Open wagons from homemade resin castings

ge_rik

ge_rik

British narrow gauge (esp. Southwold and W&LLR)
Country flag
Thought you might be interested in my latest project. After making a few open wagons from plasticard on Hartland chassis I decided to have a go at mass producing a few from resin castings.

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They are based (very loosely) on Llanfair and Welshpool prototypes. The mould produces one side and end at a time using polyeurethane resin.
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[align=left] They're not perfect. One of the problems I have yet to overcome is getting rid of air bubbles from the bolt and rivet detail. Not quite cracked that one yet (any helpful suggestions gratefully received). But I am quite pleased with the overall impression they achieve.
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If you want a more detailed blow-by-blow account - follow the link to my blog entry:

http://riksrailway.blogspot.com/2009/08/how-i-made-my-third-batch-of-open.html




Happy New Year everyone!

Rik
 
Fascinating reading your blog - I think you underestimate your efforts.!

Certainly the best way of mass producing a rake of wagons, rather than producing one at a time like I seem to do.

You could most probably sell castings like that to other members of this forum...............................!!!!!!!!!!!
 
Miamigo259 said:
Fascinating reading your blog - I think you underestimate your efforts.!

Certainly the best way of mass producing a rake of wagons, rather than producing one at a time like I seem to do.

You could most probably sell castings like that to other members of this forum...............................!!!!!!!!!!!
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Thanks for the encouragement. I don't think the castings are good enough to sell on to others. Maybe one day when I have more time I'll have a go at producing some of better quality. These are very much a 'first go'.

Rik
 
They look very good in the pictures - your paint finish is nicely observed, too. I can see that the raw castings might need a bit of work, but the end result is excellent. They certainly pass the "ten foot" rule and could probably bear much closer scrutiny. If I modelled the British scene, I'd be beating a path to your door!
 
Bob P said:
Sorry I cann't beat a path to your door because I'm to far away. If you decide to sell some on to menbers please let me know.
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Thanks chaps. The blemishes show up far more on the photos than they do in reality. If I could solve the problem of air pockets in the finer detailing I'd be a lot happier.

Not sure if I could find the time at present to turn out more than needed for my own needs - but I'm aiming to retire in a few months, so who knows then .............

Rik
 
L.N.R. said:
As a suggestion, have you tried using a small paint brush, to apply a thin coat of resin particularly to the rivet/bolt detail, then add your resin. Surface tension is generally why air is trapped, resin will flow onto resin, but sometimes has difficulty whetting out mold surfaces. Hope this helps,
Grant.
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Grant

No - hadn't thought of that. It sounds like a really good strategy, I'm surprised the Garden Railways article didn't mention it.

I've tried: tapping the mould, shaking it, using an orbital sander to vibrate it (that succeeded in separating out the two constituents of the resin), dusting the mould with talc, pouring the resin very slowly, and omitting the filler. None of them worked. I'll definitely give the whetting approach a go - it sounds so logical. Thanks for the suggestion.

Rik
 
hi Rik
good read and found it fascinating personally i never had any success with small resin parts so well done to you
barry:thumbup:
 
ge_rik said:
I'll definitely give the whetting approach a go - it sounds so logical. Thanks for the suggestion.
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Cracked it! Thanks to Grant. Just had a go at whetting the inside of the mould with resin before pouring in the rest of the resin, and I now have a set of near perfect castings - the first ones so far. I had to work quickly as the pot life for this particular resin is around fifteen minutes - but the results are so much better.

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Thanks Grant

Rik
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barryw said:
hi Rik
good read and found it fascinating personally i never had any success with small resin parts so well done to you
barry:thumbup:
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Thanks Barry

The first few mouldings were a bit naff and I still have the occasional disaster if I haven't quite mixed the resin and hardener well enough. But I'm beginning to be won over to this approach, particularly for mass production. My aim is to eventually have around a dozen open wagons and this seems like a fairly cost effective way of upping the fleet.

Rik
 
L.N.R. said:
Hi Rik
Just another small point, when mixing the resin, use a stirring stick at least an inch or so wide, (goes for paint also) stir more slowly, including across the bottom. Apart from mixing more thoroughly and quicker this should not leave unmixed resin, a round stick used with speed often aerates a mix and adds heat. The quicker mixing time may allow just a little more time to fill the mold.
Happy New Year
Grant.
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Grant

Another useful tip - thanks. I've been using coffee stirrers which are a bit on the thin side. I've got a few wooden tongue depressers which are not quite an inch but are much wider (amazing what you accumulate as a modeller). I'll give them a go.

Thanks

Rik
 
L.N.R. said:
Rik,
Hope I'm not teaching you how to suck eggs, if so I apologise, but you need a square end on the stirrer in order to keep wiping the bottom of the container to pick up the unmixed resin. The tongue depressors I have are round both ends.
Grant.
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Grant

I have no problems with egg-sucking apprenticeship, particularly if it short-cuts the trial and error process. Will square-off one end before the next mix.

Hopefully our dialogue will one day help another to tread the same path by reading about my journey before taking it themselves.

Thanks

Rik

PS - I wonder how many metaphors it's possible to include in a single posting?
 
Good stuff Rik, really pleased it went well and you have some superb wagons now. The brushing should work to fill the rivets.

You have more patience than me. I've stopped making them because the pay-back has disappeared... but I still have a pile of castings, although mine are based on the L&B wagons.
 
Graham

Yes, I remember your posting about castings for open wagons on Hartland chassis on the GSM forum - which is what put me in mind to have a go myself.

So, another thank you due here. I think it's this sort of sharing of ideas, experience and expertise that makes this forum (and GSM) so worthwhile.

Rik
 
hi
i would like to have a go at making some castings of my own. any links as to how one would go about it.
yours look very professional, i applaud you
 
They look excellent.

Something else on the "I should have a go at that someday" list.

What is the cost per wagon roughly, say for a rake of 6?
 
Use a sharp pin, usually you can see the bubbles and poke them with it. The brush method seems to work well also , did not know about it. I used to cast a lot, but got tired of it and the materials seemed to double in price.
 
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