Signaller69's projects

[Signaller69]

The air bubble issue appears resolved with using black PU resin, the extra minute or two curing time allows for poking all the recesses, making all the difference. I have thus been able to cast and make up a couple of hopper units. As it is handed, the small letter 'V' cast into this end of the hopper shows the Vacuum Cylinder end.

The brake linkage has an (invisible here) shaped piece of handrail wire embedded to add strength, and further wire forming the retaining loops around it at either end, along with the horizontal wire through the hopper outlet to which the hopper operating wheels will be attached after cutting to length.

 

And in situ:

 

A more normal viewing angle:

 

And seen from the other side:

 

Painting and weathering should make it all stand out a bit more.

 

Much as I would like to cut away the chunky moulded handbrake lever and replace it with something finer, I don't want to risk damage to the rather nicely moulded axlebox and suspension area so it will have to stay as it is.

[cheesysmith]

Any linkys to what you have used for the moulds and the resin? Need to try some of this as looking at a lot of engine/Underfloor bits needed for my DMUs.

[Signaller69]

12 hours ago, cheesysmith said:

Any linkys to what you have used for the moulds and the resin? Need to try some of this as looking at a lot of engine/Underfloor bits needed for my DMUs.

 

No problem, I use MB Fibreglass for supplies, with reliable and quick delivery; links below are from this company.

 

This is the silicone rubber I am currently using:

https://www.mbfg.co.uk/gp-3481-f.html

 

Black PU casting resin:

https://www.mbfg.co.uk/polycraft-fc-3680-black-polyurethane.html

 

Pigments for mixing into the resin are also available in different colours.

https://www.mbfg.co.uk/polyurethane-lr-pigments.html

 

However, the Moulding & Casting starter packs are good value as they include mixing bowls, stirrers, disposable gloves (as the materials can cause irritation in some cases) and good instructions with lots of tips etc. although the resin is usually the creamy colour, fast curing type (2.5 - 3 mins).

https://www.mbfg.co.uk/polycraft-moulding-casting-resin-kit-small.html

 

(As a rough guide the small set will be enough for a  couple of moulds approx 8cm x 8cm x 2cm approx, which will probably be enough to do a DMU power and trailer set undergubbins, depending on layout).

 

All the kits, silicone rubber and resins are available in different quantities and curing times,  bare in mind the raw product (ie as supplied, prior to mixing) shelf life is about 6 months, so it is best to buy quantities you are likely to use in this time.

 

Obviously all products are extremely messy to work with in their liquid forms so care needs to be taken. Mixing needs to be accurate (digital scales are a good investment) and thorough, and there will most likely be some wastage and failures during use. (Mixing the correct amount of resin to "just" fill the mould becomes a bit of a holy grail, as does pouring, poking air bubbles out of recesses and removing excess resin from the surface of the mould, before it cures!)

 

Usual disclaimer, I have no connection other than as a satisfied customer and other suppliers are no doubt available.

 

Martyn.

Edited May 25, 2021 by Signaller69

[MJI]

Do you get problems with PU resin expanding?

 

I am slightly underfilling but still getting bubble overs, most can be ignored or chopped off by I have to find 18 good bogie frames from my pile.

 

None are usable without a lot of sanding.

[Signaller69]

4 hours ago, MJI said:

Do you get problems with PU resin expanding?

 

I am slightly underfilling but still getting bubble overs, most can be ignored or chopped off by I have to find 18 good bogie frames from my pile.

 

None are usable without a lot of sanding.

Hi Martin, 

Hmmm, no I've not noticed any expanding, but the heat generated during curing must cause a small amount of expansion I would have thought? I'm sure I read in the blurb with my resin that it actually shrinks by a tiny amount though?

 

I tend to overfill very slightly and draw the flat edge of a spatula over the mould once filled though, as the resin is JUST starting to cure, so that the liquid excess forms very thin "flash" around the edges of each piece - this prevents the "meniscus" effect of curved surface edges and ensures the cast part isn't deeper than it should be. If anything, I find the resin then settles back very slightly.

