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In depth idiot
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Discussion Starter · #1 ·
H-D's introduction of moulded plastic wagon bodies was quite a step forward in fidelity 'just too late' in that business' existence. (I have made systematic use of just one of these since prices went to rock bottom some years ago, the 'Blue Spot' fish vans, and both the H-D and Wrenn versions are a good basis for upgrading, especially as the appearance is overall superior to the recent Hornby release which has a serious error in the roof radius.)

Anyhoo, a small collection of H-D wagons came my way some time past, and among them was the lowmac, which I have never previously looked at, since the Airfix GMR tooling of the same subject (now with Hornby) is much superior. The moulding looked OK overall, but when I started work on it yesterday the small sections of the W irons and brake gear are variously crumbling, brittle, cracked and weak, to the extent that removing the wheelsets led to breakage.

Now I have often observed that on models like the horsebox with opening doors the doors have detached. Is this from same cause? It suggests to me that this may be loss of plasticiser(s) from the moulding compound, which always affects the finest sections first. (Old information obtained from polymer chemists once in the employ of ICI plastics division, roughly contemporary with the production date of such moulded H-D items.)
 

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Dragon Trainer
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Some lubricants can affect plastics, so on the Lowmac, possibly this deterioration is from previous applications of lubricant to the axle journals?

The Horsebox door hinges are very fragile. Possibly just the inherent fragility, but you are correct, plastic can age. Especially when exposed to Ultraviolet light, sunlight…
 

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In depth idiot
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Discussion Starter · #3 ·
If the specific Lowmac I looked at ever had lubricant applied, it was a long time ago, the axle ends were grooved and the metal retainers worn. (Then again, there were ample rusty iron filings in the area around each axlebox, good natural weathering!)

Now I have applied brain to this, and looked at some of the items of no interest, the small bodywork detail on the couple of H-D Grano was also clearly brittle and chipping off all over the bodies, well away from the axles, and thus lubricant..

Unfortunately the some time owner is long deceased, no way of getting information about how the items were used. (Got these helping a friend with house clearance following the death of his mother, 30 years a widow. My friend didn't know his dad even had a train set!)
 

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The chemical formulation of plastics has changed over the years. My experience with them has been that plastics dating from the early 1970's tend to be quite hard, but also quite brittle. Plastics from the 1980's were better and of course, nylon became common with the advent of Lima - they used it on all bogies.

I have a small number of HD 'High Goods' wagons which I refitted the bodies onto Dapol chassis in the mid 1990's. As far as I can tell, the bodies are as good today as they ever were.

I've also found that plastics can be affected by the environment they are kept in. Here in Australia, even today, some plastics don't stand up to the climate and crumble or just shrink - P4 track company sleepers shrink in length which is a nightmare for P4 modellers with gauge narrowing! White plastics also go cream in colour after about 10 years.

The interesting thing is, when you compare the later HD bodies with their modern day Dapol equivalents, the HD versions are actually better - finer and more detailed! Who would have thought?
 

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In depth idiot
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Discussion Starter · #5 ·
...I've also found that plastics can be affected by the environment they are kept in. Here in Australia, even today, some plastics don't stand up to the climate and crumble or just shrink - P4 track company sleepers shrink in length which is a nightmare for P4 modellers with gauge narrowing! White plastics also go cream in colour after about 10 years...
I have direct experience of this from my own career. There's something in the air, and my informed suspicion is that it is the output of all those Eucalyptus trees. So a product that worked reliably long term all over the world, didn't have the same endurance on the East coast of Oz. And when the failure analysis showed that the one detectable change in the failed component was a functional characteristic of a polymer that had degraded; the best answer that some very specialist organic chemistry analysts could suggest was barely detectable eucalyptus oil congeners present, which very definitely weren't in the original formulation.

The business decision was to accept the reduced life, with a pragmatic solution of only shipping in quantities which the demand case would see sold within months, insistence on a rigid FIFO distribution and a specified replacement rate, unique to this territory. (All obsolete now, since the early 1990's.)

...The interesting thing is, when you compare the later HD bodies with their modern day Dapol equivalents, the HD versions are actually better - finer and more detailed! Who would have thought?
Same applies to the Airfix GMR wagon body toolings still produced by Dapol. I have been told (by a one time model railway injection moulded kit manufacturer) that the Dapol tooling was copied from the original Airfix GMR tools, before they moved on into Hornby's possession.
 

