The molds are sitting on a paver. The molds are being preheated outside per position in pics. Normally preheat them till I see a dull glow.
I just finished another batch tonight. These turned out much better than previous pours.
Apologies its taken so long to respond tied up in Reno's
Just a suggestion
You're loosing a tremendous amount of heat as your paver is basically acting as a heat sink drawing heat away from the mold. Also any heating in open air draws even more heat away.You would be amazed at the different heating and retention times this causes.
A simple, affordable solution is to use Hebel autoclaved air rated concrete a soft thermally efficient brick that comes in large construction sizes.
A firing area can easily be constructed like a hearth that reduces wind and thermals and placing the mold directly onto the hebel (AAC)
You can cut heel with an old hand saw into desired configurations if necessary as well.
Various Building suppliers will have it in stock.My local Bunnings had a lot a while ago but it was a special order.
Its not that expensive, light enough to easily move around but with enough weight to lay blocks on top of each other for a permanent fixture.Fixings or glue can also be used to join if desired.No cement necessary.
The initial out lay in $$$ will easily be offset against a years running costs in gas
Info from site
Explore the versatility of Hebel's AAC, a lightweight and strong building material ideal for various applications. Discover sustainable solutions today.
hebel.com.au
Fire resistant
is a non-combustible building material and renowned for its fire resistant properties.
Hope this was some what informative
Regards
RB
PS: one more thing just looking at the pic.See that big flame ball coming out of your furnace. Dont loose it > use it
Place both your crucibles on top of your furnace adjacent to each other leaving a third of a hole free for venting.Your furnace will do the majority of the job heating them to 70% Temp then you can give them the torch directly close to pouring time.