[Gary]

Further to a discussion elsewhere about the merits of diecast and injection moulding lets continue the discusion here.

The images below are from Model Rail Forum reviews of a Trix diecast loco and a Hornby injection moulded loco:-

How do we think the two compare for sharpness/crispness of detail?

I am looking at the boiler door hinges and the general texture of the surface finishes.

Another image showing detail on a Hornby injection moulded model:-

And a Brawa diecast model:-

There is a capiliary effect around the edges and rims of the moulded diecast detail that is not present with the injection moulded examples where the main surface retains its flatness right to the edge of any contour change. The lighting is intense and probably exagerates any issues if there are any.

Which looks the more natural?

Happy modelling
Gary

 

[alastairq]

My personal feelings are in favour of die casting for large masses such as boilers, with inj or lost wax for fine detail.

Die casting gives a very good, steel/iron surface finish......inj is just too smooth in this respect...

in the end it's about 'mass'...?

Incedentally, do you know Model Die Casting, from the US?

Their small, old-time[?] consolidation [at least the ones I have ] seem to combine die casting with an overlay of injection moulding, for fine detail...???

 

[dwb]

I was hoping to post some photos of a Trix Re460 which has a die cast body. Unfortunately my NiMH batteries are flat and will take a few hours to charge. I was having a close look at it earlier this evening and was impressed with the crispness of the detail that's there. You don't get the see through grills that are appearing on the latest Bristish models but for someone who is used to Wrenn it's an eye opener.

I probably won't be able to post photos until tomorrow but doing so should take one variable out of the equation - it will be same camera, lighting and photographer as the Scot photos, so any debates on those items will be null and void.

For the record, I am taking the photos with a Fuji FinePix S9500 in macro mode with Aperture preference. The primary light source is an OttLite. The images are 9M pixel with the normal save setting.

David

 

[neil_s_wood]

I guees I'd better pop out to the garage and get some photos!

My main reason for preferring metal bodies is the durability and even distribution of weight throughout the body. I find the robustness of metal makes for easier handling. My understanding is the the detail on plastic and metal bodies is about the same, my issues are more about the fragility of plastic especially on those US, German and Australian locos with loads of pipes on the exterior.

BTW one of the issues with the below depicted Garratt was weight. If this had die cast tenders, this problem would have been resolved.

As mentioned on the other thread the problem is mainly with steam locos. With diesels there is usually plenty of room inside for weight, motors and sound equipment.

 

[ozwarrior]

As few things are black and white perhaps subject headings could be 'cf' instead of 'v'.

There's little doubt metal would be heavier and therefore aid traction. Ultimately as well as detail it'd be the ability to add more detail or not and cost that'd be the determining factor. I get the feeling German modellers are less likely to take a drill or saw to a model. And not because it's already perfect. Also be more willing to part with the hard earned.
Putting motors in the loco has not been the boon that central drive has been to D&E. I sometime wonder (without wishing to start an argument) that the thing wrong with tender drive was not tender drive but what was done with it. (But that's another topic anyway.)
The British market is a different kettle (no pun!) of fish to the German and we know the last time plastic blew metal out of the water. It would be nice I think if one was tried as a tester to see how it would go.
It'll be interesting to view comparative pics I think.
Regards.

 

[34C]

I would frame this discussion in terms of appropriate material choices for the job. Main structural components like boiler, smokebox and footplating diecast in metal, for strength and weight. Thin section components like smoke deflectors in etched brass. Applied detail as required, cast handrail knobs, metal wire handrails, injection moulded plastic for small detail pieces like the lubricators. All the recent productions are already multi-part, to enable the expected detail to be incorporated, so the change is a different material choice for some of the pieces.

From current Bachmann Blue Riband UK steam models it is not that great a leap, the footplating and boiler backhead are typically two separate cast metal pieces, with a screw together assembly into diecast ballast weights fitted very closely inside the plastic mouldings. In this context to move the boiler and smokebox barrel from injection moulded plastic to diecast metal is a relatively small step. I would draw attention to the close fits achieved in existing product between diecast and injection moulded parts: the technique is clearly well proven and delivers very satisfactory results; further this is present already on reasonably priced UK prototype RTR.