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I have direct experience of this from my own career...
Initially, when I started reading your reply and I saw the mention of Eucalyptus, I thought humour was involved. Mind you, Eucalyptus probably has effects on people too!!! Humour whether intended or not accepted.
Seriously though, it doesn't surprise me. I'd suggest that it is probably more likely that deterioration is a result of the very high UV levels here, certainly outside..

Same applies to the Airfix GMR wagon body toolings still produced by Dapol. I have been told (by a one time model railway injection moulded kit manufacturer) that the Dapol tooling was copied from the original Airfix GMR tools, before they moved on into Hornby's possession.
Dapol actually purchased the Airfix toolings, although not all of them as some of them (that weren't in the factory Dapol purchased from) found their way through the Mainline (Palitoy), Replica and later, early Bachmann ranges. Hornby later purchased what was in Dapol's posession.

This has been my personal experience of Dapol 'copying' toolings: Centenary Coach Errors - Model Railways On-Line
 

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Well I probably have the most Wrenn/Dublo models on here and you mention two of the worst.

1. The lowmac may distort because the whole item is a unitary moulding of plastic and thus there is no metal and the wheels fit to the body. I find them poor performers and do not use them, One of the Pennine steam videos of the S&C shows Lowmacs carrying Austin cars towards Scotland a train of them anyway I do not use any of them at all.
2. The LNER fish/insul van another where the chassis is plastic, it's Ok but as I have so many better runners again I do not use them, these have become a bit brittle but the trick here is keep them away from direct sunlight.
3. The horse box, look a nice model but those doors are a nuisance, again I have stopped using these because the doors fall open and the wagon can be damaged so I have one that sits in the old station parcel depot with some other vans
Generally if the wagon has an aluminium chassis they will last another hundred years whether round end axles or pinpoints with plastic push in inserts the weight of the chassis helps the wagon

Now when it comes to wheels the Wrenn type tends to suffer from a little contraction and the metal outer tyre comes loose and this not surprisingly suffers from rail running problems, I check these from time to time and glue them back in place and this helps, the other need for smooth running is to get the back to backs right but this is tighter than the more usual OO gauge requirement so for instance the handy gauge made by DCCConcepts is too wide, back along I reset a whole load of them and made a ramp with about 6 peco points and had them roll through the points, if they ran smooth then I got it right.

The long wheel base van toward the back is the best of the odd Wrenn/Dublo wagons these are nice runners - metal chassis again
 

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In depth idiot
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Discussion Starter · #11 ·
...The LNER fish/insul van another where the chassis is plastic, it's OK but as I have so many better runners again I do not use them, these have become a bit brittle but the trick here is keep them away from direct sunlight.
This is the one H-D originated wagon I have majored on, because the 'Blue Spot' is a key vehicle for a BR steam period East Coast main line modeller; not a trace of brittleness among them, whether H-D or the later Wrenn. No trouble with the Prestwin either, have a couple of those. Long ago gave up on the H-D Grano as a potential for modification into a scale model, consistently too brittle, the exterior small sections always chipped off. (The Wrenn version too expensive to consider for hacking, better to use kits.)

...Dapol actually purchased the Airfix toolings, although not all of them as some of them (that weren't in the factory Dapol purchased from) found their way through the Mainline (Palitoy), Replica and later, early Bachmann ranges. Hornby later purchased what was in Dapol's possession...
What's annoying about the former Airfix GMR wagon toolings is that one of the most useful hasn't ever been used by Hornby, the standard LMS van; and Dapol's copy tooling is not only rough but rarely presented in an adequate livery for BR operation. (Hornby's handling of the former Airfix GMR tools it has used to produce models for their range has been consistently fair to good: weakest the five plank general merchandise open, which is however the only example of such a vital type in RTR.)

Hats off to those involved in making the Airfix GMR wagon subject selection, it was all good. The LMS van, most numerous Big 4 period general merchandise van, and a choice of a five plank general merchandise open design that well represents vehicles built by all the Big 4 in the later 1930s, endlessly capable of being lightly modified by an owner; just those two well demonstrate the good thinking that went into their wagon range.
 

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I don't think you are lucky possibly other commentators were unlucky for whatever reason, as I can see no issues with any of my SD stock EXCEPT of course, the horsebox doors. I assume the reason being the unequal shape and the tiny pivots. I think that anyone who can come up with a replica (at a reasonable price) with a more usable shape could make quite a profit!
 
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