Atlantic's works: Portable layout - Scenic details next

[Danby Wiske]

I'm wondering, now that you've finished one, how long it's going to be before the V4 is announced by one of the manufacturers.

It'll be a long while before anyone does a 174 though!

Splendid work Graeme - 3 very interesting locos. What's next?

[Atlantic 3279]

Thanks to all for the positive comments.

I imagine an RTR V4 might be in prospect if and when a new-build real V4 is actually seen to be taking shape with real likelihood of being completed. On which general topic I notice by the way that not only does the V4 project supposedly follow the P2, but that V3 and K3 are listed after that. Will any of these be completed within the lifetimes of the current "main players" in the team? Also, will anybody be allowed to burn any carbon based fuels by then?

My next projects? Resin castings to make in response to a couple of enquiries late last year, then an attempt to make viable moulds for D7 parts. After that, I might be turning to some woodwork, track laying, wiring, and scenery, as I'd like a change from fiddling around with minute details...

[Woodcock29]

Hi Graeme
I like the sound of moulds for D7 castings!
Regards
Andrew

[nzpaul]

. Will any of these be completed within the lifetimes of the current "main players" in the team? Also, will anybody be allowed to burn any carbon based fuels by then?

Surely that has to be sitting in the back of the minds of the entire rail preservation industry.
It was reported over here recently that the group who operate the TSS Earnslaw out of Queenstown are looking at alternatives to coal fired boilers, my question is what's the point? a steam ship or loco is a multi sense experience. Without the smell from burning coal, hot oil etc, it may as well be powered by batteries, the attraction of the machines will be lost.

Paul

[James Harrison]

I'll be watching the D7 parts with interest. Though at my current rate of progress it might be a photo finish between my getting around to building one and 567 entering traffic.

[Atlantic 3279]

I seem to have allowed myself to get rather out-of-practice in resin casting matters and I've consequently made a complete mess of something I've done successfully many times before - even though I read and followed my own notes on what were previously the main pitfalls to avoid! It looks like you should have plenty of time to finish other jobs before any D7 castings become a reality...

[Atlantic 3279]

By the way, just so that I do not mislead anybody by failing to give information...

In just under three weeks a layout with which I am associated will be appearing at a major show. Based on current circumstances, it is highly unlikely that either I, or the substantial amount of rolling stock that I usually contribute, will be present at that show. I would have been willing to go, had the organisers committed to continued insistence on protective mask wear by all, but despite an indication earlier this week that they would do so, the updated information for the public on their website says something quite different. Covid infection rates are still very high with no guarantee of a continuing rapid fall, and as there is not yet enough published evidence to convince me that the risk of severe consequences of infection is now negligible. I simply don't see why I should take risks in order to support an event that is not being run as safely as I think it so easily might be run.

[Chas Levin]

Fully support your stand on that Graeme; some very cavalier attitudes to others' safety around presently.

[Atlantic 3279]

Tempus fugit, but I have at last, to my tremendous relief, finished attacking excess vegetation in the garden and started (with success) the moulds for reproduction of D7 parts. Many of the moulds now are done in fact, but I've been working up to the most complex one for the loco running plate, splashers and cab sides combined. I decided that the more I refreshed my memory by doing the other moulds first, and the more I thought about the spatial relationships before taking action, the better the chances of making a mould successfully and of finding that I had made it convenient to use...

Anyway, as I'm avoiding the potential Covid super-spreader large exhibition this weekend, then after a visit today from similarly careful family members I should still be in good health and clear-minded for getting on with further mould making tomorrow.

Onward, I hope.

[Woodcock29]

I like the sound of progress on mould making for the D7 Graeme.
Regards
Andrew

[Atlantic 3279]

Having been without a useable computer from 14th February until the last couple of days, I've been unable to post any updates regarding the D7. I have however been trying to continue with the production of moulds and castings, alongside the great irritation of trying to sort out the consequences of an apparently terminal problem with my previous computer's hard-drive. Thanks to suitable back-ups of intentionally saved documents and images I haven't lost everything, but with no system image from which to simply clone an identical new system I've had to spend a lot of time finding and installing (at the right times) suitable device drivers and programmes (where still available, in my preferred versions) in order to create a new system that is sufficiently similar to the old one to permit effortless use!
Anyway, enough of my bleating. I have now produced most of seven or eight sets of castings for a D7 and tender. Owing to the time that has been taken up, and my need / urge to get on with other projects, I don't intend to produce more of these castings for the time being. Two of the sets I've made are for my own use and I'll be assembling at least one set to prove the result before I offer any parts to others. Those who have previously expressed interest will then have priority of course.
When I get more time I'll post up some images (and notes if necessary) showing key stages in the making of some of the moulding boxes, moulds and castings. For the time being, here's just one showing some of the main master parts with first examples of successful castings alongside.

