Atlantic's works: Portable layout - Scenic details next

[Atlantic 3279]

Chassis is effectively 80 thou plastikard (strictly two layers 40 thou) with brass bearings inserted for the axles.

[Atlantic 3279]

J6 after some more twiddling and tweaking. More or less ready for mould making now. Additional bits and pieces now include:

Lifting access patch on cab roof and reverse rod cover.

Valve front covers/guides (from 0.9mm brass wire, 1/16th" brass tube, Romford crankpin washers and discs of plastic), NEM mount for front coupling (Grantham spec), Nickel silver screw-on guard irons (try breaking those off if you can!) and a strip of 10 thou plastic to thicken the otherwise fragile edge lip of the running plate which was originally only a "scale" but impractical-for-resin 8 thou thick.

Filling in beneath the remaining thin areas under the running plate and other unwanted voids, along with filling and rubbing down of visible joints has also been attended to. another waft of primer and a final inspection/clean up to remove lingering imperfections will follow. I've already been giving thought to the procedures for making the moulds and pouring the castings. Let's hope I've thought about it properly!

Now getting ahead of myself, I'm sure that the separate chunks of the cast replicas will be capable of modification with minimal effort in order to produce a credible J2.....

[Dunluce Castle]

Fantastic work! Very neat and tidy, I look forward to the resin casting process

[Woodcock29]

Hi Graeme

You can put me down for a J6 body (this will replace the awful WSM body I have currently running around - it runs very well on its etched N/S chassis but the body castings are awfully crude even with the sheet metal cab I made to replace the W/M one) and in due course a J2 body.

I wonder in the future - a J1 maybe? It has the same driving wheelbase.

Many thanks for your work in this area.

Woodcock29

[Neville Hill]

A lovely piece of work: particularly impressed by the piston valve guides; very neat. A good-looking (and very plausible) GNR/LNER 0-6-0 is on it's way!
Hope the casting process goes well for you, Graeme.

Neville Hill

[earlswood nob]

Good morning all

I am following the construction of the J6 with great interest, as I attempted a J1 a couple of years ago and had to pause as I couldn't get the front splashers to look right.

I have since worked out how construct the splashers to 00 gauge with the front sandboxes to EM spacing.

The J2 would be easier as the steam chests are flush with the front of the splashers.

Atlantic's construction method of piston valve heads looks great, and would also be suitable for the J2 and even the Q3, if I get round to converting the spare Cotswold/NuCast kit thats in my rountuit cupboard. The Q1 boiler is earmarked to fit to an old Kay's C1, to produce a C2.

Great work as usual.

Earlswood nob

[Atlantic 3279]

Time to find out whether my mould making and casting plans will work. I've started with the boiler. To the basic boiler I firstly added, in 5 thou plastic and sellotape, this strange nosecone, extensions/enclosures to the firebox and what I imagine might approximate to a boat's keel board.

The cone and the sheeting added to the firebox serve to close off the interior of the boiler which will be filled by a rubber core piece, the coning at the front helping to centralise the front of the core piece when the inner and outer parts of the mould are assembled. the "keel board" is there to create a close-fitting division in the outer mould, along the bottom of the boiler, allowing the mould to be peeled back to facilitate extraction of a casting - especially the base of the smokebox which would otherwise lock any casting into the mould.

Instead of creating that keel board I could of course have just relied on cutting the base of the mould open with a blade once it had cured, but I don't want to risk damaging the original boiler with a blade just in case I choose (or need) to use it as the master for further moulds.

With a couple more strips of tape attaching the keel board to one wall of the moulding box, here's the boiler nose down with moulding rubber already poured in to fill most of the box. The box is tilted to allow/encourage any rising air bubbles to glide of the front of the valve chest and front of the firebox, rather than lodge against those faces. Fifteen minutes or so after pouring the rubber, before it begins to set, the mould will be placed properly upright so that the top face of the rubber sets "square" to the lines of the boiler. The core piece when finished will butt up to that flat face of the rubber.

