Moulding

[chalkie]

RTV Silicone Mould Making Rubber 260g Kit: 250g Silicone + 10g Catalyst - Shore Hardness A28

Is this what I need for test  moulding ? Like brick walls and the like .

Paul

[Techno]

That sounds very similar to the stuff that I have sitting out in one of the barns Paul.....Though I haven't tried to RTV anything for years now.
Not sure what you'd need in the way of Shore Hardness 'rating' for walls and the like.....I've only ever used Silicone Rubber, in the past, to copy fairly small items.....and I've now been put onto "Instant Mold" for that sort of work form the forum.
I M is much quicker and far less messy for that type of stuff.....and you can use it over and over again.

Hopefully someone with more experience in RTVing will give you some help.

Cheers - Phil

[chalkie]

Hi Phil,
            I see, but in your opinion would it do for a small building ? See Iam just seeing if I can do it successfully , was thinking about solid walls , not the ones I do before and like bunkers of pallisades that kind of thing .

Paul.

[Leon]

I'm not sure on the Shore ratings either, but any silicon rubber should be OK for making a test piece.

[chalkie]

It's on it's way ,  cost under a tenner so if it doesn't work then no great loss.

Thanks lads.

[TinyTerrain]

It should be fine. I've done a fair bit with RTV so holler if you need any help.

Cheers,

Craig

[Techno]

Good !
I was hoping you'd jump in Craig !
Cheers - Phil.

[chalkie]

Thanks Craig , might just do that. 

Paul.

[Hertsblue]

I did a lot of RTV casting back in the eighties, Chalkie, although metal figures. You don't say exactly what you intend to mould - metal or resin. Assuming the latter you will presumably need some kind of release agent, one to get the master out of the mould and possibly another to get the moulded article out. With metal I used vaseline disolved in white spirit for the moulding and graphite or talcum powder for the casting. Whether either would work with resin I don't know.

You will also find Lego bricks and plasticene useful for containing the mould while it sets. Flatten out the modelling clay and build a box of Lego bricks on top. Sit the master in the middle and then pour the rubber compound over it (not forgetting the release agent, of course). I always allowed twenty-four hours for curing before attempting to extract the master. You should then have a useable mould.

Good luck.

Ray

[fsn]

I did a lot of RTV casting back in the eighties,

Wow! You were on Irish telly?

[Fenton]

Wow! You were on Irish telly?

No.  just finding actors for Ros a Run and the Riordan's

[chalkie]

Hertsblue, I was going to try casting plaster, is that ok for walls etc ? Thought of the releasing agents , same as what you have mentioned actually. I will keep you posted on how I get on.

Cheers,

Paul.

[Techno]

I was going to try casting plaster, is that ok for walls etc ?

Don't see why not...God luck Paul..Look forward to seeing the results.
Cheers - Phil

[Hertsblue]

Wow! You were on Irish telly?

No.  just finding actors for Ros a Run and the Riordan's

Sorry, guys, that went straight over my head. 

[GordonY]

Chalkie, the stuff you want to be using is called Herculite 2, not that cheap but way more durable than Plaster of Paris. And if all you want to do is cast plaster you might want to give a thought to making your moulds from latex.