[Chas Levin]

Looks like excellent work Graeme - hope the IT woes have come to an end and you're back working as usual?

[Woodcock29]

Looking great Graeme. I trust you've seen the last of your IT woes - there's nothing more frustrating to me than IT stuff!
I look forward to hearing more.
Regards
Andrew

[Atlantic 3279]

Thanks to you both for moral support!

While the production of moulds for the tender tank/bunker, the tender soleplate, and the loco boiler simply invloved careful repetition of methods that I've used (and shown on here) previously (see the way I produced the boilers for the B3 for instance) the matter of the combined loco running plate, splashers and cab sides required some thought. I had considered most of it at a much earlier stage, and then gradually forgotten what I'd decided in the long interval between completion of the master model and the start of mould production! Anyway, I did remember that I had realised that the mould would require two separate core pieces, one to form the underside of the running plate and the spaces under the splashers, the other one to form the space inside the cab. This was because I had quite deliberately made the cab sides and splashers integral with running plate, eliminating the challenge of lining them up and bonding them on each future model, at the same time giving strength and stiffness to the whole structure of the rear of the loco body. The cab core piece needed to extend above the tops of the cab sides and to the rear of those, so that flat "waste" areas of the core piece would be in tight contact with the outer mould during the casting process, trapping the cab core piece in the correct position to produce cab sides, front and floor of correct thicknesses. The first requirement was some suitable shuttering added to the cab of the master model to create a suitable box into which the mould rubber could be poured. In order to ultimately get minimal thickness of resin flash around the cab edges, and to avoid unwanted thickening or damaging to the cab sides, I used only a layer of sellotape to bridge (internally) the cut-outs in the cab sides and to project beyond the cab edges. To those projections I stuck some thin plasticard, save for the piece closing off the rear of the box which was thicker material allowing me to create a strong joint with solvent where it met the sides of the shuttering.

I sealed the other joints as much as I could with plastic solvent and then with additional sellotape in some areas. Where I could see, or where I suspected awkward little gaps I used a little PVA glue to bridge and plug.
The silicone rubber pour went quite well, with minimal leakage in areas where it was easy to peel off once cured.

On removal off the plastic shuttering and careful trimming away of projecting remnants of sellotape with a really sharp blade (without disturbing the rubber core piece from its position), then trimming the edges of the rubber to get a bevel rather than the raised edge of the meniscus from the original liquid state, I had a good result and could move on to other parts of the job.

[Atlantic 3279]

In order to allow the main core piece for the mould to form separately from the outer mould, I had of course to also close off the space between the splashers in which the firebox / gearbox / motor of a finished model would sit. That was done mostly with 0.005" plasticard stuck to the underside of each splasher, avoiding too much overlap (in case choice of wheels dictated maximum available space in side the splashers I didn't want to find that there was lot of un-necessary resin thickness needing to be scraped away). The very thin shuttering shows up in white in the image below.
I also added (in black) shuttering under the edges of the angle irons at the edges of the running plate, and under the buffer beam and drag beam. I extended this downwards to form a low plinth supporting the running plate on the base of what would become the mould box, once the sides were added. I also created stepped edges to that plinth. Those were reproduced in the rubber when the outer mould was poured, after which I removed the black shuttering forming the plinth, and the base of the moulding box. The inverted outer rubber mould and still trapped master can then receive the liquid rubber that forms the main core piece, which ends up with stepped edges exactly matching those of the outer mould. A barrier or release agent such as petroleum jelly does of course have to be applied to the exposed faces of the cured rubber of the existing parts of the mould before the core piece is poured, otherwise the whole lot sticks very firmly together! With the matching stepped edges if the mould parts, when casting the resin it is then possible to push the core piece into the outer mould to exactly the correct depth and no further, ensuring that the running plate and splashers have the correct thickness.

A closer look at the stepped edges of the plinth:

As you can also see in the top image, I had by this stage also produced a mould box for the tender soleplate and for the loco bogie, in fact one half of the mould for the latter had already been poured too. Hindsight tells me that the way I chose to make the mould for the tender soleplate, while appealingly simple, wasn't the best thing for easy production of the best castings. My simple method ultimately produced a mould that splits around the top edge of the running plate. Any slight failure to push the top-piece of this mould down firmly in all places results in a soleplate that is very visibly too thick. I should have gone to the same trouble that I did with the loco running plate...