 

You could try part filling the mould and when set, add a second layer over this to the level of the mould?

 

How are you going about axle end location? Drilling out individual axle boxes?

 

Martyn.

[MJI]

Just will drill big holes so they can fit on mjt frames

[PaulCheffus]

Hi

 

When casting my sideframes I made a block of silicone that I could place on top of the mould whilst it cured. I fill the mould wait a while and then place the solid block of silicone on top. Leave until cured and then I have a perfectly flat back to the casting.

 

Cheers

 

Paul

[Signaller69]

1 hour ago, PaulCheffus said:

Hi

 

When casting my sideframes I made a block of silicone that I could place on top of the mould whilst it cured. I fill the mould wait a while and then place the solid block of silicone on top. Leave until cured and then I have a perfectly flat back to the casting.

 

Cheers

 

Paul

Thanks Paul, I had considered something along those lines if I do sideframes, where the top silicone part (which forms the axle box holes inside the frame) locates via pegs moulded as part of the upper and lower moulds, to ensure correct alignment every time. 

 

Do you use the sideframes as a standalone or mount them onto sub frames (eg MJT) as Martin intends? If the former, do you add anything to add strength to the frame?

 

Thanks,

Martyn.

[Signaller69]

The first 2 wagons to receive new lower hoppers are done, although new buffer heads are in the post to replace the rather chunky originals, which pull out.

 

This one is a 1970s Liliput model, a bit battered around the edges. It has had the moulded frame for bodyside hoardings removed as well as the hopper mod:

 

Below is a 1990/2000s Bachmann version; apart from the tension lock mount (now removed) and better livery application it is identical to the Liliput 'as bought' version (and currently retains the bodyside framework in this case; I have some spare Liliput hoardings somewhere):

 

Given their age, despite being about 1.5mm too short I think they hold up quite well now.

[Enterprisingwestern]

8 hours ago, Signaller69 said:

Given their age, despite being about 1.5mm too short I think they hold up quite well now.

 

Nice work on the hopper undergubbins.

If ever a model was crying out for a modern updated version, this must be it.

As long as you don't mix them with Triang or Lima more proper sized ones they pass muster.

 

Mike.

[ISW]

1 hour ago, Enterprisingwestern said:

As long as you don't mix them with Triang or Lima more proper sized ones they pass muster.

It's not often I see 'praise' on RMWeb for Triang and Lima models ... Makes a pleasant change.

 

I have quite a 'fleet' of Lima coaches and wagons and, with a bit of 'fettling', they can look very acceptable.

 

Ian

[PaulCheffus]

10 hours ago, Signaller69 said:

Thanks Paul, I had considered something along those lines if I do sideframes, where the top silicone part (which forms the axle box holes inside the frame) locates via pegs moulded as part of the upper and lower moulds, to ensure correct alignment every time. 

 

Do you use the sideframes as a standalone or mount them onto sub frames (eg MJT) as Martin intends? If the former, do you add anything to add strength to the frame?

 

Thanks,

Martyn.

Hi

 

I mount my sideframes to etched sub frames supplied by the 2mm Scale Association which I think are similar to the MJT type.

 

Cheers

 

Paul

[Signaller69]

3 hours ago, Enterprisingwestern said:

 

Nice work on the hopper undergubbins.

If ever a model was crying out for a modern updated version, this must be it.

As long as you don't mix them with Triang or Lima more proper sized ones they pass muster.

 

Mike.

Thanks Mike,

I agree a new model is overdue, although I like fettling the older stuff I have to say. The Lima and Hornby wagons have slight issues too, the Lima is too tall due to an overly deep chassis and the Hornby bodysides are too tall istr, and again lack underframe detail. Dropping the Lima version on Cambrian suspension units means they fit in quite comfortably with Liliput / Bachy types, being of different body styles in any case, the slight length difference not being apparent in my view. (Bachmann left, Lima right):

Martyn.