As for the surface finish of diecast metal over injection moulded plastic, I will take the slightly rougher look of metal every time. Locos were industrial equipment; the steel corroded, the paint finishes rapidly deteriorated, dents and abrasions were regular occurences: in short they took a hammering and it showed!

 

[neil_s_wood]

I went out to my layout and took some pictures of metal and plastic locos for comparative purposes. The first comparison is between a recent Hornby A4 and a Brawa BR06. The detail seems as crisp on each. Wires seem a bit thinner on the Brawa maybe. Rivets possibly smaller. Hard to say without measuring them. I really don't think there is any truth in saying that there is a loss of detail with metal at all. If anything I would say it has possibly better detail than plastic, e.g. finer wires and rivets from what I'm, seeing. Why would they make fine detailed models out of brass if plastic is better?

Second comparison is between a PCM N7W Y6b (metal) and an NSWGR AD60 (plastic). Again it's hard to say without having some means to measure the fineness of the wires and rivets.

Final comparison, no clues. See if you can guess which is metal and which is plastic?

Green one or black? It really is hard to tell.

 

[Richard Johnson]

QUOTE (neil_s_wood @ 12 Nov 2007, 12:20) <{POST_SNAPBACK}>Final comparison, no clues. See if you can guess which is metal and which is plastic?

Green one or black? It really is hard to tell.

***Good call Neil: I don't think any form of enthusiasm for a brand or country of origin can influence this one . Its really impossible to compare unless you compare two loco's created within a narrow period - especially if they are from different manufacturers.

Plastic Vs metal is a simple Mfr choice - and will give a similar result if the tooling and the production process are both properly controlled. There is no shortage of crispness in the detail of a well made cast metal loco. (but neil - I don't agree re the comment re "wire bits" - these are added accessories not part of the tooling/material process and can b as fine as the Mfr wants them to be.

And of course... The wire handrails on an HO loco should be visibly thinner than one made in OO - hence my comment that you can only compare two loco's from the same brand/period etc...

I see nothing to say that EU loco's are cast as they are "correct" first time and don't need change any more than I see that UK prototype are plastic because they are easier to modify that way. Read the EU reviews as they are released and any shortcomings are soon "outed"....

There are detail enthusiasts in all hobby areas and countries
there are always detail refinements irrespective of brand and prototype that will help the accuracy of most RTR loco's if you are fussy enough
but
99% of buyers in bot hcases will be happy and run them just as they are....

The differences in base material are obvious only in weight and perhaps - in strength and durability - fine detail will break off easily in all cases... and because of the greater mass, drop a cast loco and the damage will be just as great if not greater than the result of dropping a plastic one - it all depends how it lands!!

Why do one or the other.
cost
brand habit
skillset of the Mfr or tooling maker
market perception of quality
Plastic can give super fine detail at a lower tooling cost.

As I am often installing DCC and sound for a variety of clients, I get to open tham all up and take a look at many prototypes from many brands. The best of the cast loco's are as good as the best of the plastic ones. The cost to buy them will have been way different though!!

ONE place that metal rules supreme though - N scale steam loco's. (Having the added mass of a metal body makes a BIG difference to pickup quality for N which is usually quite light). I suspect too that Neils AD60 would be a far better loco with the added mass of a cast body as by both personal test and general reputation, its a bit of a wimp in pulling power unless its modified a bit to add weight despite its 4-8-4+4-8-4 wheel arrangement!!

Finally Neil - I'm pleased you sued the Brawa loco's as an example - I have two here now and they really are superbly cast!!

Richard
DCCconcepts

 

[Makemineadouble]

Almost all loco bodies that are die cast are in fact pressure diecast, not gravity diecast. Pressure diecasting is a process similar to injection moulding and the die requirements and costs are similar. With injection moulding plastic granule's are heated, extruded and injected into the mould under high pressure in order to fill the mould cavities. Pressure diecasting using molten metal to achieve a similar process. I generally prefer the Bachmann bodies because of the large element of cast material, however the multitude of different size screws is always a problem.

Extracting the chassis from the body on the Hornby Scot recently took me a good 10 minutes in order to avoid damage, these modern bodies are proving to be a nightmare. BTW has anyone else spotted a major change to the method of routing power on the Hornby Scot, both poles are now transmitted to the DCC plug by wire rather than one pole through the body. This is a major change for Hornby, and one that should make their chassis a bit more reliable.

