Hard Core

[doubleboost]

Hi
Lads
More casting video

John

[vtsteam]

So, John was the core still too hard with the change in sand? Or did it turn out okay?

[awemawson]

For softer cores John, add less Sodium Silicate. 4% by weight at the top end working down as low as 1% for really friable ones.  For easier breakdown post casting add icing sugar to the core mix.

Years ago when I started using Sodium Silicate I made a series of test cores. I made a 8% mix, made a core, mixed in more sand to reduce the % sodium Silicate, made another core etc each time using digital kitchen scales to accurately assess the %.

The ideal does vary with the sand grain size and make up of the sodium silicate (which oddly isn't a specific composition but a ratio)

[vtsteam]

Awemawson, what was the composition of your sodium silicate then, when you did your tests to arrive at that usable percentage range?

[awemawson]

The drum is in my remote 'awaiting ROUND TUITS' storage shed - I'll make a note of the composition when I'm next in there.

[Fredbare]

Another fine video, with out-takes, thanks.

John

[S. Heslop]

Nice video. I've got a couple more to watch too since I just had my internet connection fixed at last.

I'm excited about trying my hand at casting at some point but i'd better get somewhere with the armour stuff first.

[krv3000]

well dun john 

[awemawson]

Awemawson, what was the composition of your sodium silicate then, when you did your tests to arrive at that usable percentage range?

Well the good news is I found the drum of sodium silicate    The bad news is it seems to have failed to be put away in the shipping container I use - it has been sat outside for the last 5 years - the label is faded to a plain white unreadable sheet, and when I went to pick the plastic drum up by its handle, the top of the drum broke away having gone brittle with uv - so my next job is to decant it into another drum then probably throw it away

[vtsteam]

Sorry to hear that awemawson -- thanks for trying anyway. 

[awemawson]

Now decanted into a 20 litre "Ariel Liquid" liquid soap drum - it actually looks OK and I don't suppose this stuff goes 'off' unless exposed to a dose of CO2 in concentration so I'll keep it and try a few experiments.

Just after the war I remember my parents preserving eggs on those rare occasions when they were available (we were still on food ration books then) by dipping them one by one into an Isinglass solution - which is sodium silicate. It gave them a glazed look - I suppose it sealed the pores to keep them fresh.

[vtsteam]

Glad to hear you may be able to re-use it! 

Preserving eggs with water glass (isinglass is different -- it's a precipitation agent for brewing derived from fish bladders) was also practiced on cruising sailboats for long voyages without refrigeration back in the day.

[awemawson]

Yep you're entirely correct - it was 'Waterglass'