Yr Hen Felin & Yr Orsaf Newydd

[gilfachphil]

Hi Phil
Your use of magnets is interesting. Sorry to hear your point springs are failing. What is it three years since you laid the circuit? I was pondering with using Omega springs, similar setup to the GEM products of yesteryear. I must have miss read your post magnetic brass that's a new one on me.

Hi Chris,

I think the layout is now 2 years old. I have never found the point springs very positive in action, though the latest of the CB points I have bought is a new design and clicks over more firmly. I did get hold of a couple of old Gem type levers, which I have used on the front loop, they only just have a big enough throw, no omega loops involved.

The use of a 5mm cubed magnet acting on a steel bolt has enough attractive force to hold the point over and with it set leaving a small gap between magnet and bolt when the point is switched gives a little springing effect.

When adding the magnet to the L & M buffer I thought I might have to seek carefully in my pot of couplings for a steel one but when I waved a magnet close by lots jumped up!

Phil

[gilfachphil]

I often have a 'helper' when running trains:-

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Sometimes she just sits in the way, others she follows the train!

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Phil

[Petersfield]

I often have a 'helper' when running trains...

That's a strange way to spell 'supervisor'!

PS - Or should that be 'The Furry Controller'?

[Old Man Aaron]

I'm just glad mine are indoor cats. They get in the way enough as it is.

[gilfachphil]

It’s quite nerve wracking when she sits on the line with a live steamer heading towards her! So far she has jumped down before the collision. Unfortunately I don’t have a whistle in any of the three locomotives.

Phil

[Scrat]

Cats and railway are a funny combination.
We had a cat many years ago.
It was sunday, I had fired up the 5" gauge Maxitrak Swallow.
Cat came, looked at it, put her head to the side tank and......

WOOOOSH!

The safety-valve went off.

Cat jumped vertically into the air, began running before even touching down and shot out of sight.
Now I know where the crtoon designers got their inspiration from.

[gilfachphil]

Earlier in this thread I posted about the Woodleigh Engineering models of Welshpool wagons and have shown the finished ones to friends in the local 16mm NGS group. Unfortunately on a not particularly hot day last week I ran them outdoors for a few hours only to find that the van particularly had deformed:-

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I emailed Joe of Woodleigh to show him pictures of what had happened and he immediately replied that he would send me replacement kits, which came yesterday along with a bonus gift.

It states clearly in the instructions that the kits need to be protected with a matt lacquer before outdoor use and Joe suggests Plasti-kote 24002 Matte Clear. I could not find this locally but did manage to get:-

IMG_5267.jpeg (1.55 MiB) Viewed 20360 times

from Toolstation which I hoped has the same UV absorbent properties.

An issue with using a colourless transparent finish is knowing how much to use and whether it will have any adverse effects. I gave the wagons one spray coat of this before using them.

As it does not matter if I spoil the wagons I have now given them a further four coats of the lacquer, two with the wagons inverted and a further two the right way up. I'm pleased to say that there is no noticeable change to the wagons, even though I sprayed generously.

I shall use these two wagons outside in adverse conditions and see what happens. The two new wagons will not be exposed to the same treatment, though they will be lacquered generously.

This lacquer could be a useful product for modellers where a matt finish needs to be applied to a finished model in my view.

Phil

[Phil.P]

Phil,
What are the wagons made from, and what paint had you used?

If painted, that should give some protection from UV. - Though not all paints are good, in this respect.

I have a very early Bole Laser model. PLA filament, I believe?
This has deformed though it was in a box. - That very hot period we had.

Phil.P

[philipy]

This lacquer could be a useful product for modellers where a matt finish needs to be applied to a finished model in my view.

I used to use this all the time and was very happy with it. Then I had two duff cans, bought at separate times. The first was solid in the valve before I had even used it ( although I had had it in stock for a few months admittedly). The second can, bought to replace the previous one, I got one spray session from, then when I went to use it again a few days later, that had solidified in the valve as well ( Yes, I do invert and spray to clear the nozzle after use). I haven't touched it since, its too expensive to risk that - Once bitten twice shy, as they say!

[gilfachphil]

Phil,
What are the wagons made from, and what paint had you used?

If painted, that should give some protection from UV. - Though not all paints are good, in this respect.

I have a very early Bole Laser model. PLA filament, I believe?
This has deformed though it was in a box. - That very hot period we had.

Phil.P

Phil,

they are made from PLA but totally unpainted. The great thing about them is that they are self coloured meaning no need to pick out the detail of the iron work in black paint with less than steady hands!

Once I have built the replacement ones I will be very careful when and where I use them. My storage space does not get hot so there should be no issues there but taking them somewhere in the car in summer is not going to be wise, if it is heat that has deformed them. Garden railway wagons that cannot safely be used in the garden ...

Phil

[GTB]

Once I have built the replacement ones I will be very careful when and where I use them. My storage space does not get hot so there should be no issues there but taking them somewhere in the car in summer is not going to be wise, if it is heat that has deformed them. Garden railway wagons that cannot safely be used in the garden ...

Probably less of an issue in the past in the UK, but the interior of cars left in sunlight on a hot day can be up to 30-40degC higher than the outside temp.

Plastics have a property called 'glass transition temperature' (Tg) which is the temperature at which the molecular structure changes and the plastic converts from a rigid object to a rubbery one. It's an effect well known to Aust modellers and I've seen examples of HO rtr models that have become banana shaped after being left in a car on a hot day.

