Bill Bedford 3D wagon kits

[pheald]

I have three NSR open wagons and one LNWR glass wagon. Two of these are out of square, they are ‘warped’. At least one has warped recently the other some time ago.

I believe this warping could be rectified by stress relieving. I have in mind clamping square and warming up to say around 100 degrees C and then cooling to room temperature slowly.

Has anyone any experience In rectifying a warped body. Does a ‘repair’ last? It is unfortunate as the bodies are really very good and the NSR opens easy to build. (Nice kit Bill. )

These are for my layout as yet still unnamed, seen at the 2019 Aberdeen MRC exhibition.

[dal-t]

I have a couple suffering from the same problem which I haven't got around to sorting yet, but my planned approach is the standard for warped plastic/resin (or indeed flat plastic you want forming to a shape), that is attach firmly to a suitable shape - wood block from an old rubber stamp usually works well for wagon bodies - and immerse in hot/boiling water for longer than you think should be necessary. A refinement (if that's the word) I have added recently is to transfer the victim from its hot bath directly to a cold one, hoping to 'set' the restored shape. This appears to have some effect, but it is still necessary if forming plastic sheet to a curve to use a former with a smaller radius than you want to end up with, since some 'relaxation' inevitably follows. I'm not sure how practical it would be to use a 'wide' former on a wagon in order for it to settle back square, but I do have one or two plastic bodied opens that I have splayed a la prototype, using lengths of plastic sprue (properly called runners, I know) glued across the sides then concealed by dummy loads. I shall be interested to hear thoughts/experience from others, and assuming your modelling proceeds faster than my usual glacial pace I'll also look forward to seeing how you get on - and, of course, we might get some words from the Master himself ...

[billbedford]

Are these printed or cast resin?, ie dark or light grey?

[Craig Warton]

Are these printed or cast resin?, ie dark or light grey?

Bill,

I have 3 x LNWR 3 plank wagons with the same issue. These are in a very dark grey (It looks near black to me) So I assume printed. They have all bowed inwards and the bowing has also affected the floor.

Regards,

Craig W

[seanmcs]

I also have a couple of printed BB items: LNWR D 39 Glass Wagon and LNWR D 32 van. They were received in early July 2019, but unopened for a year due to a house move. Examined in late July 2020, these exceptionally stiff boxes were in excellent shape. However, the van chassis is bowed; the van body has a transverse strut that is broken; and, part of one end has a triangular piece missing - not in the plastic bag. The roof and/or the body would need some work to sit down flat. The Glass Wagon chassis is twisted, as are the two uprights and one of which is snapped off. I'm disinclined to invest time in trying to rectify particularly the Glass Wagon. So, quite disappointing.

Sean in Sydney

[dal-t]

This is the worst of mine, a 3-plank in the dark plastic. Another, similar, is less bowed, and a couple of D.33 vans in the lighter resin show slight signs of bowing but should not be a problem with some internal bracing and the roof fitted (although I might still try the hot/cold water treatment on them, unless someone tells me they will dissolve into messy plastic puddles).

[Guy Rixon]

... I might still try the hot/cold water treatment on them, unless someone tells me they will dissolve into messy plastic puddles).

It would help if Bill could tell us what kind of resin he's used. I assume it's some kind of polyurethane, but I don't know which grade. It should have a spec sheet on which we could look up melting points and such.

[Craig Warton]

I just found out that my three are in fact LNWR 2 plank wagons, in the same material as the one shown by dal-t. All wagons have a degree of bowing of the sides and with the centre being higher and the floor being visibly bowed. Two of them also have a twist as I have tried to show in the final photo.

I would be interested in knowing if the bowing can be removed and more importantly that it does not return.

Regards,

Craig W

[billbedford]

This is interesting. Since no one has mentioned painting I presume that all these models have been kept in their wrappings since they were bought?

I've not used the black resin for over 3 years, and the version I used was superseded with a re-formulation in April 2017.

These are photo-acrylic resins, they can be susceptible to UV light, heat and will take on a set if unevenly loaded. It is impossible to melt them, they will burn before melting. Raising the temperature will soften them and they can be manipulated back to shape with finger pressure. The resin info sheet gives this:

Heat Deflection Temp. @ 66 psi: green - 49.7ºC; cured - 73.1ºC

So any temperature above ~70ºC will soften the plastic enough to be manipulated, though the hotter it is the softer it will become.

I have acquired a UV oven to cure some new resins, and I used it to heat a distorted black resin wagon to 80ºC, and then it was a matter of a few minutes manipulation to get it back to shape. Will it last? - I don't know, but given that none of the comments have come from people who have finished, painted models, I suspect that painting, especially with acrylics, and a UV blocking varnish will give some degree of protection from future warping.

[pheald]

Bill my kits are ;

NSR longbottom 3pl medium grey resin
LNWR Glass wagon, light grey -3D

Both these kits have been stored in their original box and were in a bubble wrap bag which was not sealed. Both boxes were stored in a draw, therefore in the dark.

I do not believe UV light is a factor here but would accept oxidation might be be. Degradation of polymers is generally by oxidation or UV or solvent exposure leading to a stress corrosion cracking process.

I think residual stress release is the real issue. I suspect a body manlipulated back to shape as Bill has suggested and then painted to protect from UV and or oxygen degradation would be beneficial. I have no evidence of my next thought that is the body needs to be cooled slowly otherwise there will be residual stress present.

[billbedford]

I did wonder if there was something in the bubblewrap that could have affected the resin.

My experience of heating this material is that it cools quickly, and I'm always glad I get it to be more or less right before it is too hard to work.

[jon price]

Just looked at my Mousa models kits bought some time back and currently resting in the to-do pile. Two glass wagons, and three single plank. All in original bubble wrap packets inside cardboard boxes. All kits in light grey material. No warping in any dimension.

[MarkS]

I bought two D299 5 plank wagons at Scaleforum 2018, mid grey colour.
Built and painted that winter - Both are straight and square.

[dclift]

I bought two D299 5 plank wagons at Scaleforum 2018, mid grey colour.
Built and painted that winter - Both are straight and square.

Likewise. My two grey D299s were bought at Scaleforum 2018 and built and painted very soon after I retuned to Melbourne. No problems with warping. I suspect that painting them promptly might be the reason why. It is vey unusual for me not to allow my purchases to mature for a decade or five.

[Craig Warton]

I bought two D299 5 plank wagons at Scaleforum 2018, mid grey colour.
Built and painted that winter - Both are straight and square.

Likewise. My two grey D299s were bought at Scaleforum 2018 and built and painted very soon after I retuned to Melbourne. No problems with warping. I suspect that painting them promptly might be the reason why. It is vey unusual for me not to allow my purchases to mature for a decade or five.

David,
I also have two x D299 and they have no signs of warping at all. They have been in the cupboard for a while too. It is only the darker coloured material which has the warped.

Regards

Craig (located in Sydney)

[pheald]

Here is in an image of my two wagons. Longbottom open above LNWR glass wagon below. The centre door wagon is interesting in that one side is warped, the side where there is daylight between door and side.


As you see the amount of warping is very slight and should be put right following comment above.

[billbedford]

Peter, Both those wagons are cast resin, rather than 3D printed. Printed ones have the springs and axleboxes, and later the axleguards, printed in place.

[pheald]

Thanks Bill.

It would appear this is a problem in resin bodies. Very likely related to the mixing of the parts or the actual casting.

I therefore suspect that they can be brought back to square by warming in hot water.