Accucraft to Roundhouse Burner Conversion - Overhaul of an Accucraft Ruby

I'd like to see more of those horrible Accucraft burners replaced with something more reliable and quiet. To that end, here's how I did mine.

It was easier than I expected. Mind you, this was before Jason at The Train Department started selling

their drop-in Accucraft replacement burners. I've not seen them in action but I'd be very surprised if they didn't function as advertised.

Early 2019 - My first loco, a Ruby I'd owned from new for five years by this point, was heavily modified.

Frankly, I think most are aware of the reputation held by Accucraft burners - Replacing it should've been the loco's first mod. I'd cleared the workbench and was ready to try retrofitting a Roundhouse burner. Whilst it was in bits, the loco would receive yet more modifications:

• Replace the piston rings (weren't yet due for replacement, but they were originals and would soon have been due, if left alone)
• Tighten up some slack in the motion
• Add and improve some detailing
• Rewire the headlight, and fit a rear headlight
• Replace the loco's plastic "safe case" box
• Add a driver

And finally, have a go at at the job of weathering this live steamer. No more "NRM-esque", immaculate locos lugging filthy wagons around, for me..


13/03/2019
In order for the RH burner to "drop-in", the Accu-Crap burner's brass mounting plug had to be removed from the boiler.


Bit of a pain to do, but still less trouble than taking the boiler to be re-hydro-tested if I'd have simply de-soldered the plug.

18/03/19
On test - the burner mounted in much the same way as it would be on a RH boiler, with a spare boiler band. The countersunk screw under the burner "foot" is finger-tightened against the footplate to further support the burner. For now, I'm borrowing the gas tank, valve and pipework from RH Fowler "Victoria".

The original Accucraft gas tank has given me no problems in the past, and like the steam regulator, has a fine-control valve from The Train Department. so I'll be re-using those, and make a new "adapter" gas pipe - one end having an Accuraft M5x0.5mm fitting, the other having a Roundhouse ¼"x 40ME fitting.


Certainly not the most elegant solution, but this loco finally has an acceptable burner.

Slightly quicker to raise steam, silent running, lights far more easily and stays lit. Night-and-day difference to the Accu-Crap burner - To the bin with that, and good riddance.

After stripping the boiler back to bare, the headlight conduit was soft-soldered onto the steel boiler bands. (Pilfered the brass originals for my Mamod TE1A, years back)

05/04/19
Having wasted too much time on useless commercial paint strippers in the past, I usually strip with lacquer thinners and an old toothbrush or brass-wire equivalent. I like to keep the thinner in a glass jar, (occasionally straining out the paint lumps) and re-use it for some months, until it eventually loses it's potency.

 The blower pipe and smokebox braces (ex-bicycle spokes) were also soft-soldered on, along with dummy mounting flanges cut from brass, with dressmaker's pins as rivet heads.

The Ruby chimney, not having the usual saddle casting where it attaches to the smokebox, also received a flange. Still looks a bit odd, but now passable for a welded replacement made in a sugar mill's workshop, after the original Baldwin cast iron chimney was shattered in an accident. Well, that's the excuse I'm running with..

This however, means the chimney itself is effectively soldered onto the smokebox - so the screws holding holding the smokebox onto the saddle aren't accessible in the usual way, namely by removing the chimney, and using a Phillips screwdriver through it's mounting hole. Instead, I've soldered M2 studs into the saddle, so the smokebox is now retained similarly to full-scale practice, with nuts. The screw holes in the bottom of the smokebox were slightly enlarged, allowing it to be wiggled onto the studs. Whilst it's now fiddlier to fit nuts on the studs, I no longer have to deal with the stripped-out Phillips screws the saddle originally had.

04/06/19
To this day, I still don't know just how Accucraft finishes their locos, but it's the toughest coating the works here have yet encountered; I'll give them that. I figured it was powder-coat or something. But it was still chipped, glossy, and I wanted satin - the plan being to scotch-brite the original gloss finish, de-grease the chassis in enamel thinners, then etch prime and engine enamel.
Returning to the thinners bath a few hours later, I was dismayed to find I now had several more days of work to do, scrubbing the half-lifted remains of the original finish, out of every nook and cranny. Areas such as behind the wheels and eccentrics were left alone and painted over, as for whatever reason, they weren't as badly affected by the thinners..

The rocker arm locking screws were replaced with some spare Roundhouse cheese-heads; As the original grub screws tended to seize, resulting in their sockets being stripped out trying to loosen them. I also added a third lubrication pipe. Now the eccentrics and both axles can be oiled without having to upturn the loco. With a little effort, the "little ends" of the eccentric rods can also be oiled with a fine-tipped nozzle passed under the side tanks. I apologise for the horrific sight I've made of the pipes; A recently-bought set of tube-bending springs should see my copper-mangling consigned to the past..


10/07/19
After masking the moving and mating parts, the boiler and chassis were done with black etch primer, lightly scuffed with scotchbrite, followed by satin black engine enamel. The smoke/fire boxes were hit with potbelly black. We use the exact same stuff (albeit brushed) on smoke/fire boxes at Woodford.