Common plastics used for models like ABS have a Tg over 100degC and can still warp in a hot car. PLA has a low Tg around 80degC (I've seen figures as low as 60DegC quoted), so it is going to be more sensitive to getting hot.

The UV in sunshine will fade and crack plastics over time, but would be unlikely to warp it.

This online page has some comment on the subject of PLA and heat, in amongst all the adverts and clickbait. It appears to be a known issue in the 3D printing community.

https://all3dp.com/2/pla-petg-glass-tra ... -printing/

Regards,
Graeme

[gilfachphil]

Thanks Graeme,

An interesting article that has helped my understanding of the glass transition point. I expect that as that temperature is approached any stresses within the model will be revealed as deformations,

Phil

[GTB]

An interesting article that has helped my understanding of the glass transition point. I expect that as that temperature is approached any stresses within the model will be revealed as deformations,

That's my understanding. The loss of rigidity as the Tg approaches is gradual like most polymer properties.

The release of residual stress with heat can be quite spectacular in injection moulded parts. In the case of filament printed parts the residual stresses could be lower and perhaps some of the deformation due to heat could be the part sagging under it's own weight as it softens.

Graeme

[gilfachphil]

I was thinking more about the inward bow on both sides of the W&L box van. Maybe stresses with how the kit is assembled might be a factor,

Phil

[gilfachphil]

After my friend's visit in mid May I felt more storage space in the station could be usefully gained by adding another siding. It only (!) required the purchase of another point as I had some odd bits of track left. One duly came from Cliff Barker and was installed towards the left hand end of the platform as seen below:-

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The early points I had were of this form at the Vee:-

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The new point shows a redesign:-

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I have not been entirely happy with running properties across the new point in the curved direction. There were often a bump or two as vehicles crossed and an odd derailment. Yesterday afternoon I ran Russell and the Welshpool coaches and it really did not like going round the loop behind the platform.

On close examination the leading driving wheel would sometimes ride up onto the Vee. I checked the back to back and found it to be about 28.9mm, the rear driving wheel a little less. The Roundhouse brass back to back gauge is 28.3mm.

The two rails leading away from the Vee are separate from the Vee in the new version whereas they are soldered together to form the Vee in the earlier version. These two rails were found to sit low compared to the outer running rails so the engine could rock passing over the Vee. The exit rail could also pivot causing it to rise at the exit of the Vee. The points are made with loose sleepers in a number of places so are not very rigid in the horizontal plane.

Onto a new post so I can add more photos:-

[gilfachphil]

I packed the sleepers at the end of the point with a 1.5mm thick piece of plasticard. I also had to raise the rail of the track leading to the next point to get them level:-

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These two packing pieces eliminated the bumps where the Vee meets the exit rails and where the exit rail joins the next piece of track.

Having also adjusted the back to back to be tight to the Roundhouse gauge Russell would now cross the Vee smoothly but there was a noticeable bump in reverse where the moving point blade meets the running rail on the curved side. I eventually suspected it was caused by the plastic rail joiner featured here in CB points. I took it out and added a Peco one instead, a smooth transit!

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I have found the plastic joiner prone to failure in two of the earlier points.

A last adjustment was to slightly round off the tip of the Vee. The earlier points have this, the recent one was much sharper.

Result, I can push Russell at speed in both directions through this troublesome place!

Phil

[GTB]

I was thinking more about the inward bow on both sides of the W&L box van. Maybe stresses with how the kit is assembled might be a factor,

I've no experience with PLA kits, but I've found out the hard way over the years when scratchbuilding with polystyrene sheet (HIPS, Plasticard) that it can move around if the joint surfaces aren't smooth and dead square before assembly.
Graeme

[Preseli Chris]

Phil sorry to hear about your issues with your recently acquired wagon kits . Apart from owning a L and B crane which I only run on dull days .. I have in the past bought some 3d printed n gauge railcar bodies , the ones that fit over a modified Kato motor chassis . They came with a waxy coating so had to be de waxed before painting .
the first attempt was a disaster with body warping . the next attempt was better, iirc about 50c hot enough to melt the wax but not the model. I remember the old Tri-ang ( obviously not 3d printed) early plastic post bakelite oo coaches and series 1 track shrank and warped over time ,yet the Tri-ang tt models which were first produced back in 57 are still without issue. A different polymer compound ?
Good to see you have sorted out your point work .

Chris

[GTB]

I remember the old Tri-ang ( obviously not 3d printed) early plastic post bakelite oo coaches and series 1 track shrank and warped over time ,yet the Tri-ang tt models which were first produced back in 57 are still without issue. A different polymer compound ?

The plastic used for Tri-ang OO/HO trains changed in the mid '50s. From the time the first train set was introduced in the early '50s under the Rovex name the injection moulded parts were made from Cellulose Acetate. This tends to shrink and distort over time, even at room temperature. It can decompose over time as well if not stored/used under the right conditions.

In the mid '50s, Tri-ang changed to using High Impact Polystyrene (HIPS) for injection moulded parts, which is stable at normal temperatures, but can still turn into a pretzel if left in a car in hot weather. The change in material used came about before the TT range was introduced.


Graeme

[philipy]

I had a Tri-ang train set in the early 50's ( '52/'53-ish?). I well remember the bow sided coaches with banana roofs!