[Signaller69]

Just a note on my resin experience from the last few days; the creamy coloured resin (as supplied in the starter kits linked earlier) is slightly less viscous than the black resin, meaning it pours and spreads a little more easily into all nooks and crannies more easily, thus needing less probing for air bubbles etc.

 

However both are similar in detail definition. Thus for small and/or complex shapes I would recommend using the creamy colour over the black resin.

Edited May 30, 2021 by Signaller69

[Signaller69]

On 26/05/2021 at 13:15, MJI said:

Do you get problems with PU resin expanding?

 

Interestingly, having never had an issue before I have now experienced this very phenomenon. One casting out of well over 100. Whatever else was cast in the same batch seems to have been ok. A dozen or so of this exact casting have been fine, strangely this odd one on the right has not set solid and expanded on all axes can be seen.

I have pressed it back into shape but it just bulges out again (it has the consistency of a wine gum).

I can only put it down to a small amount of resin that has not been mixed quite as thoroughly as it should.

 

Most odd.

[Enterprisingwestern]

 

IMHO, the right hand one looks good as a badly stacked pile of sacks, maybe you could make a few "properly" wrong?

 

Mike.

[Signaller69]

1 hour ago, Enterprisingwestern said:

 

IMHO, the right hand one looks good as a badly stacked pile of sacks, maybe you could make a few "properly" wrong?

 

Mike.

Yes think it might work as that! Not sure I could repeat it if I wanted too, nothing worse than non setting resin once it has been poured into the mould.....

[Signaller69]

After a few casting sessions, various bits and pieces are being painted, mainly various loads and other details, plus another EFE lorry conversion almost done.

[Clive Mortimore]

On 01/06/2021 at 20:35, Signaller69 said:

 

Interestingly, having never had an issue before I have now experienced this very phenomenon. One casting out of well over 100. Whatever else was cast in the same batch seems to have been ok. A dozen or so of this exact casting have been fine, strangely this odd one on the right has not set solid and expanded on all axes can be seen.

I have pressed it back into shape but it just bulges out again (it has the consistency of a wine gum).

I can only put it down to a small amount of resin that has not been mixed quite as thoroughly as it should.

 

Most odd.

One stacked properly.....one stacked by Clive.

[Signaller69]

2 hours ago, Clive Mortimore said:

One stacked properly.....one stacked by Clive.

And still a better job than I could have done!

[Fat Controller]

On 02/06/2021 at 06:36, Enterprisingwestern said:

 

IMHO, the right hand one looks good as a badly stacked pile of sacks, maybe you could make a few "properly" wrong?

 

Mike.

Remember stacks like this at Longport in 1979/80. They'd been loaded on pallets in Germany, but not secured with pallet-wrap or banding. You can imagine the state of them after crossing from Zeebrugge on the train ferry; they blocked the doors, which meant even getting into the wagons was a nightmare.

[AlfaZagato]

Wait until you experience the state of unbound bags on a container.   I did not enjoy unloading such orders...

[Fat Controller]

55 minutes ago, AlfaZagato said:

Wait until you experience the state of unbound bags on a container.   I did not enjoy unloading such orders...

I have encountered loose boxes in containers that had crossed the Irish Sea- the preferred method of opening the doors was to get someone else to do it....

[Signaller69]

13 hours ago, Fat Controller said:

Remember stacks like this at Longport in 1979/80. They'd been loaded on pallets in Germany, but not secured with pallet-wrap or banding. You can imagine the state of them after crossing from Zeebrugge on the train ferry; they blocked the doors, which meant even getting into the wagons was a nightmare.

I wonder when polythene wrapping of pallet loads became common? 1980s perhaps? Or later?

[Gibbo675]

6 hours ago, Signaller69 said:

I wonder when polythene wrapping of pallet loads became common? 1980s perhaps? Or later?

Hi Martyn,

 

My Saturday and holiday job was in a vegetable pack house starting in 1986 and pallet wrap was used then, it is nothing more than thick clingfilm. Some of the pallets also had webbing nets to secure stacked loads of either boxes or sacks also along with the webbing straps fitted to rails within the body and to the bed of the lorry.

 

Gibbo.