7mm On Heather's Workbench - Prairie ago-go

[Heather Kay]

Thanks everyone! The news isn’t all good, but it’s not getting worse. Save for ankles swelling up like barrage balloons.



Which is why I have illustrated the workbench in this iPad digital zoomed and rubbish image from the relative comfort of my sofa. I’m simply too lazy to stand up and do it while I can have my feet up for a bit!

Prairie work has been slow. Yesterday and today I fought the cab. For whatever reason, these loco kits are designed with gaps in the cab front where the backhead sits. Without something bunging the gaps up, the casting would just fall through the hole. I was going to be really clever and make a neat folded-up filler, but gave up. It wouldn’t fit, and the backhead would still be miles out. In the end, I made a brass sheet plate that plugged the gap. It’s a bit like a brass tombstone at the moment. Having not-quite-lost that battle, I then installed the half-etch rivet strips along the bottom of the tanks. I might get to adding further cab detail tomorrow, and then fitting the bunker overlays.

 

[Heather Kay]

For the early shift, here’s a closer view of the loco body as it sits. You can see the "tombstone" poking up from the front of the cab.

 

[Wagonman]

Another one late to the party (I've been hiding under the duvet for the most of the last two months); so sorry to hear you've been poorly and wish you the very best for a speedy recovery.

 

[Heather Kay]

I've been hiding under the duvet for the most of the last two months

There’s a lot to be said in favour of doing just that, especially of late.

 

[Heather Kay]

I like doing the fiddly bits.



Lubrication all over the upper motion plate. Satisfying. The etch part has recesses to take the oil boxes. The cast brass ones overhang, so I flipped the plate over and mounted everything on the flat side. You can’t really see the recesses on the reverse. The little oil pot was mounted on a tiny bracket filed up from brass angle.

Right, what’s next? I think a little sit down to rest my ankles.

 

[Phil O]

Nice work, Heather, it's the small bits that lift a model from the mundane.

Sorry to hear about the ankles.

 

[Heather Kay]

Today's flummoxation. How am I supposed to form a neat curved joint for the bunker back plate that matches the rivet strip?

I really have not the foggiest. Any clues or actual ideas/techniques would be muchly appreciated at this point.

I’ve run out of patience with this today. I suppose I could look at forming up the boiler and firebox.

 

[Phil O]

Heather, could you please post a shot showing more of the bunker top, so that I can see where those pieces fit. I also assume that there is another piece to go, to finish the bunker back.

 

[Heather Kay]

Here you go.







What’s bothering me is there doesn’t seem to be sufficient material spare on side or ends to form an adequate radius. The instruction are of no use as they’re written for 4mm scale and assume a solder fillet inside the join.

I’m doing something else now. This is annoying me. Sorry to sound so negative.

 

[simond]

Heather,

your reaction is entirely understandable, trying to form a “saddle” (that’s two opposing curves whose axes are not parallel) is beyond the metal bashing abilities of any but the most skilful of tinsmiths (or saddlers, I suppose). And trying to do it whilst retaining rivet detail is yet more challenging.

I have seen cast brass upper corners for GW bunkers, but I cannot recall who sells them, maybe one of the merry throng can advise. You could at least cut away the existing brass to suit, but you do need the lower back corners to be radiused.

At some point, I have a large prairie to do. It’s from Warren Shepherd and I assume it’ll be like the 52xx





Hopefully these “warts & all” shots help - the join between side & rear is wrapped onto the rear above the bunker extension, and is wrapped onto the sides below it. I recall making a wooden former around which to beat the metal into submission.

maybe something similar might be possible with your 45?

atb
Simon

 

[Heather Kay]

Cheers Simon.

To wrap around the sides would need a new rear plate. It currently fits between the sides. I could wrap the sides to the rear, but there’s about 1.5mm of useable material. Not sure that would provide quite enough radius!

I’m letting it fester, in best fashion. A solution will turn up, I’m sure.

Incidentally, this problem wasn’t as big on the 4400, as it had the earliest squared type of bunker. The radius wasn’t as pronounced, and didn’t have the later extension at the top.

 

[daifly]

This probably won't help except to show where you're heading. Good luck!

Dave

 

[Phil O]

Hi Heather, my best suggestion is to use brass quadrant of a suitable radius, to give you the corners or the best next size and either file or fill to suit. I don't remember you having problem with the previous 45xx I know that you modified the bunker, but most of that was not building the extended bunker. Is the kit from the same stable?

 

[Heather Kay]

Is the kit from the same stable?

It is. Essentially, it’s the same kit bar a few detail bits here and there.

Anyway, festering seems to worked. I have a potential solution, but more on that tomorrow. For now, it’s all dumped at the back of the bench - the modelling equivalent of the naughty step.

 

[Yorkshire Dave]

Perhaps a few aircraft might be what the doctor orders in the meantime.

 

[Heather Kay]

Perhaps a few aircraft might be what the doctor orders in the meantime.

Like this one, you mean?

 

[Pencarrow]

Here you go.

View attachment 123888

View attachment 123886

View attachment 123887

What’s bothering me is there doesn’t seem to be sufficient material spare on side or ends to form an adequate radius. The instruction are of no use as they’re written for 4mm scale and assume a solder fillet inside the join.

I’m doing something else now. This is annoying me. Sorry to sound so negative.

On the 1366 we don't talk about, I had just the same issue. I resolved it by soldering some solid square brass section in the corner and then setting to with a file. Not very elegant but it worked.

 

[SimonT]

All I can suggest is to solder some 2.5mm copper wire to the inside of the corner along the joint and flood it with solder. Then take a large file to it. The prototype is something like 4" radius, so 2.33mm. This is a bit like forming a GW Belpaire firebox front but it is a bit 4mm for a bunker. Laurie at MM1 does brass castings for the upper flare on the 2-8-0s as does Dave Sharpe for his 64 and 48.
Good Luck!
Simon

 

[Peter Cross]

Heather
I would build the bunker with square corners. And solder in some copper wire, shaped to follow the corner that needs a radius. Then file and sand outside to shape. Carefully thin the inside at the top. Either using a wheel in the drill or with a needle file. It only needs to be the top millimetre or so as coal will cover the rest.
It's a pita but works well.

 

[Peter Cross]

All I can suggest is to solder some 2.5mm copper wire to the inside of the corner along the joint and flood it with solder. Then take a large file to it. The prototype is something like 4" radius, so 2.33mm. This is a bit like forming a GW Belpaire firebox front but it is a bit 4mm for a bunker. Laurie at MM1 does brass castings for the upper flare on the 2-8-0s as does Dave Sharpe for his 64 and 48.
Good Luck!
Simon

Snap