Using Jigstones to make a mould query

[listerboy]

I'm currently using Jigstones to make a viaduct. I've made one arch, and I'm wondering if I can use silicone sealant to make a mould of the arch to make the other 3 arches?

I know it would have to be greased/oiled to release it. Any thoughts?

[philipy]

I'm currently using Jigstones to make a viaduct.  I've made one arch, and I'm wondering if I can use silicone sealant to make a mould of the arch to make the other 3 arches?

I know it would have to be greased/oiled to release it.  Any thoughts?

I think you'll have problems using silicone sealer, it won't cure fast enough and with the thickness required for a big mould it may never completely cure. The flexibility for demoulding could be an issue as well.
Far better to use a 2-part mould-making silicone that is designed for the job you want to do.

There was a thread by bazzer that covered it, earlier this year:

http://gardenrails.myfreeforum.org/ftop ... asc-15.php

[bazzer42]

It will definitely be quicker, you'll be casting in 24hrs!
I use Tomps for silicone. It will be an investment but the mould will always be there for the future.