I've actually jumped the gun a little by pouring a substantial part of the core piece at this stage too. Having noted how well the rubber bonds to itself, even when fresh rubber is poured onto previously cured stuff, I hope to be able to get away with a delay of up to 36 hours before I complete the core piece without finding the core piece tearing in two when pulled out of the boiler. The weight of the rubber within the boiler was helpful in negating the buoyancy that would have arisen with a light plastic air-filled boiler immersed in dense liquid rubber. I haven't forgotten the time when my air-filled GC bogie coal wagon body broke loose in its moulding box and bobbed up to the surface of the still liquid rubber! Obviously, when I apply Vaseline to the faces of the mould where I don't want things to stick together I'll take great care not to get any onto the strong joint that I want in the core piece.

[JASd17]

Dark arts 'Atlantic 3279'.

Are we going to have a 'band', 'party' or 'scold' of ex-GNR 'J' class locos?

Cheers,

John

[Danby Wiske]

Are we going to have a 'band', 'party' or 'scold' of ex-GNR 'J' class locos?

Surely the appropriate collective noun would be a 'cast'...

[Horsetan]

Are we going to have a 'band', 'party' or 'scold' of ex-GNR 'J' class locos?

Surely the appropriate collective noun would be a 'cast'...

It won't be "a cast of thousands", though....

[Atlantic 3279]

Dark arts 'Atlantic 3279'.

Are we going to have a 'band', 'party' or 'scold' of ex-GNR 'J' class locos?

Cheers,

John

I see that somebody has been checking up on corvidae terminology.

[Atlantic 3279]

I was going to make use of this afternoon in a leisurely fashion to post various updates on the casting of J6 parts, which has been going well. As it turned out, as well as mowing the lawn and fixing mother-in-law's kitchen extractor hood, I've spent rather a lot of time messing about with the J6 prototype chassis, determined to see whether I could in fact install multi-stage reduction gearing using those cheap nylon gears from Squires. As it turns out, it IS possible, but it certainly wasn't straightforward. I've had to bore out gear centres to suit different spindle/axle sizes, thin down wide gears, tilt the motor to a very specific angle in order to still fit within the firebox, slightly re-design one of the stretchers in the chassis and trim away some of the base of the firebox. I've also had to fiddle around quite a lot in order to get gears into suitable hidden positions, drilling various holes in the chassis for spindles, only to realise in some cases that I hadn't planned carefully enough and would either have to plug the original hole and drill a new one elsewhere, or worse still try to "move" the hole by just a fraction! However, I hope there will be gains from this exercise too:

1. These nylon gears as stated are MUCH cheaper than the usual model railway gear-sets or gearboxes.
2. It should be easy to keep the gearing very quiet even if lubrication gets overlooked.
3. I hope the nylon material and the staged reduction will give more efficient power transmission.
4. The change from the Romford 40:1 ratio that I was using to 1:48 now installed should let the motor spin 20% faster for the same line speeds. Electrical effects such as the higher back EMF from the faster spinning motor, combined with more efficient conversion of power through the gears (if obtained) should, I hope, result in the motor drawing less current and not getting so hot when hauling a decent load. This point had been concerning me somewhat with the original gearing. We don't want to see fireboxes going soft with the heat and caving in, do we? Unlike most locos with at least a metal chassis, or some that are all metal, an all resin J6 won't have any effective heat sink...

I will post those other updates as soon as time allows.

[Seagull]

2. It should be easy to keep the gearing very quiet even if lubrication gets overlooked.

The best bet is to apply a white silicone grease when you assemble the gears.

Unlike oils, or oil based greases it does not degrade the nylon and tends to stick around rather than being thrown off the gears.
You can get it from your local Maplin (expensive) or look around online and find it on @mazon or Fleabay much cheaper.

Alan

[john coffin]

Looks interesting Graeme.

Just a word of caution about Silicone Grease, be careful where and how you spray it if you intend to paint in the vicinity, it can have
a bad impact on paint finish, particularly spraying.

Paul

[Horsetan]

I have read that car automatic transmission fluid - Dexron II or III - also works well in loco geartrains. 1 litre will keep you going almost in perpetuity.