 

[pedromorgan]

re the body removal pro
blem. is this not just a case of our loco's still being slightly smaller than our continental counterparts? also on many continental loco's the body is high above the chassis (more like the 9F). i really dont understand why they dont just have the flap with a space under it like that fleishmann DMU. it seemed like such an elegant soloution to the problem.

Anyway, comming back to the topic. i actually thought it cost about the same to tool a model for injection moulding as it did for die casting. but the die casting toold wear out much more quickly. this is why so many of the die cast models are limited editions. not because they wanted to limit supply but because the tools were shot!

Peter

 

[34C]

QUOTE (Makemineadouble @ 12 Nov 2007, 08:07) <{POST_SNAPBACK}>Extracting the chassis from the body on the Hornby Scot recently took me a good 10 minutes in order to avoid damage, these modern bodies are proving to be a nightmare. BTW has anyone else spotted a major change to the method of routing power on the Hornby Scot, both poles are now transmitted to the DCC plug by wire rather than one pole through the body. This is a major change for Hornby, and one that should make their chassis a bit more reliable.
Don't know when fully wired connections commenced, but they were present on the Britannia, the most recent of Hornby's steam introductions I have purchased. That also had a plug and socket connection to the tender pick-ups. Two steps forward on one model toward the 'minimum baseline' for build quality. Unfortunately the plug-in connection has proved to be a 'flash in the pan', also the associated near scale loco-tender drawbar; not seen on subsequent products.

As for getting bodies off, have had to struggle with an example each of an A3 and a Britannia. In both cases a very tight fit between body moulding and chassis, compounded on the A3 by some of the soft tack adhesive used to hold wires getting between chassis and body, so it was effectively part glued on, and needed a shearing force to break it out. The only reason for body removal on the Brit was decoder installation. If the socket had been readily accessible in the tender, the factory grease lubed drive train would have eliminated the need to ever remove the body.

Hornby continue to give me the impression that they are unsure whether to progress into explicitly high grade model territory. My feeling is that they may have decided that 'superior toy' is the limit of their ambition. The continued use of the very dated loco-tender coupling, and persisting with an inaccurate tender on the Scot and Patriot, without NEM coupler pocket, lead me to think that the Britannia may prove to be the 'high water mark' in their steam model progress.

 

[Gary]

Any chance of seeing diecast work close up in a colour other than black?

Happy modelling
Gary

 

[Ravenser]

34C
QUOTE The continued use of the very dated loco-tender coupling, and persisting with an inaccurate tender on the Scot and Patriot, without NEM coupler pocket, lead me to think that the Britannia may prove to be the 'high water mark' in their steam model progress.

There's a simple explanation here - they've reused the Stanier tender from the Black 5 and 8F because the prototypes all had them. I'm not sure we can use this to say any future tenders from new tooling (say GW or LNER) would regress from the Britannia.

Richard Johnson:
QUOTE I see nothing to say that EU loco's are cast as they are "correct" first time and don't need change any more than I see that UK prototype are plastic because they are easier to modify that way. Read the EU reviews as they are released and any shortcomings are soon "outed"....

Actually , this wasn;t quite what I was trying to say. More that if the body was diecast then it would be far more difficult to do anything with it (like produce a different varient) - ie it would reduce the scope for any modelling

 

[dwb]

I promised some photos (and they're not black) so here are a couple of close ups of a Trix Re460. These photos are 1:1 clips. If you have difficulty seeing them properly, they can be viewed individually in the Gallery section in my "Other Models" album.

First a close up of the front. I took this to show that Maerklin have attached very small grab handles and windscreen wipers to the front of the loco.

And now some roof detail which shows the grills. They are not see through. I think the panel detail is rather fine. You definitely get the impression that the panels are separate parts whereas in fact they are part of the main moulding.

These photos are so large you can actually see the screening rosettes in the Maerklin image printed on the loco sides. Those ribs are also part of the casting.

