Masterclass????

[tramcar trev]

Excellent blog Trev. I've learnt a huge amount after one reading. Not sure that I have the guts/skill/gumption to try the moulding, but after a few reads, who knows?

Thank you for sharing your knowledge.

Mate all of us start out regarding these things with incredible apprehension. Just remember what Anthony Horden said "while I live I'll grow". Sure you may have some failures, I still do, probably a 25% rate of fizzers, but what have you to loose if you give it a go? I had to call on years of previous experience, I used to be the equivalent of "Q", and as the area I'm modelling there is not so much available commercially plus living on a war vets pension makes this more a necessity. Its fun and I enjoy the journey with this tramway more than I will enjoy running it - eventually....

 

[3Valve]

Great stuff.

I must admit when I first looked at the blog I though "too much text to wade through", but how wrong I was.
So glad that I went back to it and read it through.

Really informative stuff.

 

[tramcar trev]

This addendum to the master class in casting things in rubber moulds is because I was remiss in NOT disclosing this important detail. It was drawn to my attention by a person who had the temerity to actually email me with the question; “How do you get the rubber to go into the holes for the handles on the lamps?” The answer lies with Pascal's principle: Pressure applied to an enclosed fluid is transmitted undiminished to every part of the fluid, as well as to the walls of the container. I use the atmosphere to provide the pressure…. Ok maybe I’m just so over the moon that a thinker has asked a question but that’s how it’s done. Ok if you look at the picture it will become obvious. I put a piece of wire though the hole, doesn’t matter if it’s a lot longer that’s better actually….
Go through the mould pouring routine making sure that the rubber has flowed around the masters and allow the mould to settle, let any visible air bubbles surface and wiggle the wires around the wiggling helps work the rubber into the space around the wires….
Now to apply Pascal’s principle, this is the good bit, the execution is exquisite…. Slide the wires sideways out of the holes you want filled with rubber and presto the atmosphere provides around 14PSI to fill the void left by the now departed wires with the only thing it can force into the holes, the silicone rubber (unless you have had the misfortune to have a rather tenacious bubble attached to the wire).

Then there is the matter of the thieving magpie. I heard some magpies carolling and went to investigate and here is this bird picking up leftover bits of wire…… He/she was most interested in a length of about 2m of the white insulated wire….. He/she could not take off with it so I cut it into shorter lengths…… Went back about an hour later and it was all taken, what a simple way to dispose of rubbish? A musical interlude is called for a nice and most apt piece by Rossini, used to cause havoc in the good old days of Standing for the National Anthem, Starts with a drum roll and everyone leaps to their feet assuming it’s the National Anthem….. Not this version though….. And it is Rossini not Verdi
http://www.youtube.com/watch?v=iOMX...ad2_pEfKGCdN_qd9Tlm0BWoCvuYyYblYdOECAvlrEHeQf
Note the Organist has a page turner and stop pusher outer and pusher inner, his hands and feet being fully occupied….

Ok gotta go rummage through my records to find the “Mr Blackpool” version..

 

[mike]

you sir.. are a bloody geiuse

 

[Martino]

Thank you Trev.

I have gone and bought all the bits to start learning how to cast resin.

Wouldn't have done it without your inspiration.

Now let's see what a Horlicks I can make of it!

 

[tramcar trev]

Nothing wrong with Horlicks, very hard to get here....

I have actually been commissioned to make a different version of "Tail light" with a lens to the rear and both sides with a smaller lens at the back of the lamp. Roughly 9mmx9mmx10mm.....

 

[Martino]

Trev,

Just wanted to say thank you.

Inspired by your Masterclass, I bought an Alumilite molding kit and this weekend had a first go. I'm working on a GRS station building kit, and wanted covered entrances both sides of the building. This doesn't come with the kit. So using pieces from the kit as 'originals', I created a mold. The mold is on the right of the photo. Today I made the pieces - surprise, they cam out fine first time! The originals are the grey colour, the copies are the tan colour.

Now I can try being creative myself - which of course is when it all goes pear shaped!

Thanks again.

M

 

[tramcar trev]

WOW!!!! brilliant..... Now you will discover that you can also make moulds of sheets of profiles; stone, brick weatherboards etc etc etc... but for that you can use plaster d' paris....

 

[Martino]

Another master class?

 

[tramcar trev]

Well the only difference with using plaster as opposed to rubber is that plaster is rigid and will not stretch over any undercuts. Also with plaster a suitable mould release is essential and I use the PVA release on plaster as it does not contaminate the surface of the moulded article and washes off with water.....
Plaster is also a hell of a lot cheaper and is more suited to flat items such as making sheets of fibreglass stone, brickwork, sides of buildings etc etc.
Was there not a thread by a chap who made his own individual stone blocks here somewhere, they were quite clever?

 

[Martino]

Yes, the cost of the rubber stuff is a bit steep.

I like the idea of producing sheets of textured, brick or stone, stuff.

I remember as a kid having a brick kit where you used pre made bricks and wallpaper past to build O gauge buildings . I know there are JigStones now, which is a fine idea.

I'm going to try some more resin castings of smaller pieces and see this that goes. Stuff like vacuum pipes!

 

[tramcar trev]

Here are 2 of my moulds for bricks and weatherboard... I made a sheet of experimental bricks; a chap was so enraptured with them he took them to make something.... I first applied PVA release, then a thin coat of resin all over then using a tea strainer sprinkled fine "brick" coloured sand over that and let it gel, tilt the mould up gently tap of the excess sand. Then another coat of resin and lay a piece of fibreglass into it, continuing applying resin till it was nicely wetted out. Set aside to cure then peel of the mould and ENSURE it is laid flat until it is fully cured, around 3 days... Immodest of me as it may sound the bricks looked superb especially after I had wiped some grey paint over the sheet to fill in the courses and perpends, and cleaned it off the face of the bricks.... They don't fade outside either...
I'm thinking of making a small stone church and I was going to use Jigstones but in Australia they are prohibitively priced so I will make my own moulds and make stone tiles that can be stuck to a substrate. That way each stone is individual and can be made from coloured sand mixed with resin.... Then applied like a "Tile"...

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