 Prior to painting the chassis, some styrene scraps were epoxied together, filling the unsightly gap between footplate and boiler. Opting for styrene was partially because I was very tired that day, and partially just testing the limits of the stuff. Worst case, if it goes droopy, I'll knock up a brass equivalent.

Over some other days, a dummy firebox and ashpan were knocked up from brass - A little rough, but it'll do.

I then had to flip the trailing wheelset frame upside down, and machine a longer pivot pin for it. The paint was removed from treads and flanges with cotton buds dipped in thinners.

 The original ceramic smokebox insulation disintegrated when it was removed, and was replaced with new material.

 The cab finally received a rear "arch", with provision to mount a rear headlight. The grab rail was another long-overdue mod.

Because I'd added the waist-high rear wall to the cab, it couldn't be removed for refilling the gas tank. So up until now, I was lifting away the cab roof, retaining it with very thin smears of Blu-Tac. This wasn't very reliable, so some rare-earth magnets have been epoxied into the cab. The original screw holes were slightly enlarged, and slotted on one side to help the roof align more easily. 

As for the roof itself, M2x5mm countersunk screws were silver-soldered into the roof's original mounting holes & slots, then cleaned up with the dremel. The screws will function as locators to the holes in the previous photo. 

On top, the screw heads were sanded flush with the dremel. As I lack the equipment needed to simply roll a new roof from steel, with upturned side edges as rain gutters, the home-made steel rain strips I fitted years back were re-used, this time soft-soldered on. A bit of bog deals with the screws' sockets.

07/08/19
After six years, the running crews now have steps and grabs to access the tank fillers.

Xmas is coming up, but I prefer hanging primed loco parts on machine tools, to decorations on trees. 

New gas pipe silver-soldered, to adapt the Accy tank to the RH burner.

I didn't photograph the process of re-assembly, painting or weathering; Because as this was my first time weathering a live steamer, it meant a lot of experimentation and such, that would be difficult and tedious to follow in writing. This was also my first time weathering with enamel paints - I usually use Tamiya acrylics for weathering, but that won't fly around heat, oil and water. For this loco, I'd started with Humbrol tinlets, but soon learned all about their now-abysmal quality, and promptly binned them in favor of Tamiya's enamel equivalent.

A Baldwin-style "knob" handle for the sand dome was machined and fitted. My old home-made headlight generator was replaced with a proper whitemetal Stones job from Roundhouse. A scanned copy of an original Stones service manual was invaluable in adding the missing conduits and pipework to the generator. The worksplates were fitted with JB Weld, and the nameplates with black silicone. A rear headlight was turned from aluminium, and both were fitted with 3V grain-of-wheat bulbs and glass lenses, the latter sold as replacements for wrist-watches.

28/11/19
Washes, drybrushing, powders and some miniature spray-gunning seemed to produce the result I wanted - a hard-worked loco, but owned by one of those rare mills that actually takes some pride in their fleet. The effect is a bit less subtle than the camera made it look; could've picked a better time and place for lighting, too.
With no permanent line on which to test, some lengths of flex track were plonked on the lawn.

"Baron" performed extremely well, if a little tightly, due to the new o-rings. When I get the chance, I'll have to take the loco down to the club track at Zillmere for a proper test. 

A proper roll-on/off carrier was made to fit a new box. Mini bungee straps hold the loco in place, with clean soft rags to protect the paintwork. I think this is the way to go, for me, as the oil stays around the bottom of the cylinders and away from the weathered finish. It also means far less handling of the loco, reducing the chance of damage, and frequency of touch-ups. 

 The box is a steel "ammo" style toolbox. The lettering isn't perfect, but it was never quite meant to be - and this box made good practice fodder for signwriting more critical things, for example, that pub in the background.

 The lighting was also entirely re-wired, with a charge socket, fuse, and center-off switch. The plugs will allow me to remove the cab if and when needed in future.

The Baldwin, as I now prefer to call it, still needs a few bits of "loco clutter" befitting a canefields machine - and a driver, now here waiting for paint.
Barring a proper test run when I have the chance, "Baron" should be about done. A "couple of weeks" burner replacement, that snowballed into a nearly bare-frames rebuild over thirteen months.

The Fowler "Victoria" is next for weathering, and now that I've some clue as to what I'm doing, I can properly document that job, with a view to encouraging others to have a go at weathering.
 
*ADDENDUM*

The test run at Zillmere revealed an issue that went unnoticed in the previous brief test run:
The burner frequently self-extinguished. The problem was that in having a standard Roundhouse jet fitted, too much butane was being supplied to the burner. This resulted in more combustion gases than could be exhausted from the smokebox, resulting in back-pressure against the burner, which soon extinguished it. The solution was to supply less butane, by fitting a smaller jet.
A No.3 size from Chuffed2Bits was fitted and has solved the issue.
For context, the bore of a Roundhouse jet is 0.24mm. The Chuffed2Bits No.3 jet is 0.18mm.