron; modern soldering iron bits are iron coated so will rust if left exposed to air, solder and flux.

Steph

 

[Locomodels]

Why don't you use the 'Safety Flux' ?

It works on everything for me, and that includes steel. Perhaps not stainless, though I have never tried it.
You still need to wash things thoroughly, but soft soap and water are just perfect.

I used to be a dyed-in-the-wool Bakers Fluid man, but the Safety Flux is so good I don't need to be any more.
Bakers Fluid is really agressive, as are some of the Carr's fluxes. It is also not good for ones respiratory system.

 

[Rob Pulham]

Why don't you use the 'Safety Flux' ?

Its what I use for everything I solder and despite buying in a stock of it I am only just into my second bottle since 2010 - I do use a large syringe to apply it though which I find so much more controllable than the brush that I used to use to apply it......

 

[alcazar]

Another vote for Safety Flux.

 

[Ragstone Andy]

Graham, that's correct, the drawing is for the GN 8 wheel coal rail tender, however, cross reference with other photos and information show that the brake shaft and linkages appear to match the rest of the LNER 8 wheel tender fleet, certainly Gresley and Thompson and the layshaft arrangement matches photos of Tornado and Blue Peter, but then being preserved there is no evidence that these follow as built tenders, certainly not Tornado

What is as yet undetermined is the brake cylinder arrangement, this drawing shows two vacuum cylinders, being as the Peppercorn locos have steam brakes, then it may be that the tenders followed suit, unlike previous 8 wheel tenders in Gresley and Thompsons days, Peppercorn pacifics did not swap tenders. Being as I really don't need to model that aspect it's not too much of an issue, though I do concede, some sort of light block needs to be added in there somewhere I think.

NRM do GA's for most 8 wheel tenders so one could get the required info, though I'm told the A1 tender drawings do not exist and they used Gresley patterns for the non corridor example on Tornado, could just be wild hearsay

Hi Mick,

Yes, the above is my understanding of them, plus:

They were steam braked, hence A1 did not work the non stop services as (vac braked) corridor tenders could not be easily fitted (RCTS 2a p198)

Not sure about the GA (there probably isn't one) : Again ref to RCTS 2a, they were the same as A2/3 - and the entry for their tenders is :
No new tender drawing/used drawing issued in March 38/this drawing was a combined revision of the mods to the streamlined non corridors tenders of 1936 - see p170

Brake cylinder - 60532 has the only surviving tender of this type, I have some pics, just a matter of locating them!

Andy

 

[mickoo]

It is. If you think about it the vapour concentrates the acid as well as giving more energy. I too use Baker's fluid, but anything that's been on the workbench gets a wash in hot water at the end of every modelling session; so far no real problems with the stuff. I also make sure the soldering iron bit is well coated with solder before turning off the iron; modern soldering iron bits are iron coated so will rust if left exposed to air, solder and flux.

Steph

Steph, makes sense, I've no issues with Bakers and it fluxes all materials with out problems and the iron tip is always well fluxed and only really suffers if I push it to 400°C ! where upon it often dries out so to speak, but at 300°C it's always clean

 

[mickoo]

Hi Mick,

Yes, the above is my understanding of them, plus:

They were steam braked, hence A1 did not work the non stop services as (vac braked) corridor tenders could not be easily fitted (RCTS 2a p198)

Not sure about the GA (there probably isn't one) : Again ref to RCTS 2a, they were the same as A2/3 - and the entry for their tenders is :
No new tender drawing/used drawing issued in March 38/this drawing was a combined revision of the mods to the streamlined non corridors tenders of 1936 - see p170

Brake cylinder - 60532 has the only surviving tender of this type, I have some pics, just a matter of locating them!

Andy

Andy, cheers, I forgot to reference ACTS it'd make sense if the loo was steam braked to make the tender steam braked as well.

Re 60532, photos would be nice but I'm guessing there's only one cylinder and probably quite small, I was surprised how small the A1 loco cylinder was when compared to previous vacuum braked Pacific's.

 

[mickoo]

Why don't you use the 'Safety Flux' ?

It works on everything for me, and that includes steel. Perhaps not stainless, though I have never tried it.
You still need to wash things thoroughly, but soft soap and water are just perfect.

I used to be a dyed-in-the-wool Bakers Fluid man, but the Safety Flux is so good I don't need to be any more.
Bakers Fluid is really agressive, as are some of the Carr's fluxes. It is also not good for ones respiratory system.

Paul, Jeff, Rob, never heard of it will have to look this up

Having said that, Bakers is free from stores at work and safety flux is £££? so, one uses Bakers and respects it's limitations for free or uses safety flux and pays your money LOL, but, I think a trial bottle will be winging it's way toward my bench at some near point in the future

I do tend to liberally soak the victim joint with copious amounts of flux before soldering, it is free after all, probably too much in all honesty and I've no ill effects from the fumes....yet....that I'm aware of

 

[Susie]

Hi Mick,

Your 'snubbing blocks' are actually Spencer Auxillary Springs. They are an akwardly shaped steel casting with a rubber block inside at the top, with a steel pressure plate at the bottom on which bears the nut attaching it to the suspension rod from the end of the spring. The nut is kept in place with a shaped keeper that is screwed onto the plate. The works drawing is 0/341. There are eight items all together in each spring. They were designed and produced by the Spencer Moulton Company of Bradford-on-Avon, and act as shock absorbers to the main leaf-springs

All the best,

Susie