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Starting my first furnace

Murdoch

Active Member
I have a quick question for the pro's.
I was just talking to someone about the placement of the burner for the furnace.
He tells me that living in Toronto that the burner has to be in the clockwise position because of being in the northern hemisphere. Is there any validity to this claim? Thanks in advance guys
 

kevin.decelles

Jack of all trades -- Master of none
Premium Member
Swirl is important, I don't aim the flame directly at crucible, but direction is irrelevant imho


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Murdoch

Active Member
I accidentally posted this question in the wrong area.
Take two.
Does anyone have a recipe for making castable refractory?
Thanks so much...
 

Tom O

Ultra Member
You could use fireclay / sand but it will be heavy, I'd still go with the blanket because the castable mix takes more fuel to heat up the refractory where the blanket is basically instant, also the castable will be hot for a very long time compared to the blanket.
 

Bofobo

M,Mizera(BOFOBO)
Plaster of paris and sand in 2parts plaster 1 part sand works but takes a very long time to cure and will fall apart. Good only if blanket is not available and will degrade over time best if left undisturbed ie; stationary forge vs mobile
 

GrayTech

Member
Line it with a mix of perlite and sodium silicate. It's very light and very insulating with a very good high temperature resistance. There are YouTube videos on the process.
 

Tom O

Ultra Member
I have used sodium silicate to glue the blanket to the sides of the furnace and for making sand cores but not for refractory I would think it would break down fairly fast.
 

Johnwa

Ultra Member
I used “sodium silicate” (aka furnace cement) mixed with perlite in my first furnace. It lasted 10 years of moderate use before it rusted out. It wasn’t cheap but it was obtainable. I’ve also heard of pure sodium silicate being used as a rigidizer for the blanket insulation.

I tried to purchase some ciment fondu from lafarge to make my own castable but they only sell it by the pallet.
 

kevin.decelles

Jack of all trades -- Master of none
Premium Member
I bought bagged commercial refractory , not cheap but has lasted.

Tom is correct , first melt takes time to heat refractory, but second, third melts are much quicker

My furnace will stay hot for hours


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GrayTech

Member
I went with the perlite and sodium silicate because it was a very inexpensive option. Sodium silicate can be made from silica crystals (cat litter) and sodium hydroxide (drain cleaner). Perlite is cheap from the garden store. PPE required for sodium hydroxide!
As stated, it holds up very well with the added advantage of being super light and movable. It does not get hot on the outside either so I imagine it's very energy efficient.
 

Murdoch

Active Member
Well tomorrow I will make the trip to Smelko foundry supply to pick-up castable refractory and some petrobond and whatever else I can afford lol.
 

Murdoch

Active Member
Petro bond 50lbs bag $130. No tx cash
Castable refractory 50lbs bag $70. No tx cash
Waiting on Amazon for the ceramic blanket...
 
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