David

 

[Makemineadouble]

Fantastic quality, something to rave about !. I'm not sure what material they use for the moulds, but I would imagine running temperatures are critical to control shrinkage, much the same as injection moulding. Often to save money, weight, and improve cooling on some moulds they use kirksite
Kirksite, although I've never seen it on injection moulds probably due to the higher pressures involved.
Mazak the material normally used for castings has increased tremendously due to eastern demand, so it's probably increased at a similar rate to the polyethylene
group of materials .
Wikipeaia diecast toys

 

[neil_s_wood]

QUOTE (Makemineadouble @ 13 Nov 2007, 07:10) <{POST_SNAPBACK}>Fantastic quality, something to rave about !. I'm not sure what material they use for the moulds, but I would imagine running temperatures are critical to control shrinkage, much the same as injection moulding. Often to save money, weight, and improve cooling on some moulds they use kirksite
Kirksite, although I've never seen it on injection moulds probably due to the higher pressures involved.
Mazak the material normally used for castings has increased tremendously due to eastern demand, so it's probably increased at a similar rate to the polyethylene
group of materials .
Wikipeaia diecast toys
You are right MMaD, there was an atricle last year about how they cast the bodies for the Henschel Wegman loco in the Trix Profi magazine. It is a form of injection moulding.

QUOTE (but neil - I don't agree re the comment re "wire bits" - these are added accessories not part of the tooling/material process and can b as fine as the Mfr wants them to be. True.

QUOTE Any chance of seeing diecast work close up in a colour other than black?

Whats wrong with black?

 

[Gary]

QUOTE Whats wrong with black?

A large number of British locos are not black. Casting flaws may be harder to disguise on a Crimson Lake or Garter Blue or Malachite Green casting. Think of Wrenn and Dublo. If the main finish is to be enamel or a form of paint then inevitably detail will suffer from a touch of jelly mould syndrome.

Another point is that German locos do have a lot of external plumbing which can draw the eye away from the casting and any flaws and seams. British locos are much plainer externally and the casting and seams would become critical.

The pictures here are great by the way. All I am saying is that British models are unique and may not be best suited to diecast for any number of reasons including the economics of relatively small production runs by comparison with German models.

Happy modelling
Gary

 

[34C]

QUOTE (Ravenser @ 12 Nov 2007, 17:59) <{POST_SNAPBACK}>There's a simple explanation here - they've reused the Stanier tender from the Black 5 and 8F because the prototypes all had them. I'm not sure we can use this to say any future tenders from new tooling (say GW or LNER) would regress from the Britannia.
Well, the Arthur must be all new tooling and was introduced since the Brit, and uses the old loco-tender coupling; not the much superior arrangement so far only seen on the Brit. That's clearly regression. And just because Hornby have components available from previous models (as in the case of the LMS 4-6-0's and Bulleid light pacifics) doesn't buy them any relief from the need to maintain improvement.

 

[34C]

QUOTE (Gary @ 12 Nov 2007, 22:23) <{POST_SNAPBACK}>.. Another point is that German locos do have a lot of external plumbing which can draw the eye away from the casting and any flaws and seams. British locos are much plainer externally and the casting and seams would become critical.

The pictures here are great by the way. All I am saying is that British models are unique and may not be best suited to diecast for any number of reasons including the economics of relatively small production runs by comparison with German models. ..
Well, if that silver finished Marklin model is diecast, that's one of the most revealing surface finishes on large plain areas. Looks more than OK to me.

So UK diecast would cost a bit more than an equivalent plastic bodied model. That's fine: the best in any given category always does, and it may well expand the market for higher grade model railway products. Heavy and solid, well detailed and finished, excellent drive, range of DCC options: fitted with a quality decoder, easy access to a decoder socket, and sound fitted versions. Let's have a Beemer option or two alongside the Fords.

 

[neil_s_wood]

QUOTE (34C @ 13 Nov 2007, 09:36) <{POST_SNAPBACK}>Well, if that silver finished Marklin model is diecast, that's one of the most revealing surface finishes on large plain areas. Looks more than OK to me.

So UK diecast would cost a bit more than an equivalent plastic bodied model. That's fine: the best in any given category always does, and it may well expand the market for higher grade model railway products. Heavy and solid, well detailed and finished, excellent drive, range of DCC options: fitted with a quality decoder, easy access to a decoder socket, and sound fitted versions. Let's have a Beemer option or two alongside the Fords.
I've been saying this for ages, It's good to get someone in agreement.